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<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodStartLabel"/>
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  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodEndLabel"/>
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel"/>
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel"/>
  <link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
    <link:label id="lab_art_AtlantaGatewayGA2Member_019e1743-a921-711e-bdbd-25f770ff6f34_terseLabel_en-US" xlink:label="lab_art_AtlantaGatewayGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Gateway, GA</link:label>
    <link:label id="lab_art_AtlantaGatewayGA2Member_label_en-US" xlink:label="lab_art_AtlantaGatewayGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Gateway, GA 2 [Member]</link:label>
    <link:label id="lab_art_AtlantaGatewayGA2Member_documentation_en-US" xlink:label="lab_art_AtlantaGatewayGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Gateway, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaGatewayGA2Member" xlink:href="art-20260806.xsd#art_AtlantaGatewayGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaGatewayGA2Member" xlink:to="lab_art_AtlantaGatewayGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PortlandME2Member_019e1743-aaf8-78fc-8caf-06cde9791e44_terseLabel_en-US" xlink:label="lab_art_PortlandME2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Portland, ME</link:label>
    <link:label id="lab_art_PortlandME2Member_label_en-US" xlink:label="lab_art_PortlandME2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Portland, ME 2 [Member]</link:label>
    <link:label id="lab_art_PortlandME2Member_documentation_en-US" xlink:label="lab_art_PortlandME2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Portland, ME 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PortlandME2Member" xlink:href="art-20260806.xsd#art_PortlandME2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PortlandME2Member" xlink:to="lab_art_PortlandME2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_019e1743-aaf8-7a6d-b6a7-172fccf957ec_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Expected return on plan assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Return (Loss) on Plan Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_019e1743-ab7d-7e9f-874a-788f30c44576_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Estimated Future Benefit Payments</link:label>
    <link:label id="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Expected Benefit Payments [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HoustonTX2Member_019e1743-ab7d-7b41-a28a-c6c120da2ffd_terseLabel_en-US" xlink:label="lab_art_HoustonTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Houston, TX</link:label>
    <link:label id="lab_art_HoustonTX2Member_label_en-US" xlink:label="lab_art_HoustonTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Houston, TX 2 [Member]</link:label>
    <link:label id="lab_art_HoustonTX2Member_documentation_en-US" xlink:label="lab_art_HoustonTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Houston, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HoustonTX2Member" xlink:href="art-20260806.xsd#art_HoustonTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HoustonTX2Member" xlink:to="lab_art_HoustonTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaPleasantdaleGA1Member_019e1743-aa65-7b51-a2be-c6447925a2e7_terseLabel_en-US" xlink:label="lab_art_AtlantaPleasantdaleGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Pleasantdale, GA</link:label>
    <link:label id="lab_art_AtlantaPleasantdaleGA1Member_label_en-US" xlink:label="lab_art_AtlantaPleasantdaleGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Pleasantdale, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaPleasantdaleGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaPleasantdaleGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Pleasantdale, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaPleasantdaleGA1Member" xlink:href="art-20260806.xsd#art_AtlantaPleasantdaleGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaPleasantdaleGA1Member" xlink:to="lab_art_AtlantaPleasantdaleGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GrandIslandNE1Member_019e1743-ab7d-7b89-b109-9e71b6d64e66_terseLabel_en-US" xlink:label="lab_art_GrandIslandNE1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Grand Island, NE</link:label>
    <link:label id="lab_art_GrandIslandNE1Member_label_en-US" xlink:label="lab_art_GrandIslandNE1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Grand Island, NE 1 [Member]</link:label>
    <link:label id="lab_art_GrandIslandNE1Member_documentation_en-US" xlink:label="lab_art_GrandIslandNE1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Grand Island, NE 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GrandIslandNE1Member" xlink:href="art-20260806.xsd#art_GrandIslandNE1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GrandIslandNE1Member" xlink:to="lab_art_GrandIslandNE1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_019e1743-aaf8-77ea-bff6-70c038a03afe_terseLabel_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indefinite-lived Intangible Assets [Axis]</link:label>
    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_label_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Indefinite-Lived Intangible Assets [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityFileNumber_019e1743-aa64-7a54-b938-ad2c59efef7f_terseLabel_en-US" xlink:label="lab_dei_EntityFileNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity File Number</link:label>
    <link:label id="lab_dei_EntityFileNumber_label_en-US" xlink:label="lab_dei_EntityFileNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity File Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityFileNumber" xlink:to="lab_dei_EntityFileNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AnaheimCA2Member_019e1743-ab7d-7bce-95d6-5c45b69e3c44_terseLabel_en-US" xlink:label="lab_art_AnaheimCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Anaheim, CA</link:label>
    <link:label id="lab_art_AnaheimCA2Member_label_en-US" xlink:label="lab_art_AnaheimCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Anaheim, CA 2 [Member]</link:label>
    <link:label id="lab_art_AnaheimCA2Member_documentation_en-US" xlink:label="lab_art_AnaheimCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anaheim, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AnaheimCA2Member" xlink:href="art-20260806.xsd#art_AnaheimCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AnaheimCA2Member" xlink:to="lab_art_AnaheimCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_019e1743-aaf8-7a37-bed3-be852d67684a_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total plan assets allocated</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Target Allocation, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherFacilitiesCostsMember_019e1743-aaf8-7dc7-8471-bc42e32e871f_terseLabel_en-US" xlink:label="lab_art_OtherFacilitiesCostsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other facilities costs</link:label>
    <link:label id="lab_art_OtherFacilitiesCostsMember_label_en-US" xlink:label="lab_art_OtherFacilitiesCostsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Facilities Costs [Member]</link:label>
    <link:label id="lab_art_OtherFacilitiesCostsMember_documentation_en-US" xlink:label="lab_art_OtherFacilitiesCostsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Facilities Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherFacilitiesCostsMember" xlink:href="art-20260806.xsd#art_OtherFacilitiesCostsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherFacilitiesCostsMember" xlink:to="lab_art_OtherFacilitiesCostsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_019e1743-aaf8-7273-a97e-852b3005eab9_terseLabel_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Recent Accounting Pronouncements</link:label>
    <link:label id="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WallulaWA2Member_019e1743-aaf8-77df-b7b2-f4ecf788f743_terseLabel_en-US" xlink:label="lab_art_WallulaWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wallula, WA</link:label>
    <link:label id="lab_art_WallulaWA2Member_label_en-US" xlink:label="lab_art_WallulaWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wallula, WA 2 [Member]</link:label>
    <link:label id="lab_art_WallulaWA2Member_documentation_en-US" xlink:label="lab_art_WallulaWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Wallula, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WallulaWA2Member" xlink:href="art-20260806.xsd#art_WallulaWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WallulaWA2Member" xlink:to="lab_art_WallulaWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract_019e1743-aa65-7b98-95c5-9fad60bfc33d_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Allocation of purchase price of business combinations, net of cash acquired to:</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill, Less Noncontrolling Interest [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterestAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueAbstract_019e1743-aaf8-7cb3-9af2-35fd393b47de_terseLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Lease Payments</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueAbstract_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments Due [Abstract]</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueAbstract_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments Due [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDueAbstract" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDueAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDueAbstract" xlink:to="lab_art_LeaseLiabilityPaymentsDueAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerTextBlock_019e1743-aa64-7b79-9408-1eb2ec34133d_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue from Contracts with Customers</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity_019e1743-a921-7a75-b6d3-9db5296a3f77_terseLabel_en-US" xlink:label="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of investments in partially owned entities</link:label>
    <link:label id="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity_label_en-US" xlink:label="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From The Sale of Partially Owned Entity, Investing Activity</link:label>
    <link:label id="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity_documentation_en-US" xlink:label="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From The Sale of Partially Owned Entity, Investing Activity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity" xlink:href="art-20260806.xsd#art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity" xlink:to="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityInvestingActivity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_019e1743-aa64-7536-881a-f7d8cf8fd670_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based compensation</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:to="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromUnsecuredNotesPayable_019e1743-aa65-763e-974a-6d6ce78f1b8c_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromUnsecuredNotesPayable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from public senior unsecured notes offering</link:label>
    <link:label id="lab_us-gaap_ProceedsFromUnsecuredNotesPayable_label_en-US" xlink:label="lab_us-gaap_ProceedsFromUnsecuredNotesPayable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Unsecured Notes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromUnsecuredNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromUnsecuredNotesPayable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromUnsecuredNotesPayable" xlink:to="lab_us-gaap_ProceedsFromUnsecuredNotesPayable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage_019e1743-aa65-71bd-8917-104011e7fd2c_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Purchase price option percentage</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Purchase Price Option, Percentage</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Purchase Price Option, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionPurchasePriceOptionPercentage" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionPurchasePriceOptionPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionPurchasePriceOptionPercentage" xlink:to="lab_art_SaleLeasebackTransactionPurchasePriceOptionPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1_019e1743-a9d5-78c8-89ae-f4b2e7d88434_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on put option</link:label>
    <link:label id="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1_019e1743-a9d5-70bd-9032-0f0b909e84c1_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss on put option</link:label>
    <link:label id="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1_label_en-US" xlink:label="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Option, Changes in Fair Value, Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueOptionChangesInFairValueGainLoss1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:to="lab_us-gaap_FairValueOptionChangesInFairValueGainLoss1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_019e1743-ab7d-74a3-b2b1-b8f892a2c69e_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock issuance related to employee stock purchase plan (in shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Shares, Employee Stock Purchase Plans</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Savannah2GA2Member_019e1743-a9d5-78a6-b1f7-ee9dc3f162aa_terseLabel_en-US" xlink:label="lab_art_Savannah2GA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Savannah 2, GA</link:label>
    <link:label id="lab_art_Savannah2GA2Member_label_en-US" xlink:label="lab_art_Savannah2GA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Savannah 2, GA 2 [Member]</link:label>
    <link:label id="lab_art_Savannah2GA2Member_documentation_en-US" xlink:label="lab_art_Savannah2GA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Savannah 2, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Savannah2GA2Member" xlink:href="art-20260806.xsd#art_Savannah2GA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Savannah2GA2Member" xlink:to="lab_art_Savannah2GA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MurfreesboroTN1Member_019e1743-a9d5-782c-aa65-8bc3475dc71e_terseLabel_en-US" xlink:label="lab_art_MurfreesboroTN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Murfreesboro, TN</link:label>
    <link:label id="lab_art_MurfreesboroTN1Member_label_en-US" xlink:label="lab_art_MurfreesboroTN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Murfreesboro, TN 1 [Member]</link:label>
    <link:label id="lab_art_MurfreesboroTN1Member_documentation_en-US" xlink:label="lab_art_MurfreesboroTN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Murfreesboro, TN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MurfreesboroTN1Member" xlink:href="art-20260806.xsd#art_MurfreesboroTN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MurfreesboroTN1Member" xlink:to="lab_art_MurfreesboroTN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LebanonTN1Member_019e1743-aaf8-709a-848a-42fc3050b83c_terseLabel_en-US" xlink:label="lab_art_LebanonTN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lebanon, TN</link:label>
    <link:label id="lab_art_LebanonTN1Member_label_en-US" xlink:label="lab_art_LebanonTN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lebanon, TN 1 [Member]</link:label>
    <link:label id="lab_art_LebanonTN1Member_documentation_en-US" xlink:label="lab_art_LebanonTN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lebanon, TN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LebanonTN1Member" xlink:href="art-20260806.xsd#art_LebanonTN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LebanonTN1Member" xlink:to="lab_art_LebanonTN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskPercentage1_019e1743-aa65-7224-94d1-06963cc62076_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskPercentage1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Collective-bargaining arrangement, percentage of participants</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskPercentage1_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskPercentage1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskPercentage1" xlink:to="lab_us-gaap_ConcentrationRiskPercentage1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationPercentage_019e1743-a9d5-7564-8dc3-f0d2a404c832_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance obligation, percentage of revenue</link:label>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationPercentage_label_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage" xlink:to="lab_us-gaap_RevenueRemainingPerformanceObligationPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_019e1743-aa64-7ef6-b550-d612aae3b8f4_verboseLabel_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Pension Plan</link:label>
    <link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_019e1743-aa64-7627-b27e-95fc2a289f1f_terseLabel_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension</link:label>
    <link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_label_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pension Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionPlansDefinedBenefitMember" xlink:to="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PortSt.JohnMember_019e1743-aa65-7ffe-8275-7ee6fe9d8aea_terseLabel_en-US" xlink:label="lab_art_PortSt.JohnMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Port St. John</link:label>
    <link:label id="lab_art_PortSt.JohnMember_label_en-US" xlink:label="lab_art_PortSt.JohnMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Port St. John [Member]</link:label>
    <link:label id="lab_art_PortSt.JohnMember_documentation_en-US" xlink:label="lab_art_PortSt.JohnMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Port St. John</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PortSt.JohnMember" xlink:href="art-20260806.xsd#art_PortSt.JohnMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PortSt.JohnMember" xlink:to="lab_art_PortSt.JohnMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeStockOptionMember_019e1743-aaf8-7eaf-a935-b8afd6858970_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeStockOptionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employee stock options</link:label>
    <link:label id="lab_us-gaap_EmployeeStockOptionMember_label_en-US" xlink:label="lab_us-gaap_EmployeeStockOptionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Option [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeStockOptionMember" xlink:to="lab_us-gaap_EmployeeStockOptionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SegmentContribution_019e1743-a922-7f57-9aaf-76847eb34e82_terseLabel_en-US" xlink:label="lab_art_SegmentContribution" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment contribution:</link:label>
    <link:label id="lab_art_SegmentContribution_label_en-US" xlink:label="lab_art_SegmentContribution" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Contribution</link:label>
    <link:label id="lab_art_SegmentContribution_documentation_en-US" xlink:label="lab_art_SegmentContribution" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Segment Contribution</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SegmentContribution" xlink:href="art-20260806.xsd#art_SegmentContribution"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SegmentContribution" xlink:to="lab_art_SegmentContribution" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter_019e1743-a9d5-7d7e-ab6d-6bf5a807ffe3_terseLabel_en-US" xlink:label="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter_label_en-US" xlink:label="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Thereafter</link:label>
    <link:label id="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Thereafter</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter" xlink:href="art-20260806.xsd#art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter" xlink:to="lab_art_DefinedBenefitPlanExpectedFutureBenefitPaymentThereafter" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019e1743-a9d5-793d-8bae-fb24f7269cd4_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Antidilutive Securities [Axis]</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentNumberOfTranches_019e1743-aaf8-7c80-880e-f89ef4287eba_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentNumberOfTranches" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of tranches</link:label>
    <link:label id="lab_art_DebtInstrumentNumberOfTranches_label_en-US" xlink:label="lab_art_DebtInstrumentNumberOfTranches" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Number Of Tranches</link:label>
    <link:label id="lab_art_DebtInstrumentNumberOfTranches_documentation_en-US" xlink:label="lab_art_DebtInstrumentNumberOfTranches" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Number Of Tranches</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentNumberOfTranches" xlink:href="art-20260806.xsd#art_DebtInstrumentNumberOfTranches"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentNumberOfTranches" xlink:to="lab_art_DebtInstrumentNumberOfTranches" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesAuthorized_019e1743-aaf8-72c0-88f3-73ae1c724301_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares, shares authorized (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Shares Authorized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesAuthorized" xlink:to="lab_us-gaap_CommonStockSharesAuthorized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstatePeriodIncreaseDecrease_019e1743-aa64-7192-9757-68173d258e08_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment</link:label>
    <link:label id="lab_us-gaap_RealEstatePeriodIncreaseDecrease_label_en-US" xlink:label="lab_us-gaap_RealEstatePeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Period Increase (Decrease)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstatePeriodIncreaseDecrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePeriodIncreaseDecrease" xlink:to="lab_us-gaap_RealEstatePeriodIncreaseDecrease" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RealEstateNotUnderConstructionMember_019e1743-aaf8-71d6-9eb5-4f55efbdae93_terseLabel_en-US" xlink:label="lab_art_RealEstateNotUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets Not Under Construction</link:label>
    <link:label id="lab_art_RealEstateNotUnderConstructionMember_label_en-US" xlink:label="lab_art_RealEstateNotUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Not Under Construction [Member]</link:label>
    <link:label id="lab_art_RealEstateNotUnderConstructionMember_documentation_en-US" xlink:label="lab_art_RealEstateNotUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Real Estate Not Under Construction [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RealEstateNotUnderConstructionMember" xlink:href="art-20260806.xsd#art_RealEstateNotUnderConstructionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RealEstateNotUnderConstructionMember" xlink:to="lab_art_RealEstateNotUnderConstructionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrisbaneHemmant1Member_019e1743-a921-7235-8592-3e59a7f89c50_terseLabel_en-US" xlink:label="lab_art_BrisbaneHemmant1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brisbane - Hemmant</link:label>
    <link:label id="lab_art_BrisbaneHemmant1Member_label_en-US" xlink:label="lab_art_BrisbaneHemmant1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brisbane - Hemmant 1 [Member]</link:label>
    <link:label id="lab_art_BrisbaneHemmant1Member_documentation_en-US" xlink:label="lab_art_BrisbaneHemmant1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brisbane - Hemmant 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrisbaneHemmant1Member" xlink:href="art-20260806.xsd#art_BrisbaneHemmant1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrisbaneHemmant1Member" xlink:to="lab_art_BrisbaneHemmant1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues_019e1743-aaf8-7532-a9e0-0583ebb8be57_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net proceeds from issuance of common stock (in shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Shares, New Issues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PascoWA2Member_019e1743-a921-7433-973a-5a9261923a2f_terseLabel_en-US" xlink:label="lab_art_PascoWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pasco, WA</link:label>
    <link:label id="lab_art_PascoWA2Member_label_en-US" xlink:label="lab_art_PascoWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pasco, WA 2 [Member]</link:label>
    <link:label id="lab_art_PascoWA2Member_documentation_en-US" xlink:label="lab_art_PascoWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pasco, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PascoWA2Member" xlink:href="art-20260806.xsd#art_PascoWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PascoWA2Member" xlink:to="lab_art_PascoWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FinanceLeaseCost1Abstract_019e1743-aaf8-7f13-abc8-41b873e0d97f_terseLabel_en-US" xlink:label="lab_art_FinanceLeaseCost1Abstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Financing lease cost:</link:label>
    <link:label id="lab_art_FinanceLeaseCost1Abstract_label_en-US" xlink:label="lab_art_FinanceLeaseCost1Abstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Cost1 [Abstract]</link:label>
    <link:label id="lab_art_FinanceLeaseCost1Abstract_documentation_en-US" xlink:label="lab_art_FinanceLeaseCost1Abstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Finance Lease, Cost1 [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FinanceLeaseCost1Abstract" xlink:href="art-20260806.xsd#art_FinanceLeaseCost1Abstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FinanceLeaseCost1Abstract" xlink:to="lab_art_FinanceLeaseCost1Abstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract_019e1743-aaf8-7322-9dcd-e333fb871585_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amounts in accumulated other comprehensive (income) loss consist of:</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossAfterTaxAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019e1743-aaf8-7476-9b3e-d809d9ce8f91_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MediumTermNotesMember_019e1743-aaf8-720d-a561-b37d363c4cba_terseLabel_en-US" xlink:label="lab_us-gaap_MediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Term Loans</link:label>
    <link:label id="lab_us-gaap_MediumTermNotesMember_label_en-US" xlink:label="lab_us-gaap_MediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Medium-Term Note [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumTermNotesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MediumTermNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MediumTermNotesMember" xlink:to="lab_us-gaap_MediumTermNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainContingenciesTable_019e1743-a921-7ac4-a252-5eb872d72686_terseLabel_en-US" xlink:label="lab_us-gaap_GainContingenciesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain Contingencies [Table]</link:label>
    <link:label id="lab_us-gaap_GainContingenciesTable_label_en-US" xlink:label="lab_us-gaap_GainContingenciesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain Contingencies [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainContingenciesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainContingenciesTable" xlink:to="lab_us-gaap_GainContingenciesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_019e1743-aa65-7e62-965f-770346dc048f_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercisable (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019e1743-aa65-7f2b-824f-b3587bb76f32_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss attributable to noncontrolling interests</link:label>
    <link:label id="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:to="lab_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_019e1743-a9d5-7897-a5a4-665bc7e9c4d9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rate of compensation increase</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BridgeLoanMember_019e1743-a9d5-7e7b-81e0-4bad9ea76fe0_terseLabel_en-US" xlink:label="lab_us-gaap_BridgeLoanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bridge Loan</link:label>
    <link:label id="lab_us-gaap_BridgeLoanMember_label_en-US" xlink:label="lab_us-gaap_BridgeLoanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bridge Loan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BridgeLoanMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BridgeLoanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BridgeLoanMember" xlink:to="lab_us-gaap_BridgeLoanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_YorkWillowSpringsPA2Member_019e1743-ab7d-78b3-b15f-029dc217a7ee_terseLabel_en-US" xlink:label="lab_art_YorkWillowSpringsPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">York-Willow Springs, PA</link:label>
    <link:label id="lab_art_YorkWillowSpringsPA2Member_label_en-US" xlink:label="lab_art_YorkWillowSpringsPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">York-Willow Springs, PA 2 [Member]</link:label>
    <link:label id="lab_art_YorkWillowSpringsPA2Member_documentation_en-US" xlink:label="lab_art_YorkWillowSpringsPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">York-Willow Springs, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_YorkWillowSpringsPA2Member" xlink:href="art-20260806.xsd#art_YorkWillowSpringsPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_YorkWillowSpringsPA2Member" xlink:to="lab_art_YorkWillowSpringsPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BurlingtonWA1Member_019e1743-a9d5-78ae-87e2-8d01b9d5582a_terseLabel_en-US" xlink:label="lab_art_BurlingtonWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Burlington, WA</link:label>
    <link:label id="lab_art_BurlingtonWA1Member_label_en-US" xlink:label="lab_art_BurlingtonWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Burlington, WA 1 [Member]</link:label>
    <link:label id="lab_art_BurlingtonWA1Member_documentation_en-US" xlink:label="lab_art_BurlingtonWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Burlington, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BurlingtonWA1Member" xlink:href="art-20260806.xsd#art_BurlingtonWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BurlingtonWA1Member" xlink:to="lab_art_BurlingtonWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_019e1743-aa64-73ba-b2c0-570ee19db90a_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, by Property [Table]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, by Property [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationByPropertyTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationByPropertyTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_019e1743-a9d5-7249-ac5c-2bdbc168c4d8_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentLineItems" xlink:to="lab_us-gaap_DebtInstrumentLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PiedmontSC2Member_019e1743-a9d5-7a7b-930c-c62445838d6d_terseLabel_en-US" xlink:label="lab_art_PiedmontSC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Piedmont, SC</link:label>
    <link:label id="lab_art_PiedmontSC2Member_label_en-US" xlink:label="lab_art_PiedmontSC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Piedmont, SC 2 [Member]</link:label>
    <link:label id="lab_art_PiedmontSC2Member_documentation_en-US" xlink:label="lab_art_PiedmontSC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Piedmont, SC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PiedmontSC2Member" xlink:href="art-20260806.xsd#art_PiedmontSC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PiedmontSC2Member" xlink:to="lab_art_PiedmontSC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019e1743-a9d5-79b3-9a26-79da0eca7a0b_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredCostsCurrentAndNoncurrent_019e1743-ab7d-7f71-ad87-9f1c3fd36246_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred costs</link:label>
    <link:label id="lab_us-gaap_DeferredCostsCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:to="lab_us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash_019e1743-a921-7167-8fd2-bd3766b9e3f3_terseLabel_en-US" xlink:label="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Conversion of OP units to cash</link:label>
    <link:label id="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash_label_en-US" xlink:label="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period Value Conversion Of Units Into Cash</link:label>
    <link:label id="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash_documentation_en-US" xlink:label="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Stock Issued During Period Value Conversion Of Units Into Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash" xlink:href="art-20260806.xsd#art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash" xlink:to="lab_art_StockIssuedDuringPeriodValueConversionOfUnitsIntoCash" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities_019e1743-aa65-79f9-b930-fe23a5b0c297_terseLabel_en-US" xlink:label="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Noncontrolling interest in joint ventures, number of entities</link:label>
    <link:label id="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities_label_en-US" xlink:label="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncontrolling Interest in Joint Ventures, Number Of Entities</link:label>
    <link:label id="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities_documentation_en-US" xlink:label="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncontrolling Interest in Joint Ventures, Number Of Entities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NoncontrollingInterestInJointVenturesNumberOfEntities" xlink:href="art-20260806.xsd#art_NoncontrollingInterestInJointVenturesNumberOfEntities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NoncontrollingInterestInJointVenturesNumberOfEntities" xlink:to="lab_art_NoncontrollingInterestInJointVenturesNumberOfEntities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WoodburnOR2Member_019e1743-a9d5-731f-a722-60ba008b4bd2_terseLabel_en-US" xlink:label="lab_art_WoodburnOR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Woodburn, OR</link:label>
    <link:label id="lab_art_WoodburnOR2Member_label_en-US" xlink:label="lab_art_WoodburnOR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Woodburn, OR 2 [Member]</link:label>
    <link:label id="lab_art_WoodburnOR2Member_documentation_en-US" xlink:label="lab_art_WoodburnOR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Woodburn, OR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WoodburnOR2Member" xlink:href="art-20260806.xsd#art_WoodburnOR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WoodburnOR2Member" xlink:to="lab_art_WoodburnOR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease_019e1743-a921-7ad9-b6aa-fa23d8c872e6_terseLabel_en-US" xlink:label="lab_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss on foreign currency translation</link:label>
    <link:label id="lab_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease_label_en-US" xlink:label="lab_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AOCI Including Portion Attributable to Noncontrolling Interest, Period Increase (Decrease)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease" xlink:to="lab_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestPeriodIncreaseDecrease" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CompensationAndRetirementDisclosureAbstract_019e1743-aa65-75c6-aa74-31afd0b76a22_terseLabel_en-US" xlink:label="lab_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Benefits [Abstract]</link:label>
    <link:label id="lab_us-gaap_CompensationAndRetirementDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Benefits [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CompensationAndRetirementDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:to="lab_us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NorthLittleRockAR1Member_019e1743-a922-7712-b696-cfbd79ee6409_terseLabel_en-US" xlink:label="lab_art_NorthLittleRockAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">North Little Rock, AR</link:label>
    <link:label id="lab_art_NorthLittleRockAR1Member_label_en-US" xlink:label="lab_art_NorthLittleRockAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">North Little Rock, AR 1 [Member]</link:label>
    <link:label id="lab_art_NorthLittleRockAR1Member_documentation_en-US" xlink:label="lab_art_NorthLittleRockAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">North Little Rock, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NorthLittleRockAR1Member" xlink:href="art-20260806.xsd#art_NorthLittleRockAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NorthLittleRockAR1Member" xlink:to="lab_art_NorthLittleRockAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PendergrassGA1Member_019e1743-aa65-7e6f-8d7b-ec464fdaaa04_terseLabel_en-US" xlink:label="lab_art_PendergrassGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pendergrass, GA</link:label>
    <link:label id="lab_art_PendergrassGA1Member_label_en-US" xlink:label="lab_art_PendergrassGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pendergrass, GA 1 [Member]</link:label>
    <link:label id="lab_art_PendergrassGA1Member_documentation_en-US" xlink:label="lab_art_PendergrassGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pendergrass, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PendergrassGA1Member" xlink:href="art-20260806.xsd#art_PendergrassGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PendergrassGA1Member" xlink:to="lab_art_PendergrassGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_JeffersonWI2Member_019e1743-a9d5-750c-8690-d5a6faf5c3b2_terseLabel_en-US" xlink:label="lab_art_JeffersonWI2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Jefferson, WI</link:label>
    <link:label id="lab_art_JeffersonWI2Member_label_en-US" xlink:label="lab_art_JeffersonWI2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Jefferson, WI 2 [Member]</link:label>
    <link:label id="lab_art_JeffersonWI2Member_documentation_en-US" xlink:label="lab_art_JeffersonWI2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Jefferson, WI 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_JeffersonWI2Member" xlink:href="art-20260806.xsd#art_JeffersonWI2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_JeffersonWI2Member" xlink:to="lab_art_JeffersonWI2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_019e1743-a9d5-72ad-a97c-b721bccce111_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of property, buildings, and equipment</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Property, Plant, and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:to="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward_019e1743-a9d5-7243-905e-bc8c5bfac5bf_terseLabel_en-US" xlink:label="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Depreciation:</link:label>
    <link:label id="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:to="lab_us-gaap_ReconciliationOfRealEstateAccumulatedDepreciationRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherServiceCostMember_019e1743-aaf8-7d84-b8ce-abb17d036959_terseLabel_en-US" xlink:label="lab_art_OtherServiceCostMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other services costs</link:label>
    <link:label id="lab_art_OtherServiceCostMember_label_en-US" xlink:label="lab_art_OtherServiceCostMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Service Cost [Member]</link:label>
    <link:label id="lab_art_OtherServiceCostMember_documentation_en-US" xlink:label="lab_art_OtherServiceCostMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Service Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherServiceCostMember" xlink:href="art-20260806.xsd#art_OtherServiceCostMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherServiceCostMember" xlink:to="lab_art_OtherServiceCostMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_IncentiveStockOptionsMember_019e1743-a921-7760-a879-601623f969b3_terseLabel_en-US" xlink:label="lab_art_IncentiveStockOptionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Incentive Stock Options</link:label>
    <link:label id="lab_art_IncentiveStockOptionsMember_label_en-US" xlink:label="lab_art_IncentiveStockOptionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incentive Stock Options [Member]</link:label>
    <link:label id="lab_art_IncentiveStockOptionsMember_documentation_en-US" xlink:label="lab_art_IncentiveStockOptionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Incentive Stock Options</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_IncentiveStockOptionsMember" xlink:href="art-20260806.xsd#art_IncentiveStockOptionsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_IncentiveStockOptionsMember" xlink:to="lab_art_IncentiveStockOptionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperations_019e1743-aaf8-7425-b7b6-5602d39f0dd6_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net loss from continuing operations</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperations_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperations"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperations" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperations" xlink:type="arc" order="1"/>
    <link:label id="lab_stpr_TX_019e1743-a921-7a59-b0dd-06d5760b3ddd_terseLabel_en-US" xlink:label="lab_stpr_TX" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Texas</link:label>
    <link:label id="lab_stpr_TX_label_en-US" xlink:label="lab_stpr_TX" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">TEXAS</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_TX" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_TX"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_stpr_TX" xlink:to="lab_stpr_TX" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_019e1743-a9d5-74d1-ae83-3bb19282c1f5_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S.</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations before Income Taxes, Domestic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold_019e1743-a9d5-7e9e-9e34-e7b9be439c99_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Below Threshold Level</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Below Threshold</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Below Threshold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold" xlink:to="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageBelowThreshold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_019e1743-a921-78e6-b0ca-68865fd41281_terseLabel_en-US" xlink:label="lab_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Costs incurred to develop software for internal use and purchased software</link:label>
    <link:label id="lab_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_label_en-US" xlink:label="lab_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Software and Software Development Costs [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:to="lab_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_019e1743-a9d5-70bf-b698-03607d2de225_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rate of compensation increase</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_HedgingRelationshipDomain_019e1743-a921-79d7-b0d5-14d934c43b60_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingRelationshipDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hedging Relationship [Domain]</link:label>
    <link:label id="lab_us-gaap_HedgingRelationshipDomain_label_en-US" xlink:label="lab_us-gaap_HedgingRelationshipDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hedging Relationship [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HedgingRelationshipDomain" xlink:to="lab_us-gaap_HedgingRelationshipDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedTranslationAdjustmentMember_019e1743-a922-7ed5-a3fe-95be841c2a15_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign currency:</link:label>
    <link:label id="lab_us-gaap_AccumulatedTranslationAdjustmentMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Foreign Currency Adjustment Attributable to Parent [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:to="lab_us-gaap_AccumulatedTranslationAdjustmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ValenciaMember_019e1743-ab7d-7127-afcb-be4fa10cd93e_terseLabel_en-US" xlink:label="lab_art_ValenciaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Valencia</link:label>
    <link:label id="lab_art_ValenciaMember_label_en-US" xlink:label="lab_art_ValenciaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Valencia [Member]</link:label>
    <link:label id="lab_art_ValenciaMember_documentation_en-US" xlink:label="lab_art_ValenciaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Valencia</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ValenciaMember" xlink:href="art-20260806.xsd#art_ValenciaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ValenciaMember" xlink:to="lab_art_ValenciaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ViennaMember_019e1743-aa65-748a-b147-f8ed1a52d5d8_terseLabel_en-US" xlink:label="lab_art_ViennaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vienna</link:label>
    <link:label id="lab_art_ViennaMember_label_en-US" xlink:label="lab_art_ViennaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vienna [Member]</link:label>
    <link:label id="lab_art_ViennaMember_documentation_en-US" xlink:label="lab_art_ViennaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vienna</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ViennaMember" xlink:href="art-20260806.xsd#art_ViennaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ViennaMember" xlink:to="lab_art_ViennaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AustriaPlanMember_019e1743-aa65-7c24-9a6a-aaecf3c831a7_terseLabel_en-US" xlink:label="lab_art_AustriaPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Austria Plans</link:label>
    <link:label id="lab_art_AustriaPlanMember_label_en-US" xlink:label="lab_art_AustriaPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Austria Plan [Member]</link:label>
    <link:label id="lab_art_AustriaPlanMember_documentation_en-US" xlink:label="lab_art_AustriaPlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Austria Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AustriaPlanMember" xlink:href="art-20260806.xsd#art_AustriaPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AustriaPlanMember" xlink:to="lab_art_AustriaPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_TradingSymbol_019e1743-aaf8-757f-aa9e-c285140d1927_terseLabel_en-US" xlink:label="lab_dei_TradingSymbol" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trading Symbol</link:label>
    <link:label id="lab_dei_TradingSymbol_label_en-US" xlink:label="lab_dei_TradingSymbol" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Symbol</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_TradingSymbol" xlink:to="lab_dei_TradingSymbol" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_019e1743-ab7d-78d4-a6a1-0fed40a3b6cc_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019e1743-ab7d-79db-b10d-713419750df2_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock issuance related to stock-based payment plans, net of shares withheld for employee taxes (in shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e1743-aa65-702d-b10b-e751dabaf809_terseLabel_en-US" xlink:label="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Effect of foreign currency translation on cash, cash equivalents and restricted cash</link:label>
    <link:label id="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_label_en-US" xlink:label="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="lab_us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ChambersburgPA1Member_019e1743-aaf8-7d8b-8bfb-407bf5d5cfc0_terseLabel_en-US" xlink:label="lab_art_ChambersburgPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chambersburg, PA</link:label>
    <link:label id="lab_art_ChambersburgPA1Member_label_en-US" xlink:label="lab_art_ChambersburgPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chambersburg, PA 1 [Member]</link:label>
    <link:label id="lab_art_ChambersburgPA1Member_documentation_en-US" xlink:label="lab_art_ChambersburgPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chambersburg, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ChambersburgPA1Member" xlink:href="art-20260806.xsd#art_ChambersburgPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ChambersburgPA1Member" xlink:to="lab_art_ChambersburgPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_019e1743-aaf8-7fed-ac29-e0ff50c3baa5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Foreign currency translation loss</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsNet_019e1743-a9d5-76ff-8158-d73bf32044a4_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total net deferred tax assets</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsNet_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Net of Valuation Allowance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsNet" xlink:to="lab_us-gaap_DeferredTaxAssetsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_019e1743-a9d5-79aa-bbd1-49fcb0662940_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restricted stock units</link:label>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_019e1743-a9d5-73a0-84ea-52144681a197_verboseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Restricted Stock Units</link:label>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_label_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restricted Stock Units (RSUs) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:to="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold_019e1743-ab7d-7858-a342-5299972869f8_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dispositions</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold_label_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Investment in Real Estate Sold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAccumulatedDepreciationRealEstateSold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:to="lab_us-gaap_RealEstateAccumulatedDepreciationRealEstateSold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SeveranceCosts1_019e1743-ab7d-7f47-8611-bfb92f974449_terseLabel_en-US" xlink:label="lab_us-gaap_SeveranceCosts1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Severance costs</link:label>
    <link:label id="lab_us-gaap_SeveranceCosts1_label_en-US" xlink:label="lab_us-gaap_SeveranceCosts1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Severance Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeveranceCosts1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SeveranceCosts1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SeveranceCosts1" xlink:to="lab_us-gaap_SeveranceCosts1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MortgagesSeniorNotesandMediumTermNotesMember_019e1743-aaf8-72d3-b796-8d88f8b4f6b9_terseLabel_en-US" xlink:label="lab_art_MortgagesSeniorNotesandMediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgages, Senior Notes and Term Loans</link:label>
    <link:label id="lab_art_MortgagesSeniorNotesandMediumTermNotesMember_label_en-US" xlink:label="lab_art_MortgagesSeniorNotesandMediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgages, Senior Notes and Medium-Term Notes [Member]</link:label>
    <link:label id="lab_art_MortgagesSeniorNotesandMediumTermNotesMember_documentation_en-US" xlink:label="lab_art_MortgagesSeniorNotesandMediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mortgages, Senior Notes and Medium-Term Notes [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MortgagesSeniorNotesandMediumTermNotesMember" xlink:href="art-20260806.xsd#art_MortgagesSeniorNotesandMediumTermNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MortgagesSeniorNotesandMediumTermNotesMember" xlink:to="lab_art_MortgagesSeniorNotesandMediumTermNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferred1_019e1743-a9d5-7c4e-b6ad-0ecfea0d1705_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consideration</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationConsiderationTransferred1_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Consideration Transferred</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:to="lab_us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019e1743-aaf8-7bb4-910d-60127766bb38_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_019e1743-a922-7b9a-9a50-5bfcb179c6f5_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated other comprehensive (income) loss</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract_019e1743-a921-7b23-a663-7574c8a8dcda_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Adjustments</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract" xlink:to="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItemsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e1743-a9d5-7ae3-8b78-dedc3af33261_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Outstanding (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_019e1743-a9d5-739a-b3b4-ea479caa17ad_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Outstanding (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfLinesOfCredit_019e1743-a922-7da4-b80c-a601f646dd71_terseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Repayments of lines of credit</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLinesOfCredit_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Lines of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLinesOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfLinesOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfLinesOfCredit" xlink:to="lab_us-gaap_RepaymentsOfLinesOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewZealandIntercompanyLoanMember_019e1743-aaf8-7085-91a3-22bae46f6dd7_terseLabel_en-US" xlink:label="lab_art_NewZealandIntercompanyLoanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New Zealand Intercompany Loan</link:label>
    <link:label id="lab_art_NewZealandIntercompanyLoanMember_label_en-US" xlink:label="lab_art_NewZealandIntercompanyLoanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Zealand Intercompany Loan [Member]</link:label>
    <link:label id="lab_art_NewZealandIntercompanyLoanMember_documentation_en-US" xlink:label="lab_art_NewZealandIntercompanyLoanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">New Zealand Intercompany Loan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewZealandIntercompanyLoanMember" xlink:href="art-20260806.xsd#art_NewZealandIntercompanyLoanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewZealandIntercompanyLoanMember" xlink:to="lab_art_NewZealandIntercompanyLoanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities_019e1743-aa65-7149-ade0-1f7077dd77ce_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capital expenditures to Maintain Real Estate Facilities</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Capital Expenditures for Existing Facilities</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Capital Expenditures for Existing Facilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresforExistingFacilities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SavannahGA1Member_019e1743-a9d5-7d8e-b354-c8db06f06a37_terseLabel_en-US" xlink:label="lab_art_SavannahGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Savannah, GA</link:label>
    <link:label id="lab_art_SavannahGA1Member_label_en-US" xlink:label="lab_art_SavannahGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Savannah, GA 1 [Member]</link:label>
    <link:label id="lab_art_SavannahGA1Member_documentation_en-US" xlink:label="lab_art_SavannahGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Savannah, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SavannahGA1Member" xlink:href="art-20260806.xsd#art_SavannahGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SavannahGA1Member" xlink:to="lab_art_SavannahGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_019e1743-aaf8-7dc3-b691-d47b12b62bc3_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_019e1743-a9d5-75a7-aa90-ecb9d054a5d6_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Interest portion</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_019e1743-a9d5-73ec-a03a-cc4f9e345895_negatedLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: Interest</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesOutstanding_019e1743-aaf8-7cff-848e-7731c5725625_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares, shares outstanding (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesOutstanding_019e1743-aaf8-77d8-b21b-6afce188ca49_periodStartLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning balance (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesOutstanding_019e1743-aaf8-73b8-8072-34c9570153ce_periodEndLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending balance (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesOutstanding_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Shares, Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesOutstanding" xlink:to="lab_us-gaap_CommonStockSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainLossOnSaleOfOtherAssets_019e1743-aa65-7349-a751-e5e7217d6adf_terseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfOtherAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on sale of non-real estate assets</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfOtherAssets_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfOtherAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Disposition of Other Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfOtherAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnSaleOfOtherAssets" xlink:to="lab_us-gaap_GainLossOnSaleOfOtherAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_019e1743-ab7d-7278-8b97-7ce5dd99e6a3_verboseLabel_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Change in reserve due to the provision</link:label>
    <link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_label_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Credit Loss Expense (Reversal)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProvisionForDoubtfulAccounts" xlink:to="lab_us-gaap_ProvisionForDoubtfulAccounts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_019e1743-ab7d-72fe-8a3c-c04f6eae5177_terseLabel_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Current:</link:label>
    <link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Income Tax Expense (Benefit), Continuing Operations [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:to="lab_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock_019e1743-aa65-775d-9fba-64bfde60600d_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquisition, Cyber Incident and Other, Net</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock_label_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition Related Cost, Cyber Incident And Other Special Charges Disclosure [Text Block]</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock_documentation_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition Related Cost, Cyber Incident And Other Special Charges Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock" xlink:href="art-20260806.xsd#art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock" xlink:to="lab_art_BusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_019e1743-ab7d-75f2-8200-2913ba723202_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_019e1743-ab7d-7e90-942a-8146e65c9ff8_totalLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total accounts payable and accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable and Accrued Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:to="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019e1743-a921-7ae8-a96f-49fcad708fcf_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Units (In&#160;thousands)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member_019e1743-a9d5-7320-b833-e79517b7f3ba_terseLabel_en-US" xlink:label="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 1 Maturing July 30 2027</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member_label_en-US" xlink:label="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 1 Maturing July 30 2027 [Member]</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member_documentation_en-US" xlink:label="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 1 Maturing July 30 2027</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_InterestRateSwapAgreement1MaturingJuly302027Member" xlink:href="art-20260806.xsd#art_InterestRateSwapAgreement1MaturingJuly302027Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_InterestRateSwapAgreement1MaturingJuly302027Member" xlink:to="lab_art_InterestRateSwapAgreement1MaturingJuly302027Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantInterestCoverageRatio_019e1743-aa65-7e21-863f-2f27aa64c0ce_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantInterestCoverageRatio" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, interest coverage ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantInterestCoverageRatio_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantInterestCoverageRatio" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Interest Coverage Ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantInterestCoverageRatio_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantInterestCoverageRatio" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Interest Coverage Ratio</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantInterestCoverageRatio" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantInterestCoverageRatio"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantInterestCoverageRatio" xlink:to="lab_art_DebtInstrumentCovenantInterestCoverageRatio" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HendersonNV1Member_019e1743-aaf8-7cf5-8481-703362e75260_terseLabel_en-US" xlink:label="lab_art_HendersonNV1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Henderson, NV</link:label>
    <link:label id="lab_art_HendersonNV1Member_label_en-US" xlink:label="lab_art_HendersonNV1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Henderson, NV 1 [Member]</link:label>
    <link:label id="lab_art_HendersonNV1Member_documentation_en-US" xlink:label="lab_art_HendersonNV1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Henderson, NV 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HendersonNV1Member" xlink:href="art-20260806.xsd#art_HendersonNV1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HendersonNV1Member" xlink:to="lab_art_HendersonNV1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_019e1743-aaf8-74d7-9f30-16f8d4dc9062_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xml:lang="en-US">Total income tax benefit</link:label>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaGACorporateMember_019e1743-a921-765d-bb44-925fac9d4772_terseLabel_en-US" xlink:label="lab_art_AtlantaGACorporateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta, GA - Corporate</link:label>
    <link:label id="lab_art_AtlantaGACorporateMember_label_en-US" xlink:label="lab_art_AtlantaGACorporateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta, GA - Corporate [Member]</link:label>
    <link:label id="lab_art_AtlantaGACorporateMember_documentation_en-US" xlink:label="lab_art_AtlantaGACorporateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta, GA - Corporate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaGACorporateMember" xlink:href="art-20260806.xsd#art_AtlantaGACorporateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaGACorporateMember" xlink:to="lab_art_AtlantaGACorporateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019e1743-aaf8-76c3-a426-d9ceb9c23028_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Basis spread on variable rate</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Basis Spread on Variable Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:to="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LakevilleMN2Member_019e1743-a9d5-756f-ae9c-2b290f928ef9_terseLabel_en-US" xlink:label="lab_art_LakevilleMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lakeville, MN</link:label>
    <link:label id="lab_art_LakevilleMN2Member_label_en-US" xlink:label="lab_art_LakevilleMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lakeville, MN 2 [Member]</link:label>
    <link:label id="lab_art_LakevilleMN2Member_documentation_en-US" xlink:label="lab_art_LakevilleMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lakeville, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LakevilleMN2Member" xlink:href="art-20260806.xsd#art_LakevilleMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LakevilleMN2Member" xlink:to="lab_art_LakevilleMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaEastPointGA2Member_019e1743-a9d5-71a9-b6cf-06816642e559_terseLabel_en-US" xlink:label="lab_art_AtlantaEastPointGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Appleton, WI</link:label>
    <link:label id="lab_art_AtlantaEastPointGA2Member_label_en-US" xlink:label="lab_art_AtlantaEastPointGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - East Point, GA 2 [Member]</link:label>
    <link:label id="lab_art_AtlantaEastPointGA2Member_documentation_en-US" xlink:label="lab_art_AtlantaEastPointGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - East Point, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaEastPointGA2Member" xlink:href="art-20260806.xsd#art_AtlantaEastPointGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaEastPointGA2Member" xlink:to="lab_art_AtlantaEastPointGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsegmentsAxis_019e1743-aaf8-779b-bc30-9aefeec12be6_terseLabel_en-US" xlink:label="lab_us-gaap_SubsegmentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsegments [Axis]</link:label>
    <link:label id="lab_us-gaap_SubsegmentsAxis_label_en-US" xlink:label="lab_us-gaap_SubsegmentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsegments [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsegmentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsegmentsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsegmentsAxis" xlink:to="lab_us-gaap_SubsegmentsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentGross_019e1743-aa64-7e59-8eb3-98f1e84a385b_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, gross</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentGross_019e1743-aa64-7646-9314-af8cc3475ed0_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Land and buildings and improvements, gross value</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentGross_019e1743-aa64-7556-9459-fc11ff1a773b_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Property, buildings and equipment gross value</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentGross_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentGross" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentGross" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MountvillePA2Member_019e1743-aa65-7c99-9acf-63673c3f0b10_terseLabel_en-US" xlink:label="lab_art_MountvillePA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mountville, PA</link:label>
    <link:label id="lab_art_MountvillePA2Member_label_en-US" xlink:label="lab_art_MountvillePA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mountville, PA 2 [Member]</link:label>
    <link:label id="lab_art_MountvillePA2Member_documentation_en-US" xlink:label="lab_art_MountvillePA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mountville, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MountvillePA2Member" xlink:href="art-20260806.xsd#art_MountvillePA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MountvillePA2Member" xlink:to="lab_art_MountvillePA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionEffectiveInterestRate_019e1743-a9d5-734d-847a-97a238ef50c4_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionEffectiveInterestRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionEffectiveInterestRate_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionEffectiveInterestRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Effective Interest Rate</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionEffectiveInterestRate_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionEffectiveInterestRate" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Effective Interest Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionEffectiveInterestRate" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionEffectiveInterestRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionEffectiveInterestRate" xlink:to="lab_art_SaleLeasebackTransactionEffectiveInterestRate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BensonNC1Member_019e1743-a9d5-7d88-b911-1e861a89bb93_terseLabel_en-US" xlink:label="lab_art_BensonNC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Benson, NC</link:label>
    <link:label id="lab_art_BensonNC1Member_label_en-US" xlink:label="lab_art_BensonNC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Benson, NC 1 [Member]</link:label>
    <link:label id="lab_art_BensonNC1Member_documentation_en-US" xlink:label="lab_art_BensonNC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benson, NC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BensonNC1Member" xlink:href="art-20260806.xsd#art_BensonNC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BensonNC1Member" xlink:to="lab_art_BensonNC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DiscontinuedOperationsHeldforsaleMember_019e1743-a9d5-718c-92bb-5c1fcd584e7b_terseLabel_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discontinued Operations, Held-for-Sale</link:label>
    <link:label id="lab_us-gaap_DiscontinuedOperationsHeldforsaleMember_label_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discontinued Operations, Held-for-Sale [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DiscontinuedOperationsHeldforsaleMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:to="lab_us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortWorthSamuelsTX2Member_019e1743-aaf8-7eba-8159-6d0c4cf9a7e1_terseLabel_en-US" xlink:label="lab_art_FortWorthSamuelsTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Worth-Samuels, TX</link:label>
    <link:label id="lab_art_FortWorthSamuelsTX2Member_label_en-US" xlink:label="lab_art_FortWorthSamuelsTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Worth-Samuels, TX 2 [Member]</link:label>
    <link:label id="lab_art_FortWorthSamuelsTX2Member_documentation_en-US" xlink:label="lab_art_FortWorthSamuelsTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Worth-Samuels, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortWorthSamuelsTX2Member" xlink:href="art-20260806.xsd#art_FortWorthSamuelsTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortWorthSamuelsTX2Member" xlink:to="lab_art_FortWorthSamuelsTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BridgeLoan_019e1743-aa64-7232-8ea1-d82f4c2f7724_terseLabel_en-US" xlink:label="lab_us-gaap_BridgeLoan" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bridge loan</link:label>
    <link:label id="lab_us-gaap_BridgeLoan_label_en-US" xlink:label="lab_us-gaap_BridgeLoan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bridge Loan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BridgeLoan" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BridgeLoan"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BridgeLoan" xlink:to="lab_us-gaap_BridgeLoan" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio_019e1743-a921-717a-b37f-a8447d338d0d_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, assets to unsecured indebtedness ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Assets To Unsecured Indebtedness Ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Assets To Unsecured Indebtedness Ratio</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio" xlink:to="lab_art_DebtInstrumentCovenantAssetsToUnsecuredIndebtednessRatio" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_019e1743-aa65-75e3-ab24-540a108d55f9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:to="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SeabrookNJ1Member_019e1743-a9d5-7687-9584-b21250e83556_terseLabel_en-US" xlink:label="lab_art_SeabrookNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Seabrook, NJ</link:label>
    <link:label id="lab_art_SeabrookNJ1Member_label_en-US" xlink:label="lab_art_SeabrookNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Seabrook, NJ 1 [Member]</link:label>
    <link:label id="lab_art_SeabrookNJ1Member_documentation_en-US" xlink:label="lab_art_SeabrookNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Seabrook, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SeabrookNJ1Member" xlink:href="art-20260806.xsd#art_SeabrookNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SeabrookNJ1Member" xlink:to="lab_art_SeabrookNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromStockOptionsExercised_019e1743-aaf8-7a27-ba8a-7c8de0a43e72_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromStockOptionsExercised" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from stock options exercised</link:label>
    <link:label id="lab_us-gaap_ProceedsFromStockOptionsExercised_label_en-US" xlink:label="lab_us-gaap_ProceedsFromStockOptionsExercised" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Stock Options Exercised</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromStockOptionsExercised" xlink:to="lab_us-gaap_ProceedsFromStockOptionsExercised" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019e1743-ab7d-7060-8022-05d3235db483_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Business combinations, net of cash acquired</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_019e1743-ab7d-7844-969a-bf21c186a4b3_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate cash consideration</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Businesses, Net of Cash Acquired</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:to="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxPaidFederalAfterRefundReceived_019e1743-a921-7d3c-b982-ef57610767de_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPaidFederalAfterRefundReceived" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. federal</link:label>
    <link:label id="lab_us-gaap_IncomeTaxPaidFederalAfterRefundReceived_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPaidFederalAfterRefundReceived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Paid, Federal, after Refund Received</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPaidFederalAfterRefundReceived" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidFederalAfterRefundReceived"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPaidFederalAfterRefundReceived" xlink:to="lab_us-gaap_IncomeTaxPaidFederalAfterRefundReceived" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BuildingAndBuildingImprovementsMember_019e1743-aa65-7f52-8629-e4214ae77a11_terseLabel_en-US" xlink:label="lab_us-gaap_BuildingAndBuildingImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Building and improvements</link:label>
    <link:label id="lab_us-gaap_BuildingAndBuildingImprovementsMember_label_en-US" xlink:label="lab_us-gaap_BuildingAndBuildingImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building and Building Improvements [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BuildingAndBuildingImprovementsMember" xlink:to="lab_us-gaap_BuildingAndBuildingImprovementsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BelvidereImronIL2Member_019e1743-aa64-724b-a60b-622ce83a26eb_terseLabel_en-US" xlink:label="lab_art_BelvidereImronIL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Belvidere-Imron, IL</link:label>
    <link:label id="lab_art_BelvidereImronIL2Member_label_en-US" xlink:label="lab_art_BelvidereImronIL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Belvidere-Imron, IL 2 [Member]</link:label>
    <link:label id="lab_art_BelvidereImronIL2Member_documentation_en-US" xlink:label="lab_art_BelvidereImronIL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Belvidere-Imron, IL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BelvidereImronIL2Member" xlink:href="art-20260806.xsd#art_BelvidereImronIL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BelvidereImronIL2Member" xlink:to="lab_art_BelvidereImronIL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ManchesterPA1Member_019e1743-a9d5-738d-b9b4-324ca80fff43_terseLabel_en-US" xlink:label="lab_art_ManchesterPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Manchester, PA</link:label>
    <link:label id="lab_art_ManchesterPA1Member_label_en-US" xlink:label="lab_art_ManchesterPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Manchester, PA 1 [Member]</link:label>
    <link:label id="lab_art_ManchesterPA1Member_documentation_en-US" xlink:label="lab_art_ManchesterPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Manchester, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ManchesterPA1Member" xlink:href="art-20260806.xsd#art_ManchesterPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ManchesterPA1Member" xlink:to="lab_art_ManchesterPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AssociateMember_019e1743-a9d5-7c3f-8823-adb7914573d9_terseLabel_en-US" xlink:label="lab_art_AssociateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Associates</link:label>
    <link:label id="lab_art_AssociateMember_label_en-US" xlink:label="lab_art_AssociateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Associate [Member]</link:label>
    <link:label id="lab_art_AssociateMember_documentation_en-US" xlink:label="lab_art_AssociateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Associate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AssociateMember" xlink:href="art-20260806.xsd#art_AssociateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AssociateMember" xlink:to="lab_art_AssociateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract_019e1743-a922-726c-bccf-c1763f651a9d_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationOtherAdjustments_019e1743-a921-7490-a9b6-fc9a85d35847_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationOtherAdjustments_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other Adjustments, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:to="lab_us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MakoMako2Member_019e1743-aaf8-78b7-8987-8e3bb45e37d3_terseLabel_en-US" xlink:label="lab_art_MakoMako2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mako Mako</link:label>
    <link:label id="lab_art_MakoMako2Member_label_en-US" xlink:label="lab_art_MakoMako2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mako Mako 2 [Member]</link:label>
    <link:label id="lab_art_MakoMako2Member_documentation_en-US" xlink:label="lab_art_MakoMako2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mako Mako 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MakoMako2Member" xlink:href="art-20260806.xsd#art_MakoMako2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MakoMako2Member" xlink:to="lab_art_MakoMako2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_019e1743-a9d5-7796-95b2-caa3818af045_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated benefit obligation</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_019e1743-aa65-766f-8d38-16960e582207_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:to="lab_us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member_019e1743-ab7d-7fe1-80b3-900757998f51_terseLabel_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Private Series C Notes</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member_label_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series C Notes, Due 2030 [Member]</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member_documentation_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series C Notes, Due 2030</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member" xlink:href="art-20260806.xsd#art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member" xlink:to="lab_art_PrivateSeniorUnsecuredSeriesCNotesDue2030Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AllentownPA1Member_019e1743-a9d5-7f53-9aec-6c94d4ec29d7_terseLabel_en-US" xlink:label="lab_art_AllentownPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Allentown, PA</link:label>
    <link:label id="lab_art_AllentownPA1Member_label_en-US" xlink:label="lab_art_AllentownPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Allentown, PA 1 [Member]</link:label>
    <link:label id="lab_art_AllentownPA1Member_documentation_en-US" xlink:label="lab_art_AllentownPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Allentown, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AllentownPA1Member" xlink:href="art-20260806.xsd#art_AllentownPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AllentownPA1Member" xlink:to="lab_art_AllentownPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeMarsIA1Member_019e1743-aa65-7bc6-87de-97aac447d101_terseLabel_en-US" xlink:label="lab_art_LeMarsIA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Le Mars, IA</link:label>
    <link:label id="lab_art_LeMarsIA1Member_label_en-US" xlink:label="lab_art_LeMarsIA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Le Mars, IA 1 [Member]</link:label>
    <link:label id="lab_art_LeMarsIA1Member_documentation_en-US" xlink:label="lab_art_LeMarsIA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Le Mars, IA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeMarsIA1Member" xlink:href="art-20260806.xsd#art_LeMarsIA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeMarsIA1Member" xlink:to="lab_art_LeMarsIA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GaffneySC2Member_019e1743-aa65-7f0b-8189-3a235e074b20_terseLabel_en-US" xlink:label="lab_art_GaffneySC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gaffney, SC</link:label>
    <link:label id="lab_art_GaffneySC2Member_label_en-US" xlink:label="lab_art_GaffneySC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gaffney, SC 2 [Member]</link:label>
    <link:label id="lab_art_GaffneySC2Member_documentation_en-US" xlink:label="lab_art_GaffneySC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gaffney, SC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GaffneySC2Member" xlink:href="art-20260806.xsd#art_GaffneySC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GaffneySC2Member" xlink:to="lab_art_GaffneySC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfShortTermDebt_019e1743-a921-7053-86cf-8027dc09d704_terseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfShortTermDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Repayments of bridge loan</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfShortTermDebt_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfShortTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Short-Term Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfShortTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfShortTermDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfShortTermDebt" xlink:to="lab_us-gaap_RepaymentsOfShortTermDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTable_019e1743-a921-7939-a224-903422f5aba8_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation [Table]</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTable_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract_019e1743-aaf8-7184-99ab-27caf090bcc8_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method Investments and Joint Ventures [Abstract]</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments and Joint Ventures [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract" xlink:to="lab_us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DelhiLA1Member_019e1743-aaf8-75e3-b4c0-bd3301a6796b_terseLabel_en-US" xlink:label="lab_art_DelhiLA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Delhi, LA</link:label>
    <link:label id="lab_art_DelhiLA1Member_label_en-US" xlink:label="lab_art_DelhiLA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Delhi, LA 1 [Member]</link:label>
    <link:label id="lab_art_DelhiLA1Member_documentation_en-US" xlink:label="lab_art_DelhiLA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Delhi, LA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DelhiLA1Member" xlink:href="art-20260806.xsd#art_DelhiLA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DelhiLA1Member" xlink:to="lab_art_DelhiLA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_019e1743-aaf8-7bc3-95df-7f74c35d838c_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Useful lives</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Useful Life</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfMultiemployerPlansTable_019e1743-aaf8-7576-9504-86ef8cd5f7c4_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfMultiemployerPlansTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Multiemployer Plans [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfMultiemployerPlansTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfMultiemployerPlansTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plan [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMultiemployerPlansTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfMultiemployerPlansTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfMultiemployerPlansTable" xlink:to="lab_us-gaap_ScheduleOfMultiemployerPlansTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TampaPlantCityFL1Member_019e1743-aaf8-7665-a539-cae06c98e1f8_terseLabel_en-US" xlink:label="lab_art_TampaPlantCityFL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tampa Plant City, FL</link:label>
    <link:label id="lab_art_TampaPlantCityFL1Member_label_en-US" xlink:label="lab_art_TampaPlantCityFL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tampa Plant City, FL 1 [Member]</link:label>
    <link:label id="lab_art_TampaPlantCityFL1Member_documentation_en-US" xlink:label="lab_art_TampaPlantCityFL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tampa Plant City, FL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TampaPlantCityFL1Member" xlink:href="art-20260806.xsd#art_TampaPlantCityFL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TampaPlantCityFL1Member" xlink:to="lab_art_TampaPlantCityFL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BirminghamAL1Member_019e1743-ab7d-7213-9031-9fd4fd4131d4_terseLabel_en-US" xlink:label="lab_art_BirminghamAL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Birmingham, AL</link:label>
    <link:label id="lab_art_BirminghamAL1Member_label_en-US" xlink:label="lab_art_BirminghamAL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Birmingham, AL 1 [Member]</link:label>
    <link:label id="lab_art_BirminghamAL1Member_documentation_en-US" xlink:label="lab_art_BirminghamAL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Birmingham, AL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BirminghamAL1Member" xlink:href="art-20260806.xsd#art_BirminghamAL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BirminghamAL1Member" xlink:to="lab_art_BirminghamAL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BarneveldMember_019e1743-a9d5-7dd9-8405-c751bd8bc9c6_terseLabel_en-US" xlink:label="lab_art_BarneveldMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Barneveld</link:label>
    <link:label id="lab_art_BarneveldMember_label_en-US" xlink:label="lab_art_BarneveldMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Barneveld [Member]</link:label>
    <link:label id="lab_art_BarneveldMember_documentation_en-US" xlink:label="lab_art_BarneveldMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Barneveld</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BarneveldMember" xlink:href="art-20260806.xsd#art_BarneveldMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BarneveldMember" xlink:to="lab_art_BarneveldMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SanfordNC2Member_019e1743-a9d5-7f17-a406-7c41fcfdd37d_terseLabel_en-US" xlink:label="lab_art_SanfordNC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sanford, NC</link:label>
    <link:label id="lab_art_SanfordNC2Member_label_en-US" xlink:label="lab_art_SanfordNC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sanford, NC 2 [Member]</link:label>
    <link:label id="lab_art_SanfordNC2Member_documentation_en-US" xlink:label="lab_art_SanfordNC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sanford, NC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SanfordNC2Member" xlink:href="art-20260806.xsd#art_SanfordNC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SanfordNC2Member" xlink:to="lab_art_SanfordNC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DouglasGA2Member_019e1743-aa65-73df-be00-942ebe34ff28_terseLabel_en-US" xlink:label="lab_art_DouglasGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Douglas, GA</link:label>
    <link:label id="lab_art_DouglasGA2Member_label_en-US" xlink:label="lab_art_DouglasGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Douglas, GA 2 [Member]</link:label>
    <link:label id="lab_art_DouglasGA2Member_documentation_en-US" xlink:label="lab_art_DouglasGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Douglas, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DouglasGA2Member" xlink:href="art-20260806.xsd#art_DouglasGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DouglasGA2Member" xlink:to="lab_art_DouglasGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubleaseIncome_019e1743-a9d5-733f-b982-c0d0a973441b_negatedLabel_en-US" xlink:label="lab_us-gaap_SubleaseIncome" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Sublease income</link:label>
    <link:label id="lab_us-gaap_SubleaseIncome_label_en-US" xlink:label="lab_us-gaap_SubleaseIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sublease Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubleaseIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubleaseIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubleaseIncome" xlink:to="lab_us-gaap_SubleaseIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NumberOfReportableSegments_019e1743-aa64-7d46-9f8a-4ffbfe5744a6_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of reportable segments</link:label>
    <link:label id="lab_us-gaap_NumberOfReportableSegments_label_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Reportable Segments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfReportableSegments" xlink:to="lab_us-gaap_NumberOfReportableSegments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WhitchurchMember_019e1743-aaf8-7ffa-b7f4-9b55fd74cae0_terseLabel_en-US" xlink:label="lab_art_WhitchurchMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Whitchurch</link:label>
    <link:label id="lab_art_WhitchurchMember_label_en-US" xlink:label="lab_art_WhitchurchMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Whitchurch [Member]</link:label>
    <link:label id="lab_art_WhitchurchMember_documentation_en-US" xlink:label="lab_art_WhitchurchMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Whitchurch</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WhitchurchMember" xlink:href="art-20260806.xsd#art_WhitchurchMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WhitchurchMember" xlink:to="lab_art_WhitchurchMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member_019e1743-aaf8-76a1-8e26-705896766bf7_terseLabel_en-US" xlink:label="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 1 Maturing December 31 2027</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member_label_en-US" xlink:label="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 1 Maturing December 31 2027 [Member]</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member_documentation_en-US" xlink:label="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 1 Maturing December 31 2027</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_InterestRateSwapAgreement1MaturingDecember312027Member" xlink:href="art-20260806.xsd#art_InterestRateSwapAgreement1MaturingDecember312027Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_InterestRateSwapAgreement1MaturingDecember312027Member" xlink:to="lab_art_InterestRateSwapAgreement1MaturingDecember312027Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives_019e1743-a9d5-76be-a76b-ddfa86a17918_terseLabel_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on debt extinguishment and termination of derivative instruments</link:label>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives_label_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Extinguishment of Debt and Termination of Derivatives</link:label>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives_documentation_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Extinguishment of Debt and Termination of Derivatives</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives" xlink:href="art-20260806.xsd#art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives" xlink:to="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivatives" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract_019e1743-a9d5-7c9c-b60b-adf48489ef9e_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred tax assets:</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Net of Valuation Allowance [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:to="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressStateOrProvince_019e1743-a9d5-722e-89e9-2f2e53fcfd04_terseLabel_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, State or Province</link:label>
    <link:label id="lab_dei_EntityAddressStateOrProvince_label_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, State or Province</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressStateOrProvince" xlink:to="lab_dei_EntityAddressStateOrProvince" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019e1743-a9d5-7fb8-9172-02fef54b728e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Antidilutive Security, Excluded EPS Calculation [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Security, Excluded EPS Calculation [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DividendsCommonStock_019e1743-ab7d-7355-b2c5-cdefe548777f_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DividendsCommonStock" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Distributions on common stock, restricted stock and OP units</link:label>
    <link:label id="lab_us-gaap_DividendsCommonStock_label_en-US" xlink:label="lab_us-gaap_DividendsCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsCommonStock" xlink:to="lab_us-gaap_DividendsCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_019e1743-aa65-7ec0-8d0a-236996cb1ec0_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum_019e1743-a9d5-7e53-b9eb-5fc358f8dfdc_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum secured leverage ratio after material acquisition</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Secured Leverage Ratio After Material Acquisition, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Secured Leverage Ratio After Material Acquisition, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum" xlink:to="lab_art_DebtInstrumentCovenantSecuredLeverageRatioAfterMaterialAcquisitionMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionNetBookValue_019e1743-aa65-74ad-9610-007271408add_terseLabel_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionNetBookValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total sale-leaseback financing&#160;obligations</link:label>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionNetBookValue_label_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionNetBookValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Net Book Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionNetBookValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionNetBookValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleLeasebackTransactionNetBookValue" xlink:to="lab_us-gaap_SaleLeasebackTransactionNetBookValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_019e1743-aa65-794d-a755-96175c0621d4_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate facilities, at cost - ending balance</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LineofCreditandMediumTermNotesMember_019e1743-a9d5-70a8-a5d3-43945da7b20d_terseLabel_en-US" xlink:label="lab_art_LineofCreditandMediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Term Loans and Credit Facility</link:label>
    <link:label id="lab_art_LineofCreditandMediumTermNotesMember_label_en-US" xlink:label="lab_art_LineofCreditandMediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit and Medium-Term Notes [Member]</link:label>
    <link:label id="lab_art_LineofCreditandMediumTermNotesMember_documentation_en-US" xlink:label="lab_art_LineofCreditandMediumTermNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of Credit and Medium-Term Notes [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LineofCreditandMediumTermNotesMember" xlink:href="art-20260806.xsd#art_LineofCreditandMediumTermNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LineofCreditandMediumTermNotesMember" xlink:to="lab_art_LineofCreditandMediumTermNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_019e1743-aaf8-7ad2-a0e5-19271acab151_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Distributions paid on common stock, restricted stock units and noncontrolling interests in OP</link:label>
    <link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments of Ordinary Dividends, Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDividendsCommonStock" xlink:to="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member_019e1743-aa65-7d89-b1e3-edfd1ce5d083_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 1</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 1 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member" xlink:to="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember_019e1743-ab7d-7ee3-85b5-7bc047373883_terseLabel_en-US" xlink:label="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022 Senior Unsecured Term Loan A</link:label>
    <link:label id="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember_label_en-US" xlink:label="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Twenty Twenty Two Senior Unsecured Term Loan A [Member]</link:label>
    <link:label id="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember_documentation_en-US" xlink:label="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Twenty Twenty Two Senior Unsecured Term Loan A</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember" xlink:href="art-20260806.xsd#art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember" xlink:to="lab_art_TwentyTwentyTwoSeniorUnsecuredTermLoanAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NonCashLeaseExpense_019e1743-a922-747e-a692-22311fba3550_terseLabel_en-US" xlink:label="lab_art_NonCashLeaseExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-cash operating lease expenses</link:label>
    <link:label id="lab_art_NonCashLeaseExpense_label_en-US" xlink:label="lab_art_NonCashLeaseExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-cash Lease Expense</link:label>
    <link:label id="lab_art_NonCashLeaseExpense_documentation_en-US" xlink:label="lab_art_NonCashLeaseExpense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Non-cash Lease Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NonCashLeaseExpense" xlink:href="art-20260806.xsd#art_NonCashLeaseExpense"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_019e1743-aaf8-726f-8355-876e0a75df65_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Effect of settlement</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanSettlementsBenefitObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum_019e1743-aaf8-7e94-bc10-609e7e8a1bfb_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum unencumbered leverage ratio after material acquisition</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unencumbered Leverage Ratio After Material Acquisition, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unencumbered Leverage Ratio After Material Acquisition, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum" xlink:to="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioAfterMaterialAcquisitionMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ForestMS2Member_019e1743-a921-764f-ac60-cf3d2852aa92_terseLabel_en-US" xlink:label="lab_art_ForestMS2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forest, MS</link:label>
    <link:label id="lab_art_ForestMS2Member_label_en-US" xlink:label="lab_art_ForestMS2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forest, MS 2 [Member]</link:label>
    <link:label id="lab_art_ForestMS2Member_documentation_en-US" xlink:label="lab_art_ForestMS2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Forest, MS 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ForestMS2Member" xlink:href="art-20260806.xsd#art_ForestMS2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ForestMS2Member" xlink:to="lab_art_ForestMS2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LaborMember_019e1743-aaf8-700c-a47c-8ac83c283bcf_terseLabel_en-US" xlink:label="lab_art_LaborMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Labor</link:label>
    <link:label id="lab_art_LaborMember_label_en-US" xlink:label="lab_art_LaborMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Labor [Member]</link:label>
    <link:label id="lab_art_LaborMember_documentation_en-US" xlink:label="lab_art_LaborMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Labor</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LaborMember" xlink:href="art-20260806.xsd#art_LaborMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LaborMember" xlink:to="lab_art_LaborMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities_019e1743-a921-7b08-9b70-f18bad7aa6c4_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash proceeds</link:label>
    <link:label id="lab_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities_label_en-US" xlink:label="lab_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Derivative Instrument, Investing Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities" xlink:to="lab_us-gaap_ProceedsFromDerivativeInstrumentInvestingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_019e1743-a9d5-7514-9c5b-195d2c3a743a_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditSettlementGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_019e1743-a9d5-79c0-9696-406f87f26199_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Funded status</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Funded (Unfunded) Status of Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:to="lab_us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainsLossesOnSalesOfOtherRealEstate_019e1743-a921-78af-bee3-3614b3a1b6cd_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnSalesOfOtherRealEstate" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net loss (gain) from sale of real estate</link:label>
    <link:label id="lab_us-gaap_GainsLossesOnSalesOfOtherRealEstate_label_en-US" xlink:label="lab_us-gaap_GainsLossesOnSalesOfOtherRealEstate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gains (Losses) on Sales of Other Real Estate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnSalesOfOtherRealEstate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnSalesOfOtherRealEstate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainsLossesOnSalesOfOtherRealEstate" xlink:to="lab_us-gaap_GainsLossesOnSalesOfOtherRealEstate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlanOtherMember_019e1743-aa65-7ddc-b94f-94cc70885dae_terseLabel_en-US" xlink:label="lab_art_DefinedBenefitPlanOtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_art_DefinedBenefitPlanOtherMember_label_en-US" xlink:label="lab_art_DefinedBenefitPlanOtherMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Other [Member]</link:label>
    <link:label id="lab_art_DefinedBenefitPlanOtherMember_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlanOtherMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlanOtherMember" xlink:href="art-20260806.xsd#art_DefinedBenefitPlanOtherMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlanOtherMember" xlink:to="lab_art_DefinedBenefitPlanOtherMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueTable_019e1743-a9d5-70b4-918f-8c15c54609a0_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disaggregation of Revenue [Table]</link:label>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueTable_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disaggregation of Revenue [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable" xlink:to="lab_us-gaap_DisaggregationOfRevenueTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019e1743-a9d5-7a90-9000-5494aa3c7f5e_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-Lived Tangible Asset [Axis]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Lived Tangible Asset [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand_019e1743-ab7d-742a-9f4c-318d34f7fc32_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Initial Costs, Land</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost of Land</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GloucesterRogersMA1Member_019e1743-aaf8-7a40-88ac-96331b38b771_terseLabel_en-US" xlink:label="lab_art_GloucesterRogersMA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gloucester - Rogers, MA</link:label>
    <link:label id="lab_art_GloucesterRogersMA1Member_label_en-US" xlink:label="lab_art_GloucesterRogersMA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gloucester - Rogers, MA 1 [Member]</link:label>
    <link:label id="lab_art_GloucesterRogersMA1Member_documentation_en-US" xlink:label="lab_art_GloucesterRogersMA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gloucester - Rogers, MA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GloucesterRogersMA1Member" xlink:href="art-20260806.xsd#art_GloucesterRogersMA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GloucesterRogersMA1Member" xlink:to="lab_art_GloucesterRogersMA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_019e1743-a9d5-7a81-bf4c-14f72fa5aedf_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_019e1743-aaf8-7396-8cde-aeb95d9f29c7_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCentralIndexKey_019e1743-a921-75aa-a529-d4f5ee7a98bd_terseLabel_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:label id="lab_dei_EntityCentralIndexKey_label_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCentralIndexKey" xlink:to="lab_dei_EntityCentralIndexKey" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract_019e1743-aaf8-7204-9a41-3ea57593222c_terseLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash, cash equivalents and restricted cash:</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffectAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Revenues_019e1743-ab7d-7663-baa8-f0d491ae1cf5_terseLabel_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total revenues</link:label>
    <link:label id="lab_us-gaap_Revenues_label_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Revenues" xlink:to="lab_us-gaap_Revenues" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PaymentsForTheDivestitureOfBusiness_019e1743-a9d5-73a1-b50c-1ed490f39b3a_negatedTerseLabel_en-US" xlink:label="lab_art_PaymentsForTheDivestitureOfBusiness" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net payments for sale of business (discontinued operations)</link:label>
    <link:label id="lab_art_PaymentsForTheDivestitureOfBusiness_label_en-US" xlink:label="lab_art_PaymentsForTheDivestitureOfBusiness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for the Divestiture of Business</link:label>
    <link:label id="lab_art_PaymentsForTheDivestitureOfBusiness_documentation_en-US" xlink:label="lab_art_PaymentsForTheDivestitureOfBusiness" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Payments for the Divestiture of Business</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PaymentsForTheDivestitureOfBusiness" xlink:href="art-20260806.xsd#art_PaymentsForTheDivestitureOfBusiness"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PaymentsForTheDivestitureOfBusiness" xlink:to="lab_art_PaymentsForTheDivestitureOfBusiness" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019e1743-aa64-74f7-b414-83fbf2136bc9_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract_019e1743-a921-7277-b6aa-a902b17fde75_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nontaxable or Nondeductible Items</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract" xlink:to="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CollectiveBargainingArrangementAxis_019e1743-a9d5-7b12-b7e6-5bd86c21cae0_terseLabel_en-US" xlink:label="lab_us-gaap_CollectiveBargainingArrangementAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement [Axis]</link:label>
    <link:label id="lab_us-gaap_CollectiveBargainingArrangementAxis_label_en-US" xlink:label="lab_us-gaap_CollectiveBargainingArrangementAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollectiveBargainingArrangementAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CollectiveBargainingArrangementAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CollectiveBargainingArrangementAxis" xlink:to="lab_us-gaap_CollectiveBargainingArrangementAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BensonHodgesNC2Member_019e1743-aa65-7d41-a909-03a79d4d97f6_terseLabel_en-US" xlink:label="lab_art_BensonHodgesNC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Benson Hodges, NC</link:label>
    <link:label id="lab_art_BensonHodgesNC2Member_label_en-US" xlink:label="lab_art_BensonHodgesNC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Benson Hodges, NC 2 [Member]</link:label>
    <link:label id="lab_art_BensonHodgesNC2Member_documentation_en-US" xlink:label="lab_art_BensonHodgesNC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benson Hodges, NC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BensonHodgesNC2Member" xlink:href="art-20260806.xsd#art_BensonHodgesNC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BensonHodgesNC2Member" xlink:to="lab_art_BensonHodgesNC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_019e1743-a9d5-7e4c-ae7d-2ea098091394_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax_019e1743-a921-76a3-9524-d176c72b5825_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Removal of hedge designation</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Cash Flow Hedge, Reclassification for Discontinuance, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember_019e1743-ab7d-72e9-be9c-ab0f80a9f9ba_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Large cap</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Equity Securities, US, Large Cap [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember" xlink:to="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VolumeOfWarehouses_019e1743-a921-78ff-aff2-37371ef9264c_terseLabel_en-US" xlink:label="lab_art_VolumeOfWarehouses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Warehouse volume</link:label>
    <link:label id="lab_art_VolumeOfWarehouses_label_en-US" xlink:label="lab_art_VolumeOfWarehouses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Volume of Warehouses</link:label>
    <link:label id="lab_art_VolumeOfWarehouses_documentation_en-US" xlink:label="lab_art_VolumeOfWarehouses" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Volume of Warehouses</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VolumeOfWarehouses" xlink:href="art-20260806.xsd#art_VolumeOfWarehouses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VolumeOfWarehouses" xlink:to="lab_art_VolumeOfWarehouses" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CarsonCA1Member_019e1743-ab7d-77c4-ac03-89d2b617da23_terseLabel_en-US" xlink:label="lab_art_CarsonCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carson, CA</link:label>
    <link:label id="lab_art_CarsonCA1Member_label_en-US" xlink:label="lab_art_CarsonCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Carson, CA 1 [Member]</link:label>
    <link:label id="lab_art_CarsonCA1Member_documentation_en-US" xlink:label="lab_art_CarsonCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carson, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CarsonCA1Member" xlink:href="art-20260806.xsd#art_CarsonCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CarsonCA1Member" xlink:to="lab_art_CarsonCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdditionalFairValueElementsAbstract_019e1743-a9d5-7056-981f-80e5ac6a7215_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalFairValueElementsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disclosed at fair value:</link:label>
    <link:label id="lab_us-gaap_AdditionalFairValueElementsAbstract_label_en-US" xlink:label="lab_us-gaap_AdditionalFairValueElementsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Fair Value Elements [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalFairValueElementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalFairValueElementsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalFairValueElementsAbstract" xlink:to="lab_us-gaap_AdditionalFairValueElementsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MosesLakeWA2Member_019e1743-aaf8-7199-8420-38cc33efbe13_terseLabel_en-US" xlink:label="lab_art_MosesLakeWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Moses Lake, WA</link:label>
    <link:label id="lab_art_MosesLakeWA2Member_label_en-US" xlink:label="lab_art_MosesLakeWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Moses Lake, WA 2 [Member]</link:label>
    <link:label id="lab_art_MosesLakeWA2Member_documentation_en-US" xlink:label="lab_art_MosesLakeWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Moses Lake, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MosesLakeWA2Member" xlink:href="art-20260806.xsd#art_MosesLakeWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MosesLakeWA2Member" xlink:to="lab_art_MosesLakeWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_019e1743-aa65-7db0-92bb-a72e2102ac40_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Financial Instruments</link:label>
    <link:label id="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Instruments and Hedging Activities Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:to="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_019e1743-a9d5-77aa-a6f7-2c16c65d8653_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of net periodic benefit cost (less than)</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Amortization of Prior Service Cost (Credit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:to="lab_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HermistonOR1Member_019e1743-ab7d-77ec-afb0-055f32008e2f_terseLabel_en-US" xlink:label="lab_art_HermistonOR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hermiston, OR</link:label>
    <link:label id="lab_art_HermistonOR1Member_label_en-US" xlink:label="lab_art_HermistonOR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hermiston, OR 1 [Member]</link:label>
    <link:label id="lab_art_HermistonOR1Member_documentation_en-US" xlink:label="lab_art_HermistonOR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Hermiston, OR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HermistonOR1Member" xlink:href="art-20260806.xsd#art_HermistonOR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HermistonOR1Member" xlink:to="lab_art_HermistonOR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019e1743-a9d5-7040-9b43-56a3d8a47367_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_label_en-US" xlink:label="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019e1743-aa65-71ac-849b-a6ef1d5ea45b_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name of Property [Domain]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Name of Property [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TauntonMA1Member_019e1743-aaf8-7963-b817-e9bc86e3d571_terseLabel_en-US" xlink:label="lab_art_TauntonMA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Taunton, MA</link:label>
    <link:label id="lab_art_TauntonMA1Member_label_en-US" xlink:label="lab_art_TauntonMA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Taunton, MA 1 [Member]</link:label>
    <link:label id="lab_art_TauntonMA1Member_documentation_en-US" xlink:label="lab_art_TauntonMA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Taunton, MA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TauntonMA1Member" xlink:href="art-20260806.xsd#art_TauntonMA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TauntonMA1Member" xlink:to="lab_art_TauntonMA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestRateDerivativeAssetsAtFairValue_019e1743-a921-77ba-9be9-5bfec995685b_terseLabel_en-US" xlink:label="lab_us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of derivatives</link:label>
    <link:label id="lab_us-gaap_InterestRateDerivativeAssetsAtFairValue_label_en-US" xlink:label="lab_us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Derivative Assets, at Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateDerivativeAssetsAtFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:to="lab_us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CostsAndExpenses_019e1743-aa65-7d81-94c9-5e07c2575ae0_totalLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total operating expenses</link:label>
    <link:label id="lab_us-gaap_CostsAndExpenses_label_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Costs and Expenses</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostsAndExpenses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostsAndExpenses" xlink:to="lab_us-gaap_CostsAndExpenses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019e1743-a9d5-7c49-b5e6-d131c1638f37_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Forfeited (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019e1743-a9d5-7196-8e49-8e712da7279d_negatedLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Forfeited (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CollectiveBargainingArrangementOtherMember_019e1743-aa65-7c65-982a-a6218ad57c4e_terseLabel_en-US" xlink:label="lab_us-gaap_CollectiveBargainingArrangementOtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangements</link:label>
    <link:label id="lab_us-gaap_CollectiveBargainingArrangementOtherMember_label_en-US" xlink:label="lab_us-gaap_CollectiveBargainingArrangementOtherMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement, Other [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollectiveBargainingArrangementOtherMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CollectiveBargainingArrangementOtherMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CollectiveBargainingArrangementOtherMember" xlink:to="lab_us-gaap_CollectiveBargainingArrangementOtherMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtFairValue_019e1743-a9d5-77af-8aa8-d2f309e7930a_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disclosed at fair value</link:label>
    <link:label id="lab_us-gaap_LongTermDebtFairValue_label_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtFairValue" xlink:to="lab_us-gaap_LongTermDebtFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RepurchaseAgreementCounterpartyNameDomain_019e1743-ab7d-7df6-82f8-7434cf0dc247_terseLabel_en-US" xlink:label="lab_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Counterparty Name [Domain]</link:label>
    <link:label id="lab_srt_RepurchaseAgreementCounterpartyNameDomain_label_en-US" xlink:label="lab_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Counterparty Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:to="lab_srt_RepurchaseAgreementCounterpartyNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Rockmart1Member_019e1743-ab7d-72f3-b6b2-00cb6202db32_terseLabel_en-US" xlink:label="lab_art_Rockmart1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rockmart</link:label>
    <link:label id="lab_art_Rockmart1Member_label_en-US" xlink:label="lab_art_Rockmart1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rockmart 1 [Member]</link:label>
    <link:label id="lab_art_Rockmart1Member_documentation_en-US" xlink:label="lab_art_Rockmart1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rockmart 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Rockmart1Member" xlink:href="art-20260806.xsd#art_Rockmart1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Rockmart1Member" xlink:to="lab_art_Rockmart1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainesvilleGA2Member_019e1743-ab7d-78ed-8491-a6d42e99d702_terseLabel_en-US" xlink:label="lab_art_GainesvilleGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gainesville, GA</link:label>
    <link:label id="lab_art_GainesvilleGA2Member_label_en-US" xlink:label="lab_art_GainesvilleGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gainesville, GA 2 [Member]</link:label>
    <link:label id="lab_art_GainesvilleGA2Member_documentation_en-US" xlink:label="lab_art_GainesvilleGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gainesville, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainesvilleGA2Member" xlink:href="art-20260806.xsd#art_GainesvilleGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainesvilleGA2Member" xlink:to="lab_art_GainesvilleGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember_019e1743-a921-77e5-915a-0064d7dd6045_terseLabel_en-US" xlink:label="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">AFFO Performance Based Restricted Stock Units</link:label>
    <link:label id="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember_label_en-US" xlink:label="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AFFO Performance Based Restricted Stock Units [Member]</link:label>
    <link:label id="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember_documentation_en-US" xlink:label="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">AFFO Performance Based Restricted Stock Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AFFOPerformanceBasedRestrictedStockUnitsMember" xlink:href="art-20260806.xsd#art_AFFOPerformanceBasedRestrictedStockUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AFFOPerformanceBasedRestrictedStockUnitsMember" xlink:to="lab_art_AFFOPerformanceBasedRestrictedStockUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost_019e1743-a921-753f-a817-2df23f21308b_periodStartLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning Balance</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost_019e1743-a921-7dc4-aebd-2e316e620a05_periodEndLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending Balance</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateandAccumulatedDepreciationInitialCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_019e1743-aaf8-7d8b-b591-4d4aa5854e33_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_019e1743-a9d5-70f4-b9d8-ea8ad929d506_terseLabel_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Letter of credit amount outstanding</link:label>
    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_label_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Letters of Credit Outstanding, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LettersOfCreditOutstandingAmount" xlink:to="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesLeasingArrangements_019e1743-aa64-7011-8daa-3e9f52a7c762_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesLeasingArrangements" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Lease right-of-use assets</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesLeasingArrangements_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesLeasingArrangements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Leasing Arrangements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesLeasingArrangements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxLiabilitiesLeasingArrangements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesLeasingArrangements" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesLeasingArrangements" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AssembledWorkforceMember_019e1743-aa65-77f1-9eb9-5f2f218518f4_terseLabel_en-US" xlink:label="lab_art_AssembledWorkforceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assembled workforce</link:label>
    <link:label id="lab_art_AssembledWorkforceMember_label_en-US" xlink:label="lab_art_AssembledWorkforceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assembled Workforce [Member]</link:label>
    <link:label id="lab_art_AssembledWorkforceMember_documentation_en-US" xlink:label="lab_art_AssembledWorkforceMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Assembled Workforce [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AssembledWorkforceMember" xlink:href="art-20260806.xsd#art_AssembledWorkforceMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AssembledWorkforceMember" xlink:to="lab_art_AssembledWorkforceMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LandMember_019e1743-aaf8-7e24-9962-072ea78761b9_terseLabel_en-US" xlink:label="lab_us-gaap_LandMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:label id="lab_us-gaap_LandMember_label_en-US" xlink:label="lab_us-gaap_LandMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LandMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LandMember" xlink:to="lab_us-gaap_LandMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_019e1743-aa65-7107-8270-2b21ad6ee145_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_019e1743-a9d5-7e1d-b9fc-1e3bae9d494a_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueLineItems_019e1743-a9d5-765d-95db-6c2d07a7a800_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disaggregation of Revenue [Line Items]</link:label>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueLineItems_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disaggregation of Revenue [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems" xlink:to="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems_019e1743-a9d5-7c6b-932f-0678067deecb_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan Disclosure [Line Items]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan Disclosure [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LoganTownshipNJ1Member_019e1743-aaf8-780b-9c7c-3874f2453e89_terseLabel_en-US" xlink:label="lab_art_LoganTownshipNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Logan Township, NJ</link:label>
    <link:label id="lab_art_LoganTownshipNJ1Member_label_en-US" xlink:label="lab_art_LoganTownshipNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Logan Township, NJ 1 [Member]</link:label>
    <link:label id="lab_art_LoganTownshipNJ1Member_documentation_en-US" xlink:label="lab_art_LoganTownshipNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Logan Township, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LoganTownshipNJ1Member" xlink:href="art-20260806.xsd#art_LoganTownshipNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LoganTownshipNJ1Member" xlink:to="lab_art_LoganTownshipNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LisbonMember_019e1743-a9d5-7e2c-9053-c42a8ca6fef7_terseLabel_en-US" xlink:label="lab_art_LisbonMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lisbon</link:label>
    <link:label id="lab_art_LisbonMember_label_en-US" xlink:label="lab_art_LisbonMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lisbon [Member]</link:label>
    <link:label id="lab_art_LisbonMember_documentation_en-US" xlink:label="lab_art_LisbonMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lisbon</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LisbonMember" xlink:href="art-20260806.xsd#art_LisbonMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LisbonMember" xlink:to="lab_art_LisbonMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanTypeDomain_019e1743-a9d5-7e1b-bac0-85f9273bf0b0_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Plan Type [Domain]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanTypeDomain_label_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanTypeDomain" xlink:to="lab_us-gaap_RetirementPlanTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrightonDenver2CO1Member_019e1743-aa65-7f28-8e96-4697f4f2e748_terseLabel_en-US" xlink:label="lab_art_BrightonDenver2CO1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brighton (Denver 2), CO</link:label>
    <link:label id="lab_art_BrightonDenver2CO1Member_label_en-US" xlink:label="lab_art_BrightonDenver2CO1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brighton (Denver 2), CO 1 [Member]</link:label>
    <link:label id="lab_art_BrightonDenver2CO1Member_documentation_en-US" xlink:label="lab_art_BrightonDenver2CO1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brighton (Denver 2), CO 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrightonDenver2CO1Member" xlink:href="art-20260806.xsd#art_BrightonDenver2CO1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrightonDenver2CO1Member" xlink:to="lab_art_BrightonDenver2CO1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_019e1743-ab7d-77c0-846d-c96a8008b75d_terseLabel_en-US" xlink:label="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]</link:label>
    <link:label id="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_label_en-US" xlink:label="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract" xlink:to="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential_019e1743-a921-7492-97ae-8a41fe61c2f7_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other Foreign Jurisdictions</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAssetsDisclosureTextBlock_019e1743-a921-7e44-b924-43ddc30f802f_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Assets</link:label>
    <link:label id="lab_us-gaap_OtherAssetsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_OtherAssetsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsDisclosureTextBlock" xlink:to="lab_us-gaap_OtherAssetsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PerryvilleMD2Member_019e1743-ab7d-75de-b337-c7855814b09b_terseLabel_en-US" xlink:label="lab_art_PerryvilleMD2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Perryville, MD</link:label>
    <link:label id="lab_art_PerryvilleMD2Member_label_en-US" xlink:label="lab_art_PerryvilleMD2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Perryville, MD 2 [Member]</link:label>
    <link:label id="lab_art_PerryvilleMD2Member_documentation_en-US" xlink:label="lab_art_PerryvilleMD2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Perryville, MD 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PerryvilleMD2Member" xlink:href="art-20260806.xsd#art_PerryvilleMD2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PerryvilleMD2Member" xlink:to="lab_art_PerryvilleMD2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EuroInterbankOfferedRateMember_019e1743-aa65-70fe-beee-b99e7cd7fde1_terseLabel_en-US" xlink:label="lab_art_EuroInterbankOfferedRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">EURIBOR</link:label>
    <link:label id="lab_art_EuroInterbankOfferedRateMember_label_en-US" xlink:label="lab_art_EuroInterbankOfferedRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Euro Interbank Offered Rate [Member]</link:label>
    <link:label id="lab_art_EuroInterbankOfferedRateMember_documentation_en-US" xlink:label="lab_art_EuroInterbankOfferedRateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Euro Interbank Offered Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EuroInterbankOfferedRateMember" xlink:href="art-20260806.xsd#art_EuroInterbankOfferedRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EuroInterbankOfferedRateMember" xlink:to="lab_art_EuroInterbankOfferedRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member_019e1743-a921-7ca5-8e81-cd4b9bc656e1_terseLabel_en-US" xlink:label="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bridge Loan Agreement With RSA Joint Venture, Phase 3</link:label>
    <link:label id="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member_label_en-US" xlink:label="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bridge Loan Agreement With RSA Joint Venture, Phase 3 [Member]</link:label>
    <link:label id="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member_documentation_en-US" xlink:label="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bridge Loan Agreement With RSA Joint Venture, Phase 3</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member" xlink:href="art-20260806.xsd#art_BridgeLoanAgreementWithRSAJointVenturePhase3Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member" xlink:to="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase3Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment_019e1743-a921-758b-992a-cf7ce37615d0_terseLabel_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other comprehensive (loss) income</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment_label_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Net Of Tax, Portion Attributable To Parent, Excluding Hyperinflation Adjustment</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment_documentation_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Net Of Tax, Portion Attributable To Parent, Excluding Hyperinflation Adjustment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment" xlink:href="art-20260806.xsd#art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment" xlink:to="lab_art_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentExcludingHyperinflationAdjustment" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairmontCityIL1Member_019e1743-aaf8-75c9-9474-509a0a709594_terseLabel_en-US" xlink:label="lab_art_FairmontCityIL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fairmont City, IL</link:label>
    <link:label id="lab_art_FairmontCityIL1Member_label_en-US" xlink:label="lab_art_FairmontCityIL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fairmont City, IL 1 [Member]</link:label>
    <link:label id="lab_art_FairmontCityIL1Member_documentation_en-US" xlink:label="lab_art_FairmontCityIL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fairmont City, IL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairmontCityIL1Member" xlink:href="art-20260806.xsd#art_FairmontCityIL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairmontCityIL1Member" xlink:to="lab_art_FairmontCityIL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenuesAbstract_019e1743-aa65-78f6-abe1-6f8309bb5b92_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues:</link:label>
    <link:label id="lab_us-gaap_RevenuesAbstract_label_en-US" xlink:label="lab_us-gaap_RevenuesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenuesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuesAbstract" xlink:to="lab_us-gaap_RevenuesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries_019e1743-aaf8-761d-8526-ea5c7690ba83_terseLabel_en-US" xlink:label="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cyber incident related costs, net of insurance recoveries</link:label>
    <link:label id="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries_label_en-US" xlink:label="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acquisition, Cyber Incident Related Costs, Net of Insurance Recoveries</link:label>
    <link:label id="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries_documentation_en-US" xlink:label="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Acquisition, Cyber Incident Related Costs, Net of Insurance Recoveries</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries" xlink:href="art-20260806.xsd#art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries" xlink:to="lab_art_AcquisitionCyberIncidentRelatedCostsNetOfInsuranceRecoveries" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanSponsorLocationDomain_019e1743-aa65-7cf3-8aa7-55481e71fb0a_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Plan Sponsor Location [Domain]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanSponsorLocationDomain_label_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Sponsor Location [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain" xlink:to="lab_us-gaap_RetirementPlanSponsorLocationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MississaugaSurveyorMember_019e1743-aaf8-7570-8011-21c1c769de8a_terseLabel_en-US" xlink:label="lab_art_MississaugaSurveyorMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mississauga Surveyor</link:label>
    <link:label id="lab_art_MississaugaSurveyorMember_label_en-US" xlink:label="lab_art_MississaugaSurveyorMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mississauga Surveyor [Member]</link:label>
    <link:label id="lab_art_MississaugaSurveyorMember_documentation_en-US" xlink:label="lab_art_MississaugaSurveyorMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mississauga Surveyor</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MississaugaSurveyorMember" xlink:href="art-20260806.xsd#art_MississaugaSurveyorMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MississaugaSurveyorMember" xlink:to="lab_art_MississaugaSurveyorMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount_019e1743-aa65-7e76-ac7a-178dab97a356_terseLabel_en-US" xlink:label="lab_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum contribution to multiemployer plan</link:label>
    <link:label id="lab_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount_label_en-US" xlink:label="lab_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plan, Pension, Significant, Future Employer Contribution, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount" xlink:to="lab_us-gaap_MultiemployerPlanPensionSignificantFutureEmployerContributionAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredIncomeTaxLiabilities_019e1743-a922-7ed4-b6de-899f82954c9e_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilities" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xml:lang="en-US">Total gross deferred tax liabilities</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxLiabilities_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxLiabilities" xlink:to="lab_us-gaap_DeferredIncomeTaxLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_019e1743-aaf8-70fb-9918-d7894a7abcfd_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BankBillSwapRateMember_019e1743-ab7d-7610-a6ee-22c371a29285_terseLabel_en-US" xlink:label="lab_art_BankBillSwapRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">BBSW</link:label>
    <link:label id="lab_art_BankBillSwapRateMember_label_en-US" xlink:label="lab_art_BankBillSwapRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bank Bill Swap Rate [Member]</link:label>
    <link:label id="lab_art_BankBillSwapRateMember_documentation_en-US" xlink:label="lab_art_BankBillSwapRateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bank Bill Swap Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BankBillSwapRateMember" xlink:href="art-20260806.xsd#art_BankBillSwapRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BankBillSwapRateMember" xlink:to="lab_art_BankBillSwapRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition_019e1743-aaf8-7324-9cbf-042a745bb043_terseLabel_en-US" xlink:label="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss from partial investment pre-acquisition</link:label>
    <link:label id="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition_label_en-US" xlink:label="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) From Disposal Of Discontinued Operation From Partial Investment Pre-Acquisition</link:label>
    <link:label id="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition_documentation_en-US" xlink:label="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gain (Loss) From Disposal Of Discontinued Operation From Partial Investment Pre-Acquisition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition" xlink:href="art-20260806.xsd#art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition" xlink:to="lab_art_GainLossFromDisposalOfDiscontinuedOperationFromPartialInvestmentPreAcquisition" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VictorvilleCA2Member_019e1743-aaf8-7b6d-9ffc-d5a2eb7cee03_terseLabel_en-US" xlink:label="lab_art_VictorvilleCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Victorville, CA</link:label>
    <link:label id="lab_art_VictorvilleCA2Member_label_en-US" xlink:label="lab_art_VictorvilleCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Victorville, CA 2 [Member]</link:label>
    <link:label id="lab_art_VictorvilleCA2Member_documentation_en-US" xlink:label="lab_art_VictorvilleCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Victorville, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VictorvilleCA2Member" xlink:href="art-20260806.xsd#art_VictorvilleCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VictorvilleCA2Member" xlink:to="lab_art_VictorvilleCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ColumbiaSC1Member_019e1743-aa65-7bf0-a06a-875f1420540a_terseLabel_en-US" xlink:label="lab_art_ColumbiaSC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Columbia, SC</link:label>
    <link:label id="lab_art_ColumbiaSC1Member_label_en-US" xlink:label="lab_art_ColumbiaSC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Columbia, SC 1 [Member]</link:label>
    <link:label id="lab_art_ColumbiaSC1Member_documentation_en-US" xlink:label="lab_art_ColumbiaSC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Columbia, SC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ColumbiaSC1Member" xlink:href="art-20260806.xsd#art_ColumbiaSC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ColumbiaSC1Member" xlink:to="lab_art_ColumbiaSC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges_019e1743-ab7d-7c8a-af90-2b6fd2e06e99_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impact of foreign exchange rate changes</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Foreign Exchange Rate Changes</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Foreign Exchange Rate Changes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesForeignExchangeRateChanges" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SuffieldCTMember_019e1743-a921-7712-9145-c384847480ac_terseLabel_en-US" xlink:label="lab_art_SuffieldCTMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Suffield, CT</link:label>
    <link:label id="lab_art_SuffieldCTMember_label_en-US" xlink:label="lab_art_SuffieldCTMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Suffield, CT [Member]</link:label>
    <link:label id="lab_art_SuffieldCTMember_documentation_en-US" xlink:label="lab_art_SuffieldCTMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Suffield, CT</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SuffieldCTMember" xlink:href="art-20260806.xsd#art_SuffieldCTMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SuffieldCTMember" xlink:to="lab_art_SuffieldCTMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OPUnitsMember_019e1743-ab7d-7a40-9850-c3f900c12b01_terseLabel_en-US" xlink:label="lab_art_OPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Partnership units</link:label>
    <link:label id="lab_art_OPUnitsMember_label_en-US" xlink:label="lab_art_OPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">OP Units [Member]</link:label>
    <link:label id="lab_art_OPUnitsMember_documentation_en-US" xlink:label="lab_art_OPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">OP Units [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OPUnitsMember" xlink:href="art-20260806.xsd#art_OPUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OPUnitsMember" xlink:to="lab_art_OPUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_019e1743-aa65-7ed4-9d07-b75ca4c9fe5a_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureTextBlock" xlink:to="lab_us-gaap_DebtDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SebreeKY2Member_019e1743-aaf8-7af3-ae98-a5513791666d_terseLabel_en-US" xlink:label="lab_art_SebreeKY2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sebree, KY</link:label>
    <link:label id="lab_art_SebreeKY2Member_label_en-US" xlink:label="lab_art_SebreeKY2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sebree, KY 2 [Member]</link:label>
    <link:label id="lab_art_SebreeKY2Member_documentation_en-US" xlink:label="lab_art_SebreeKY2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sebree, KY 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SebreeKY2Member" xlink:href="art-20260806.xsd#art_SebreeKY2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SebreeKY2Member" xlink:to="lab_art_SebreeKY2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DividendsPayableCurrentAndNoncurrent_019e1743-ab7d-77f3-b2a6-7dc36efbeeaf_terseLabel_en-US" xlink:label="lab_us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dividends payable</link:label>
    <link:label id="lab_us-gaap_DividendsPayableCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:to="lab_us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfSeniorDebt_019e1743-a922-7be5-84bc-e1ce84d6dc99_terseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfSeniorDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Repayments of senior notes</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfSeniorDebt_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfSeniorDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Senior Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSeniorDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfSeniorDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfSeniorDebt" xlink:to="lab_us-gaap_RepaymentsOfSeniorDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_019e1743-a921-785e-bf6d-71b77fad3225_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies</link:label>
    <link:label id="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:to="lab_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_019e1743-aaf8-7f18-bffa-34f863df32da_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Revenue</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e1743-aa65-7a60-bafa-0e99c2fc4949_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average common stock outstanding &#8211; diluted (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019e1743-aa65-76d9-82df-f19766549a41_totalLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Weighted average common shares outstanding &#8211; diluted (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Diluted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SouthPlainfieldNJ1Member_019e1743-aaf8-73ac-a5f7-bab79d2e460d_terseLabel_en-US" xlink:label="lab_art_SouthPlainfieldNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">South Plainfield, NJ</link:label>
    <link:label id="lab_art_SouthPlainfieldNJ1Member_label_en-US" xlink:label="lab_art_SouthPlainfieldNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">South Plainfield, NJ 1 [Member]</link:label>
    <link:label id="lab_art_SouthPlainfieldNJ1Member_documentation_en-US" xlink:label="lab_art_SouthPlainfieldNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">South Plainfield, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SouthPlainfieldNJ1Member" xlink:href="art-20260806.xsd#art_SouthPlainfieldNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SouthPlainfieldNJ1Member" xlink:to="lab_art_SouthPlainfieldNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeTable_019e1743-aa65-7c7c-8a21-ebd7b606678a_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative [Table]</link:label>
    <link:label id="lab_us-gaap_DerivativeTable_label_en-US" xlink:label="lab_us-gaap_DerivativeTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeTable" xlink:to="lab_us-gaap_DerivativeTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewportMN2Member_019e1743-aa65-7572-bfde-eac88663d299_terseLabel_en-US" xlink:label="lab_art_NewportMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Newport, MN</link:label>
    <link:label id="lab_art_NewportMN2Member_label_en-US" xlink:label="lab_art_NewportMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Newport, MN 2 [Member]</link:label>
    <link:label id="lab_art_NewportMN2Member_documentation_en-US" xlink:label="lab_art_NewportMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Newport, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewportMN2Member" xlink:href="art-20260806.xsd#art_NewportMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewportMN2Member" xlink:to="lab_art_NewportMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GouldsboroPA1Member_019e1743-a9d5-7513-a379-e961a23a0000_terseLabel_en-US" xlink:label="lab_art_GouldsboroPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gouldsboro, PA</link:label>
    <link:label id="lab_art_GouldsboroPA1Member_label_en-US" xlink:label="lab_art_GouldsboroPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gouldsboro, PA 1 [Member]</link:label>
    <link:label id="lab_art_GouldsboroPA1Member_documentation_en-US" xlink:label="lab_art_GouldsboroPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gouldsboro, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GouldsboroPA1Member" xlink:href="art-20260806.xsd#art_GouldsboroPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GouldsboroPA1Member" xlink:to="lab_art_GouldsboroPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue_019e1743-a9d5-7cdf-93ee-439a5ecddde1_totalLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total minimum payments</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VinelandNJ1Member_019e1743-aa65-7913-8a2f-45cb3af273eb_terseLabel_en-US" xlink:label="lab_art_VinelandNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vineland, NJ</link:label>
    <link:label id="lab_art_VinelandNJ1Member_label_en-US" xlink:label="lab_art_VinelandNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vineland, NJ 1 [Member]</link:label>
    <link:label id="lab_art_VinelandNJ1Member_documentation_en-US" xlink:label="lab_art_VinelandNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vineland, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VinelandNJ1Member" xlink:href="art-20260806.xsd#art_VinelandNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VinelandNJ1Member" xlink:to="lab_art_VinelandNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Brampton1Member_019e1743-aa65-79bb-bba2-ecdcf4cae5d9_terseLabel_en-US" xlink:label="lab_art_Brampton1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brampton</link:label>
    <link:label id="lab_art_Brampton1Member_label_en-US" xlink:label="lab_art_Brampton1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brampton 1 [Member]</link:label>
    <link:label id="lab_art_Brampton1Member_documentation_en-US" xlink:label="lab_art_Brampton1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brampton 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Brampton1Member" xlink:href="art-20260806.xsd#art_Brampton1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Brampton1Member" xlink:to="lab_art_Brampton1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentPeriodEndDate_019e1743-aaf8-72d6-8296-ccdad7e8aa7b_terseLabel_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Period End Date</link:label>
    <link:label id="lab_dei_DocumentPeriodEndDate_label_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Period End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentPeriodEndDate" xlink:to="lab_dei_DocumentPeriodEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TarboroNC1Member_019e1743-a9d5-7e8e-b3a4-ab473916c4bc_terseLabel_en-US" xlink:label="lab_art_TarboroNC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tarboro, NC</link:label>
    <link:label id="lab_art_TarboroNC1Member_label_en-US" xlink:label="lab_art_TarboroNC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tarboro, NC 1 [Member]</link:label>
    <link:label id="lab_art_TarboroNC1Member_documentation_en-US" xlink:label="lab_art_TarboroNC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tarboro, NC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TarboroNC1Member" xlink:href="art-20260806.xsd#art_TarboroNC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TarboroNC1Member" xlink:to="lab_art_TarboroNC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_019e1743-aa65-7a85-a0e8-9c47d4c51fa9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, allowance</link:label>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_019e1743-aa65-7186-b750-bd933833b006_periodStartLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance at beginning of year</link:label>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_019e1743-aa65-76e0-9331-ea2b3d6fdd80_periodEndLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance at end of year</link:label>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:to="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture_019e1743-a9d5-7cd9-b043-ec7c20a4f8f7_negatedTerseLabel_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Reclassification of CTA to earnings upon sale of partially owned entity</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture_label_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Reclassification, Derecognition Of Cumulative Foreign Currency Translation Upon Deconsolidation Of Entity Contributed To a Joint Venture</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture_documentation_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Reclassification, Derecognition Of Cumulative Foreign Currency Translation Upon Deconsolidation Of Entity Contributed To a Joint Venture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture" xlink:href="art-20260806.xsd#art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture" xlink:to="lab_art_OtherComprehensiveIncomeLossReclassificationDerecognitionOfCumulativeForeignCurrencyTranslationUponDeconsolidationOfEntityContributedToAJointVenture" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDue_019e1743-ab7d-7197-bea6-62fd600b6e06_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total future minimum lease payments</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDue_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDue" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDue" xlink:to="lab_art_LeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_019e1743-aaf8-7ba6-b539-8ba477bda498_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating lease liabilities</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Operating Lease Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e1743-aa64-72f5-b91d-c4444a7d0032_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total equity</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e1743-aa64-7019-a362-3fe748fb2bc2_periodStartLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning balance</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019e1743-aa64-7be7-9f9e-8e64dfc87e8a_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending balance</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity, Including Portion Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_019e1743-a921-71cc-b866-a821f83a0cc3_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total outstanding restricted stock units (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_019e1743-a921-731a-95d1-bb874a15e3a1_totalLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total outstanding restricted stock units (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_019e1743-aaf8-723c-9ced-2b6e02ec7f2f_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss per Common Share</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareTextBlock" xlink:to="lab_us-gaap_EarningsPerShareTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CartersvilleGA2Member_019e1743-ab7d-7d0c-878c-9a59e6da5c31_terseLabel_en-US" xlink:label="lab_art_CartersvilleGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cartersville, GA</link:label>
    <link:label id="lab_art_CartersvilleGA2Member_label_en-US" xlink:label="lab_art_CartersvilleGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cartersville, GA 2 [Member]</link:label>
    <link:label id="lab_art_CartersvilleGA2Member_documentation_en-US" xlink:label="lab_art_CartersvilleGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cartersville, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CartersvilleGA2Member" xlink:href="art-20260806.xsd#art_CartersvilleGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CartersvilleGA2Member" xlink:to="lab_art_CartersvilleGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdditionalPaidInCapital_019e1743-aaf8-7519-9f49-1ba58a7ee79f_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapital" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Paid-in capital</link:label>
    <link:label id="lab_us-gaap_AdditionalPaidInCapital_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapital" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Paid in Capital</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapital" xlink:to="lab_us-gaap_AdditionalPaidInCapital" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductOrServiceAxis_019e1743-aa65-73a7-ae5a-6c1d8caec6ce_terseLabel_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Product and Service [Axis]</link:label>
    <link:label id="lab_srt_ProductOrServiceAxis_label_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Product and Service [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductOrServiceAxis" xlink:to="lab_srt_ProductOrServiceAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LancasterPA2Member_019e1743-aa65-7a46-97ed-521efbbb7312_terseLabel_en-US" xlink:label="lab_art_LancasterPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lancaster, PA</link:label>
    <link:label id="lab_art_LancasterPA2Member_label_en-US" xlink:label="lab_art_LancasterPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lancaster, PA 2 [Member]</link:label>
    <link:label id="lab_art_LancasterPA2Member_documentation_en-US" xlink:label="lab_art_LancasterPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lancaster, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LancasterPA2Member" xlink:href="art-20260806.xsd#art_LancasterPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LancasterPA2Member" xlink:to="lab_art_LancasterPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_St.PaulMN1Member_019e1743-a9d5-7dbd-9ffd-c86501e54177_terseLabel_en-US" xlink:label="lab_art_St.PaulMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">St. Paul, MN</link:label>
    <link:label id="lab_art_St.PaulMN1Member_label_en-US" xlink:label="lab_art_St.PaulMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">St. Paul, MN 1 [Member]</link:label>
    <link:label id="lab_art_St.PaulMN1Member_documentation_en-US" xlink:label="lab_art_St.PaulMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">St. Paul, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_St.PaulMN1Member" xlink:href="art-20260806.xsd#art_St.PaulMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_St.PaulMN1Member" xlink:to="lab_art_St.PaulMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Ft.WorthTXMeacham2Member_019e1743-a922-7c2a-90c7-b8949f32582f_terseLabel_en-US" xlink:label="lab_art_Ft.WorthTXMeacham2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Meacham)</link:label>
    <link:label id="lab_art_Ft.WorthTXMeacham2Member_label_en-US" xlink:label="lab_art_Ft.WorthTXMeacham2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Meacham) 2 [Member]</link:label>
    <link:label id="lab_art_Ft.WorthTXMeacham2Member_documentation_en-US" xlink:label="lab_art_Ft.WorthTXMeacham2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Meacham) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Ft.WorthTXMeacham2Member" xlink:href="art-20260806.xsd#art_Ft.WorthTXMeacham2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Ft.WorthTXMeacham2Member" xlink:to="lab_art_Ft.WorthTXMeacham2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MonmouthIL1Member_019e1743-aaf8-7641-b3b5-e493ff87f5da_terseLabel_en-US" xlink:label="lab_art_MonmouthIL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Monmouth, IL</link:label>
    <link:label id="lab_art_MonmouthIL1Member_label_en-US" xlink:label="lab_art_MonmouthIL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Monmouth, IL 1 [Member]</link:label>
    <link:label id="lab_art_MonmouthIL1Member_documentation_en-US" xlink:label="lab_art_MonmouthIL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Monmouth, IL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MonmouthIL1Member" xlink:href="art-20260806.xsd#art_MonmouthIL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MonmouthIL1Member" xlink:to="lab_art_MonmouthIL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Massillon17thOH1Member_019e1743-aa64-7716-8ff8-094885469be7_terseLabel_en-US" xlink:label="lab_art_Massillon17thOH1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Massillon 17th, OH</link:label>
    <link:label id="lab_art_Massillon17thOH1Member_label_en-US" xlink:label="lab_art_Massillon17thOH1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Massillon 17th, OH 1 [Member]</link:label>
    <link:label id="lab_art_Massillon17thOH1Member_documentation_en-US" xlink:label="lab_art_Massillon17thOH1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Massillon 17th, OH 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Massillon17thOH1Member" xlink:href="art-20260806.xsd#art_Massillon17thOH1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Massillon17thOH1Member" xlink:to="lab_art_Massillon17thOH1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RangeAxis_019e1743-ab7d-74e7-a22d-b00cc45a664b_terseLabel_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:label id="lab_srt_RangeAxis_label_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeAxis" xlink:to="lab_srt_RangeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GrandPrairieTX2Member_019e1743-a9d5-7ba3-9271-d7cdf335804e_terseLabel_en-US" xlink:label="lab_art_GrandPrairieTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Grand Prairie, TX</link:label>
    <link:label id="lab_art_GrandPrairieTX2Member_label_en-US" xlink:label="lab_art_GrandPrairieTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Grand Prairie, TX 2 [Member]</link:label>
    <link:label id="lab_art_GrandPrairieTX2Member_documentation_en-US" xlink:label="lab_art_GrandPrairieTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Grand Prairie, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GrandPrairieTX2Member" xlink:href="art-20260806.xsd#art_GrandPrairieTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GrandPrairieTX2Member" xlink:to="lab_art_GrandPrairieTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LossContingencyAccrualAtCarryingValue_019e1743-aaf8-7a76-a8ce-5b6e19bfbe75_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyAccrualAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss contingency accrual</link:label>
    <link:label id="lab_us-gaap_LossContingencyAccrualAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_LossContingencyAccrualAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency Accrual</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyAccrualAtCarryingValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyAccrualAtCarryingValue" xlink:to="lab_us-gaap_LossContingencyAccrualAtCarryingValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SalinasCA2Member_019e1743-aa65-7828-acf9-6bb872ca3bfd_terseLabel_en-US" xlink:label="lab_art_SalinasCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Salinas, CA</link:label>
    <link:label id="lab_art_SalinasCA2Member_label_en-US" xlink:label="lab_art_SalinasCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Salinas, CA 2 [Member]</link:label>
    <link:label id="lab_art_SalinasCA2Member_documentation_en-US" xlink:label="lab_art_SalinasCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Salinas, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SalinasCA2Member" xlink:href="art-20260806.xsd#art_SalinasCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SalinasCA2Member" xlink:to="lab_art_SalinasCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeFixedInterestRate_019e1743-a9d5-7313-83d1-70400fd49978_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFixedInterestRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fixed Base Interest Rate Swap</link:label>
    <link:label id="lab_us-gaap_DerivativeFixedInterestRate_label_en-US" xlink:label="lab_us-gaap_DerivativeFixedInterestRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Fixed Interest Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeFixedInterestRate" xlink:to="lab_us-gaap_DerivativeFixedInterestRate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member_019e1743-aaf8-7118-ada4-28fb6694cd39_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 3</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 3 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 3</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member" xlink:to="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche3Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_019e1743-a9d5-7c37-8e46-efe1b5f5692c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intrinsic value of options exercised</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GreenBayWI1Member_019e1743-aaf8-7291-96e0-2d6c45ab4d82_terseLabel_en-US" xlink:label="lab_art_GreenBayWI1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Green Bay, WI</link:label>
    <link:label id="lab_art_GreenBayWI1Member_label_en-US" xlink:label="lab_art_GreenBayWI1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Green Bay, WI 1 [Member]</link:label>
    <link:label id="lab_art_GreenBayWI1Member_documentation_en-US" xlink:label="lab_art_GreenBayWI1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Green Bay, WI 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GreenBayWI1Member" xlink:href="art-20260806.xsd#art_GreenBayWI1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GreenBayWI1Member" xlink:to="lab_art_GreenBayWI1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_PreCommencementTenderOffer_019fcfa6-ece2-7876-8eb1-2b70c07163ea_terseLabel_en-US" xlink:label="lab_dei_PreCommencementTenderOffer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pre-commencement Tender Offer</link:label>
    <link:label id="lab_dei_PreCommencementTenderOffer_label_en-US" xlink:label="lab_dei_PreCommencementTenderOffer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pre-commencement Tender Offer</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_PreCommencementTenderOffer" xlink:to="lab_dei_PreCommencementTenderOffer" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ModestoCA1Member_019e1743-a9d5-7d6b-9d1f-8fd34b3ddbca_terseLabel_en-US" xlink:label="lab_art_ModestoCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Modesto, CA</link:label>
    <link:label id="lab_art_ModestoCA1Member_label_en-US" xlink:label="lab_art_ModestoCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Modesto, CA 1 [Member]</link:label>
    <link:label id="lab_art_ModestoCA1Member_documentation_en-US" xlink:label="lab_art_ModestoCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Modesto, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ModestoCA1Member" xlink:href="art-20260806.xsd#art_ModestoCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ModestoCA1Member" xlink:to="lab_art_ModestoCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember_019e1743-aa64-770e-ae65-1aaac71ebf15_terseLabel_en-US" xlink:label="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Central States SE &amp; SW Areas Health and Welfare Pension Plans</link:label>
    <link:label id="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember_label_en-US" xlink:label="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Central States SE &amp; SW Areas Health and Welfare Pension Plans [Member]</link:label>
    <link:label id="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember_documentation_en-US" xlink:label="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Central States SE &amp; SW Areas Health and Welfare Pension Plans [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember" xlink:href="art-20260806.xsd#art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember" xlink:to="lab_art_CentralStatesSESWAreasHealthandWelfarePensionPlansMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueInputsLevel1Member_019e1743-a9d5-72c9-a8c4-cae07638ffec_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Level 1</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel1Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 1 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel1Member" xlink:to="lab_us-gaap_FairValueInputsLevel1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCredit_019e1743-ab7d-7fb7-956f-04e691d400ef_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Borrowings under revolving line of credit</link:label>
    <link:label id="lab_us-gaap_LineOfCredit_label_en-US" xlink:label="lab_us-gaap_LineOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Line of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCredit" xlink:to="lab_us-gaap_LineOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_019e1743-aaf8-7781-80ad-7203fca31c22_totalLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Diluted loss per share (in USD per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Diluted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareDiluted" xlink:to="lab_us-gaap_EarningsPerShareDiluted" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SinesMember_019e1743-aa65-74b4-89d3-782d2945ede1_terseLabel_en-US" xlink:label="lab_art_SinesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sines</link:label>
    <link:label id="lab_art_SinesMember_label_en-US" xlink:label="lab_art_SinesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sines [Member]</link:label>
    <link:label id="lab_art_SinesMember_documentation_en-US" xlink:label="lab_art_SinesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sines</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SinesMember" xlink:href="art-20260806.xsd#art_SinesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SinesMember" xlink:to="lab_art_SinesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SpaldingBowmanMember_019e1743-a9d5-7ffa-8cde-57ca1de686fa_terseLabel_en-US" xlink:label="lab_art_SpaldingBowmanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Spalding - Bowman</link:label>
    <link:label id="lab_art_SpaldingBowmanMember_label_en-US" xlink:label="lab_art_SpaldingBowmanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Spalding - Bowman [Member]</link:label>
    <link:label id="lab_art_SpaldingBowmanMember_documentation_en-US" xlink:label="lab_art_SpaldingBowmanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Spalding - Bowman</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SpaldingBowmanMember" xlink:href="art-20260806.xsd#art_SpaldingBowmanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SpaldingBowmanMember" xlink:to="lab_art_SpaldingBowmanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived_019e1743-a922-7be5-9458-39a9689889e7_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">State</link:label>
    <link:label id="lab_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Paid, State and Local, after Refund Received</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived" xlink:to="lab_us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationLineItems_019e1743-aa65-7b2e-8a35-b45248c6d6ee_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationLineItems_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_019e1743-a9d5-786e-b7c7-d8f723b55df9_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_label_en-US" xlink:label="lab_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:to="lab_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RevenuePerformanceObligationPaymentTerms_019e1743-aaf8-75f4-9c0a-6c968b5d2092_terseLabel_en-US" xlink:label="lab_art_RevenuePerformanceObligationPaymentTerms" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payment terms</link:label>
    <link:label id="lab_art_RevenuePerformanceObligationPaymentTerms_label_en-US" xlink:label="lab_art_RevenuePerformanceObligationPaymentTerms" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Performance Obligation, Payment Terms</link:label>
    <link:label id="lab_art_RevenuePerformanceObligationPaymentTerms_documentation_en-US" xlink:label="lab_art_RevenuePerformanceObligationPaymentTerms" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Revenue, Performance Obligation, Payment Terms</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RevenuePerformanceObligationPaymentTerms" xlink:href="art-20260806.xsd#art_RevenuePerformanceObligationPaymentTerms"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RevenuePerformanceObligationPaymentTerms" xlink:to="lab_art_RevenuePerformanceObligationPaymentTerms" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock_019e1743-ab7d-7bd0-a96a-1e2193cd7d37_terseLabel_en-US" xlink:label="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Basis of Presentation and Principles of Consolidation</link:label>
    <link:label id="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock_label_en-US" xlink:label="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basis Of Presentation And Consolidation, Policy [Policy Text Block]</link:label>
    <link:label id="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock_documentation_en-US" xlink:label="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Basis of Presentation and Consolidation, Policy</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock" xlink:href="art-20260806.xsd#art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock" xlink:to="lab_art_BasisOfPresentationAndConsolidationPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses_019e1743-aaf8-750f-9ee1-0e4bc2c7ed3a_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Goodwill Impairment</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:to="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PrepaidExpenseCurrentAndNoncurrent_019e1743-aaf8-73bb-aadb-4c6c086441a6_terseLabel_en-US" xlink:label="lab_us-gaap_PrepaidExpenseCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prepaid assets</link:label>
    <link:label id="lab_us-gaap_PrepaidExpenseCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_PrepaidExpenseCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidExpenseCurrentAndNoncurrent" xlink:to="lab_us-gaap_PrepaidExpenseCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss_019e1743-aaf8-7480-ab22-1020da3bb3e2_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Actuarial (loss) gain</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:to="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_art_IntercompanyLoanPayableMember_019e1743-aaf8-7f95-820d-f163f9b262f6_terseLabel_en-US" xlink:label="lab_art_IntercompanyLoanPayableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany Loan Payable</link:label>
    <link:label id="lab_art_IntercompanyLoanPayableMember_label_en-US" xlink:label="lab_art_IntercompanyLoanPayableMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intercompany Loan Payable [Member]</link:label>
    <link:label id="lab_art_IntercompanyLoanPayableMember_documentation_en-US" xlink:label="lab_art_IntercompanyLoanPayableMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Intercompany Loan Payable [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_IntercompanyLoanPayableMember" xlink:href="art-20260806.xsd#art_IntercompanyLoanPayableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_IntercompanyLoanPayableMember" xlink:to="lab_art_IntercompanyLoanPayableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_019e1743-aaf8-7b30-9a93-1b3732730ff4_negatedLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: Interest</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PedricktownNJ2Member_019e1743-a9d5-7d38-bef4-14218f2b56af_terseLabel_en-US" xlink:label="lab_art_PedricktownNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pedricktown, NJ</link:label>
    <link:label id="lab_art_PedricktownNJ2Member_label_en-US" xlink:label="lab_art_PedricktownNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pedricktown, NJ 2 [Member]</link:label>
    <link:label id="lab_art_PedricktownNJ2Member_documentation_en-US" xlink:label="lab_art_PedricktownNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pedricktown, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PedricktownNJ2Member" xlink:href="art-20260806.xsd#art_PedricktownNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PedricktownNJ2Member" xlink:to="lab_art_PedricktownNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WichitaKS2Member_019e1743-aaf8-76a5-a537-ce0a3797132c_terseLabel_en-US" xlink:label="lab_art_WichitaKS2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wichita, KS</link:label>
    <link:label id="lab_art_WichitaKS2Member_label_en-US" xlink:label="lab_art_WichitaKS2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wichita, KS 2 [Member]</link:label>
    <link:label id="lab_art_WichitaKS2Member_documentation_en-US" xlink:label="lab_art_WichitaKS2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Wichita, KS 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WichitaKS2Member" xlink:href="art-20260806.xsd#art_WichitaKS2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WichitaKS2Member" xlink:to="lab_art_WichitaKS2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther_019e1743-a921-7729-b03d-69299e3f2a7d_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeesportPA2Member_019e1743-aaf8-781d-8b53-7e9bec5f55ad_terseLabel_en-US" xlink:label="lab_art_LeesportPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Leesport, PA</link:label>
    <link:label id="lab_art_LeesportPA2Member_label_en-US" xlink:label="lab_art_LeesportPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leesport, PA 2 [Member]</link:label>
    <link:label id="lab_art_LeesportPA2Member_documentation_en-US" xlink:label="lab_art_LeesportPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Leesport, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeesportPA2Member" xlink:href="art-20260806.xsd#art_LeesportPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeesportPA2Member" xlink:to="lab_art_LeesportPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ChesapeakeVA1Member_019e1743-aa65-7bcf-9df3-b84ef14175e9_terseLabel_en-US" xlink:label="lab_art_ChesapeakeVA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chesapeake, VA</link:label>
    <link:label id="lab_art_ChesapeakeVA1Member_label_en-US" xlink:label="lab_art_ChesapeakeVA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chesapeake, VA 1 [Member]</link:label>
    <link:label id="lab_art_ChesapeakeVA1Member_documentation_en-US" xlink:label="lab_art_ChesapeakeVA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chesapeake, VA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ChesapeakeVA1Member" xlink:href="art-20260806.xsd#art_ChesapeakeVA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ChesapeakeVA1Member" xlink:to="lab_art_ChesapeakeVA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member_019e1743-a9d5-7bf6-a938-343b68fab012_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 6</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 6 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 6</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member" xlink:to="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche6Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_019e1743-ab7d-706f-a8ba-4c9e6abda806_totalLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total future minimum lease payments</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GardenCityKS2Member_019e1743-a922-79a2-a152-0a17ce757532_terseLabel_en-US" xlink:label="lab_art_GardenCityKS2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Garden City, KS</link:label>
    <link:label id="lab_art_GardenCityKS2Member_label_en-US" xlink:label="lab_art_GardenCityKS2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Garden City, KS 2 [Member]</link:label>
    <link:label id="lab_art_GardenCityKS2Member_documentation_en-US" xlink:label="lab_art_GardenCityKS2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Garden City, KS 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GardenCityKS2Member" xlink:href="art-20260806.xsd#art_GardenCityKS2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GardenCityKS2Member" xlink:to="lab_art_GardenCityKS2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TradeNamesMember_019e1743-a9d5-79da-b1c7-4334e13cc03d_terseLabel_en-US" xlink:label="lab_us-gaap_TradeNamesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trade name</link:label>
    <link:label id="lab_us-gaap_TradeNamesMember_label_en-US" xlink:label="lab_us-gaap_TradeNamesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trade Names [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeNamesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TradeNamesMember" xlink:to="lab_us-gaap_TradeNamesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CharlotteNC2Member_019e1743-aaf8-73ff-bdaa-b8d4aec69e85_terseLabel_en-US" xlink:label="lab_art_CharlotteNC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Charlotte, NC</link:label>
    <link:label id="lab_art_CharlotteNC2Member_label_en-US" xlink:label="lab_art_CharlotteNC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Charlotte, NC 2 [Member]</link:label>
    <link:label id="lab_art_CharlotteNC2Member_documentation_en-US" xlink:label="lab_art_CharlotteNC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Charlotte, NC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CharlotteNC2Member" xlink:href="art-20260806.xsd#art_CharlotteNC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CharlotteNC2Member" xlink:to="lab_art_CharlotteNC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TacomaWA2Member_019e1743-a9d5-7693-966d-fea21ca9952c_terseLabel_en-US" xlink:label="lab_art_TacomaWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tacoma, WA</link:label>
    <link:label id="lab_art_TacomaWA2Member_label_en-US" xlink:label="lab_art_TacomaWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tacoma, WA 2 [Member]</link:label>
    <link:label id="lab_art_TacomaWA2Member_documentation_en-US" xlink:label="lab_art_TacomaWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tacoma, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TacomaWA2Member" xlink:href="art-20260806.xsd#art_TacomaWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TacomaWA2Member" xlink:to="lab_art_TacomaWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EastDubuqueIL1Member_019e1743-ab7d-7520-903c-9294c2882913_terseLabel_en-US" xlink:label="lab_art_EastDubuqueIL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">East Dubuque, IL</link:label>
    <link:label id="lab_art_EastDubuqueIL1Member_label_en-US" xlink:label="lab_art_EastDubuqueIL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">East Dubuque, IL 1 [Member]</link:label>
    <link:label id="lab_art_EastDubuqueIL1Member_documentation_en-US" xlink:label="lab_art_EastDubuqueIL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">East Dubuque, IL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EastDubuqueIL1Member" xlink:href="art-20260806.xsd#art_EastDubuqueIL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EastDubuqueIL1Member" xlink:to="lab_art_EastDubuqueIL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_019e1743-aa65-7699-ace5-b7887b955495_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProductInformationLineItems_019e1743-a921-7f83-a0ee-b36a0a2981d7_terseLabel_en-US" xlink:label="lab_us-gaap_ProductInformationLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Product Information [Line Items]</link:label>
    <link:label id="lab_us-gaap_ProductInformationLineItems_label_en-US" xlink:label="lab_us-gaap_ProductInformationLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Product Information [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductInformationLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProductInformationLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProductInformationLineItems" xlink:to="lab_us-gaap_ProductInformationLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateCostOfRealEstateSold_019e1743-a922-7aff-9f2e-9273068c6bde_negatedLabel_en-US" xlink:label="lab_us-gaap_RealEstateCostOfRealEstateSold" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Disposition</link:label>
    <link:label id="lab_us-gaap_RealEstateCostOfRealEstateSold_label_en-US" xlink:label="lab_us-gaap_RealEstateCostOfRealEstateSold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Cost of Investment in Real Estate Sold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateCostOfRealEstateSold" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateCostOfRealEstateSold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateCostOfRealEstateSold" xlink:to="lab_us-gaap_RealEstateCostOfRealEstateSold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsTextBlock_019e1743-aa65-7713-a3fe-fe5e4fbfceb6_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Investments in and Advances to Partially Owned</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsTextBlock_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentsTextBlock" xlink:to="lab_us-gaap_EquityMethodInvestmentsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_019e1743-aa65-7238-82c5-ef9f7e7813d1_totalLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Property, buildings, and equipment &#8211; net</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_019e1743-aa65-7328-a378-980125a3c466_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, net</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_019e1743-aa65-7bd1-9de5-c219b7842b47_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Land and buildings and improvements, net value</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_019e1743-aa65-7e3f-99c7-18470f43fe45_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accounts Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeesportPA1Member_019e1743-aaf8-760f-8f2a-96ec9c997803_terseLabel_en-US" xlink:label="lab_art_LeesportPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Leesport, PA</link:label>
    <link:label id="lab_art_LeesportPA1Member_label_en-US" xlink:label="lab_art_LeesportPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leesport, PA 1 [Member]</link:label>
    <link:label id="lab_art_LeesportPA1Member_documentation_en-US" xlink:label="lab_art_LeesportPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Leesport, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeesportPA1Member" xlink:href="art-20260806.xsd#art_LeesportPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeesportPA1Member" xlink:to="lab_art_LeesportPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MiddleboroMA2Member_019e1743-ab7d-7609-8cdb-2565a65b8f35_terseLabel_en-US" xlink:label="lab_art_MiddleboroMA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Middleboro, MA</link:label>
    <link:label id="lab_art_MiddleboroMA2Member_label_en-US" xlink:label="lab_art_MiddleboroMA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Middleboro, MA 2 [Member]</link:label>
    <link:label id="lab_art_MiddleboroMA2Member_documentation_en-US" xlink:label="lab_art_MiddleboroMA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Middleboro, MA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MiddleboroMA2Member" xlink:href="art-20260806.xsd#art_MiddleboroMA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MiddleboroMA2Member" xlink:to="lab_art_MiddleboroMA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TransportationMember_019e1743-aaf8-7658-9737-3cfcc99803c5_terseLabel_en-US" xlink:label="lab_art_TransportationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transportation</link:label>
    <link:label id="lab_art_TransportationMember_label_en-US" xlink:label="lab_art_TransportationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Transportation [Member]</link:label>
    <link:label id="lab_art_TransportationMember_documentation_en-US" xlink:label="lab_art_TransportationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Transportation [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TransportationMember" xlink:href="art-20260806.xsd#art_TransportationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TransportationMember" xlink:to="lab_art_TransportationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SuperannuationMember_019e1743-a921-76da-9128-279951c99ece_terseLabel_en-US" xlink:label="lab_art_SuperannuationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Superannuation</link:label>
    <link:label id="lab_art_SuperannuationMember_019e1743-a921-731e-9b84-bfb6efd898e9_verboseLabel_en-US" xlink:label="lab_art_SuperannuationMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Superannuation</link:label>
    <link:label id="lab_art_SuperannuationMember_label_en-US" xlink:label="lab_art_SuperannuationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Superannuation [Member]</link:label>
    <link:label id="lab_art_SuperannuationMember_documentation_en-US" xlink:label="lab_art_SuperannuationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Superannuation [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SuperannuationMember" xlink:href="art-20260806.xsd#art_SuperannuationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SuperannuationMember" xlink:to="lab_art_SuperannuationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_019e1743-aa65-7908-8d57-db121f3d7f27_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Income taxes from continuing operations at the statutory rate</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:to="lab_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GdanskPolandMember_019e1743-aa65-79d7-a31c-f38ccbefa2f3_terseLabel_en-US" xlink:label="lab_art_GdanskPolandMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gdansk, Poland</link:label>
    <link:label id="lab_art_GdanskPolandMember_label_en-US" xlink:label="lab_art_GdanskPolandMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gdansk, Poland [Member]</link:label>
    <link:label id="lab_art_GdanskPolandMember_documentation_en-US" xlink:label="lab_art_GdanskPolandMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gdansk, Poland</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GdanskPolandMember" xlink:href="art-20260806.xsd#art_GdanskPolandMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GdanskPolandMember" xlink:to="lab_art_GdanskPolandMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AccumulatedGainLossHedgeParentMember_019e1743-aa65-7eaf-a58f-59deb76a1b13_terseLabel_en-US" xlink:label="lab_art_AccumulatedGainLossHedgeParentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Designated derivatives:</link:label>
    <link:label id="lab_art_AccumulatedGainLossHedgeParentMember_label_en-US" xlink:label="lab_art_AccumulatedGainLossHedgeParentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Gain (Loss), Hedge, Parent [Member]</link:label>
    <link:label id="lab_art_AccumulatedGainLossHedgeParentMember_documentation_en-US" xlink:label="lab_art_AccumulatedGainLossHedgeParentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accumulated Gain (Loss), Hedge, Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AccumulatedGainLossHedgeParentMember" xlink:href="art-20260806.xsd#art_AccumulatedGainLossHedgeParentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AccumulatedGainLossHedgeParentMember" xlink:to="lab_art_AccumulatedGainLossHedgeParentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019e1743-ab7d-795a-9e42-2694fb744bce_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net loss (gain) from sale of real estate</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_019e1743-ab7d-79a5-ae97-8446da18a21e_verboseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Net (loss) gain from sale of real estate</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Disposition of Property Plant Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:to="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member_019e1743-a921-7fbc-a308-574e975c27de_terseLabel_en-US" xlink:label="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2025 Term Loan</link:label>
    <link:label id="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member_label_en-US" xlink:label="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2025 Term Loan, SOFR Plus 0 Point 95 Percent, Due 2026 [Member]</link:label>
    <link:label id="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member_documentation_en-US" xlink:label="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2025 Term Loan, SOFR Plus 0 Point 95 Percent, Due 2026</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member" xlink:href="art-20260806.xsd#art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member" xlink:to="lab_art_A2025TermLoanSOFRPlus0Point95PercentDue2026Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_019e1743-a9d5-727d-897c-9dca98d2bc0c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:to="lab_us-gaap_StatementOfFinancialPositionAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MarshallMO2Member_019e1743-aa64-75b6-9e87-17689bf16daf_terseLabel_en-US" xlink:label="lab_art_MarshallMO2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Marshall, MO</link:label>
    <link:label id="lab_art_MarshallMO2Member_label_en-US" xlink:label="lab_art_MarshallMO2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Marshall, MO 2 [Member]</link:label>
    <link:label id="lab_art_MarshallMO2Member_documentation_en-US" xlink:label="lab_art_MarshallMO2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Marshall, MO 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MarshallMO2Member" xlink:href="art-20260806.xsd#art_MarshallMO2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MarshallMO2Member" xlink:to="lab_art_MarshallMO2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_019e1743-a921-77f9-92bc-6330485eac2b_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">State Income taxes, net of federal income tax benefit</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtConversionConvertedInstrumentAmount1_019e1743-a921-71fc-90f7-32aefaeb9d93_terseLabel_en-US" xlink:label="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt conversion, converted instrument, amount</link:label>
    <link:label id="lab_us-gaap_DebtConversionConvertedInstrumentAmount1_label_en-US" xlink:label="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Conversion, Converted Instrument, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:to="lab_us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019e1743-aa65-7550-a308-df9e381c1e4b_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EQTPartnersMember_019fcf58-a1d5-7be7-b6a1-8883f66da8be_terseLabel_en-US" xlink:label="lab_art_EQTPartnersMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">EQT Partners</link:label>
    <link:label id="lab_art_EQTPartnersMember_label_en-US" xlink:label="lab_art_EQTPartnersMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">EQT Partners [Member]</link:label>
    <link:label id="lab_art_EQTPartnersMember_documentation_en-US" xlink:label="lab_art_EQTPartnersMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">EQT Partners</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EQTPartnersMember" xlink:href="art-20260806.xsd#art_EQTPartnersMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EQTPartnersMember" xlink:to="lab_art_EQTPartnersMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BaytownTXMember_019e1743-a922-70b3-8234-fa12faf73f33_terseLabel_en-US" xlink:label="lab_art_BaytownTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Baytown, TX</link:label>
    <link:label id="lab_art_BaytownTXMember_label_en-US" xlink:label="lab_art_BaytownTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Baytown, TX [Member]</link:label>
    <link:label id="lab_art_BaytownTXMember_documentation_en-US" xlink:label="lab_art_BaytownTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Baytown, TX</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BaytownTXMember" xlink:href="art-20260806.xsd#art_BaytownTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BaytownTXMember" xlink:to="lab_art_BaytownTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestRateContractMember_019e1743-a9d5-733d-9e2d-43f1be71c049_terseLabel_en-US" xlink:label="lab_us-gaap_InterestRateContractMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swaps</link:label>
    <link:label id="lab_us-gaap_InterestRateContractMember_label_en-US" xlink:label="lab_us-gaap_InterestRateContractMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Contract [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateContractMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestRateContractMember" xlink:to="lab_us-gaap_InterestRateContractMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RussellvilleARElmira2Member_019e1743-aa65-70f6-bfef-0e60b73933cd_terseLabel_en-US" xlink:label="lab_art_RussellvilleARElmira2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Russellville, AR - Elmira</link:label>
    <link:label id="lab_art_RussellvilleARElmira2Member_label_en-US" xlink:label="lab_art_RussellvilleARElmira2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Russellville, AR - Elmira 2 [Member]</link:label>
    <link:label id="lab_art_RussellvilleARElmira2Member_documentation_en-US" xlink:label="lab_art_RussellvilleARElmira2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Russellville, AR - Elmira 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RussellvilleARElmira2Member" xlink:href="art-20260806.xsd#art_RussellvilleARElmira2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RussellvilleARElmira2Member" xlink:to="lab_art_RussellvilleARElmira2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaSouthgateGA2Member_019e1743-aaf8-76d7-97cb-80c5b30d5c0b_terseLabel_en-US" xlink:label="lab_art_AtlantaSouthgateGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Southgate, GA</link:label>
    <link:label id="lab_art_AtlantaSouthgateGA2Member_label_en-US" xlink:label="lab_art_AtlantaSouthgateGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Southgate, GA 2 [Member]</link:label>
    <link:label id="lab_art_AtlantaSouthgateGA2Member_documentation_en-US" xlink:label="lab_art_AtlantaSouthgateGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Southgate, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaSouthgateGA2Member" xlink:href="art-20260806.xsd#art_AtlantaSouthgateGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaSouthgateGA2Member" xlink:to="lab_art_AtlantaSouthgateGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019e1743-aaf8-76be-9752-30cf31b3d80b_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Antidilutive securities excluded from computation of earnings per share (in shares)</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:to="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019e1743-ab7d-7a4f-850d-02aa0c7a4fdc_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CanadianDollarOfferedRateMember_019e1743-ab7d-74e3-b551-f2b2e9ec6345_verboseLabel_en-US" xlink:label="lab_art_CanadianDollarOfferedRateMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">CORRA</link:label>
    <link:label id="lab_art_CanadianDollarOfferedRateMember_label_en-US" xlink:label="lab_art_CanadianDollarOfferedRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Canadian Dollar Offered Rate [Member]</link:label>
    <link:label id="lab_art_CanadianDollarOfferedRateMember_documentation_en-US" xlink:label="lab_art_CanadianDollarOfferedRateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Canadian Dollar Offered Rate [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CanadianDollarOfferedRateMember" xlink:href="art-20260806.xsd#art_CanadianDollarOfferedRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CanadianDollarOfferedRateMember" xlink:to="lab_art_CanadianDollarOfferedRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_019e1743-aa65-742d-bfc8-e15cf522f10e_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease Accounting</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:to="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TacomaWA1Member_019e1743-a9d5-77dc-a4cd-51e8b3c28262_terseLabel_en-US" xlink:label="lab_art_TacomaWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tacoma, WA</link:label>
    <link:label id="lab_art_TacomaWA1Member_label_en-US" xlink:label="lab_art_TacomaWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tacoma, WA 1 [Member]</link:label>
    <link:label id="lab_art_TacomaWA1Member_documentation_en-US" xlink:label="lab_art_TacomaWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tacoma, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TacomaWA1Member" xlink:href="art-20260806.xsd#art_TacomaWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TacomaWA1Member" xlink:to="lab_art_TacomaWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortWorthBlueMoundTX2Member_019e1743-aaf8-7810-ae62-927495909cb7_terseLabel_en-US" xlink:label="lab_art_FortWorthBlueMoundTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Worth-Blue Mound, TX</link:label>
    <link:label id="lab_art_FortWorthBlueMoundTX2Member_label_en-US" xlink:label="lab_art_FortWorthBlueMoundTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Worth-Blue Mound, TX 2 [Member]</link:label>
    <link:label id="lab_art_FortWorthBlueMoundTX2Member_documentation_en-US" xlink:label="lab_art_FortWorthBlueMoundTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Worth-Blue Mound, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortWorthBlueMoundTX2Member" xlink:href="art-20260806.xsd#art_FortWorthBlueMoundTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortWorthBlueMoundTX2Member" xlink:to="lab_art_FortWorthBlueMoundTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_019e1743-a9d5-7f8c-aa32-6a75da21bdcb_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Phoenix2AZ2Member_019e1743-aa64-7f28-a727-db45a228cce6_terseLabel_en-US" xlink:label="lab_art_Phoenix2AZ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Phoenix2, AZ</link:label>
    <link:label id="lab_art_Phoenix2AZ2Member_label_en-US" xlink:label="lab_art_Phoenix2AZ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Phoenix2, AZ 2 [Member]</link:label>
    <link:label id="lab_art_Phoenix2AZ2Member_documentation_en-US" xlink:label="lab_art_Phoenix2AZ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Phoenix2, AZ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Phoenix2AZ2Member" xlink:href="art-20260806.xsd#art_Phoenix2AZ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Phoenix2AZ2Member" xlink:to="lab_art_Phoenix2AZ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupClassificationDomain_019e1743-a9d5-77e7-b724-7dd1e7f4dd2b_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Domain]</link:label>
    <link:label id="lab_us-gaap_DisposalGroupClassificationDomain_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain" xlink:to="lab_us-gaap_DisposalGroupClassificationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock_019e1743-a9d5-7b34-954f-b519ae1085ca_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule III - Real Estate and Accumulated Depreciation</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_019e1743-a9d5-72df-af3a-f4a68f176187_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of equity method investments</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Equity Method Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:to="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease_019e1743-aa64-7d66-93ee-ec0fec27cccf_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in reserve due to the interest and other adjustments</link:label>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease" xlink:to="lab_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ValenciaSpainMember_019e1743-a921-7d90-8950-9c358384954e_terseLabel_en-US" xlink:label="lab_art_ValenciaSpainMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Valencia, Spain</link:label>
    <link:label id="lab_art_ValenciaSpainMember_label_en-US" xlink:label="lab_art_ValenciaSpainMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Valencia, Spain [Member]</link:label>
    <link:label id="lab_art_ValenciaSpainMember_documentation_en-US" xlink:label="lab_art_ValenciaSpainMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Valencia, Spain</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ValenciaSpainMember" xlink:href="art-20260806.xsd#art_ValenciaSpainMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ValenciaSpainMember" xlink:to="lab_art_ValenciaSpainMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SmartsRd1Member_019e1743-a9d5-7889-85e2-676bd4558b93_terseLabel_en-US" xlink:label="lab_art_SmartsRd1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Smarts Rd</link:label>
    <link:label id="lab_art_SmartsRd1Member_label_en-US" xlink:label="lab_art_SmartsRd1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Smarts Rd 1 [Member]</link:label>
    <link:label id="lab_art_SmartsRd1Member_documentation_en-US" xlink:label="lab_art_SmartsRd1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Smarts Rd 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SmartsRd1Member" xlink:href="art-20260806.xsd#art_SmartsRd1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SmartsRd1Member" xlink:to="lab_art_SmartsRd1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrooklynParkMN2Member_019e1743-ab7d-7379-98d0-4d3b746c3217_terseLabel_en-US" xlink:label="lab_art_BrooklynParkMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brooklyn Park, MN</link:label>
    <link:label id="lab_art_BrooklynParkMN2Member_label_en-US" xlink:label="lab_art_BrooklynParkMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brooklyn Park, MN 2 [Member]</link:label>
    <link:label id="lab_art_BrooklynParkMN2Member_documentation_en-US" xlink:label="lab_art_BrooklynParkMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brooklyn Park, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrooklynParkMN2Member" xlink:href="art-20260806.xsd#art_BrooklynParkMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrooklynParkMN2Member" xlink:to="lab_art_BrooklynParkMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NumberOfRealEstateProperties_019e1743-a9d5-7be7-ba52-ba766e4bdbfb_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfRealEstateProperties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of warehouses</link:label>
    <link:label id="lab_us-gaap_NumberOfRealEstateProperties_label_en-US" xlink:label="lab_us-gaap_NumberOfRealEstateProperties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Real Estate Properties</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfRealEstateProperties" xlink:to="lab_us-gaap_NumberOfRealEstateProperties" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_019e1743-aaf8-7300-896e-9ee24dc9bee1_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Outstanding (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_019e1743-aaf8-7f47-b021-d5dc486dde69_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Outstanding (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_019e1743-aaf8-75d6-9f72-70c485adf2ce_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares, shares issued (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Shares, Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesIssued" xlink:to="lab_us-gaap_CommonStockSharesIssued" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_019e1743-ab7d-7ab1-914e-4b0dc70c3a2f_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Asset, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_label_en-US" xlink:label="lab_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Asset, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration" xlink:to="lab_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_019e1743-a9d5-7af1-b9c7-35eba1c6cccc_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Weighted Average Remaining Lease Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:to="lab_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Phoenix2AZ1Member_019e1743-a922-74c7-96ca-b3ae29d6f145_terseLabel_en-US" xlink:label="lab_art_Phoenix2AZ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Phoenix2, AZ</link:label>
    <link:label id="lab_art_Phoenix2AZ1Member_label_en-US" xlink:label="lab_art_Phoenix2AZ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Phoenix2, AZ 1 [Member]</link:label>
    <link:label id="lab_art_Phoenix2AZ1Member_documentation_en-US" xlink:label="lab_art_Phoenix2AZ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Phoenix2, AZ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Phoenix2AZ1Member" xlink:href="art-20260806.xsd#art_Phoenix2AZ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Phoenix2AZ1Member" xlink:to="lab_art_Phoenix2AZ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestExpenseNonoperating_019e1743-aa65-7511-873f-a8810df18738_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseNonoperating" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Interest expense</link:label>
    <link:label id="lab_us-gaap_InterestExpenseNonoperating_label_en-US" xlink:label="lab_us-gaap_InterestExpenseNonoperating" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Expense, Nonoperating</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpenseNonoperating" xlink:to="lab_us-gaap_InterestExpenseNonoperating" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLeaseIncome_019e1743-aa65-76bb-b21a-4bbf0d1a23f3_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLeaseIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease revenue</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLeaseIncome_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLeaseIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Lease Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLeaseIncome" xlink:to="lab_us-gaap_OperatingLeaseLeaseIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_019e1743-ab7d-7531-b705-082e1aa50aca_terseLabel_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate, Type of Property [Axis]</link:label>
    <link:label id="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_label_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate, Type of Property [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:to="lab_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LossContingenciesLineItems_019e1743-aaf8-7621-8ae5-fb20855c0cc1_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingenciesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss Contingencies [Line Items]</link:label>
    <link:label id="lab_us-gaap_LossContingenciesLineItems_label_en-US" xlink:label="lab_us-gaap_LossContingenciesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingencies [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesLineItems" xlink:to="lab_us-gaap_LossContingenciesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortDodgeIA2Member_019e1743-ab7d-7790-b2e6-182263fc26bb_terseLabel_en-US" xlink:label="lab_art_FortDodgeIA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Dodge, IA</link:label>
    <link:label id="lab_art_FortDodgeIA2Member_label_en-US" xlink:label="lab_art_FortDodgeIA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Dodge, IA 2 [Member]</link:label>
    <link:label id="lab_art_FortDodgeIA2Member_documentation_en-US" xlink:label="lab_art_FortDodgeIA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Dodge, IA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortDodgeIA2Member" xlink:href="art-20260806.xsd#art_FortDodgeIA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortDodgeIA2Member" xlink:to="lab_art_FortDodgeIA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_SecurityExchangeName_019e1743-ab7d-7047-88d0-a8b2ac12a551_terseLabel_en-US" xlink:label="lab_dei_SecurityExchangeName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Security Exchange Name</link:label>
    <link:label id="lab_dei_SecurityExchangeName_label_en-US" xlink:label="lab_dei_SecurityExchangeName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Security Exchange Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_SecurityExchangeName" xlink:to="lab_dei_SecurityExchangeName" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxPaidForeignAfterRefundReceived_019e1743-a921-70da-90cd-89d840cf6be5_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPaidForeignAfterRefundReceived" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign</link:label>
    <link:label id="lab_us-gaap_IncomeTaxPaidForeignAfterRefundReceived_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPaidForeignAfterRefundReceived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Paid, Foreign, after Refund Received</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPaidForeignAfterRefundReceived" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidForeignAfterRefundReceived"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPaidForeignAfterRefundReceived" xlink:to="lab_us-gaap_IncomeTaxPaidForeignAfterRefundReceived" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_019e1743-aa65-7b62-a8a1-e2b92229ba43_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AmericoldRetirementIncomePlanMember_019e1743-aaf8-7ee3-b085-7a40d2ff441a_terseLabel_en-US" xlink:label="lab_art_AmericoldRetirementIncomePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Americold Retirement Income Plan</link:label>
    <link:label id="lab_art_AmericoldRetirementIncomePlanMember_label_en-US" xlink:label="lab_art_AmericoldRetirementIncomePlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Americold Retirement Income Plan [Member]</link:label>
    <link:label id="lab_art_AmericoldRetirementIncomePlanMember_documentation_en-US" xlink:label="lab_art_AmericoldRetirementIncomePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Americold Retirement Income Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmericoldRetirementIncomePlanMember" xlink:href="art-20260806.xsd#art_AmericoldRetirementIncomePlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmericoldRetirementIncomePlanMember" xlink:to="lab_art_AmericoldRetirementIncomePlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_019e1743-ab7d-75d7-920c-f919814ee5ee_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Addition of property, buildings and equipment on accrual</link:label>
    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_label_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Expenditures Incurred but Not yet Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:to="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019e1743-ab7d-7de6-a927-d19ff4ca0d93_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolver borrowing capacity</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanAssetCategoriesDomain_019e1743-aaf8-7d79-a919-24dc4d2e64dd_terseLabel_en-US" xlink:label="lab_us-gaap_PlanAssetCategoriesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Domain]</link:label>
    <link:label id="lab_us-gaap_PlanAssetCategoriesDomain_label_en-US" xlink:label="lab_us-gaap_PlanAssetCategoriesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain" xlink:to="lab_us-gaap_PlanAssetCategoriesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ComfrioJVMember_019e1743-ab7d-7be7-8afb-987d1277327b_terseLabel_en-US" xlink:label="lab_art_ComfrioJVMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Comfrio JV</link:label>
    <link:label id="lab_art_ComfrioJVMember_label_en-US" xlink:label="lab_art_ComfrioJVMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comfrio JV [Member]</link:label>
    <link:label id="lab_art_ComfrioJVMember_documentation_en-US" xlink:label="lab_art_ComfrioJVMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Comfrio JV</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ComfrioJVMember" xlink:href="art-20260806.xsd#art_ComfrioJVMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ComfrioJVMember" xlink:to="lab_art_ComfrioJVMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsForHedgeInvestingActivities_019e1743-aaf8-7ed9-bbd8-dd8650015ebd_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForHedgeInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payments for settlement of hedge</link:label>
    <link:label id="lab_us-gaap_PaymentsForHedgeInvestingActivities_label_en-US" xlink:label="lab_us-gaap_PaymentsForHedgeInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Hedge, Investing Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForHedgeInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForHedgeInvestingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForHedgeInvestingActivities" xlink:to="lab_us-gaap_PaymentsForHedgeInvestingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant_019e1743-a9d5-71aa-838e-8ea9a3db5c9d_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plan participants&#8217; contributions</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Contributions by Plan Participant</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementLineItems_019e1743-a9d5-725c-ae37-4747010d09ac_terseLabel_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:label id="lab_us-gaap_StatementLineItems_label_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementLineItems" xlink:to="lab_us-gaap_StatementLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_019e1743-aa65-7b18-8478-63191af9d396_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash, cash equivalents, and restricted cash</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockMember_019e1743-aa65-72aa-8829-3c80b57d0dd1_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common Stock</link:label>
    <link:label id="lab_us-gaap_CommonStockMember_label_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockMember" xlink:to="lab_us-gaap_CommonStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e1743-aa65-7a1c-926a-92aa15d3123f_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vested (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e1743-aa65-7e80-ac5c-e2a194e8593c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Vested (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019e1743-aa65-798c-b06c-cef992e3cb14_negatedLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Vested (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_019e1743-aaf8-7cd3-923e-8050cd666d78_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finance Lease Payments</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:to="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum_019e1743-a9d5-7ba1-bad1-9675e0d3af58_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum leverage ratio after material acquisition</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Leverage Ratio After Material Acquisition, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Leverage Ratio After Material Acquisition, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum" xlink:to="lab_art_DebtInstrumentCovenantLeverageRatioAfterMaterialAcquisitionMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TomahWI2Member_019e1743-a9d5-7391-a9a4-d1d86439decb_terseLabel_en-US" xlink:label="lab_art_TomahWI2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tomah, WI</link:label>
    <link:label id="lab_art_TomahWI2Member_label_en-US" xlink:label="lab_art_TomahWI2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tomah, WI 2 [Member]</link:label>
    <link:label id="lab_art_TomahWI2Member_documentation_en-US" xlink:label="lab_art_TomahWI2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tomah, WI 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TomahWI2Member" xlink:href="art-20260806.xsd#art_TomahWI2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TomahWI2Member" xlink:to="lab_art_TomahWI2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AlbertvilleAL1Member_019e1743-a9d5-70a5-ba98-b05702920c88_terseLabel_en-US" xlink:label="lab_art_AlbertvilleAL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Albertville, AL</link:label>
    <link:label id="lab_art_AlbertvilleAL1Member_label_en-US" xlink:label="lab_art_AlbertvilleAL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Albertville, AL 1 [Member]</link:label>
    <link:label id="lab_art_AlbertvilleAL1Member_documentation_en-US" xlink:label="lab_art_AlbertvilleAL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Albertville, AL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AlbertvilleAL1Member" xlink:href="art-20260806.xsd#art_AlbertvilleAL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AlbertvilleAL1Member" xlink:to="lab_art_AlbertvilleAL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_019e1743-a9d5-7113-b07b-ba0a62d62bad_terseLabel_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summary of Significant Accounting Policies</link:label>
    <link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_label_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Accounting Policies [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SignificantAccountingPoliciesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RangeMember_019e1743-aa65-71aa-8ec2-a9c9934bb52a_terseLabel_en-US" xlink:label="lab_srt_RangeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Domain]</link:label>
    <link:label id="lab_srt_RangeMember_label_en-US" xlink:label="lab_srt_RangeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statistical Measurement [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeMember" xlink:to="lab_srt_RangeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_019e1743-aaf8-7dc3-88c1-c5714086995e_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, buildings and equipment</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DiscontinuedOperationEstimatedCostOnDisposal_019e1743-aa65-75ed-903a-c431157b2d12_terseLabel_en-US" xlink:label="lab_art_DiscontinuedOperationEstimatedCostOnDisposal" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated costs of disposal</link:label>
    <link:label id="lab_art_DiscontinuedOperationEstimatedCostOnDisposal_label_en-US" xlink:label="lab_art_DiscontinuedOperationEstimatedCostOnDisposal" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discontinued Operation, Estimated Cost On Disposal</link:label>
    <link:label id="lab_art_DiscontinuedOperationEstimatedCostOnDisposal_documentation_en-US" xlink:label="lab_art_DiscontinuedOperationEstimatedCostOnDisposal" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Discontinued Operation, Estimated Cost On Disposal</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DiscontinuedOperationEstimatedCostOnDisposal" xlink:href="art-20260806.xsd#art_DiscontinuedOperationEstimatedCostOnDisposal"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DiscontinuedOperationEstimatedCostOnDisposal" xlink:to="lab_art_DiscontinuedOperationEstimatedCostOnDisposal" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VinelandNJ2Member_019e1743-a9d5-73d4-b43b-4073d77fc471_terseLabel_en-US" xlink:label="lab_art_VinelandNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vineland, NJ</link:label>
    <link:label id="lab_art_VinelandNJ2Member_label_en-US" xlink:label="lab_art_VinelandNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vineland, NJ 2 [Member]</link:label>
    <link:label id="lab_art_VinelandNJ2Member_documentation_en-US" xlink:label="lab_art_VinelandNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vineland, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VinelandNJ2Member" xlink:href="art-20260806.xsd#art_VinelandNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VinelandNJ2Member" xlink:to="lab_art_VinelandNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignPlanMember_019e1743-aaf8-79e6-bcc1-afe76064fe74_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign Plan</link:label>
    <link:label id="lab_us-gaap_ForeignPlanMember_label_en-US" xlink:label="lab_us-gaap_ForeignPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignPlanMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignPlanMember" xlink:to="lab_us-gaap_ForeignPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019e1743-a9d5-77a4-9f51-b2afc602c486_terseLabel_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate [Domain]</link:label>
    <link:label id="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_label_en-US" xlink:label="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:to="lab_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestRateSwapMember_019e1743-aa65-7b6b-87c1-a91f727c0616_terseLabel_en-US" xlink:label="lab_us-gaap_InterestRateSwapMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate Swap</link:label>
    <link:label id="lab_us-gaap_InterestRateSwapMember_019e1743-aa65-746e-b62b-7a40686e1f7c_verboseLabel_en-US" xlink:label="lab_us-gaap_InterestRateSwapMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Interest rate contracts</link:label>
    <link:label id="lab_us-gaap_InterestRateSwapMember_label_en-US" xlink:label="lab_us-gaap_InterestRateSwapMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateSwapMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestRateSwapMember" xlink:to="lab_us-gaap_InterestRateSwapMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtPolicyTextBlock_019e1743-a9d5-7e32-93e4-d6e12a6f8785_terseLabel_en-US" xlink:label="lab_us-gaap_DebtPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred Financing Costs</link:label>
    <link:label id="lab_us-gaap_DebtPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_DebtPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtPolicyTextBlock" xlink:to="lab_us-gaap_DebtPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_019e1743-ab7d-78a4-b4d4-b1ea664b9889_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment of Long-Lived Assets</link:label>
    <link:label id="lab_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:to="lab_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CartersvilleGA1Member_019e1743-a9d5-7998-bbe1-50fd634adc86_terseLabel_en-US" xlink:label="lab_art_CartersvilleGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cartersville, GA</link:label>
    <link:label id="lab_art_CartersvilleGA1Member_label_en-US" xlink:label="lab_art_CartersvilleGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cartersville, GA 1 [Member]</link:label>
    <link:label id="lab_art_CartersvilleGA1Member_documentation_en-US" xlink:label="lab_art_CartersvilleGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cartersville, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CartersvilleGA1Member" xlink:href="art-20260806.xsd#art_CartersvilleGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CartersvilleGA1Member" xlink:to="lab_art_CartersvilleGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_019e1743-aa65-73c9-9384-b364d6a29d61_verboseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Loss from investments in partially owned entities</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Equity Method Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:to="lab_us-gaap_IncomeLossFromEquityMethodInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ChillicotheMO2Member_019e1743-ab7d-7e30-a777-31f92b002129_terseLabel_en-US" xlink:label="lab_art_ChillicotheMO2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chillicothe, MO</link:label>
    <link:label id="lab_art_ChillicotheMO2Member_label_en-US" xlink:label="lab_art_ChillicotheMO2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chillicothe, MO 2 [Member]</link:label>
    <link:label id="lab_art_ChillicotheMO2Member_documentation_en-US" xlink:label="lab_art_ChillicotheMO2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chillicothe, MO 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ChillicotheMO2Member" xlink:href="art-20260806.xsd#art_ChillicotheMO2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ChillicotheMO2Member" xlink:to="lab_art_ChillicotheMO2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Brampton2Member_019e1743-ab7d-72a5-a396-21e4d5936f65_terseLabel_en-US" xlink:label="lab_art_Brampton2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brampton</link:label>
    <link:label id="lab_art_Brampton2Member_label_en-US" xlink:label="lab_art_Brampton2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brampton 2 [Member]</link:label>
    <link:label id="lab_art_Brampton2Member_documentation_en-US" xlink:label="lab_art_Brampton2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brampton 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Brampton2Member" xlink:href="art-20260806.xsd#art_Brampton2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Brampton2Member" xlink:to="lab_art_Brampton2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OneWarehouse2010Member_019e1743-aa65-7775-af38-8caeb153a452_terseLabel_en-US" xlink:label="lab_art_OneWarehouse2010Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1 warehouse&#160;&#8211; 2010</link:label>
    <link:label id="lab_art_OneWarehouse2010Member_label_en-US" xlink:label="lab_art_OneWarehouse2010Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">One Warehouse, 2010 [Member]</link:label>
    <link:label id="lab_art_OneWarehouse2010Member_documentation_en-US" xlink:label="lab_art_OneWarehouse2010Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">One Warehouse, 2010 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OneWarehouse2010Member" xlink:href="art-20260806.xsd#art_OneWarehouse2010Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OneWarehouse2010Member" xlink:to="lab_art_OneWarehouse2010Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember_019e1743-ab7d-74a7-af87-8d68f70346b2_terseLabel_en-US" xlink:label="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgages, Senior Notes and Medium-Term Loan A</link:label>
    <link:label id="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember_label_en-US" xlink:label="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgages, Senior Notes and Medium-Term Loan A [Member]</link:label>
    <link:label id="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember_documentation_en-US" xlink:label="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mortgages, Senior Notes and Medium-Term Loan A</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MortgagesSeniorNotesAndMediumTermLoanAMember" xlink:href="art-20260806.xsd#art_MortgagesSeniorNotesAndMediumTermLoanAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MortgagesSeniorNotesAndMediumTermLoanAMember" xlink:to="lab_art_MortgagesSeniorNotesAndMediumTermLoanAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_019e1743-aa65-73d0-bcda-af6334b73660_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainContingenciesLineItems_019e1743-a921-7d8e-9f00-8a77ff64f36b_terseLabel_en-US" xlink:label="lab_us-gaap_GainContingenciesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain Contingencies [Line Items]</link:label>
    <link:label id="lab_us-gaap_GainContingenciesLineItems_label_en-US" xlink:label="lab_us-gaap_GainContingenciesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain Contingencies [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainContingenciesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainContingenciesLineItems" xlink:to="lab_us-gaap_GainContingenciesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand_019e1743-aaf8-7155-a209-f944deda1f60_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gross amount, Land</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Land, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions_019e1743-ab7d-79f7-8e74-72327f5a4b62_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquisitions</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Acquisitions</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Acquisitions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesAcquisitions" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesAcquisitions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesAcquisitions" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesAcquisitions" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnionizedEmployeesConcentrationRiskMember_019e1743-aaf8-79d1-a6eb-852a970d1245_terseLabel_en-US" xlink:label="lab_us-gaap_UnionizedEmployeesConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unionized Employees Concentration Risk</link:label>
    <link:label id="lab_us-gaap_UnionizedEmployeesConcentrationRiskMember_label_en-US" xlink:label="lab_us-gaap_UnionizedEmployeesConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unionized Employees Concentration Risk [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnionizedEmployeesConcentrationRiskMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnionizedEmployeesConcentrationRiskMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnionizedEmployeesConcentrationRiskMember" xlink:to="lab_us-gaap_UnionizedEmployeesConcentrationRiskMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Paisley2Member_019e1743-aaf8-7801-b923-ad15df4ced31_terseLabel_en-US" xlink:label="lab_art_Paisley2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Paisley</link:label>
    <link:label id="lab_art_Paisley2Member_label_en-US" xlink:label="lab_art_Paisley2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Paisley 2 [Member]</link:label>
    <link:label id="lab_art_Paisley2Member_documentation_en-US" xlink:label="lab_art_Paisley2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Paisley 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Paisley2Member" xlink:href="art-20260806.xsd#art_Paisley2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Paisley2Member" xlink:to="lab_art_Paisley2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired_019e1743-aaf8-7c45-8b5a-4cb4fb38f7ac_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of warehouses acquired</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number Of Units Acquired</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number Of Units Acquired</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionNumberOfUnitsAcquired" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionNumberOfUnitsAcquired"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionNumberOfUnitsAcquired" xlink:to="lab_art_SaleLeasebackTransactionNumberOfUnitsAcquired" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MarketBasedRestrictedStockUnitsMember_019e1743-a9d5-784d-b112-e0276143e7bf_terseLabel_en-US" xlink:label="lab_art_MarketBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Market-Based Restricted Stock Units</link:label>
    <link:label id="lab_art_MarketBasedRestrictedStockUnitsMember_label_en-US" xlink:label="lab_art_MarketBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Market-Based Restricted Stock Units [Member]</link:label>
    <link:label id="lab_art_MarketBasedRestrictedStockUnitsMember_documentation_en-US" xlink:label="lab_art_MarketBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Market-Based Restricted Stock Units [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MarketBasedRestrictedStockUnitsMember" xlink:href="art-20260806.xsd#art_MarketBasedRestrictedStockUnitsMember"/>
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    <link:label id="lab_us-gaap_DeferredTaxAssetsGross_019e1743-aa65-7823-a8e1-0e58ea6a7a87_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total gross deferred tax assets</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsGross_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsGross" xlink:to="lab_us-gaap_DeferredTaxAssetsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e1743-a9d5-7228-9575-7223da8a801a_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Other comprehensive loss - net of tax attributable to Americold Realty Trust, Inc.</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_019e1743-a9d5-72c7-9abd-1815beea7bdd_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net gain (loss) on pension and other postretirement benefit</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
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    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_019e1743-a9d5-7b8a-9bdb-ce8cdb2d98ec_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Segment Information</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock"/>
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    <link:label id="lab_us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract_019e1743-a922-7ad2-9e5a-88635c34c9da_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred:</link:label>
    <link:label id="lab_us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract_label_en-US" xlink:label="lab_us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Federal, State and Local, Tax Expense (Benefit) [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract"/>
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    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements_019e1743-ab7d-7136-99be-2ad7ff9b42c7_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings and improvements</link:label>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements_label_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Buildings And Improvements</link:label>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements_documentation_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Buildings And Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements" xlink:href="art-20260806.xsd#art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements" xlink:to="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildingsAndImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GreenBayWI2Member_019e1743-aaf8-7eec-9f6a-c0241d5787fd_terseLabel_en-US" xlink:label="lab_art_GreenBayWI2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Green Bay, WI</link:label>
    <link:label id="lab_art_GreenBayWI2Member_label_en-US" xlink:label="lab_art_GreenBayWI2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Green Bay, WI 2 [Member]</link:label>
    <link:label id="lab_art_GreenBayWI2Member_documentation_en-US" xlink:label="lab_art_GreenBayWI2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Green Bay, WI 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GreenBayWI2Member" xlink:href="art-20260806.xsd#art_GreenBayWI2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GreenBayWI2Member" xlink:to="lab_art_GreenBayWI2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortDodgeIA1Member_019e1743-a9d5-7286-a83a-3df454b5251e_terseLabel_en-US" xlink:label="lab_art_FortDodgeIA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Dodge, IA</link:label>
    <link:label id="lab_art_FortDodgeIA1Member_label_en-US" xlink:label="lab_art_FortDodgeIA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Dodge, IA 1 [Member]</link:label>
    <link:label id="lab_art_FortDodgeIA1Member_documentation_en-US" xlink:label="lab_art_FortDodgeIA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Dodge, IA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortDodgeIA1Member" xlink:href="art-20260806.xsd#art_FortDodgeIA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortDodgeIA1Member" xlink:to="lab_art_FortDodgeIA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Diversey2Member_019e1743-aaf8-7000-ab1b-a12b92c86155_terseLabel_en-US" xlink:label="lab_art_Diversey2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Diversey</link:label>
    <link:label id="lab_art_Diversey2Member_label_en-US" xlink:label="lab_art_Diversey2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Diversey 2 [Member]</link:label>
    <link:label id="lab_art_Diversey2Member_documentation_en-US" xlink:label="lab_art_Diversey2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Diversey 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Diversey2Member" xlink:href="art-20260806.xsd#art_Diversey2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Diversey2Member" xlink:to="lab_art_Diversey2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LisbonPortugalMember_019e1743-aaf8-7847-bf98-7f13f39d1dad_terseLabel_en-US" xlink:label="lab_art_LisbonPortugalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lisbon, Portugal</link:label>
    <link:label id="lab_art_LisbonPortugalMember_label_en-US" xlink:label="lab_art_LisbonPortugalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lisbon, Portugal [Member]</link:label>
    <link:label id="lab_art_LisbonPortugalMember_documentation_en-US" xlink:label="lab_art_LisbonPortugalMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lisbon, Portugal</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LisbonPortugalMember" xlink:href="art-20260806.xsd#art_LisbonPortugalMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LisbonPortugalMember" xlink:to="lab_art_LisbonPortugalMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_019e1743-ab7d-718e-9398-1a38d7d854e7_terseLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock-based compensation expense</link:label>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_label_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SecuredDebt_019e1743-aa65-73a2-9210-293cae5dd7b1_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior unsecured notes and term loans - net of deferred financing costs of $16,001 and $13,882 at December&#160;31, 2025 and 2024, respectively</link:label>
    <link:label id="lab_us-gaap_SecuredDebt_label_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecuredDebt" xlink:to="lab_us-gaap_SecuredDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AugustaGA1Member_019e1743-aa65-7f30-9004-f9c5a19892c6_terseLabel_en-US" xlink:label="lab_art_AugustaGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Augusta, GA</link:label>
    <link:label id="lab_art_AugustaGA1Member_label_en-US" xlink:label="lab_art_AugustaGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Augusta, GA 1 [Member]</link:label>
    <link:label id="lab_art_AugustaGA1Member_documentation_en-US" xlink:label="lab_art_AugustaGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Augusta, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AugustaGA1Member" xlink:href="art-20260806.xsd#art_AugustaGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AugustaGA1Member" xlink:to="lab_art_AugustaGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_019e1743-aa65-751b-b22a-950c2148ba86_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities and equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019e1743-aaf8-7778-b6c9-a2e3745c9ba4_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_019e1743-aa65-75c9-bf1c-04759ad9e684_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension and other postretirement benefits:</link:label>
    <link:label id="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:to="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfUnits_019e1743-aa65-732f-8036-e249997c49f4_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of warehouses</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfUnits_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number Of Units</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfUnits_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number Of Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionNumberOfUnits" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionNumberOfUnits"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionNumberOfUnits" xlink:to="lab_art_SaleLeasebackTransactionNumberOfUnits" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanRealEstateMember_019e1743-a9d5-72dc-8cee-878239f2940e_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real estate</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanRealEstateMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Employee Benefit Plan, Real Estate [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanRealEstateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:to="lab_us-gaap_DefinedBenefitPlanRealEstateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionExtensionPeriod_019e1743-aa65-73f4-889e-2909b19e2d7b_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionExtensionPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Extension period under sale-leaseback transaction</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionExtensionPeriod_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionExtensionPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Extension Period</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionExtensionPeriod_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionExtensionPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Extension Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionExtensionPeriod" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionExtensionPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionExtensionPeriod" xlink:to="lab_art_SaleLeasebackTransactionExtensionPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_019e1743-aaf8-75ac-99b0-dce053d18134_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MarketBasedOPUnitsMember_019e1743-ab7d-7951-9246-cda6447e3c8f_terseLabel_en-US" xlink:label="lab_art_MarketBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Market-Based OP Units</link:label>
    <link:label id="lab_art_MarketBasedOPUnitsMember_label_en-US" xlink:label="lab_art_MarketBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Market-Based OP Units [Member]</link:label>
    <link:label id="lab_art_MarketBasedOPUnitsMember_documentation_en-US" xlink:label="lab_art_MarketBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Market-Based OP Units [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MarketBasedOPUnitsMember" xlink:href="art-20260806.xsd#art_MarketBasedOPUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MarketBasedOPUnitsMember" xlink:to="lab_art_MarketBasedOPUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_019e1743-a921-7a76-8d78-fc07a6d5b1de_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reclassification of accumulated CTA on SuperFrio sale proceeds</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived_019e1743-aa65-7a20-8c10-cc0a2047b73c_totalLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceived" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TurlockCA22Member_019e1743-a9d5-71fe-9f84-e5fcf6f1cfec_terseLabel_en-US" xlink:label="lab_art_TurlockCA22Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Turlock, CA (#2)</link:label>
    <link:label id="lab_art_TurlockCA22Member_label_en-US" xlink:label="lab_art_TurlockCA22Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Turlock, CA (#2) 2 [Member]</link:label>
    <link:label id="lab_art_TurlockCA22Member_documentation_en-US" xlink:label="lab_art_TurlockCA22Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Turlock, CA (#2) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TurlockCA22Member" xlink:href="art-20260806.xsd#art_TurlockCA22Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TurlockCA22Member" xlink:to="lab_art_TurlockCA22Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NapoleonOH1Member_019e1743-a9d5-7809-85da-cd264ae3dab9_terseLabel_en-US" xlink:label="lab_art_NapoleonOH1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Napoleon, OH</link:label>
    <link:label id="lab_art_NapoleonOH1Member_label_en-US" xlink:label="lab_art_NapoleonOH1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Napoleon, OH 1 [Member]</link:label>
    <link:label id="lab_art_NapoleonOH1Member_documentation_en-US" xlink:label="lab_art_NapoleonOH1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Napoleon, OH 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NapoleonOH1Member" xlink:href="art-20260806.xsd#art_NapoleonOH1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NapoleonOH1Member" xlink:to="lab_art_NapoleonOH1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization_019e1743-aa65-7d55-a730-f7f9336250a4_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Right-of-Use Asset, Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_SolicitingMaterial_019fcfa6-bde7-7f64-9f30-6d4cfda0bb35_terseLabel_en-US" xlink:label="lab_dei_SolicitingMaterial" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Soliciting Material</link:label>
    <link:label id="lab_dei_SolicitingMaterial_label_en-US" xlink:label="lab_dei_SolicitingMaterial" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Soliciting Material</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_SolicitingMaterial" xlink:to="lab_dei_SolicitingMaterial" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash_019e1743-aaf8-7660-af25-e0d27aec8fcc_terseLabel_en-US" xlink:label="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Provision for doubtful accounts receivable</link:label>
    <link:label id="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash_label_en-US" xlink:label="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Credit Loss Expense (Reversal), Non-Cash</link:label>
    <link:label id="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash_documentation_en-US" xlink:label="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Credit Loss Expense (Reversal), Non-Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AccountsReceivableCreditLossExpenseReversalNonCash" xlink:href="art-20260806.xsd#art_AccountsReceivableCreditLossExpenseReversalNonCash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AccountsReceivableCreditLossExpenseReversalNonCash" xlink:to="lab_art_AccountsReceivableCreditLossExpenseReversalNonCash" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Ft.WorthTXRailhead1Member_019e1743-a9d5-7c68-b7bb-e25968ea922e_terseLabel_en-US" xlink:label="lab_art_Ft.WorthTXRailhead1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Railhead)</link:label>
    <link:label id="lab_art_Ft.WorthTXRailhead1Member_label_en-US" xlink:label="lab_art_Ft.WorthTXRailhead1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Railhead) 1 [Member]</link:label>
    <link:label id="lab_art_Ft.WorthTXRailhead1Member_documentation_en-US" xlink:label="lab_art_Ft.WorthTXRailhead1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Railhead) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Ft.WorthTXRailhead1Member" xlink:href="art-20260806.xsd#art_Ft.WorthTXRailhead1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Ft.WorthTXRailhead1Member" xlink:to="lab_art_Ft.WorthTXRailhead1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SafewayMember_019e1743-a9d5-7dd9-b0a4-810adbe56012_terseLabel_en-US" xlink:label="lab_art_SafewayMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Safeway</link:label>
    <link:label id="lab_art_SafewayMember_label_en-US" xlink:label="lab_art_SafewayMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Safeway [Member]</link:label>
    <link:label id="lab_art_SafewayMember_documentation_en-US" xlink:label="lab_art_SafewayMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Safeway</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SafewayMember" xlink:href="art-20260806.xsd#art_SafewayMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SafewayMember" xlink:to="lab_art_SafewayMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillImpairmentLoss_019e1743-aa64-7d92-8cb1-8b8992473b41_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillImpairmentLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill impairment loss</link:label>
    <link:label id="lab_us-gaap_GoodwillImpairmentLoss_label_en-US" xlink:label="lab_us-gaap_GoodwillImpairmentLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Impairment Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillImpairmentLoss" xlink:to="lab_us-gaap_GoodwillImpairmentLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_019e1743-a922-7e2f-898c-fcc5d57e5b91_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employer contributions</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Contributions by Employer</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:to="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_019e1743-aaf8-71b3-9265-c16b27ec8349_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AgroMerchantsGroupMember_019e1743-a921-707a-8e88-a4df8a72f954_terseLabel_en-US" xlink:label="lab_art_AgroMerchantsGroupMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Agro Merchants Group</link:label>
    <link:label id="lab_art_AgroMerchantsGroupMember_label_en-US" xlink:label="lab_art_AgroMerchantsGroupMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Agro Merchants Group [Member]</link:label>
    <link:label id="lab_art_AgroMerchantsGroupMember_documentation_en-US" xlink:label="lab_art_AgroMerchantsGroupMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Agro Merchants Group</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AgroMerchantsGroupMember" xlink:href="art-20260806.xsd#art_AgroMerchantsGroupMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AgroMerchantsGroupMember" xlink:to="lab_art_AgroMerchantsGroupMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_019e1743-aa65-7d23-bc11-b766a640ec29_totalLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total comprehensive loss</link:label>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comprehensive Income (Loss), Net of Tax, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod_019e1743-a922-76a9-bcd7-fb528d7f5350_terseLabel_en-US" xlink:label="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Multiemployer plans, withdrawal obligation repayment period</link:label>
    <link:label id="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod_label_en-US" xlink:label="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiple-Employer Plan Accounted for as Multiemployer Plan, Withdrawal Obligation Repayment Period</link:label>
    <link:label id="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod_documentation_en-US" xlink:label="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Multiple-Employer Plan Accounted for as Multiemployer Plan, Withdrawal Obligation Repayment Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod" xlink:href="art-20260806.xsd#art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod" xlink:to="lab_art_MultipleEmployerPlanAccountedForAsMultiemployerPlanWithdrawalObligationRepaymentPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock_019e1743-aaf8-791b-b3bf-f2be3d71e60c_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Loss from Continuing Operations Before Income Taxes</link:label>
    <link:label id="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_St.PaulMN2Member_019e1743-aaf8-72a1-b41a-71e68415bff7_terseLabel_en-US" xlink:label="lab_art_St.PaulMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">St. Paul, MN</link:label>
    <link:label id="lab_art_St.PaulMN2Member_label_en-US" xlink:label="lab_art_St.PaulMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">St. Paul, MN 2 [Member]</link:label>
    <link:label id="lab_art_St.PaulMN2Member_documentation_en-US" xlink:label="lab_art_St.PaulMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">St. Paul, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_St.PaulMN2Member" xlink:href="art-20260806.xsd#art_St.PaulMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_St.PaulMN2Member" xlink:to="lab_art_St.PaulMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BurleyID2Member_019e1743-aaf8-72b2-a02e-54b34788f04d_terseLabel_en-US" xlink:label="lab_art_BurleyID2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Burley, ID</link:label>
    <link:label id="lab_art_BurleyID2Member_label_en-US" xlink:label="lab_art_BurleyID2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Burley, ID 2 [Member]</link:label>
    <link:label id="lab_art_BurleyID2Member_documentation_en-US" xlink:label="lab_art_BurleyID2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Burley, ID 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BurleyID2Member" xlink:href="art-20260806.xsd#art_BurleyID2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BurleyID2Member" xlink:to="lab_art_BurleyID2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Vernon2CA2Member_019e1743-aa64-784a-a348-90a5ab62d6ab_terseLabel_en-US" xlink:label="lab_art_Vernon2CA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vernon 2, CA</link:label>
    <link:label id="lab_art_Vernon2CA2Member_label_en-US" xlink:label="lab_art_Vernon2CA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vernon 2, CA 2 [Member]</link:label>
    <link:label id="lab_art_Vernon2CA2Member_documentation_en-US" xlink:label="lab_art_Vernon2CA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vernon 2, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Vernon2CA2Member" xlink:href="art-20260806.xsd#art_Vernon2CA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Vernon2CA2Member" xlink:to="lab_art_Vernon2CA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet_019e1743-aaf8-7f78-8275-141259dea9b2_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred tax liability - net</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Income Tax Liabilities, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:to="lab_us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_019e1743-aaf8-735d-b912-f9aef00a06c0_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expected return on plan assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-Term Rate of Return on Plan Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxContingencyTable_019e1743-a922-72c3-aba7-d29d5a7a590a_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxContingencyTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Tax Contingency [Table]</link:label>
    <link:label id="lab_us-gaap_IncomeTaxContingencyTable_label_en-US" xlink:label="lab_us-gaap_IncomeTaxContingencyTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Contingency [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxContingencyTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxContingencyTable" xlink:to="lab_us-gaap_IncomeTaxContingencyTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebt_019e1743-a9d5-7a1b-aa6c-127236100665_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total indebtedness, net of deferred financing costs</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_label_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebt" xlink:to="lab_us-gaap_LongTermDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Assets_019e1743-aa65-75bb-b7f9-2b5b46207a76_totalLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_Assets_019e1743-aa65-7249-b106-8f128091a043_terseLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Assets</link:label>
    <link:label id="lab_us-gaap_Assets_label_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract_019e1743-aaf8-7b26-8ded-be194c304b22_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reconciliation of the Company&#8217;s accumulated depreciation to Schedule III:</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation Reconciliation [Abstract]</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation Reconciliation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationReconciliationAbstract"/>
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    <link:label id="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy_019e1743-ab7d-7e25-9cd4-183c21020779_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash, Cash Equivalents, and Restricted Cash</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:to="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SeniorUnsecuredNotesAndTermLoansMember_019e1743-aa64-749b-9072-92c397575810_terseLabel_en-US" xlink:label="lab_art_SeniorUnsecuredNotesAndTermLoansMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes and Term Loans</link:label>
    <link:label id="lab_art_SeniorUnsecuredNotesAndTermLoansMember_label_en-US" xlink:label="lab_art_SeniorUnsecuredNotesAndTermLoansMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes and Term Loans [Member]</link:label>
    <link:label id="lab_art_SeniorUnsecuredNotesAndTermLoansMember_documentation_en-US" xlink:label="lab_art_SeniorUnsecuredNotesAndTermLoansMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes and Term Loans</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SeniorUnsecuredNotesAndTermLoansMember" xlink:href="art-20260806.xsd#art_SeniorUnsecuredNotesAndTermLoansMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SeniorUnsecuredNotesAndTermLoansMember" xlink:to="lab_art_SeniorUnsecuredNotesAndTermLoansMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_SegmentGeographicalDomain_019e1743-aa65-72b4-b167-d09b88ce8df4_terseLabel_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:label id="lab_srt_SegmentGeographicalDomain_label_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SegmentGeographicalDomain" xlink:to="lab_srt_SegmentGeographicalDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_019e1743-a9d5-78d9-b738-625267eb5847_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Taxes</link:label>
    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxPolicyTextBlock" xlink:to="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WivenhoeTasmania1Member_019e1743-ab7d-7884-86f5-36455a048b61_terseLabel_en-US" xlink:label="lab_art_WivenhoeTasmania1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wivenhoe - Tasmania</link:label>
    <link:label id="lab_art_WivenhoeTasmania1Member_label_en-US" xlink:label="lab_art_WivenhoeTasmania1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wivenhoe - Tasmania 1 [Member]</link:label>
    <link:label id="lab_art_WivenhoeTasmania1Member_documentation_en-US" xlink:label="lab_art_WivenhoeTasmania1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Wivenhoe - Tasmania 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WivenhoeTasmania1Member" xlink:href="art-20260806.xsd#art_WivenhoeTasmania1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WivenhoeTasmania1Member" xlink:to="lab_art_WivenhoeTasmania1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_019e1743-a9d5-7f86-9ade-342fa5e24192_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_WrittenCommunications_019fcfa6-9cf4-7fbe-9ba7-ece2319b951c_terseLabel_en-US" xlink:label="lab_dei_WrittenCommunications" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Written Communications</link:label>
    <link:label id="lab_dei_WrittenCommunications_label_en-US" xlink:label="lab_dei_WrittenCommunications" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Written Communications</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_WrittenCommunications" xlink:to="lab_dei_WrittenCommunications" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ZumbrotaMN1Member_019e1743-aa65-77e4-8f52-e8940f4a3fe3_terseLabel_en-US" xlink:label="lab_art_ZumbrotaMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Zumbrota, MN</link:label>
    <link:label id="lab_art_ZumbrotaMN1Member_label_en-US" xlink:label="lab_art_ZumbrotaMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Zumbrota, MN 1 [Member]</link:label>
    <link:label id="lab_art_ZumbrotaMN1Member_documentation_en-US" xlink:label="lab_art_ZumbrotaMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Zumbrota, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ZumbrotaMN1Member" xlink:href="art-20260806.xsd#art_ZumbrotaMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ZumbrotaMN1Member" xlink:to="lab_art_ZumbrotaMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract_019e1743-aa65-779f-98c3-9ead86358328_terseLabel_en-US" xlink:label="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Right-of-use assets obtained in exchange for lease obligations</link:label>
    <link:label id="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract_label_en-US" xlink:label="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Right Of Use Asset Obtained In Exchange For Lease Liability [Abstract]</link:label>
    <link:label id="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract_documentation_en-US" xlink:label="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Right Of Use Asset Obtained In Exchange For Lease Liability [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract" xlink:href="art-20260806.xsd#art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract" xlink:to="lab_art_RightOfUseAssetObtainedInExchangeForLeaseLiabilityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentAdditions_019e1743-a921-7c9e-ac38-7e3300973ced_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAdditions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, additions</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentAdditions_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAdditions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Additions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAdditions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAdditions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAdditions" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentAdditions" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums_019e1743-ab7d-7844-bf5f-2fafcf5510e5_negatedTerseLabel_en-US" xlink:label="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Termination of sale-leaseback financing obligations</link:label>
    <link:label id="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums_label_en-US" xlink:label="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Termination of Sale Leaseback Financing Obligations and Related Termination Premiums</link:label>
    <link:label id="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums_documentation_en-US" xlink:label="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Termination of Sale Leaseback Financing Obligations and Related Termination Premiums</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums" xlink:href="art-20260806.xsd#art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums" xlink:to="lab_art_TerminationOfSaleLeasebackFinancingObligationsAndRelatedTerminationPremiums" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ArgoMember_019e1743-aa65-7476-bd14-37e0cadc4df4_terseLabel_en-US" xlink:label="lab_art_ArgoMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Argo</link:label>
    <link:label id="lab_art_ArgoMember_label_en-US" xlink:label="lab_art_ArgoMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Argo [Member]</link:label>
    <link:label id="lab_art_ArgoMember_documentation_en-US" xlink:label="lab_art_ArgoMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Argo</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ArgoMember" xlink:href="art-20260806.xsd#art_ArgoMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ArgoMember" xlink:to="lab_art_ArgoMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GeneralPartnerMember_019e1743-aaf8-7210-9a46-66d30cbe5d2a_terseLabel_en-US" xlink:label="lab_us-gaap_GeneralPartnerMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">General Partner</link:label>
    <link:label id="lab_us-gaap_GeneralPartnerMember_label_en-US" xlink:label="lab_us-gaap_GeneralPartnerMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">General Partner [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnerMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralPartnerMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GeneralPartnerMember" xlink:to="lab_us-gaap_GeneralPartnerMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock_019e1743-aaf8-7ddf-b492-23a4ae2d4834_terseLabel_en-US" xlink:label="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Market Performance Vesting Percentage</link:label>
    <link:label id="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock_label_en-US" xlink:label="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Payment Awards, Performance Shares Thresholds [Table Text Block]</link:label>
    <link:label id="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock_documentation_en-US" xlink:label="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Payment Awards, Performance Shares Thresholds [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock" xlink:href="art-20260806.xsd#art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock" xlink:to="lab_art_ScheduleofSharebasedPaymentAwardsPerformanceSharesThresholdsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_019e1743-aaf8-751e-9ae8-4e9313e7880c_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConsolidationVariableInterestEntityPolicy_019e1743-a921-730a-a17b-69b4e41fb4a2_terseLabel_en-US" xlink:label="lab_us-gaap_ConsolidationVariableInterestEntityPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable Interest Entities (&#8220;VIEs&#8221;)</link:label>
    <link:label id="lab_us-gaap_ConsolidationVariableInterestEntityPolicy_label_en-US" xlink:label="lab_us-gaap_ConsolidationVariableInterestEntityPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation, Variable Interest Entity, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsolidationVariableInterestEntityPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConsolidationVariableInterestEntityPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConsolidationVariableInterestEntityPolicy" xlink:to="lab_us-gaap_ConsolidationVariableInterestEntityPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract_019e1743-aaf8-7142-9e35-9b870f251e58_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-Average Remaining Contractual Terms (Years)</link:label>
    <link:label id="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract_label_en-US" xlink:label="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Award by Share-based Payment Award, Options, Average Remaining Contractual Term [Abstract]</link:label>
    <link:label id="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract_documentation_en-US" xlink:label="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Award by Share-based Payment Award, Options, Average Remaining Contractual Term [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract" xlink:href="art-20260806.xsd#art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract" xlink:to="lab_art_SharebasedCompensationAwardbySharebasedPaymentAwardOptionsAverageRemainingContractualTermAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_019e1743-a9d5-74d3-88d3-30273890f924_verboseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Operating leases</link:label>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_019e1743-a9d5-7a0e-aa73-2c5f13dd240c_terseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating leases</link:label>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Right-of-Use Asset Obtained in Exchange for Operating Lease Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:to="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_019e1743-a9d5-70ae-8cf0-cabf03ea51ed_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Final liability fair values associated with acquisition</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired, Asset</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
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    <link:label id="lab_us-gaap_EquityMethodInvestments_019e1743-ab7d-718e-9b41-2fd17a0ee97b_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity method investments</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestments" xlink:to="lab_us-gaap_EquityMethodInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent_019e1743-a921-7698-8173-ce5b10a1fed7_negatedTerseLabel_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Equity awards</link:label>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent_label_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Equity Awards, Percent</link:label>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent_documentation_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Equity Awards, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent" xlink:href="art-20260806.xsd#art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent" xlink:to="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsPercent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019e1743-a9d5-717c-8ade-72644f1c183e_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Lease Payments</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:to="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyMember_019e1743-a9d5-78b3-b303-be220c65b104_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party</link:label>
    <link:label id="lab_us-gaap_RelatedPartyMember_label_en-US" xlink:label="lab_us-gaap_RelatedPartyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related Party [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyMember" xlink:to="lab_us-gaap_RelatedPartyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member_019e1743-aaf8-72a7-b118-567ed42ee44f_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 4</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 4 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 4</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche4Member"/>
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    <link:label id="lab_art_ClearfieldUT1Member_019e1743-aaf8-74f3-b877-077242453609_terseLabel_en-US" xlink:label="lab_art_ClearfieldUT1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Clearfield, UT</link:label>
    <link:label id="lab_art_ClearfieldUT1Member_label_en-US" xlink:label="lab_art_ClearfieldUT1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Clearfield, UT 1 [Member]</link:label>
    <link:label id="lab_art_ClearfieldUT1Member_documentation_en-US" xlink:label="lab_art_ClearfieldUT1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Clearfield, UT 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ClearfieldUT1Member" xlink:href="art-20260806.xsd#art_ClearfieldUT1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ClearfieldUT1Member" xlink:to="lab_art_ClearfieldUT1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_019e1743-ab7d-7ba1-9555-090d9f922b26_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Benefit (Expense) for Income Taxes From Continuing Operations</link:label>
    <link:label id="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameAxis_019e1743-aa65-7c05-a7ee-717d439e1d0d_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:label id="lab_us-gaap_PlanNameAxis_label_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameAxis" xlink:to="lab_us-gaap_PlanNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_019e1743-aaf8-7d67-b23d-e62119e0ab75_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Buildings and Equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ProspectASCCorporate1Member_019e1743-ab7d-749e-a158-e5daf5ebf044_terseLabel_en-US" xlink:label="lab_art_ProspectASCCorporate1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prospect/ASC Corporate</link:label>
    <link:label id="lab_art_ProspectASCCorporate1Member_label_en-US" xlink:label="lab_art_ProspectASCCorporate1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prospect/ASC Corporate 1 [Member]</link:label>
    <link:label id="lab_art_ProspectASCCorporate1Member_documentation_en-US" xlink:label="lab_art_ProspectASCCorporate1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Prospect/ASC Corporate 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ProspectASCCorporate1Member" xlink:href="art-20260806.xsd#art_ProspectASCCorporate1Member"/>
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    <link:label id="lab_art_AmortizationOfSwapTerminationCosts_019e1743-aa65-7741-a4e3-d3a9cd9129e3_negatedTerseLabel_en-US" xlink:label="lab_art_AmortizationOfSwapTerminationCosts" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Amortization of swap termination costs</link:label>
    <link:label id="lab_art_AmortizationOfSwapTerminationCosts_label_en-US" xlink:label="lab_art_AmortizationOfSwapTerminationCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization Of Swap Termination Costs</link:label>
    <link:label id="lab_art_AmortizationOfSwapTerminationCosts_documentation_en-US" xlink:label="lab_art_AmortizationOfSwapTerminationCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amortization Of Swap Termination Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmortizationOfSwapTerminationCosts" xlink:href="art-20260806.xsd#art_AmortizationOfSwapTerminationCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmortizationOfSwapTerminationCosts" xlink:to="lab_art_AmortizationOfSwapTerminationCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Massillon17thOH2Member_019e1743-ab7d-74f5-97ab-7755f907dab5_terseLabel_en-US" xlink:label="lab_art_Massillon17thOH2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Massillon 17th, OH</link:label>
    <link:label id="lab_art_Massillon17thOH2Member_label_en-US" xlink:label="lab_art_Massillon17thOH2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Massillon 17th, OH 2 [Member]</link:label>
    <link:label id="lab_art_Massillon17thOH2Member_documentation_en-US" xlink:label="lab_art_Massillon17thOH2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Massillon 17th, OH 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Massillon17thOH2Member" xlink:href="art-20260806.xsd#art_Massillon17thOH2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Massillon17thOH2Member" xlink:to="lab_art_Massillon17thOH2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_country_US_019e1743-aa65-751a-ae11-c3ae01dbef94_terseLabel_en-US" xlink:label="lab_country_US" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">North America</link:label>
    <link:label id="lab_country_US_label_en-US" xlink:label="lab_country_US" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">UNITED STATES</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_US" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_US"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_US" xlink:to="lab_country_US" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease_019e1743-aa65-7ad3-98ef-9d815cadd85a_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Others</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Period Increase (Decrease)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" xlink:to="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsPeriodIncreaseDecrease" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_019e1743-a9d5-7ad6-9691-c2a6049c3cc2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Property, buildings and equipment</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Property, Plant and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfMediumTermNotes_019e1743-a9d5-79e8-b1b6-c086c62a70c2_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfMediumTermNotes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from senior unsecured term loans</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfMediumTermNotes_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfMediumTermNotes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of Medium-Term Note</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfMediumTermNotes" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfMediumTermNotes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceOfMediumTermNotes" xlink:to="lab_us-gaap_ProceedsFromIssuanceOfMediumTermNotes" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GlobalIntangibleLowTaxIncomeDividend_019e1743-aaf8-73ef-9bc4-fb1f22d7dbd4_terseLabel_en-US" xlink:label="lab_art_GlobalIntangibleLowTaxIncomeDividend" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Taxable deemed dividend estimated</link:label>
    <link:label id="lab_art_GlobalIntangibleLowTaxIncomeDividend_label_en-US" xlink:label="lab_art_GlobalIntangibleLowTaxIncomeDividend" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Global Intangible Low-Tax Income Dividend</link:label>
    <link:label id="lab_art_GlobalIntangibleLowTaxIncomeDividend_documentation_en-US" xlink:label="lab_art_GlobalIntangibleLowTaxIncomeDividend" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Global Intangible Low-Tax Income Dividend</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GlobalIntangibleLowTaxIncomeDividend" xlink:href="art-20260806.xsd#art_GlobalIntangibleLowTaxIncomeDividend"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GlobalIntangibleLowTaxIncomeDividend" xlink:to="lab_art_GlobalIntangibleLowTaxIncomeDividend" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetainedEarningsMember_019e1743-aa65-7c65-8ed3-881fb843f32c_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Deficit and Distributions in Excess of Net Earnings</link:label>
    <link:label id="lab_us-gaap_RetainedEarningsMember_label_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retained Earnings [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsMember" xlink:to="lab_us-gaap_RetainedEarningsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e1743-a9d5-7103-b487-c7f8af10a343_periodStartLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning of period</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019e1743-a9d5-7162-a808-a1b24a963545_periodEndLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">End of period</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeAssets_019e1743-a9d5-77b2-ada4-2c39052454ae_verboseLabel_en-US" xlink:label="lab_us-gaap_DerivativeAssets" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Derivative Assets</link:label>
    <link:label id="lab_us-gaap_DerivativeAssets_019e1743-a9d5-71f1-a8b7-86de726f4667_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap assets</link:label>
    <link:label id="lab_us-gaap_DerivativeAssets_label_en-US" xlink:label="lab_us-gaap_DerivativeAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Asset</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeAssets" xlink:to="lab_us-gaap_DerivativeAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NorthAmericanJointVentureMember_019fcf58-32c6-7057-ae93-392f1ac76a3f_terseLabel_en-US" xlink:label="lab_art_NorthAmericanJointVentureMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">North American Joint Venture</link:label>
    <link:label id="lab_art_NorthAmericanJointVentureMember_label_en-US" xlink:label="lab_art_NorthAmericanJointVentureMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">North American Joint Venture [Member]</link:label>
    <link:label id="lab_art_NorthAmericanJointVentureMember_documentation_en-US" xlink:label="lab_art_NorthAmericanJointVentureMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">North American Joint Venture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NorthAmericanJointVentureMember" xlink:href="art-20260806.xsd#art_NorthAmericanJointVentureMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NorthAmericanJointVentureMember" xlink:to="lab_art_NorthAmericanJointVentureMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SikestonMO2Member_019e1743-ab7d-79dc-ac41-15643f5dafa8_terseLabel_en-US" xlink:label="lab_art_SikestonMO2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sikeston, MO</link:label>
    <link:label id="lab_art_SikestonMO2Member_label_en-US" xlink:label="lab_art_SikestonMO2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sikeston, MO 2 [Member]</link:label>
    <link:label id="lab_art_SikestonMO2Member_documentation_en-US" xlink:label="lab_art_SikestonMO2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sikeston, MO 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SikestonMO2Member" xlink:href="art-20260806.xsd#art_SikestonMO2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SikestonMO2Member" xlink:to="lab_art_SikestonMO2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestExpenseMember_019e1743-a9d5-7e51-9a78-75fb27d4a436_terseLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest expense</link:label>
    <link:label id="lab_us-gaap_InterestExpenseMember_label_en-US" xlink:label="lab_us-gaap_InterestExpenseMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Expense [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpenseMember" xlink:to="lab_us-gaap_InterestExpenseMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementsNonrecurringMember_019e1743-aaf8-772f-9466-6dd0d0f3fbc6_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsNonrecurringMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measured at fair value on a non-recurring basis</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsNonrecurringMember_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsNonrecurringMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Nonrecurring [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringMember" xlink:to="lab_us-gaap_FairValueMeasurementsNonrecurringMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_019e1743-aa65-71b1-bcb7-19fe82f12b51_terseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Identifiable intangible assets &#8211; net</link:label>
    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_label_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Assets, Net (Excluding Goodwill)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:to="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ModestoCA2Member_019e1743-ab7d-747f-92ed-64b28e387c07_terseLabel_en-US" xlink:label="lab_art_ModestoCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Modesto, CA</link:label>
    <link:label id="lab_art_ModestoCA2Member_label_en-US" xlink:label="lab_art_ModestoCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Modesto, CA 2 [Member]</link:label>
    <link:label id="lab_art_ModestoCA2Member_documentation_en-US" xlink:label="lab_art_ModestoCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Modesto, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ModestoCA2Member" xlink:href="art-20260806.xsd#art_ModestoCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ModestoCA2Member" xlink:to="lab_art_ModestoCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_019e1743-aaf8-7459-98c3-ca0857f36ce7_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss per common share from continuing operations - diluted (in USD per share)</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations, Per Diluted Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProfitLoss_019e1743-aaf8-77e7-aebb-5ba021ddb5d8_totalLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_ProfitLoss_019e1743-aaf8-7842-b4c2-2d5ad800328c_terseLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_ProfitLoss_019e1743-aaf8-7e9c-bd4c-35315912a5c6_verboseLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_ProfitLoss_019e1743-aaf8-7595-911b-6afda14fd152_netLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_ProfitLoss_label_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProfitLoss" xlink:to="lab_us-gaap_ProfitLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_019e1743-a9d5-73f6-aec5-e6119df85664_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_019e1743-a9d5-7f03-beee-7fe019014617_terseLabel_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_019e1743-aaf8-7d2c-9406-be5b67ee6e3d_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net (gain) loss</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019e1743-a921-7c15-8ffb-2da70e636788_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measured at fair value on a non-recurring basis:</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Measurements, Nonrecurring Value Measurement [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract" xlink:to="lab_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CityAreaCode_019e1743-a922-76f6-8298-1b082c29b69c_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">City Area Code</link:label>
    <link:label id="lab_dei_CityAreaCode_label_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">City Area Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CityAreaCode" xlink:to="lab_dei_CityAreaCode" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HalwynDr1Member_019e1743-ab7d-7fc7-8658-722ac1a7e15b_terseLabel_en-US" xlink:label="lab_art_HalwynDr1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Halwyn Dr</link:label>
    <link:label id="lab_art_HalwynDr1Member_label_en-US" xlink:label="lab_art_HalwynDr1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Halwyn Dr 1 [Member]</link:label>
    <link:label id="lab_art_HalwynDr1Member_documentation_en-US" xlink:label="lab_art_HalwynDr1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Halwyn Dr 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HalwynDr1Member" xlink:href="art-20260806.xsd#art_HalwynDr1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HalwynDr1Member" xlink:to="lab_art_HalwynDr1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WarehouseRentAndStorageMember_019e1743-aa65-797e-b2b6-e47e840ff925_terseLabel_en-US" xlink:label="lab_art_WarehouseRentAndStorageMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Warehouse rent and storage</link:label>
    <link:label id="lab_art_WarehouseRentAndStorageMember_label_en-US" xlink:label="lab_art_WarehouseRentAndStorageMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Warehouse Rent And Storage [Member]</link:label>
    <link:label id="lab_art_WarehouseRentAndStorageMember_documentation_en-US" xlink:label="lab_art_WarehouseRentAndStorageMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Warehouse Rent And Storage [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WarehouseRentAndStorageMember" xlink:href="art-20260806.xsd#art_WarehouseRentAndStorageMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WarehouseRentAndStorageMember" xlink:to="lab_art_WarehouseRentAndStorageMember" xlink:type="arc" order="1"/>
    <link:label id="lab_currency_USD_019e1743-aaf8-7a90-b6ef-dac2282a39db_terseLabel_en-US" xlink:label="lab_currency_USD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. dollar</link:label>
    <link:label id="lab_currency_USD_label_en-US" xlink:label="lab_currency_USD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">United States of America, Dollars</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_currency_USD" xlink:href="https://xbrl.sec.gov/currency/2025/currency-2025.xsd#currency_USD"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_currency_USD" xlink:to="lab_currency_USD" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilities_019e1743-aaf8-7153-bfc6-21ff17ed9814_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilities" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xml:lang="en-US">Net deferred tax liability</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilities_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilities" xlink:to="lab_us-gaap_DeferredTaxLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_019e1743-a922-7b3f-844d-e6fed8f353b1_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NoncurrentAssets_019e1743-ab7d-7679-a2a2-48f1b8feb9e5_terseLabel_en-US" xlink:label="lab_us-gaap_NoncurrentAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-Lived Assets</link:label>
    <link:label id="lab_us-gaap_NoncurrentAssets_label_en-US" xlink:label="lab_us-gaap_NoncurrentAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Lived Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncurrentAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoncurrentAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NoncurrentAssets" xlink:to="lab_us-gaap_NoncurrentAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_art_IndianapolisIN2Member_019e1743-aa65-7ab3-87a8-1b39158cdbd2_terseLabel_en-US" xlink:label="lab_art_IndianapolisIN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indianapolis, IN</link:label>
    <link:label id="lab_art_IndianapolisIN2Member_label_en-US" xlink:label="lab_art_IndianapolisIN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Indianapolis, IN 2 [Member]</link:label>
    <link:label id="lab_art_IndianapolisIN2Member_documentation_en-US" xlink:label="lab_art_IndianapolisIN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indianapolis, IN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_IndianapolisIN2Member" xlink:href="art-20260806.xsd#art_IndianapolisIN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_IndianapolisIN2Member" xlink:to="lab_art_IndianapolisIN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain_019e1743-aaf8-779a-859a-abf124696ae1_terseLabel_en-US" xlink:label="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Financial Statement Location of Deconsolidated Items [Domain]</link:label>
    <link:label id="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain_label_en-US" xlink:label="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Financial Statement Location of Deconsolidated Items [Domain]</link:label>
    <link:label id="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain_documentation_en-US" xlink:label="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Financial Statement Location of Deconsolidated Items [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FinancialStatementLocationOfDeconsolidatedItemsDomain" xlink:href="art-20260806.xsd#art_FinancialStatementLocationOfDeconsolidatedItemsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FinancialStatementLocationOfDeconsolidatedItemsDomain" xlink:to="lab_art_FinancialStatementLocationOfDeconsolidatedItemsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RetirementIncomePlanMember_019e1743-a9d5-7f58-be0d-4befa50a9e2c_verboseLabel_en-US" xlink:label="lab_art_RetirementIncomePlanMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Americold Retirement Income Plan (ARIP)</link:label>
    <link:label id="lab_art_RetirementIncomePlanMember_label_en-US" xlink:label="lab_art_RetirementIncomePlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Income Plan [Member]</link:label>
    <link:label id="lab_art_RetirementIncomePlanMember_documentation_en-US" xlink:label="lab_art_RetirementIncomePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Retirement Income Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RetirementIncomePlanMember" xlink:href="art-20260806.xsd#art_RetirementIncomePlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RetirementIncomePlanMember" xlink:to="lab_art_RetirementIncomePlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaTradewaterGA1Member_019e1743-a9d5-7e24-8a5b-61995fd0e1a7_terseLabel_en-US" xlink:label="lab_art_AtlantaTradewaterGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Tradewater, GA</link:label>
    <link:label id="lab_art_AtlantaTradewaterGA1Member_label_en-US" xlink:label="lab_art_AtlantaTradewaterGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Tradewater, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaTradewaterGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaTradewaterGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Tradewater, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaTradewaterGA1Member" xlink:href="art-20260806.xsd#art_AtlantaTradewaterGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaTradewaterGA1Member" xlink:to="lab_art_AtlantaTradewaterGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember_019e1743-a9d5-7c95-8f19-a7543b04bbc3_terseLabel_en-US" xlink:label="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Market Performance-based Cliff Vesting OP Units</link:label>
    <link:label id="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember_label_en-US" xlink:label="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Market Performance-based Cliff Vesting OP Units [Member]</link:label>
    <link:label id="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember_documentation_en-US" xlink:label="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Market Performance-based Cliff Vesting OP Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MarketPerformanceBasedCliffVestingOPUnitsMember" xlink:href="art-20260806.xsd#art_MarketPerformanceBasedCliffVestingOPUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MarketPerformanceBasedCliffVestingOPUnitsMember" xlink:to="lab_art_MarketPerformanceBasedCliffVestingOPUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GadsdenAL2Member_019e1743-aaf8-7770-8804-510ac5c7030d_terseLabel_en-US" xlink:label="lab_art_GadsdenAL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gadsden, AL</link:label>
    <link:label id="lab_art_GadsdenAL2Member_label_en-US" xlink:label="lab_art_GadsdenAL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gadsden, AL 2 [Member]</link:label>
    <link:label id="lab_art_GadsdenAL2Member_documentation_en-US" xlink:label="lab_art_GadsdenAL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gadsden, AL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GadsdenAL2Member" xlink:href="art-20260806.xsd#art_GadsdenAL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GadsdenAL2Member" xlink:to="lab_art_GadsdenAL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ClearfieldUT2Member_019e1743-a921-7305-bc05-0063aafa2dbf_terseLabel_en-US" xlink:label="lab_art_ClearfieldUT2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Clearfield, UT</link:label>
    <link:label id="lab_art_ClearfieldUT2Member_label_en-US" xlink:label="lab_art_ClearfieldUT2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Clearfield, UT 2 [Member]</link:label>
    <link:label id="lab_art_ClearfieldUT2Member_documentation_en-US" xlink:label="lab_art_ClearfieldUT2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Clearfield, UT 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ClearfieldUT2Member" xlink:href="art-20260806.xsd#art_ClearfieldUT2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ClearfieldUT2Member" xlink:to="lab_art_ClearfieldUT2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BelvidereImronIL1Member_019e1743-a9d5-7c5e-8faf-b387af514347_terseLabel_en-US" xlink:label="lab_art_BelvidereImronIL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Belvidere-Imron, IL</link:label>
    <link:label id="lab_art_BelvidereImronIL1Member_label_en-US" xlink:label="lab_art_BelvidereImronIL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Belvidere-Imron, IL 1 [Member]</link:label>
    <link:label id="lab_art_BelvidereImronIL1Member_documentation_en-US" xlink:label="lab_art_BelvidereImronIL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Belvidere-Imron, IL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BelvidereImronIL1Member" xlink:href="art-20260806.xsd#art_BelvidereImronIL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BelvidereImronIL1Member" xlink:to="lab_art_BelvidereImronIL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_SECScheduleIIIRealEstateNumberOfUnits_019e1743-ab7d-7824-8b18-d4956ddd1392_terseLabel_en-US" xlink:label="lab_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings</link:label>
    <link:label id="lab_srt_SECScheduleIIIRealEstateNumberOfUnits_label_en-US" xlink:label="lab_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Number of Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SECScheduleIIIRealEstateNumberOfUnits"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:to="lab_srt_SECScheduleIIIRealEstateNumberOfUnits" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TurlockCA21Member_019e1743-ab7d-7179-8747-2ee5b06d3baf_terseLabel_en-US" xlink:label="lab_art_TurlockCA21Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Turlock, CA (#2)</link:label>
    <link:label id="lab_art_TurlockCA21Member_label_en-US" xlink:label="lab_art_TurlockCA21Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Turlock, CA (#2) 1 [Member]</link:label>
    <link:label id="lab_art_TurlockCA21Member_documentation_en-US" xlink:label="lab_art_TurlockCA21Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Turlock, CA (#2) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TurlockCA21Member" xlink:href="art-20260806.xsd#art_TurlockCA21Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TurlockCA21Member" xlink:to="lab_art_TurlockCA21Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TampaBartowFLMember_019e1743-aa64-7b64-a156-f69f34fb037f_terseLabel_en-US" xlink:label="lab_art_TampaBartowFLMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tampa - Bartow, FL</link:label>
    <link:label id="lab_art_TampaBartowFLMember_label_en-US" xlink:label="lab_art_TampaBartowFLMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tampa - Bartow, FL [Member]</link:label>
    <link:label id="lab_art_TampaBartowFLMember_documentation_en-US" xlink:label="lab_art_TampaBartowFLMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tampa - Bartow, FL</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TampaBartowFLMember" xlink:href="art-20260806.xsd#art_TampaBartowFLMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TampaBartowFLMember" xlink:to="lab_art_TampaBartowFLMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AFFOPerformanceBasedOPUnitsMember_019e1743-a921-7f34-beff-9be1d1a00554_terseLabel_en-US" xlink:label="lab_art_AFFOPerformanceBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">AFFO Performance Based OP Units</link:label>
    <link:label id="lab_art_AFFOPerformanceBasedOPUnitsMember_label_en-US" xlink:label="lab_art_AFFOPerformanceBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AFFO Performance Based OP Units [Member]</link:label>
    <link:label id="lab_art_AFFOPerformanceBasedOPUnitsMember_documentation_en-US" xlink:label="lab_art_AFFOPerformanceBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">AFFO Performance Based OP Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AFFOPerformanceBasedOPUnitsMember" xlink:href="art-20260806.xsd#art_AFFOPerformanceBasedOPUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AFFOPerformanceBasedOPUnitsMember" xlink:to="lab_art_AFFOPerformanceBasedOPUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_019e1743-aaf8-7781-bca9-6ad9b3fc4d2d_verboseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Supplemental disclosures of cash flows information:</link:label>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_label_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_019e1743-aa65-709c-ba09-a8e3e09dee04_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-Average Exercise Price</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsOfDebtIssuanceCosts_019e1743-ab7d-7ccc-bf44-f53eaa950108_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Payment of debt issuance costs</link:label>
    <link:label id="lab_us-gaap_PaymentsOfDebtIssuanceCosts_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments of Debt Issuance Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:to="lab_us-gaap_PaymentsOfDebtIssuanceCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_019e1743-aaf8-74b6-85c9-24e1ec341102_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyDomain_019e1743-aa65-75a2-9d8d-d992ee0ca3bc_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party [Domain]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyDomain_label_en-US" xlink:label="lab_us-gaap_RelatedPartyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related and Nonrelated Parties [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyDomain" xlink:to="lab_us-gaap_RelatedPartyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_019e1743-a9d5-7e3d-bc93-f6d02dcb51b5_totalLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net increase (decrease) in cash, cash equivalents and restricted cash</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GouldsboroPA2Member_019e1743-ab7d-76e9-9eb5-97210fdfe75d_terseLabel_en-US" xlink:label="lab_art_GouldsboroPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gouldsboro, PA</link:label>
    <link:label id="lab_art_GouldsboroPA2Member_label_en-US" xlink:label="lab_art_GouldsboroPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gouldsboro, PA 2 [Member]</link:label>
    <link:label id="lab_art_GouldsboroPA2Member_documentation_en-US" xlink:label="lab_art_GouldsboroPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gouldsboro, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GouldsboroPA2Member" xlink:href="art-20260806.xsd#art_GouldsboroPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GouldsboroPA2Member" xlink:to="lab_art_GouldsboroPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019e1743-ab7d-7057-832a-83f49476d6be_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investments in and advances to partially owned entities</link:label>
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019e1743-ab7d-7e74-97ee-6f6e0f3baefa_verboseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total investments in and advances to partially owned entities</link:label>
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_label_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:to="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OneFacility2013Member_019e1743-a9d5-7d3e-93d2-6d90c1a801cb_terseLabel_en-US" xlink:label="lab_art_OneFacility2013Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1 facility - 2013 (Agro)</link:label>
    <link:label id="lab_art_OneFacility2013Member_label_en-US" xlink:label="lab_art_OneFacility2013Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">One Facility, 2013 [Member]</link:label>
    <link:label id="lab_art_OneFacility2013Member_documentation_en-US" xlink:label="lab_art_OneFacility2013Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">One Facility, 2013</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OneFacility2013Member" xlink:href="art-20260806.xsd#art_OneFacility2013Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OneFacility2013Member" xlink:to="lab_art_OneFacility2013Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestPaidNet_019e1743-aaf8-770b-96ee-4baa0ffbb0a8_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest paid &#8211; net of amounts capitalized</link:label>
    <link:label id="lab_us-gaap_InterestPaidNet_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid, Excluding Capitalized Interest, Operating Activity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestPaidNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidNet" xlink:to="lab_us-gaap_InterestPaidNet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairfieldOH1Member_019e1743-aa64-76af-a4be-50b7c14ab3ad_terseLabel_en-US" xlink:label="lab_art_FairfieldOH1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fairfield, OH</link:label>
    <link:label id="lab_art_FairfieldOH1Member_label_en-US" xlink:label="lab_art_FairfieldOH1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fairfield, OH 1 [Member]</link:label>
    <link:label id="lab_art_FairfieldOH1Member_documentation_en-US" xlink:label="lab_art_FairfieldOH1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fairfield, OH 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairfieldOH1Member" xlink:href="art-20260806.xsd#art_FairfieldOH1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairfieldOH1Member" xlink:to="lab_art_FairfieldOH1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrisbaneLyttonMember_019e1743-a9d5-7923-b57d-bdf91a20b570_terseLabel_en-US" xlink:label="lab_art_BrisbaneLyttonMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brisbane - Lytton</link:label>
    <link:label id="lab_art_BrisbaneLyttonMember_label_en-US" xlink:label="lab_art_BrisbaneLyttonMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brisbane - Lytton [Member]</link:label>
    <link:label id="lab_art_BrisbaneLyttonMember_documentation_en-US" xlink:label="lab_art_BrisbaneLyttonMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brisbane - Lytton</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrisbaneLyttonMember" xlink:href="art-20260806.xsd#art_BrisbaneLyttonMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrisbaneLyttonMember" xlink:to="lab_art_BrisbaneLyttonMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SikestonMO1Member_019e1743-aaf8-712b-949c-b1ccb4e0df87_terseLabel_en-US" xlink:label="lab_art_SikestonMO1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sikeston, MO</link:label>
    <link:label id="lab_art_SikestonMO1Member_label_en-US" xlink:label="lab_art_SikestonMO1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sikeston, MO 1 [Member]</link:label>
    <link:label id="lab_art_SikestonMO1Member_documentation_en-US" xlink:label="lab_art_SikestonMO1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sikeston, MO 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SikestonMO1Member" xlink:href="art-20260806.xsd#art_SikestonMO1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SikestonMO1Member" xlink:to="lab_art_SikestonMO1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_019e1743-ab7d-7b3a-bfcd-d9dc7f70710b_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating leases - net</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Right-of-Use Asset</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:to="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations_019e1743-a922-7a25-b241-b8bc9647ee9b_totalLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseCost_019e1743-a9d5-7bb1-a22d-b5b507f9a2eb_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating lease cost</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseCost_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseCost" xlink:to="lab_us-gaap_OperatingLeaseCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameDomain_019e1743-ab7d-7a98-a68a-028d9a975b0c_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:label id="lab_us-gaap_PlanNameDomain_label_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameDomain" xlink:to="lab_us-gaap_PlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OntarioOR1Member_019e1743-aaf8-7ed7-a57d-580d4a6a6a32_terseLabel_en-US" xlink:label="lab_art_OntarioOR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ontario, OR</link:label>
    <link:label id="lab_art_OntarioOR1Member_label_en-US" xlink:label="lab_art_OntarioOR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ontario, OR 1 [Member]</link:label>
    <link:label id="lab_art_OntarioOR1Member_documentation_en-US" xlink:label="lab_art_OntarioOR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ontario, OR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OntarioOR1Member" xlink:href="art-20260806.xsd#art_OntarioOR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OntarioOR1Member" xlink:to="lab_art_OntarioOR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WarehousesUnderSaleLeasebackTransactionsMember_019e1743-a9d5-7c64-98c9-1d83b5df526d_terseLabel_en-US" xlink:label="lab_art_WarehousesUnderSaleLeasebackTransactionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Warehouses Under Sale Leaseback Transactions</link:label>
    <link:label id="lab_art_WarehousesUnderSaleLeasebackTransactionsMember_label_en-US" xlink:label="lab_art_WarehousesUnderSaleLeasebackTransactionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Warehouses Under Sale Leaseback Transactions [Member]</link:label>
    <link:label id="lab_art_WarehousesUnderSaleLeasebackTransactionsMember_documentation_en-US" xlink:label="lab_art_WarehousesUnderSaleLeasebackTransactionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Warehouses Under Sale Leaseback Transactions [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WarehousesUnderSaleLeasebackTransactionsMember" xlink:href="art-20260806.xsd#art_WarehousesUnderSaleLeasebackTransactionsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WarehousesUnderSaleLeasebackTransactionsMember" xlink:to="lab_art_WarehousesUnderSaleLeasebackTransactionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SeabrookNJ2Member_019e1743-a9d5-7ddf-a28d-c5fdb5c4884c_terseLabel_en-US" xlink:label="lab_art_SeabrookNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Seabrook, NJ</link:label>
    <link:label id="lab_art_SeabrookNJ2Member_label_en-US" xlink:label="lab_art_SeabrookNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Seabrook, NJ 2 [Member]</link:label>
    <link:label id="lab_art_SeabrookNJ2Member_documentation_en-US" xlink:label="lab_art_SeabrookNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Seabrook, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SeabrookNJ2Member" xlink:href="art-20260806.xsd#art_SeabrookNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SeabrookNJ2Member" xlink:to="lab_art_SeabrookNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_019e1743-aa65-7791-bb53-73717d0ef830_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Exercised (in shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PerformanceBasedRestrictedStockUnitsMember_019e1743-ab7d-75ae-9024-ac33e4b27d96_terseLabel_en-US" xlink:label="lab_art_PerformanceBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance-Based Restricted Stock Units</link:label>
    <link:label id="lab_art_PerformanceBasedRestrictedStockUnitsMember_label_en-US" xlink:label="lab_art_PerformanceBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Performance-Based Restricted Stock Units [Member]</link:label>
    <link:label id="lab_art_PerformanceBasedRestrictedStockUnitsMember_documentation_en-US" xlink:label="lab_art_PerformanceBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Performance-Based Restricted Stock Units [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PerformanceBasedRestrictedStockUnitsMember" xlink:href="art-20260806.xsd#art_PerformanceBasedRestrictedStockUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PerformanceBasedRestrictedStockUnitsMember" xlink:to="lab_art_PerformanceBasedRestrictedStockUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaWestgateGA1Member_019e1743-aa65-7157-9e51-96c5e46bb1c5_terseLabel_en-US" xlink:label="lab_art_AtlantaWestgateGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Westgate, GA</link:label>
    <link:label id="lab_art_AtlantaWestgateGA1Member_label_en-US" xlink:label="lab_art_AtlantaWestgateGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Westgate, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaWestgateGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaWestgateGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Westgate, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaWestgateGA1Member" xlink:href="art-20260806.xsd#art_AtlantaWestgateGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaWestgateGA1Member" xlink:to="lab_art_AtlantaWestgateGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsValuationAllowance_019e1743-aaf8-79f9-a1b9-46ac1f2a25bb_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: valuation allowance</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Valuation Allowance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityAbstract_019e1743-aa65-7ac7-88d3-a5d0584d330f_terseLabel_en-US" xlink:label="lab_us-gaap_EquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity [Abstract]</link:label>
    <link:label id="lab_us-gaap_EquityAbstract_label_en-US" xlink:label="lab_us-gaap_EquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityAbstract" xlink:to="lab_us-gaap_EquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreasePercentage_019e1743-ab7d-7884-97b9-376ea2b02292_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreasePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rent increase percentage</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreasePercentage_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreasePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Rent Increase, Percentage</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreasePercentage_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreasePercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Rent Increase, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionRentIncreasePercentage" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionRentIncreasePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionRentIncreasePercentage" xlink:to="lab_art_SaleLeasebackTransactionRentIncreasePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand_019e1743-aa65-7466-bd0f-428049867809_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Land</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeMarsIA2Member_019e1743-a9d5-7b56-b624-565c957b46f5_terseLabel_en-US" xlink:label="lab_art_LeMarsIA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Le Mars, IA</link:label>
    <link:label id="lab_art_LeMarsIA2Member_label_en-US" xlink:label="lab_art_LeMarsIA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Le Mars, IA 2 [Member]</link:label>
    <link:label id="lab_art_LeMarsIA2Member_documentation_en-US" xlink:label="lab_art_LeMarsIA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Le Mars, IA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeMarsIA2Member" xlink:href="art-20260806.xsd#art_LeMarsIA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeMarsIA2Member" xlink:to="lab_art_LeMarsIA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CurrentFederalTaxExpenseBenefit_019e1743-a9d5-7421-9bc3-77923fd5280d_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">U.S. federal</link:label>
    <link:label id="lab_us-gaap_CurrentFederalTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Federal Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentFederalTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:to="lab_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019e1743-a9d5-7f80-9999-f7b3787c8b4c_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Stockholders' Equity [Roll Forward]</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Stockholders' Equity [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex_019e1743-a9d5-7018-a365-306ae57b9da6_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rent increase as a percentage of consumer price index</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Rent Increase, As a Percentage of Consumer Price Index</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Rent Increase, As a Percentage of Consumer Price Index</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex" xlink:to="lab_art_SaleLeasebackTransactionRentIncreaseAsAPercentageOfConsumerPriceIndex" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_019e1743-a9d5-7f26-9b70-99bf5cd9ea8e_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Capitalized Property Plant and Equipment</link:label>
    <link:label id="lab_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_label_en-US" xlink:label="lab_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Capitalized Property Plant and Equipment [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember" xlink:to="lab_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNoteTextBlock_019e1743-aa65-74af-a4ea-a9bfb4a5d4f5_terseLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Loss</link:label>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNoteTextBlock_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comprehensive Income (Loss) Note [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNoteTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:to="lab_us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SiouxFallsSD2Member_019e1743-a9d5-78fa-9d0f-c43ebdb3465f_terseLabel_en-US" xlink:label="lab_art_SiouxFallsSD2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sioux Falls, SD</link:label>
    <link:label id="lab_art_SiouxFallsSD2Member_label_en-US" xlink:label="lab_art_SiouxFallsSD2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sioux Falls, SD 2 [Member]</link:label>
    <link:label id="lab_art_SiouxFallsSD2Member_documentation_en-US" xlink:label="lab_art_SiouxFallsSD2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sioux Falls, SD 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SiouxFallsSD2Member" xlink:href="art-20260806.xsd#art_SiouxFallsSD2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SiouxFallsSD2Member" xlink:to="lab_art_SiouxFallsSD2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member_019e1743-ab7d-7262-b822-c47b88af0193_terseLabel_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Private Series D Notes</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member_label_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series D Notes, Due 2031 [Member]</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member_documentation_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series D Notes, Due 2031</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member" xlink:href="art-20260806.xsd#art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member" xlink:to="lab_art_PrivateSeniorUnsecuredSeriesDNotesDue2031Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SellingGeneralAndAdministrativeExpense_019e1743-aaf8-7320-9858-1dccd04970dc_terseLabel_en-US" xlink:label="lab_us-gaap_SellingGeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Selling, general, and administrative</link:label>
    <link:label id="lab_us-gaap_SellingGeneralAndAdministrativeExpense_019e1743-aaf8-724b-acd6-9ce212354304_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_SellingGeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Selling, general, and administrative</link:label>
    <link:label id="lab_us-gaap_SellingGeneralAndAdministrativeExpense_label_en-US" xlink:label="lab_us-gaap_SellingGeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Selling, General and Administrative Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SellingGeneralAndAdministrativeExpense" xlink:to="lab_us-gaap_SellingGeneralAndAdministrativeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_019e1743-aaf8-7d8c-8b97-596fcdc76b64_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Accumulated Other Comprehensive Loss</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireBuildings_019e1743-aa65-7a0b-865d-629ce9000c3b_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBuildings" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payments to acquire buildings</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireBuildings_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBuildings" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Buildings</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBuildings" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireBuildings"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireBuildings" xlink:to="lab_us-gaap_PaymentsToAcquireBuildings" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortSmithAR2Member_019e1743-a921-7797-8cd5-90ed64f921c5_terseLabel_en-US" xlink:label="lab_art_FortSmithAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Smith, AR</link:label>
    <link:label id="lab_art_FortSmithAR2Member_label_en-US" xlink:label="lab_art_FortSmithAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Smith, AR 2 [Member]</link:label>
    <link:label id="lab_art_FortSmithAR2Member_documentation_en-US" xlink:label="lab_art_FortSmithAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Smith, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortSmithAR2Member" xlink:href="art-20260806.xsd#art_FortSmithAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortSmithAR2Member" xlink:to="lab_art_FortSmithAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Diversey1Member_019e1743-aaf8-76a3-9eb4-8d23d47997de_terseLabel_en-US" xlink:label="lab_art_Diversey1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Diversey</link:label>
    <link:label id="lab_art_Diversey1Member_label_en-US" xlink:label="lab_art_Diversey1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Diversey 1 [Member]</link:label>
    <link:label id="lab_art_Diversey1Member_documentation_en-US" xlink:label="lab_art_Diversey1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Diversey 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Diversey1Member" xlink:href="art-20260806.xsd#art_Diversey1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Diversey1Member" xlink:to="lab_art_Diversey1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential_019e1743-aaf8-725c-8d8d-3f3b1bfbce8c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other Foreign Jurisdictions</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:to="lab_us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue_019e1743-aa65-71ec-8094-6b8d58496ec6_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Grant Date Fair Value (In thousands)</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants In Period, Grant Date Fair Value</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants In Period, Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue" xlink:to="lab_art_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LaPorteTX2Member_019e1743-a9d5-7f4e-85e6-89ac621a8511_terseLabel_en-US" xlink:label="lab_art_LaPorteTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LaPorte, TX</link:label>
    <link:label id="lab_art_LaPorteTX2Member_label_en-US" xlink:label="lab_art_LaPorteTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">LaPorte, TX 2 [Member]</link:label>
    <link:label id="lab_art_LaPorteTX2Member_documentation_en-US" xlink:label="lab_art_LaPorteTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">LaPorte, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LaPorteTX2Member" xlink:href="art-20260806.xsd#art_LaPorteTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LaPorteTX2Member" xlink:to="lab_art_LaPorteTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_EuropeMember_019e1743-aa65-7a1f-8676-f731194fbdeb_terseLabel_en-US" xlink:label="lab_srt_EuropeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Europe</link:label>
    <link:label id="lab_srt_EuropeMember_label_en-US" xlink:label="lab_srt_EuropeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Europe [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EuropeMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EuropeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_EuropeMember" xlink:to="lab_srt_EuropeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_019e1743-aaf8-7221-a1a1-5f7a0a240fc6_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock-Based Compensation</link:label>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_label_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:to="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019e1743-aa65-7645-b757-f5b7e1dc2776_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsAbstract_019e1743-a9d5-7bb1-b1cf-29851b085209_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:label id="lab_us-gaap_AssetsAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="lab_us-gaap_AssetsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions_019e1743-a9d5-7451-934c-fb68112e9390_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Advances to RSA, including accrued interest</link:label>
    <link:label id="lab_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions_label_en-US" xlink:label="lab_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investments in and Advances to Affiliates, at Fair Value, Gross Additions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions" xlink:to="lab_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DelhiLA2Member_019e1743-aa65-7c22-9a4d-7f046b68a7aa_terseLabel_en-US" xlink:label="lab_art_DelhiLA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Delhi, LA</link:label>
    <link:label id="lab_art_DelhiLA2Member_label_en-US" xlink:label="lab_art_DelhiLA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Delhi, LA 2 [Member]</link:label>
    <link:label id="lab_art_DelhiLA2Member_documentation_en-US" xlink:label="lab_art_DelhiLA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Delhi, LA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DelhiLA2Member" xlink:href="art-20260806.xsd#art_DelhiLA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DelhiLA2Member" xlink:to="lab_art_DelhiLA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember_019e1743-aaf8-7ed8-b9b4-f5394795c8b3_terseLabel_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on debt extinguishment, modifications and termination of derivative instruments</link:label>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember_label_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Extinguishment of Debt and Termination of Derivatives [Member]</link:label>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember_documentation_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Extinguishment of Debt and Termination of Derivatives [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember" xlink:href="art-20260806.xsd#art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember" xlink:to="lab_art_GainLossOnExtinguishmentOfDebtAndTerminationOfDerivativesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019e1743-ab7d-76ca-8ac1-a8598d3b13bf_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forfeited, grant date fair value (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold_019e1743-a9d5-747f-97e1-cda15828fa30_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Material acquisition threshold</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Material Acquisition Threshold</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Material Acquisition Threshold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantMaterialAcquisitionThreshold" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantMaterialAcquisitionThreshold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantMaterialAcquisitionThreshold" xlink:to="lab_art_DebtInstrumentCovenantMaterialAcquisitionThreshold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessAcquisitionLineItems_019e1743-ab7d-784e-9730-1acc99eae575_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combination [Line Items]</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionLineItems_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems" xlink:to="lab_us-gaap_BusinessAcquisitionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA2Member_019e1743-a9d5-7580-a694-1a8f0832786a_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tranche A-2</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA2Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A-2 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA2Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A-2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredTermLoanA2Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredTermLoanA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredTermLoanA2Member" xlink:to="lab_art_A20222020SeniorUnsecuredTermLoanA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LaPorteTX1Member_019e1743-ab7d-76c5-8bb1-0ab02cb1a6ad_terseLabel_en-US" xlink:label="lab_art_LaPorteTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LaPorte, TX</link:label>
    <link:label id="lab_art_LaPorteTX1Member_label_en-US" xlink:label="lab_art_LaPorteTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">LaPorte, TX 1 [Member]</link:label>
    <link:label id="lab_art_LaPorteTX1Member_documentation_en-US" xlink:label="lab_art_LaPorteTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">LaPorte, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LaPorteTX1Member" xlink:href="art-20260806.xsd#art_LaPorteTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LaPorteTX1Member" xlink:to="lab_art_LaPorteTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA3Member_019e1743-aaf8-7f72-a936-2daa7286bbf2_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Delayed Draw Tranche A-3</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA3Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A-3 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA3Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA3Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A-3</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredTermLoanA3Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredTermLoanA3Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredTermLoanA3Member" xlink:to="lab_art_A20222020SeniorUnsecuredTermLoanA3Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanNameDomain_019e1743-aa64-7b82-9e78-22c9fdb26bc9_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Plan Name [Domain]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanNameDomain_label_en-US" xlink:label="lab_us-gaap_RetirementPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanNameDomain" xlink:to="lab_us-gaap_RetirementPlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation_019e1743-ab7d-7a81-aea9-3032c333d672_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign currency translation gain</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member_019e1743-a9d5-7dc4-84f5-2338d17d74de_terseLabel_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Private Series E Notes</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member_label_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series E Notes, Due 2033 [Member]</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member_documentation_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series E Notes, Due 2033</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member" xlink:href="art-20260806.xsd#art_PrivateSeniorUnsecuredSeriesENotesDue2033Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member" xlink:to="lab_art_PrivateSeniorUnsecuredSeriesENotesDue2033Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionLiability_019e1743-aa65-7f92-9000-9d68d63c4aa5_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale-leaseback financing obligations</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionLiability_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Liability</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionLiability_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionLiability" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionLiability" xlink:to="lab_art_SaleLeasebackTransactionLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_019e1743-aa65-7d27-8a3c-0b640657d96e_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets held by various pension plans:</link:label>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_label_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Fair Value Disclosure</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosure" xlink:to="lab_us-gaap_AssetsFairValueDisclosure" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SalemOR1Member_019e1743-aaf8-7618-b51b-943180d5dfc6_terseLabel_en-US" xlink:label="lab_art_SalemOR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Salem, OR</link:label>
    <link:label id="lab_art_SalemOR1Member_label_en-US" xlink:label="lab_art_SalemOR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Salem, OR 1 [Member]</link:label>
    <link:label id="lab_art_SalemOR1Member_documentation_en-US" xlink:label="lab_art_SalemOR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Salem, OR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SalemOR1Member" xlink:href="art-20260806.xsd#art_SalemOR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SalemOR1Member" xlink:to="lab_art_SalemOR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum_019e1743-ab7d-71e6-9d5c-4a9e136d5c89_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, unsecured debt sercive ratio, minimum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Debt Service Ratio, Minimum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Debt Service Ratio, Minimum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum" xlink:to="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMinimum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NonRealEstateAssetsMember_019e1743-ab7d-7d51-b1d5-aa2cfd22404c_terseLabel_en-US" xlink:label="lab_art_NonRealEstateAssetsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-Real Estate Assets</link:label>
    <link:label id="lab_art_NonRealEstateAssetsMember_label_en-US" xlink:label="lab_art_NonRealEstateAssetsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-Real Estate Assets [Member]</link:label>
    <link:label id="lab_art_NonRealEstateAssetsMember_documentation_en-US" xlink:label="lab_art_NonRealEstateAssetsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Non-Real Estate Assets [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NonRealEstateAssetsMember" xlink:href="art-20260806.xsd#art_NonRealEstateAssetsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NonRealEstateAssetsMember" xlink:to="lab_art_NonRealEstateAssetsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_019e1743-aaf8-776a-b374-c51aee21d42b_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Building and improvements financing leases</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Right-of-Use Asset, before Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_019e1743-aa65-7386-bf2d-2f012749be82_verboseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value, total outstanding restricted stock units</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDebtTableTextBlock_019e1743-ab7d-757d-84eb-7c4ac297dc16_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Debt</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Debt [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDebtTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDebtTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDebtTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearFour_019e1743-a9d5-7cba-bfe1-67c2c751cb26_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Four</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearFour_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDueYearFour" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDueYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDueYearFour" xlink:to="lab_art_LeaseLiabilityPaymentsDueYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered_019e1743-aaf8-7741-a154-23e3f0554009_terseLabel_en-US" xlink:label="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of union employees covered</link:label>
    <link:label id="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered_label_en-US" xlink:label="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plan, Collective-Bargaining Arrangement, Percentage of Employer's Collective-Bargaining Participants Covered</link:label>
    <link:label id="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered_documentation_en-US" xlink:label="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Multiemployer Plan, Collective-Bargaining Arrangement, Percentage of Employer's Collective-Bargaining Participants Covered</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered" xlink:href="art-20260806.xsd#art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered" xlink:to="lab_art_MultiemployerPlanCollectiveBargainingArrangementPercentageofEmployersCollectiveBargainingParticipantsCovered" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_019e1743-a9d5-777a-a986-d115ed55fc34_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Intangible Assets Subject to Amortization</link:label>
    <link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Finite-Lived Intangible Assets [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MultiemployerPlansLineItems_019e1743-a9d5-70f8-ad70-1f556a629618_terseLabel_en-US" xlink:label="lab_us-gaap_MultiemployerPlansLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Multiemployer Plans [Line Items]</link:label>
    <link:label id="lab_us-gaap_MultiemployerPlansLineItems_label_en-US" xlink:label="lab_us-gaap_MultiemployerPlansLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plan [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlansLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlansLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MultiemployerPlansLineItems" xlink:to="lab_us-gaap_MultiemployerPlansLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_019e1743-aaf8-7781-a399-aedf500a1cb7_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss) [Table]</link:label>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss) [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_019e1743-a9d5-7252-873b-556f6b8b7af6_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income tax (expense) benefit:</link:label>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Expense (Benefit), Continuing Operations [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Calgary1Member_019e1743-ab7d-74e3-937a-12de58a2ce12_terseLabel_en-US" xlink:label="lab_art_Calgary1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Calgary</link:label>
    <link:label id="lab_art_Calgary1Member_label_en-US" xlink:label="lab_art_Calgary1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Calgary 1 [Member]</link:label>
    <link:label id="lab_art_Calgary1Member_documentation_en-US" xlink:label="lab_art_Calgary1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Calgary 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Calgary1Member" xlink:href="art-20260806.xsd#art_Calgary1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Calgary1Member" xlink:to="lab_art_Calgary1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DerivativeAmountofHedgedLiability_019e1743-a9d5-7310-a53b-466ce71ba21b_terseLabel_en-US" xlink:label="lab_art_DerivativeAmountofHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount of hedged loan</link:label>
    <link:label id="lab_art_DerivativeAmountofHedgedLiability_label_en-US" xlink:label="lab_art_DerivativeAmountofHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Amount of Hedged Liability</link:label>
    <link:label id="lab_art_DerivativeAmountofHedgedLiability_documentation_en-US" xlink:label="lab_art_DerivativeAmountofHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Derivative, Amount of Hedged Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DerivativeAmountofHedgedLiability" xlink:href="art-20260806.xsd#art_DerivativeAmountofHedgedLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DerivativeAmountofHedgedLiability" xlink:to="lab_art_DerivativeAmountofHedgedLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Ft.WorthTXRailhead2Member_019e1743-a922-795b-92ad-983eb9a6013b_terseLabel_en-US" xlink:label="lab_art_Ft.WorthTXRailhead2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Railhead)</link:label>
    <link:label id="lab_art_Ft.WorthTXRailhead2Member_label_en-US" xlink:label="lab_art_Ft.WorthTXRailhead2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Railhead) 2 [Member]</link:label>
    <link:label id="lab_art_Ft.WorthTXRailhead2Member_documentation_en-US" xlink:label="lab_art_Ft.WorthTXRailhead2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Railhead) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Ft.WorthTXRailhead2Member" xlink:href="art-20260806.xsd#art_Ft.WorthTXRailhead2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Ft.WorthTXRailhead2Member" xlink:to="lab_art_Ft.WorthTXRailhead2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GoldsboroCommercePA2Member_019e1743-aaf8-7270-aa93-c997feb56b22_terseLabel_en-US" xlink:label="lab_art_GoldsboroCommercePA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goldsboro Commerce, PA</link:label>
    <link:label id="lab_art_GoldsboroCommercePA2Member_label_en-US" xlink:label="lab_art_GoldsboroCommercePA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goldsboro Commerce, PA 2 [Member]</link:label>
    <link:label id="lab_art_GoldsboroCommercePA2Member_documentation_en-US" xlink:label="lab_art_GoldsboroCommercePA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Goldsboro Commerce, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GoldsboroCommercePA2Member" xlink:href="art-20260806.xsd#art_GoldsboroCommercePA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GoldsboroCommercePA2Member" xlink:to="lab_art_GoldsboroCommercePA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum_019e1743-aa65-78d2-918b-a0e5201e6ada_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum fixed charge coverage ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Fixed Charge Coverage Ratio, Minimum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Fixed Charge Coverage Ratio, Minimum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" xlink:to="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMinimum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member_019e1743-aaf8-74ff-8a3c-a8a350945246_terseLabel_en-US" xlink:label="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Americold Realty Operating Partnership, L.P..</link:label>
    <link:label id="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member_label_en-US" xlink:label="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Americold Realty Operating Partnership, L.P. [Member]</link:label>
    <link:label id="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member_documentation_en-US" xlink:label="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Americold Realty Operating Partnership, L.P. [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmericoldRealtyOperatingPartnershipL.P.Member" xlink:href="art-20260806.xsd#art_AmericoldRealtyOperatingPartnershipL.P.Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmericoldRealtyOperatingPartnershipL.P.Member" xlink:to="lab_art_AmericoldRealtyOperatingPartnershipL.P.Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DublinMember_019e1743-aaf8-72f1-a6e5-91e1f78af19a_terseLabel_en-US" xlink:label="lab_art_DublinMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dublin</link:label>
    <link:label id="lab_art_DublinMember_label_en-US" xlink:label="lab_art_DublinMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dublin [Member]</link:label>
    <link:label id="lab_art_DublinMember_documentation_en-US" xlink:label="lab_art_DublinMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dublin</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DublinMember" xlink:href="art-20260806.xsd#art_DublinMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DublinMember" xlink:to="lab_art_DublinMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation_019e1743-a9d5-7672-bc48-fcb9a979f935_negatedLabel_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Income tax expense</link:label>
    <link:label id="lab_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation_label_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discontinued Operation, Tax Effect of Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation" xlink:to="lab_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_019e1743-a9d5-7a0b-8dbe-91993e640172_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average assumptions used to determine net periodic benefit cost (statement of operations):</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract" xlink:to="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FremontNE1Member_019e1743-aa64-7123-98cb-d80a9461a0e1_terseLabel_en-US" xlink:label="lab_art_FremontNE1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fremont, NE</link:label>
    <link:label id="lab_art_FremontNE1Member_label_en-US" xlink:label="lab_art_FremontNE1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fremont, NE 1 [Member]</link:label>
    <link:label id="lab_art_FremontNE1Member_documentation_en-US" xlink:label="lab_art_FremontNE1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fremont, NE 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FremontNE1Member" xlink:href="art-20260806.xsd#art_FremontNE1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FremontNE1Member" xlink:to="lab_art_FremontNE1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ElevenWarehouses2007Member_019e1743-aa65-7e58-a101-f840910cceb1_terseLabel_en-US" xlink:label="lab_art_ElevenWarehouses2007Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Eleven Warehouses, 2007</link:label>
    <link:label id="lab_art_ElevenWarehouses2007Member_label_en-US" xlink:label="lab_art_ElevenWarehouses2007Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Eleven Warehouses, 2007 [Member]</link:label>
    <link:label id="lab_art_ElevenWarehouses2007Member_documentation_en-US" xlink:label="lab_art_ElevenWarehouses2007Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Eleven Warehouses, 2007 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ElevenWarehouses2007Member" xlink:href="art-20260806.xsd#art_ElevenWarehouses2007Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ElevenWarehouses2007Member" xlink:to="lab_art_ElevenWarehouses2007Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_019e1743-a921-71cf-a65b-27d9e0ab8f20_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Conversion of convertible securities</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, Conversion of Convertible Securities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019e1743-aa65-70ba-8920-f687c9123555_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock-based compensation expense</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">APIC, Share-Based Payment Arrangement, Increase for Cost Recognition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock_019e1743-a9d5-7d50-b4de-c7eb671e6bb7_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combinations and Asset Acquisitions</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combinations and Other Purchase of Business Transactions, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock" xlink:to="lab_us-gaap_BusinessCombinationsAndOtherPurchaseOfBusinessTransactionsPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortSmithAR1Member_019e1743-aa64-762d-ab88-cac1fbf1a819_terseLabel_en-US" xlink:label="lab_art_FortSmithAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Smith, AR</link:label>
    <link:label id="lab_art_FortSmithAR1Member_label_en-US" xlink:label="lab_art_FortSmithAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Smith, AR 1 [Member]</link:label>
    <link:label id="lab_art_FortSmithAR1Member_documentation_en-US" xlink:label="lab_art_FortSmithAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Smith, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortSmithAR1Member" xlink:href="art-20260806.xsd#art_FortSmithAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortSmithAR1Member" xlink:to="lab_art_FortSmithAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentDomain_019e1743-aaf8-730f-b70c-f257c22e1bbe_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segments [Domain]</link:label>
    <link:label id="lab_us-gaap_SegmentDomain_label_en-US" xlink:label="lab_us-gaap_SegmentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segments [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentDomain" xlink:to="lab_us-gaap_SegmentDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NumberOfEmployeesTotalMember_019e1743-aa64-7d0b-9029-bb0c48e6f5cd_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfEmployeesTotalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Employees</link:label>
    <link:label id="lab_us-gaap_NumberOfEmployeesTotalMember_label_en-US" xlink:label="lab_us-gaap_NumberOfEmployeesTotalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Employees, Total [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfEmployeesTotalMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfEmployeesTotalMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfEmployeesTotalMember" xlink:to="lab_us-gaap_NumberOfEmployeesTotalMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract_019e1743-a9d5-706f-8c68-73b0b4b76431_terseLabel_en-US" xlink:label="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss:</link:label>
    <link:label id="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract_label_en-US" xlink:label="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" xlink:to="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTaxAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_019e1743-aa65-7eef-b67f-4ad3125d0463_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of deferred financing costs and pension withdrawal liability</link:label>
    <link:label id="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_label_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Debt Issuance Costs and Discounts</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:to="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AssetAcquisitionsMember_019e1743-ab7d-79aa-b40b-e54f02395589_terseLabel_en-US" xlink:label="lab_art_AssetAcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset Acquisitions</link:label>
    <link:label id="lab_art_AssetAcquisitionsMember_label_en-US" xlink:label="lab_art_AssetAcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Acquisitions [Member]</link:label>
    <link:label id="lab_art_AssetAcquisitionsMember_documentation_en-US" xlink:label="lab_art_AssetAcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Asset Acquisitions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AssetAcquisitionsMember" xlink:href="art-20260806.xsd#art_AssetAcquisitionsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AssetAcquisitionsMember" xlink:to="lab_art_AssetAcquisitionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AugustaGA2Member_019e1743-a9d5-7dd4-82d9-67b148ac7447_terseLabel_en-US" xlink:label="lab_art_AugustaGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Augusta, GA</link:label>
    <link:label id="lab_art_AugustaGA2Member_label_en-US" xlink:label="lab_art_AugustaGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Augusta, GA 2 [Member]</link:label>
    <link:label id="lab_art_AugustaGA2Member_documentation_en-US" xlink:label="lab_art_AugustaGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Augusta, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AugustaGA2Member" xlink:href="art-20260806.xsd#art_AugustaGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AugustaGA2Member" xlink:to="lab_art_AugustaGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RealEstateNotUnderConstructionNettingMember_019e1743-aaf8-74ff-b2bb-33e560129e1a_terseLabel_en-US" xlink:label="lab_art_RealEstateNotUnderConstructionNettingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets Not Under Construction, Net</link:label>
    <link:label id="lab_art_RealEstateNotUnderConstructionNettingMember_label_en-US" xlink:label="lab_art_RealEstateNotUnderConstructionNettingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Not Under Construction, Netting [Member]</link:label>
    <link:label id="lab_art_RealEstateNotUnderConstructionNettingMember_documentation_en-US" xlink:label="lab_art_RealEstateNotUnderConstructionNettingMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Real Estate Not Under Construction, Netting</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RealEstateNotUnderConstructionNettingMember" xlink:href="art-20260806.xsd#art_RealEstateNotUnderConstructionNettingMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RealEstateNotUnderConstructionNettingMember" xlink:to="lab_art_RealEstateNotUnderConstructionNettingMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Murarrie1Member_019e1743-a9d5-7b7a-9823-126c472e0ebe_terseLabel_en-US" xlink:label="lab_art_Murarrie1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Murarrie</link:label>
    <link:label id="lab_art_Murarrie1Member_label_en-US" xlink:label="lab_art_Murarrie1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Murarrie 1 [Member]</link:label>
    <link:label id="lab_art_Murarrie1Member_documentation_en-US" xlink:label="lab_art_Murarrie1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Murarrie 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Murarrie1Member" xlink:href="art-20260806.xsd#art_Murarrie1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Murarrie1Member" xlink:to="lab_art_Murarrie1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WallulaWA1Member_019e1743-aa65-7705-8e6f-61a80df3a444_terseLabel_en-US" xlink:label="lab_art_WallulaWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wallula, WA</link:label>
    <link:label id="lab_art_WallulaWA1Member_label_en-US" xlink:label="lab_art_WallulaWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wallula, WA 1 [Member]</link:label>
    <link:label id="lab_art_WallulaWA1Member_documentation_en-US" xlink:label="lab_art_WallulaWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Wallula, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WallulaWA1Member" xlink:href="art-20260806.xsd#art_WallulaWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WallulaWA1Member" xlink:to="lab_art_WallulaWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HoustonTX1Member_019e1743-aa65-7fcd-8979-80a465bd62f1_terseLabel_en-US" xlink:label="lab_art_HoustonTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Houston, TX</link:label>
    <link:label id="lab_art_HoustonTX1Member_label_en-US" xlink:label="lab_art_HoustonTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Houston, TX 1 [Member]</link:label>
    <link:label id="lab_art_HoustonTX1Member_documentation_en-US" xlink:label="lab_art_HoustonTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Houston, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HoustonTX1Member" xlink:href="art-20260806.xsd#art_HoustonTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HoustonTX1Member" xlink:to="lab_art_HoustonTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SeniorNotesMember_019e1743-aaf8-787a-8397-27335c7f85df_terseLabel_en-US" xlink:label="lab_us-gaap_SeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Notes</link:label>
    <link:label id="lab_us-gaap_SeniorNotesMember_label_en-US" xlink:label="lab_us-gaap_SeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Notes [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SeniorNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SeniorNotesMember" xlink:to="lab_us-gaap_SeniorNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WWECLocal863PensionFundMember_019e1743-aa64-7487-b749-2854e654e5dc_terseLabel_en-US" xlink:label="lab_art_WWECLocal863PensionFundMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">WWEC Local 863 Pension Fund</link:label>
    <link:label id="lab_art_WWECLocal863PensionFundMember_label_en-US" xlink:label="lab_art_WWECLocal863PensionFundMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">WWEC Local 863 Pension Fund [Member]</link:label>
    <link:label id="lab_art_WWECLocal863PensionFundMember_documentation_en-US" xlink:label="lab_art_WWECLocal863PensionFundMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">WWEC Local 863 Pension Fund</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WWECLocal863PensionFundMember" xlink:href="art-20260806.xsd#art_WWECLocal863PensionFundMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WWECLocal863PensionFundMember" xlink:to="lab_art_WWECLocal863PensionFundMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_019e1743-ab7d-70e1-839b-cfafa84e1447_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Deferred Tax Assets and Liabilities</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Deferred Tax Assets and Liabilities [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockValue_019e1743-aaf8-71e9-be0b-24e33b6dd224_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock, $0.01 par value per share&#160;&#8211; 500,000,000 authorized shares; 284,871,943 and 284,265,041 shares issued and outstanding at December&#160;31, 2025 and 2024, respectively</link:label>
    <link:label id="lab_us-gaap_CommonStockValue_label_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Value, Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockValue" xlink:to="lab_us-gaap_CommonStockValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseRemainingLeaseTerm_019e1743-ab7d-738c-a8d7-51d6349ba7d6_terseLabel_en-US" xlink:label="lab_art_LeaseRemainingLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remaining lease term</link:label>
    <link:label id="lab_art_LeaseRemainingLeaseTerm_label_en-US" xlink:label="lab_art_LeaseRemainingLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Remaining Lease Term</link:label>
    <link:label id="lab_art_LeaseRemainingLeaseTerm_documentation_en-US" xlink:label="lab_art_LeaseRemainingLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Remaining Lease Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseRemainingLeaseTerm" xlink:href="art-20260806.xsd#art_LeaseRemainingLeaseTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseRemainingLeaseTerm" xlink:to="lab_art_LeaseRemainingLeaseTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_TitleOfIndividualAxis_019e1743-a9d5-7977-997d-c8216413369b_terseLabel_en-US" xlink:label="lab_srt_TitleOfIndividualAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Title and Position [Axis]</link:label>
    <link:label id="lab_srt_TitleOfIndividualAxis_label_en-US" xlink:label="lab_srt_TitleOfIndividualAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title and Position [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_TitleOfIndividualAxis" xlink:to="lab_srt_TitleOfIndividualAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock_019e1743-a921-7170-b74c-9ce652d9dc51_terseLabel_en-US" xlink:label="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Assumptions Used in Valuations</link:label>
    <link:label id="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock_label_en-US" xlink:label="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Payment Award, Performance Shares, Valuation Assumptions [Table Text Block]</link:label>
    <link:label id="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock_documentation_en-US" xlink:label="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Payment Award, Performance Shares, Valuation Assumptions [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock" xlink:href="art-20260806.xsd#art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock" xlink:to="lab_art_ScheduleofSharebasedPaymentAwardPerformanceSharesValuationAssumptionsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnassertedClaimMember_019e1743-a9d5-77cb-958f-5be1981ea3e5_terseLabel_en-US" xlink:label="lab_us-gaap_UnassertedClaimMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unasserted Claim - OSHA</link:label>
    <link:label id="lab_us-gaap_UnassertedClaimMember_label_en-US" xlink:label="lab_us-gaap_UnassertedClaimMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unasserted Claim [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnassertedClaimMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnassertedClaimMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnassertedClaimMember" xlink:to="lab_us-gaap_UnassertedClaimMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherOwnershipInterestMember_019e1743-a9d5-76be-8af7-1bc1f30485b6_terseLabel_en-US" xlink:label="lab_us-gaap_OtherOwnershipInterestMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other limited partners</link:label>
    <link:label id="lab_us-gaap_OtherOwnershipInterestMember_label_en-US" xlink:label="lab_us-gaap_OtherOwnershipInterestMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Ownership Interest [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOwnershipInterestMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherOwnershipInterestMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherOwnershipInterestMember" xlink:to="lab_us-gaap_OtherOwnershipInterestMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MakoMako1Member_019e1743-a9d5-73af-a39f-5e05c6301e2d_terseLabel_en-US" xlink:label="lab_art_MakoMako1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mako Mako</link:label>
    <link:label id="lab_art_MakoMako1Member_label_en-US" xlink:label="lab_art_MakoMako1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mako Mako 1 [Member]</link:label>
    <link:label id="lab_art_MakoMako1Member_documentation_en-US" xlink:label="lab_art_MakoMako1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mako Mako 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MakoMako1Member" xlink:href="art-20260806.xsd#art_MakoMako1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MakoMako1Member" xlink:to="lab_art_MakoMako1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember_019e1743-aa65-712e-a650-d65843bca959_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common/collective trusts</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Collective Trust [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember" xlink:to="lab_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BridgewaterNJMember_019e1743-ab7d-7bf0-b2a0-0913c0dfe87a_terseLabel_en-US" xlink:label="lab_art_BridgewaterNJMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bridgewater, NJ</link:label>
    <link:label id="lab_art_BridgewaterNJMember_label_en-US" xlink:label="lab_art_BridgewaterNJMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bridgewater, NJ [Member]</link:label>
    <link:label id="lab_art_BridgewaterNJMember_documentation_en-US" xlink:label="lab_art_BridgewaterNJMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bridgewater, NJ</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BridgewaterNJMember" xlink:href="art-20260806.xsd#art_BridgewaterNJMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BridgewaterNJMember" xlink:to="lab_art_BridgewaterNJMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_019e1743-a921-791a-a1f0-4e8af653a09c_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of OP Units Activity</link:label>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Nonvested Share Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Savannah2GA1Member_019e1743-ab7d-74b2-ade4-a8a1f586fed7_terseLabel_en-US" xlink:label="lab_art_Savannah2GA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Savannah 2, GA</link:label>
    <link:label id="lab_art_Savannah2GA1Member_label_en-US" xlink:label="lab_art_Savannah2GA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Savannah 2, GA 1 [Member]</link:label>
    <link:label id="lab_art_Savannah2GA1Member_documentation_en-US" xlink:label="lab_art_Savannah2GA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Savannah 2, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Savannah2GA1Member" xlink:href="art-20260806.xsd#art_Savannah2GA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Savannah2GA1Member" xlink:to="lab_art_Savannah2GA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_019e1743-aaf8-7b42-aea5-4825114fa12a_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ownership interest, percent</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_019e1743-aaf8-7513-8581-645289798d02_verboseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">% Ownership</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Ownership Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:to="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity_019e1743-a921-7ead-9577-ec4148120798_terseLabel_en-US" xlink:label="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain from sale of partially owned entity</link:label>
    <link:label id="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity_label_en-US" xlink:label="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From The Sale of Partially Owned Entity, Operating Activity</link:label>
    <link:label id="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity_documentation_en-US" xlink:label="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From The Sale of Partially Owned Entity, Operating Activity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity" xlink:href="art-20260806.xsd#art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity" xlink:to="lab_art_ProceedsFromTheSaleOfPartiallyOwnedEntityOperatingActivity" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SeriesDAndSeriesENotesMember_019e1743-aaf8-7219-8697-570be63a7883_terseLabel_en-US" xlink:label="lab_art_SeriesDAndSeriesENotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Series D and Series E Notes</link:label>
    <link:label id="lab_art_SeriesDAndSeriesENotesMember_label_en-US" xlink:label="lab_art_SeriesDAndSeriesENotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Series D and Series E Notes [Member]</link:label>
    <link:label id="lab_art_SeriesDAndSeriesENotesMember_documentation_en-US" xlink:label="lab_art_SeriesDAndSeriesENotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Series D and Series E Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SeriesDAndSeriesENotesMember" xlink:href="art-20260806.xsd#art_SeriesDAndSeriesENotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SeriesDAndSeriesENotesMember" xlink:to="lab_art_SeriesDAndSeriesENotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax_019e1743-a921-7fbb-84f7-45e497cd43c0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss related to reclassification of foreign currency translation adjustment</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerAbstract_019e1743-aaf8-7854-b213-0ede759206c9_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer [Abstract]</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerAbstract_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_HedgingDesignationAxis_019e1743-aa65-7e2d-8b1e-f380d688d5de_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingDesignationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hedging Designation [Axis]</link:label>
    <link:label id="lab_us-gaap_HedgingDesignationAxis_label_en-US" xlink:label="lab_us-gaap_HedgingDesignationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hedging Designation [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HedgingDesignationAxis" xlink:to="lab_us-gaap_HedgingDesignationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_StatementScenarioAxis_019e1743-a9d5-7d8a-8dd8-081ac42eb009_terseLabel_en-US" xlink:label="lab_srt_StatementScenarioAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Scenario [Axis]</link:label>
    <link:label id="lab_srt_StatementScenarioAxis_label_en-US" xlink:label="lab_srt_StatementScenarioAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Scenario [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementScenarioAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_StatementScenarioAxis" xlink:to="lab_srt_StatementScenarioAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts_019e1743-aaf8-7956-a9a0-36ae121d99b3_terseLabel_en-US" xlink:label="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued warehouse expenses</link:label>
    <link:label id="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts_label_en-US" xlink:label="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Utilities, Property Taxes, And Warehouse Costs</link:label>
    <link:label id="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts_documentation_en-US" xlink:label="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accrued Utilities, Property Taxes, And Warehouse Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts" xlink:href="art-20260806.xsd#art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts" xlink:to="lab_art_AccruedUtilitiesPropertyTaxesAndWarehouseCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges_019e1743-aa65-7227-b84f-e0a375a0ff56_negatedTerseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Impact of foreign exchange rate changes</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Foreign Exchange Rate Changes</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Foreign Exchange Rate Changes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedDepreciationForeignExchangeRateChanges" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ChillicotheMO1Member_019e1743-a9d5-7a42-8886-3f690952b89b_terseLabel_en-US" xlink:label="lab_art_ChillicotheMO1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chillicothe, MO</link:label>
    <link:label id="lab_art_ChillicotheMO1Member_label_en-US" xlink:label="lab_art_ChillicotheMO1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chillicothe, MO 1 [Member]</link:label>
    <link:label id="lab_art_ChillicotheMO1Member_documentation_en-US" xlink:label="lab_art_ChillicotheMO1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chillicothe, MO 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ChillicotheMO1Member" xlink:href="art-20260806.xsd#art_ChillicotheMO1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ChillicotheMO1Member" xlink:to="lab_art_ChillicotheMO1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DomesticPlanMember_019e1743-aa65-7733-8dc3-3fcc9103287f_terseLabel_en-US" xlink:label="lab_us-gaap_DomesticPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Domestic Plan</link:label>
    <link:label id="lab_us-gaap_DomesticPlanMember_label_en-US" xlink:label="lab_us-gaap_DomesticPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Domestic Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticPlanMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DomesticPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DomesticPlanMember" xlink:to="lab_us-gaap_DomesticPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_019e1743-aa65-79ff-bbf0-212539dbdb6c_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount of Gain or (Loss) to Earnings from AOCI Reclassifications</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeContractTypeDomain_019e1743-aa64-7ff2-bbb3-fd5b54bb3eca_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeContractTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Contract [Domain]</link:label>
    <link:label id="lab_us-gaap_DerivativeContractTypeDomain_label_en-US" xlink:label="lab_us-gaap_DerivativeContractTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Contract [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeContractTypeDomain" xlink:to="lab_us-gaap_DerivativeContractTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_019e1743-aa65-7b58-af85-50be81ceaf0c_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net proceeds from issuance of common stock</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of Common Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:to="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_019e1743-a922-773e-9d99-885f8a00b60c_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HendersonNV2Member_019e1743-a9d5-77c9-a8c4-6af98a547034_terseLabel_en-US" xlink:label="lab_art_HendersonNV2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Henderson, NV</link:label>
    <link:label id="lab_art_HendersonNV2Member_label_en-US" xlink:label="lab_art_HendersonNV2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Henderson, NV 2 [Member]</link:label>
    <link:label id="lab_art_HendersonNV2Member_documentation_en-US" xlink:label="lab_art_HendersonNV2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Henderson, NV 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HendersonNV2Member" xlink:href="art-20260806.xsd#art_HendersonNV2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HendersonNV2Member" xlink:to="lab_art_HendersonNV2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_019e1743-aaf8-79fc-b42e-90e976322716_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Additions to property, buildings and equipment</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Property, Plant, and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BelvidereLandmarkILCrossDockMember_019e1743-aaf8-749c-bb63-178ad085667c_terseLabel_en-US" xlink:label="lab_art_BelvidereLandmarkILCrossDockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Belvidere-Landmark, IL (Cross Dock)</link:label>
    <link:label id="lab_art_BelvidereLandmarkILCrossDockMember_label_en-US" xlink:label="lab_art_BelvidereLandmarkILCrossDockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Belvidere-Landmark, IL (Cross Dock) [Member]</link:label>
    <link:label id="lab_art_BelvidereLandmarkILCrossDockMember_documentation_en-US" xlink:label="lab_art_BelvidereLandmarkILCrossDockMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Belvidere-Landmark, IL (Cross Dock) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BelvidereLandmarkILCrossDockMember" xlink:href="art-20260806.xsd#art_BelvidereLandmarkILCrossDockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BelvidereLandmarkILCrossDockMember" xlink:to="lab_art_BelvidereLandmarkILCrossDockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount_019e1743-a921-7d9f-9283-8997b5da69d7_negatedTerseLabel_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Equity awards</link:label>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount_label_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Equity Awards, Amount</link:label>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount_documentation_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Equity Awards, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount" xlink:href="art-20260806.xsd#art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount" xlink:to="lab_art_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseEquityAwardsAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019e1743-a921-7298-b3ae-9d8be25da20a_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expiration period</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaTradewaterGA2Member_019e1743-a922-7c34-8fcf-df7d911fdb05_terseLabel_en-US" xlink:label="lab_art_AtlantaTradewaterGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Tradewater, GA</link:label>
    <link:label id="lab_art_AtlantaTradewaterGA2Member_label_en-US" xlink:label="lab_art_AtlantaTradewaterGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Tradewater, GA 2 [Member]</link:label>
    <link:label id="lab_art_AtlantaTradewaterGA2Member_documentation_en-US" xlink:label="lab_art_AtlantaTradewaterGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Tradewater, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaTradewaterGA2Member" xlink:href="art-20260806.xsd#art_AtlantaTradewaterGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaTradewaterGA2Member" xlink:to="lab_art_AtlantaTradewaterGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SpringdaleAR2Member_019e1743-aa65-7163-9e23-7ce6e409e7ce_terseLabel_en-US" xlink:label="lab_art_SpringdaleAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Springdale, AR</link:label>
    <link:label id="lab_art_SpringdaleAR2Member_label_en-US" xlink:label="lab_art_SpringdaleAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Springdale, AR 2 [Member]</link:label>
    <link:label id="lab_art_SpringdaleAR2Member_documentation_en-US" xlink:label="lab_art_SpringdaleAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Springdale, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SpringdaleAR2Member" xlink:href="art-20260806.xsd#art_SpringdaleAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SpringdaleAR2Member" xlink:to="lab_art_SpringdaleAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_019e1743-ab7d-7ee6-8605-0d855dc59f40_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impact of foreign currency translation</link:label>
    <link:label id="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_label_en-US" xlink:label="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Foreign Currency Translation, Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:to="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Summerville2Member_019e1743-aaf8-7e88-ba5b-35969aaf5a1d_terseLabel_en-US" xlink:label="lab_art_Summerville2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summerville</link:label>
    <link:label id="lab_art_Summerville2Member_label_en-US" xlink:label="lab_art_Summerville2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Summerville 2 [Member]</link:label>
    <link:label id="lab_art_Summerville2Member_documentation_en-US" xlink:label="lab_art_Summerville2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Summerville 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Summerville2Member" xlink:href="art-20260806.xsd#art_Summerville2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Summerville2Member" xlink:to="lab_art_Summerville2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BurleyID1Member_019e1743-aaf8-7b4b-a0b6-305af2bbd83e_terseLabel_en-US" xlink:label="lab_art_BurleyID1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Burley, ID</link:label>
    <link:label id="lab_art_BurleyID1Member_label_en-US" xlink:label="lab_art_BurleyID1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Burley, ID 1 [Member]</link:label>
    <link:label id="lab_art_BurleyID1Member_documentation_en-US" xlink:label="lab_art_BurleyID1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Burley, ID 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BurleyID1Member" xlink:href="art-20260806.xsd#art_BurleyID1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BurleyID1Member" xlink:to="lab_art_BurleyID1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainLossOnSaleOfOtherInvestments_019e1743-a9d5-7d2e-b9cd-1ef11b493e6a_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfOtherInvestments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss from investments in partially owned entities</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfOtherInvestments_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfOtherInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Sale of Other Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfOtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfOtherInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnSaleOfOtherInvestments" xlink:to="lab_us-gaap_GainLossOnSaleOfOtherInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BarneveldNetherlandsMember_019e1743-aa64-7d84-a36b-6d5b97e89213_terseLabel_en-US" xlink:label="lab_art_BarneveldNetherlandsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Barneveld, Netherlands</link:label>
    <link:label id="lab_art_BarneveldNetherlandsMember_label_en-US" xlink:label="lab_art_BarneveldNetherlandsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Barneveld, Netherlands [Member]</link:label>
    <link:label id="lab_art_BarneveldNetherlandsMember_documentation_en-US" xlink:label="lab_art_BarneveldNetherlandsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Barneveld, Netherlands</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BarneveldNetherlandsMember" xlink:href="art-20260806.xsd#art_BarneveldNetherlandsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BarneveldNetherlandsMember" xlink:to="lab_art_BarneveldNetherlandsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Oxford2Member_019e1743-aaf8-7eed-9451-cc93a5385f46_terseLabel_en-US" xlink:label="lab_art_Oxford2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Oxford</link:label>
    <link:label id="lab_art_Oxford2Member_label_en-US" xlink:label="lab_art_Oxford2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Oxford 2 [Member]</link:label>
    <link:label id="lab_art_Oxford2Member_documentation_en-US" xlink:label="lab_art_Oxford2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Oxford 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Oxford2Member" xlink:href="art-20260806.xsd#art_Oxford2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Oxford2Member" xlink:to="lab_art_Oxford2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_019e1743-ab7d-7933-ae01-85c42416805e_terseLabel_en-US" xlink:label="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Partner Type of Partners' Capital Account, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_label_en-US" xlink:label="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Partner Type of Partners' Capital Account, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:to="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock_019e1743-a9d5-7a03-9fe3-99334e4594e9_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease Accounting</link:label>
    <link:label id="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeasesOfLessorDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:to="lab_us-gaap_OperatingLeasesOfLessorDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ScenarioForecastMember_019e1743-a9d5-7363-8719-5e714a1f2347_terseLabel_en-US" xlink:label="lab_srt_ScenarioForecastMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forecast</link:label>
    <link:label id="lab_srt_ScenarioForecastMember_label_en-US" xlink:label="lab_srt_ScenarioForecastMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forecast [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioForecastMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ScenarioForecastMember" xlink:to="lab_srt_ScenarioForecastMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DerivativesNumberOfInstrumentsTerminated_019e1743-aaf8-71e6-bbb8-7253a47f15df_terseLabel_en-US" xlink:label="lab_art_DerivativesNumberOfInstrumentsTerminated" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of instruments terminated</link:label>
    <link:label id="lab_art_DerivativesNumberOfInstrumentsTerminated_label_en-US" xlink:label="lab_art_DerivativesNumberOfInstrumentsTerminated" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivatives, Number of Instruments Terminated</link:label>
    <link:label id="lab_art_DerivativesNumberOfInstrumentsTerminated_documentation_en-US" xlink:label="lab_art_DerivativesNumberOfInstrumentsTerminated" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Derivatives, Number of Instruments Terminated</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DerivativesNumberOfInstrumentsTerminated" xlink:href="art-20260806.xsd#art_DerivativesNumberOfInstrumentsTerminated"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DerivativesNumberOfInstrumentsTerminated" xlink:to="lab_art_DerivativesNumberOfInstrumentsTerminated" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskBenchmarkDomain_019e1743-aa65-7685-8129-8516f5b2721b_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Domain]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskBenchmarkDomain_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:to="lab_us-gaap_ConcentrationRiskBenchmarkDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_Security12bTitle_019e1743-aa65-775b-947a-6799b1782ec9_terseLabel_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:label id="lab_dei_Security12bTitle_label_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_Security12bTitle" xlink:to="lab_dei_Security12bTitle" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionTable_019e1743-aaf8-7e78-87be-39425d17a2cb_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Table]</link:label>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionTable_label_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable" xlink:to="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BreaCAMember_019e1743-ab7d-764b-acd2-69fb5615832d_terseLabel_en-US" xlink:label="lab_art_BreaCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brea, CA</link:label>
    <link:label id="lab_art_BreaCAMember_label_en-US" xlink:label="lab_art_BreaCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brea, CA [Member]</link:label>
    <link:label id="lab_art_BreaCAMember_documentation_en-US" xlink:label="lab_art_BreaCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brea, CA [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BreaCAMember" xlink:href="art-20260806.xsd#art_BreaCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BreaCAMember" xlink:to="lab_art_BreaCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_019e1743-aaf8-7e13-a276-ffe76add3c69_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net income (loss) per common share</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareAbstract" xlink:to="lab_us-gaap_EarningsPerShareAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_019e1743-ab7d-730f-8bb8-5638e48fb3cb_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised_019e1743-a9d5-784b-978b-b6960cf316c6_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of useful life where control maintained</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Percentage of Useful Life Where Control Exercised</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Percentage of Useful Life Where Control Exercised</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised" xlink:to="lab_art_SaleLeasebackTransactionPercentageofUsefulLifeWhereControlExercised" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SiouxCityIA2900MurraySt2Member_019e1743-aaf8-71ac-8b7d-c440f7c02478_terseLabel_en-US" xlink:label="lab_art_SiouxCityIA2900MurraySt2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2900 Murray St</link:label>
    <link:label id="lab_art_SiouxCityIA2900MurraySt2Member_label_en-US" xlink:label="lab_art_SiouxCityIA2900MurraySt2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2900 Murray St 2 [Member]</link:label>
    <link:label id="lab_art_SiouxCityIA2900MurraySt2Member_documentation_en-US" xlink:label="lab_art_SiouxCityIA2900MurraySt2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2900 Murray St 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SiouxCityIA2900MurraySt2Member" xlink:href="art-20260806.xsd#art_SiouxCityIA2900MurraySt2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SiouxCityIA2900MurraySt2Member" xlink:to="lab_art_SiouxCityIA2900MurraySt2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards_019e1743-aa65-7fbb-a00d-82240e05d4e2_terseLabel_en-US" xlink:label="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net operating loss and credits carryforwards</link:label>
    <link:label id="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards_label_en-US" xlink:label="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Operating Loss And Tax Credit Carryforwards</link:label>
    <link:label id="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards_documentation_en-US" xlink:label="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Operating Loss And Tax Credit Carryforwards</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards" xlink:href="art-20260806.xsd#art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards" xlink:to="lab_art_DeferredTaxAssetsOperatingLossAndTaxCreditCarryforwards" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_019e1743-aa65-776b-bd6d-9ae6b1818d40_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Antidilutive Potential Common Shares</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:to="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SuperfrioArmazensGeraisS.A.Member_019e1743-ab7d-7569-88f0-f01828fd9d52_terseLabel_en-US" xlink:label="lab_art_SuperfrioArmazensGeraisS.A.Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment in SuperFrio</link:label>
    <link:label id="lab_art_SuperfrioArmazensGeraisS.A.Member_label_en-US" xlink:label="lab_art_SuperfrioArmazensGeraisS.A.Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Superfrio Armazens Gerais S.A. [Member]</link:label>
    <link:label id="lab_art_SuperfrioArmazensGeraisS.A.Member_documentation_en-US" xlink:label="lab_art_SuperfrioArmazensGeraisS.A.Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Superfrio Armazens Gerais S.A. [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SuperfrioArmazensGeraisS.A.Member" xlink:href="art-20260806.xsd#art_SuperfrioArmazensGeraisS.A.Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SuperfrioArmazensGeraisS.A.Member" xlink:to="lab_art_SuperfrioArmazensGeraisS.A.Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ConnellWA1Member_019e1743-aa65-7833-a4bd-78700c686b5d_terseLabel_en-US" xlink:label="lab_art_ConnellWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Connell, WA</link:label>
    <link:label id="lab_art_ConnellWA1Member_label_en-US" xlink:label="lab_art_ConnellWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Connell, WA 1 [Member]</link:label>
    <link:label id="lab_art_ConnellWA1Member_documentation_en-US" xlink:label="lab_art_ConnellWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Connell, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ConnellWA1Member" xlink:href="art-20260806.xsd#art_ConnellWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ConnellWA1Member" xlink:to="lab_art_ConnellWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SecuredOvernightFinancingAdjustmentRateMember_019e1743-aaf8-7cb6-b407-cd6481d812d4_terseLabel_en-US" xlink:label="lab_art_SecuredOvernightFinancingAdjustmentRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SOFR</link:label>
    <link:label id="lab_art_SecuredOvernightFinancingAdjustmentRateMember_label_en-US" xlink:label="lab_art_SecuredOvernightFinancingAdjustmentRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Overnight Financing Adjustment Rate [Member]</link:label>
    <link:label id="lab_art_SecuredOvernightFinancingAdjustmentRateMember_documentation_en-US" xlink:label="lab_art_SecuredOvernightFinancingAdjustmentRateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Secured Overnight Financing Adjustment Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SecuredOvernightFinancingAdjustmentRateMember" xlink:href="art-20260806.xsd#art_SecuredOvernightFinancingAdjustmentRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SecuredOvernightFinancingAdjustmentRateMember" xlink:to="lab_art_SecuredOvernightFinancingAdjustmentRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShortTermDebtTypeAxis_019e1743-ab7d-7145-a3a4-c64674c03dc0_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Short-Term Debt, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_ShortTermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Short-Term Debt, Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis" xlink:to="lab_us-gaap_ShortTermDebtTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax_019e1743-aa64-7926-a039-3df8f4e97a4e_terseLabel_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount recognized due to special event</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax_label_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Special Event Reclassification Adjustment, After Tax</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax_documentation_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Special Event Reclassification Adjustment, After Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax" xlink:href="art-20260806.xsd#art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax" xlink:to="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanSpecialEventReclassificationAdjustmentAfterTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum_019e1743-a9d5-7fcd-8d87-5f402b251f8c_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum unencumbered leverage ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unencumbered Leverage Ratio, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unencumbered Leverage Ratio, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum" xlink:to="lab_art_DebtInstrumentCovenantUnencumberedLeverageRatioMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Summerville1Member_019e1743-aaf8-7547-a32b-daafd979638b_terseLabel_en-US" xlink:label="lab_art_Summerville1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summerville</link:label>
    <link:label id="lab_art_Summerville1Member_label_en-US" xlink:label="lab_art_Summerville1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Summerville 1 [Member]</link:label>
    <link:label id="lab_art_Summerville1Member_documentation_en-US" xlink:label="lab_art_Summerville1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Summerville 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Summerville1Member" xlink:href="art-20260806.xsd#art_Summerville1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Summerville1Member" xlink:to="lab_art_Summerville1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_019e1743-a922-7aaa-8e4a-bffefcc62bb9_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_019e1743-aaf8-74eb-936e-397989343d1f_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercised (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLossCarryforwardsLineItems_019e1743-aaf8-75a8-afe4-17b8ea227388_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards [Line Items]</link:label>
    <link:label id="lab_us-gaap_OperatingLossCarryforwardsLineItems_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwardsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems" xlink:to="lab_us-gaap_OperatingLossCarryforwardsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_019e1743-a922-73ca-9ea8-c2d576b43bc2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">State</link:label>
    <link:label id="lab_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred State and Local Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Vernon2CA1Member_019e1743-aa64-758a-8a8a-1797cfc45e62_terseLabel_en-US" xlink:label="lab_art_Vernon2CA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vernon 2, CA</link:label>
    <link:label id="lab_art_Vernon2CA1Member_label_en-US" xlink:label="lab_art_Vernon2CA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vernon 2, CA 1 [Member]</link:label>
    <link:label id="lab_art_Vernon2CA1Member_documentation_en-US" xlink:label="lab_art_Vernon2CA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vernon 2, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Vernon2CA1Member" xlink:href="art-20260806.xsd#art_Vernon2CA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Vernon2CA1Member" xlink:to="lab_art_Vernon2CA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetIncomeLoss_019e1743-ab7d-7ac4-a76f-247488a71f56_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net loss attributable to Americold Realty Trust, Inc.</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_label_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="lab_us-gaap_NetIncomeLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent_019e1743-a921-7f1b-a320-941f4ed71cb5_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reclassification of derivative net investment hedge to earnings</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments and Tax, Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsAndTaxParent" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtNoncash_019e1743-aaf8-79a5-b0ca-efdd02756e21_negatedTerseLabel_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtNoncash" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss on debt extinguishment and termination of derivative instruments</link:label>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtNoncash_label_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtNoncash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) On Extinguishment Of Debt, Noncash</link:label>
    <link:label id="lab_art_GainLossOnExtinguishmentOfDebtNoncash_documentation_en-US" xlink:label="lab_art_GainLossOnExtinguishmentOfDebtNoncash" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gain (Loss) On Extinguishment Of Debt, Noncash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainLossOnExtinguishmentOfDebtNoncash" xlink:href="art-20260806.xsd#art_GainLossOnExtinguishmentOfDebtNoncash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainLossOnExtinguishmentOfDebtNoncash" xlink:to="lab_art_GainLossOnExtinguishmentOfDebtNoncash" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LyndenWA2Member_019e1743-a9d5-793b-9a7b-0871c14051a1_terseLabel_en-US" xlink:label="lab_art_LyndenWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lynden, WA</link:label>
    <link:label id="lab_art_LyndenWA2Member_label_en-US" xlink:label="lab_art_LyndenWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lynden, WA 2 [Member]</link:label>
    <link:label id="lab_art_LyndenWA2Member_documentation_en-US" xlink:label="lab_art_LyndenWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lynden, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LyndenWA2Member" xlink:href="art-20260806.xsd#art_LyndenWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LyndenWA2Member" xlink:to="lab_art_LyndenWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_019e1743-aaf8-7234-8ef7-76a0836fe976_verboseLabel_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Gross amount, total</link:label>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_019e1743-aaf8-7d9c-bfac-9d2a33382189_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total real estate facilities gross amount per Schedule III</link:label>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateGrossAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateGrossAtCarryingValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateGrossAtCarryingValue" xlink:to="lab_us-gaap_RealEstateGrossAtCarryingValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_019e1743-aa65-7cf4-9f1a-dc722fae3239_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Effective Income Tax Rate Reconciliation</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WatsonvilleCA1Member_019e1743-ab7d-7d87-a3d3-ff2ede75630f_terseLabel_en-US" xlink:label="lab_art_WatsonvilleCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Watsonville, CA</link:label>
    <link:label id="lab_art_WatsonvilleCA1Member_label_en-US" xlink:label="lab_art_WatsonvilleCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Watsonville, CA 1 [Member]</link:label>
    <link:label id="lab_art_WatsonvilleCA1Member_documentation_en-US" xlink:label="lab_art_WatsonvilleCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Watsonville, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WatsonvilleCA1Member" xlink:href="art-20260806.xsd#art_WatsonvilleCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WatsonvilleCA1Member" xlink:to="lab_art_WatsonvilleCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e1743-aaf8-7108-ac3b-6759c76adb28_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Vesting period</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019e1743-aaf8-750d-8349-8c71f426450b_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vesting Period</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TaxesPayableCurrentAndNoncurrent_019e1743-aaf8-7861-8664-9f6bb0ca0b44_terseLabel_en-US" xlink:label="lab_us-gaap_TaxesPayableCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Value added tax payable</link:label>
    <link:label id="lab_us-gaap_TaxesPayableCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_TaxesPayableCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Taxes Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesPayableCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxesPayableCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TaxesPayableCurrentAndNoncurrent" xlink:to="lab_us-gaap_TaxesPayableCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ContractWithCustomerAssetNet_019e1743-a922-7975-a179-0e46e9cde476_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Receivables from contracts with customers</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerAssetNet_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Asset, after Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerAssetNet" xlink:to="lab_us-gaap_ContractWithCustomerAssetNet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LumbertonNC1Member_019e1743-a9d5-7a17-b0de-202f51d42565_terseLabel_en-US" xlink:label="lab_art_LumbertonNC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lumberton, NC</link:label>
    <link:label id="lab_art_LumbertonNC1Member_label_en-US" xlink:label="lab_art_LumbertonNC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lumberton, NC 1 [Member]</link:label>
    <link:label id="lab_art_LumbertonNC1Member_documentation_en-US" xlink:label="lab_art_LumbertonNC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lumberton, NC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LumbertonNC1Member" xlink:href="art-20260806.xsd#art_LumbertonNC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LumbertonNC1Member" xlink:to="lab_art_LumbertonNC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DerivativeInstrumentNameDomain_019e1743-ab7d-7c7a-8816-6314425ae1cf_terseLabel_en-US" xlink:label="lab_art_DerivativeInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Instrument, Name [Domain]</link:label>
    <link:label id="lab_art_DerivativeInstrumentNameDomain_label_en-US" xlink:label="lab_art_DerivativeInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Instrument, Name [Domain]</link:label>
    <link:label id="lab_art_DerivativeInstrumentNameDomain_documentation_en-US" xlink:label="lab_art_DerivativeInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">[Domain] for Derivative Instrument, Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DerivativeInstrumentNameDomain" xlink:href="art-20260806.xsd#art_DerivativeInstrumentNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DerivativeInstrumentNameDomain" xlink:to="lab_art_DerivativeInstrumentNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingIncomeLoss_019e1743-aaf8-7ca6-9813-c9eb169841ec_totalLabel_en-US" xlink:label="lab_us-gaap_OperatingIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Operating income (loss)</link:label>
    <link:label id="lab_us-gaap_OperatingIncomeLoss_label_en-US" xlink:label="lab_us-gaap_OperatingIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Income (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="lab_us-gaap_OperatingIncomeLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_019e1743-aaf8-7640-a634-6984e53f072f_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated deficit and distributions in excess of net earnings</link:label>
    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_label_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retained Earnings (Accumulated Deficit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:to="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CrossCurrencyInterestRateContractMember_019e1743-a921-71f8-ab0f-d1d1a66a7940_terseLabel_en-US" xlink:label="lab_us-gaap_CrossCurrencyInterestRateContractMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cross-currency swap</link:label>
    <link:label id="lab_us-gaap_CrossCurrencyInterestRateContractMember_label_en-US" xlink:label="lab_us-gaap_CrossCurrencyInterestRateContractMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cross Currency Interest Rate Contract [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember" xlink:to="lab_us-gaap_CrossCurrencyInterestRateContractMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_019e1743-a9d5-7d37-8852-b25c1f0aa23f_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment of indefinite and long-lived assets</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_label_en-US" xlink:label="lab_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Intangible Assets, Indefinite-Lived (Excluding Goodwill)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" xlink:to="lab_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther_019e1743-a9d5-70d9-9a8f-7d19de5dd5c1_totalLabel_en-US" xlink:label="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total acquisition, cyber incident, and other, net</link:label>
    <link:label id="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther_label_en-US" xlink:label="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Cyber Incident, Acquisition Related Expenses, Litigations Expense and Other</link:label>
    <link:label id="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther_documentation_en-US" xlink:label="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Cyber Incident, Acquisition Related Expenses, Litigations Expense and Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:href="art-20260806.xsd#art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:to="lab_art_BusinessCombinationCyberIncidentAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_019e1743-a9d5-7d40-a736-bc9d9d3cb19e_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment of finite-lived intangible assets</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_label_en-US" xlink:label="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Intangible Assets, Finite-Lived</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:to="lab_us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders_019e1743-aaf8-7a2a-a170-51013b988819_terseLabel_en-US" xlink:label="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity method investments, number of minority shareholders</link:label>
    <link:label id="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders_label_en-US" xlink:label="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments, Number of Minority Shareholders</link:label>
    <link:label id="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders_documentation_en-US" xlink:label="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Equity Method Investments, Number of Minority Shareholders</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EquityMethodInvestmentsNumberOfMinorityShareholders" xlink:href="art-20260806.xsd#art_EquityMethodInvestmentsNumberOfMinorityShareholders"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EquityMethodInvestmentsNumberOfMinorityShareholders" xlink:to="lab_art_EquityMethodInvestmentsNumberOfMinorityShareholders" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeasesWeightedAverageDiscountRateAbstract_019e1743-aa65-793f-adfe-3835ecd2a7af_terseLabel_en-US" xlink:label="lab_art_LeasesWeightedAverageDiscountRateAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average discount rate</link:label>
    <link:label id="lab_art_LeasesWeightedAverageDiscountRateAbstract_label_en-US" xlink:label="lab_art_LeasesWeightedAverageDiscountRateAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leases, Weighted Average Discount Rate [Abstract]</link:label>
    <link:label id="lab_art_LeasesWeightedAverageDiscountRateAbstract_documentation_en-US" xlink:label="lab_art_LeasesWeightedAverageDiscountRateAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Leases, Weighted Average Discount Rate [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeasesWeightedAverageDiscountRateAbstract" xlink:href="art-20260806.xsd#art_LeasesWeightedAverageDiscountRateAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeasesWeightedAverageDiscountRateAbstract" xlink:to="lab_art_LeasesWeightedAverageDiscountRateAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member_019e1743-aaf8-7583-82ff-636928823d0e_terseLabel_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Private Series B Notes</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member_label_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series A Notes, Due 2029 [Member]</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member_documentation_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series A Notes, Due 2029</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member" xlink:href="art-20260806.xsd#art_PrivateSeniorUnsecuredSeriesANotesDue2029Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member" xlink:to="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2029Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_019e1743-aaf8-7b73-8cb5-7f88f6de6cbb_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Financing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LyndenWA1Member_019e1743-ab7d-7f0e-8fde-db777d2e0588_terseLabel_en-US" xlink:label="lab_art_LyndenWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lynden, WA</link:label>
    <link:label id="lab_art_LyndenWA1Member_label_en-US" xlink:label="lab_art_LyndenWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lynden, WA 1 [Member]</link:label>
    <link:label id="lab_art_LyndenWA1Member_documentation_en-US" xlink:label="lab_art_LyndenWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lynden, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LyndenWA1Member" xlink:href="art-20260806.xsd#art_LyndenWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LyndenWA1Member" xlink:to="lab_art_LyndenWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_019e1743-aa65-7982-ad36-2e6a2c5a73c2_totalLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total consideration</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrisbaneHemmant2Member_019e1743-aaf8-769b-abac-ff93cc16cf51_terseLabel_en-US" xlink:label="lab_art_BrisbaneHemmant2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brisbane - Hemmant</link:label>
    <link:label id="lab_art_BrisbaneHemmant2Member_label_en-US" xlink:label="lab_art_BrisbaneHemmant2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brisbane - Hemmant 2 [Member]</link:label>
    <link:label id="lab_art_BrisbaneHemmant2Member_documentation_en-US" xlink:label="lab_art_BrisbaneHemmant2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brisbane - Hemmant 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrisbaneHemmant2Member" xlink:href="art-20260806.xsd#art_BrisbaneHemmant2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrisbaneHemmant2Member" xlink:to="lab_art_BrisbaneHemmant2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableRateDomain_019e1743-aaf8-74fa-ad53-22869122de66_terseLabel_en-US" xlink:label="lab_us-gaap_VariableRateDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable Rate [Domain]</link:label>
    <link:label id="lab_us-gaap_VariableRateDomain_label_en-US" xlink:label="lab_us-gaap_VariableRateDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Rate [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableRateDomain" xlink:to="lab_us-gaap_VariableRateDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ContractWithCustomerLiability_019e1743-ab7d-7f2a-a598-c835adb0df93_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unearned revenues</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerLiability_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerLiability" xlink:to="lab_us-gaap_ContractWithCustomerLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BurtonAustraliaMember_019e1743-a922-7f77-b28d-9b91e1ea0f18_terseLabel_en-US" xlink:label="lab_art_BurtonAustraliaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Burton</link:label>
    <link:label id="lab_art_BurtonAustraliaMember_label_en-US" xlink:label="lab_art_BurtonAustraliaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Burton, Australia [Member]</link:label>
    <link:label id="lab_art_BurtonAustraliaMember_documentation_en-US" xlink:label="lab_art_BurtonAustraliaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Burton, Australia</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BurtonAustraliaMember" xlink:href="art-20260806.xsd#art_BurtonAustraliaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BurtonAustraliaMember" xlink:to="lab_art_BurtonAustraliaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_019e1743-aaf8-79f0-8b1e-52789bbc65fd_terseLabel_en-US" xlink:label="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Post-Retirement Benefits (OPRB)</link:label>
    <link:label id="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_019e1743-aaf8-7eba-8c52-7e0542389b91_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other Post-Retirement Benefits (OPRB)</link:label>
    <link:label id="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_label_en-US" xlink:label="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Postretirement Benefits Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:to="lab_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NampaID2Member_019e1743-aa65-7906-afd2-b15080312454_terseLabel_en-US" xlink:label="lab_art_NampaID2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nampa, ID</link:label>
    <link:label id="lab_art_NampaID2Member_label_en-US" xlink:label="lab_art_NampaID2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nampa, ID 2 [Member]</link:label>
    <link:label id="lab_art_NampaID2Member_documentation_en-US" xlink:label="lab_art_NampaID2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Nampa, ID 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NampaID2Member" xlink:href="art-20260806.xsd#art_NampaID2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NampaID2Member" xlink:to="lab_art_NampaID2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CommonStockPercentageOfSharesReservedForIssuance_019e1743-a921-78ec-93c7-5640f50c2086_terseLabel_en-US" xlink:label="lab_art_CommonStockPercentageOfSharesReservedForIssuance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of shares reserved for issuance</link:label>
    <link:label id="lab_art_CommonStockPercentageOfSharesReservedForIssuance_label_en-US" xlink:label="lab_art_CommonStockPercentageOfSharesReservedForIssuance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Percentage Of Shares Reserved For Issuance</link:label>
    <link:label id="lab_art_CommonStockPercentageOfSharesReservedForIssuance_documentation_en-US" xlink:label="lab_art_CommonStockPercentageOfSharesReservedForIssuance" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Common Stock, Percentage Of Shares Reserved For Issuance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CommonStockPercentageOfSharesReservedForIssuance" xlink:href="art-20260806.xsd#art_CommonStockPercentageOfSharesReservedForIssuance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CommonStockPercentageOfSharesReservedForIssuance" xlink:to="lab_art_CommonStockPercentageOfSharesReservedForIssuance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_019e1743-ab7d-7da6-a529-e22208476031_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Stock Options Activity</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Option, Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WatsonvilleCA2Member_019e1743-aa65-7d07-89d4-dfeda7057228_terseLabel_en-US" xlink:label="lab_art_WatsonvilleCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Watsonville, CA</link:label>
    <link:label id="lab_art_WatsonvilleCA2Member_label_en-US" xlink:label="lab_art_WatsonvilleCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Watsonville, CA 2 [Member]</link:label>
    <link:label id="lab_art_WatsonvilleCA2Member_documentation_en-US" xlink:label="lab_art_WatsonvilleCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Watsonville, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WatsonvilleCA2Member" xlink:href="art-20260806.xsd#art_WatsonvilleCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WatsonvilleCA2Member" xlink:to="lab_art_WatsonvilleCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e1743-a9d5-736a-afba-154d74f1c810_netLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Weighted average common stock outstanding &#8211; basic (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019e1743-a9d5-7eb6-8ebc-28d3ff51981e_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average common shares outstanding &#8211; basic (in shares)</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DallasCatronTX1Member_019e1743-a9d5-7243-8dc1-f6b9c040672e_terseLabel_en-US" xlink:label="lab_art_DallasCatronTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dallas (Catron), TX</link:label>
    <link:label id="lab_art_DallasCatronTX1Member_label_en-US" xlink:label="lab_art_DallasCatronTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dallas (Catron), TX 1 [Member]</link:label>
    <link:label id="lab_art_DallasCatronTX1Member_documentation_en-US" xlink:label="lab_art_DallasCatronTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dallas (Catron), TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DallasCatronTX1Member" xlink:href="art-20260806.xsd#art_DallasCatronTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DallasCatronTX1Member" xlink:to="lab_art_DallasCatronTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TimeBasedGradedVestingOPUnitsMember_019e1743-ab7d-7131-b02e-7b0efa13f86b_terseLabel_en-US" xlink:label="lab_art_TimeBasedGradedVestingOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Time Based Graded Vesting OP Units</link:label>
    <link:label id="lab_art_TimeBasedGradedVestingOPUnitsMember_label_en-US" xlink:label="lab_art_TimeBasedGradedVestingOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Time Based Graded Vesting OP Units [Member]</link:label>
    <link:label id="lab_art_TimeBasedGradedVestingOPUnitsMember_documentation_en-US" xlink:label="lab_art_TimeBasedGradedVestingOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Time Based Graded Vesting OP Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TimeBasedGradedVestingOPUnitsMember" xlink:href="art-20260806.xsd#art_TimeBasedGradedVestingOPUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TimeBasedGradedVestingOPUnitsMember" xlink:to="lab_art_TimeBasedGradedVestingOPUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_DirectorMember_019e1743-ab7d-72b7-9e64-d6f19abaf5f0_terseLabel_en-US" xlink:label="lab_srt_DirectorMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Directors</link:label>
    <link:label id="lab_srt_DirectorMember_label_en-US" xlink:label="lab_srt_DirectorMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Director [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_DirectorMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_DirectorMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_DirectorMember" xlink:to="lab_srt_DirectorMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_019e1743-a9d5-7877-91ce-c0c0fe4ac703_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercisable (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LandBuildingsAndImprovementsMember_019e1743-ab7d-79ed-8e34-9c8a6645afb8_terseLabel_en-US" xlink:label="lab_us-gaap_LandBuildingsAndImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Building and land improvements</link:label>
    <link:label id="lab_us-gaap_LandBuildingsAndImprovementsMember_label_en-US" xlink:label="lab_us-gaap_LandBuildingsAndImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land, Buildings and Improvements [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandBuildingsAndImprovementsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LandBuildingsAndImprovementsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LandBuildingsAndImprovementsMember" xlink:to="lab_us-gaap_LandBuildingsAndImprovementsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_019e1743-aa65-7234-a319-e382d75af7f4_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated amortization for each of the next five years</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtDisclosureAbstract_019e1743-a922-7e03-a8a9-3ee65cf315b5_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureAbstract" xlink:to="lab_us-gaap_DebtDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_019e1743-a9d5-7e73-b3e9-e713fcd84336_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Axis]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
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    <link:label id="lab_srt_ScenarioUnspecifiedDomain_label_en-US" xlink:label="lab_srt_ScenarioUnspecifiedDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Scenario [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ScenarioUnspecifiedDomain" xlink:to="lab_srt_ScenarioUnspecifiedDomain" xlink:type="arc" order="1"/>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs"/>
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    <link:label id="lab_art_LumbertonNC2Member_documentation_en-US" xlink:label="lab_art_LumbertonNC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lumberton, NC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LumbertonNC2Member" xlink:href="art-20260806.xsd#art_LumbertonNC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LumbertonNC2Member" xlink:to="lab_art_LumbertonNC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019e1743-aa65-7561-a9e6-b94c41aebdb2_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award [Line Items]</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
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    <link:label id="lab_art_AcquisitionLitigationandOtherSpecialChargesAbstract_label_en-US" xlink:label="lab_art_AcquisitionLitigationandOtherSpecialChargesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acquisition, Litigation and Other Special Charges [Abstract]</link:label>
    <link:label id="lab_art_AcquisitionLitigationandOtherSpecialChargesAbstract_documentation_en-US" xlink:label="lab_art_AcquisitionLitigationandOtherSpecialChargesAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Acquisition, Litigation and Other Special Charges [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AcquisitionLitigationandOtherSpecialChargesAbstract" xlink:href="art-20260806.xsd#art_AcquisitionLitigationandOtherSpecialChargesAbstract"/>
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    <link:label id="lab_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock_019e1743-a9d5-7e57-bee2-3b767af77a47_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Multi-employer Plans</link:label>
    <link:label id="lab_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plan [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfMultiemployerPlansTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfMultiemployerPlansTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax_019e1743-aaf8-7258-8021-b7db8d6a06e3_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustment to accrued pension liability</link:label>
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    <link:label id="lab_art_LeaseLiabilityDueYearOne_019e1743-aa65-74ec-b06c-be341c38a86e_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityDueYearOne" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventsTextBlock" xlink:to="lab_us-gaap_SubsequentEventsTextBlock" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_AntidilutiveSecuritiesNameDomain_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities, Name [Domain]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="lab_us-gaap_AntidilutiveSecuritiesNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment_019e1743-aaf8-7c29-a14f-3799e1aa07ee_totalLabel_en-US" xlink:label="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment_label_en-US" xlink:label="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment</link:label>
    <link:label id="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlanExpectedFutureBenefitPayment" xlink:href="art-20260806.xsd#art_DefinedBenefitPlanExpectedFutureBenefitPayment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlanExpectedFutureBenefitPayment" xlink:to="lab_art_DefinedBenefitPlanExpectedFutureBenefitPayment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired_019e1743-aa65-7c1a-b1da-c815c477610f_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Acquisitions of property, buildings, equipment, and other assets, net of cash acquired</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Business Two, Net of Cash Acquired</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired" xlink:to="lab_us-gaap_PaymentsToAcquireBusinessTwoNetOfCashAcquired" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member_019e1743-a9d5-7808-aae3-67c59bea3b5b_terseLabel_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Private Senior A Notes, Due 2026</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member_label_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Private Senior Unsecured Series A Notes, Due 2026 [Member]</link:label>
    <link:label id="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member_documentation_en-US" xlink:label="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes, Due 2026 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member" xlink:href="art-20260806.xsd#art_PrivateSeniorUnsecuredSeriesANotesDue2026Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member" xlink:to="lab_art_PrivateSeniorUnsecuredSeriesANotesDue2026Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_019e1743-ab7d-722e-8ac5-4e855c64d08f_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional contribution</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Interest in Joint Venture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:to="lab_us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues_019e1743-aa65-7724-9a8d-edbc5f4c69a3_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net proceeds from issuance of common stock</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, New Issues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CounterpartyNameAxis_019e1743-aa65-7806-84a2-b0580c736a36_terseLabel_en-US" xlink:label="lab_srt_CounterpartyNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Counterparty Name [Axis]</link:label>
    <link:label id="lab_srt_CounterpartyNameAxis_label_en-US" xlink:label="lab_srt_CounterpartyNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Counterparty Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CounterpartyNameAxis" xlink:to="lab_srt_CounterpartyNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember_019e1743-a922-7631-941e-3d33bbc8988b_terseLabel_en-US" xlink:label="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minneapolis Food Distributing Industry Pension Plan</link:label>
    <link:label id="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember_label_en-US" xlink:label="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minneapolis Food Distributing Industry Pension Plan [Member]</link:label>
    <link:label id="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember_documentation_en-US" xlink:label="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Minneapolis Food Distributing Industry Pension Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MinneapolisFoodDistributingIndustryPensionPlanMember" xlink:href="art-20260806.xsd#art_MinneapolisFoodDistributingIndustryPensionPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MinneapolisFoodDistributingIndustryPensionPlanMember" xlink:to="lab_art_MinneapolisFoodDistributingIndustryPensionPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityIncorporationStateCountryCode_019e1743-aaf8-7bf2-96d2-9f6ff64d1b5c_terseLabel_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
    <link:label id="lab_dei_EntityIncorporationStateCountryCode_label_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityIncorporationStateCountryCode" xlink:to="lab_dei_EntityIncorporationStateCountryCode" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DallasCatronTX2Member_019e1743-ab7d-7707-b4ee-83682f5e72ce_terseLabel_en-US" xlink:label="lab_art_DallasCatronTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dallas (Catron), TX</link:label>
    <link:label id="lab_art_DallasCatronTX2Member_label_en-US" xlink:label="lab_art_DallasCatronTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dallas (Catron), TX 2 [Member]</link:label>
    <link:label id="lab_art_DallasCatronTX2Member_documentation_en-US" xlink:label="lab_art_DallasCatronTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dallas (Catron), TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DallasCatronTX2Member" xlink:href="art-20260806.xsd#art_DallasCatronTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DallasCatronTX2Member" xlink:to="lab_art_DallasCatronTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_019e1743-aa65-72c0-825f-a4996c39dbd0_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension and post-retirement asset (liability)</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:to="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NampaID1Member_019e1743-aaf8-76c9-8f65-1e367f4aadc8_terseLabel_en-US" xlink:label="lab_art_NampaID1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nampa, ID</link:label>
    <link:label id="lab_art_NampaID1Member_label_en-US" xlink:label="lab_art_NampaID1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nampa, ID 1 [Member]</link:label>
    <link:label id="lab_art_NampaID1Member_documentation_en-US" xlink:label="lab_art_NampaID1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Nampa, ID 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NampaID1Member" xlink:href="art-20260806.xsd#art_NampaID1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NampaID1Member" xlink:to="lab_art_NampaID1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019e1743-aa65-74bd-ad55-507d9afbe30c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Amortization</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities_019e1743-aaf8-7cc3-8ed1-d7e60c153a59_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued expenses</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:to="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SpringdaleAR1Member_019e1743-aa65-7c20-a6d1-f60526dd1e58_terseLabel_en-US" xlink:label="lab_art_SpringdaleAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Springdale, AR</link:label>
    <link:label id="lab_art_SpringdaleAR1Member_label_en-US" xlink:label="lab_art_SpringdaleAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Springdale, AR 1 [Member]</link:label>
    <link:label id="lab_art_SpringdaleAR1Member_documentation_en-US" xlink:label="lab_art_SpringdaleAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Springdale, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SpringdaleAR1Member" xlink:href="art-20260806.xsd#art_SpringdaleAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SpringdaleAR1Member" xlink:to="lab_art_SpringdaleAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalMember_019e1743-a9d5-7acf-9b83-537a0319aa01_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Paid-in Capital</link:label>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalMember_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Paid-in Capital [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapitalMember" xlink:to="lab_us-gaap_AdditionalPaidInCapitalMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract_019e1743-aaf8-70ad-9673-9a0033e0cd75_terseLabel_en-US" xlink:label="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Allocation of purchase price of property, buildings, equipment, and other assets, net of cash acquired to:</link:label>
    <link:label id="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract_label_en-US" xlink:label="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Acquisition, Allocation of Purchase Price [Abstract]</link:label>
    <link:label id="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract_documentation_en-US" xlink:label="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Asset Acquisition, Allocation of Purchase Price [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AssetAcquisitionAllocationofPurchasePriceAbstract" xlink:href="art-20260806.xsd#art_AssetAcquisitionAllocationofPurchasePriceAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AssetAcquisitionAllocationofPurchasePriceAbstract" xlink:to="lab_art_AssetAcquisitionAllocationofPurchasePriceAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Murarrie2Member_019e1743-aaf8-7e60-a5e2-d3f70427463d_terseLabel_en-US" xlink:label="lab_art_Murarrie2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Murarrie</link:label>
    <link:label id="lab_art_Murarrie2Member_label_en-US" xlink:label="lab_art_Murarrie2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Murarrie 2 [Member]</link:label>
    <link:label id="lab_art_Murarrie2Member_documentation_en-US" xlink:label="lab_art_Murarrie2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Murarrie 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Murarrie2Member" xlink:href="art-20260806.xsd#art_Murarrie2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Murarrie2Member" xlink:to="lab_art_Murarrie2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Ft.WorthTXMeacham1Member_019e1743-a921-7901-9ecb-24f62b7600af_terseLabel_en-US" xlink:label="lab_art_Ft.WorthTXMeacham1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Meacham)</link:label>
    <link:label id="lab_art_Ft.WorthTXMeacham1Member_label_en-US" xlink:label="lab_art_Ft.WorthTXMeacham1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Meacham) 1 [Member]</link:label>
    <link:label id="lab_art_Ft.WorthTXMeacham1Member_documentation_en-US" xlink:label="lab_art_Ft.WorthTXMeacham1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ft. Worth, TX (Meacham) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Ft.WorthTXMeacham1Member" xlink:href="art-20260806.xsd#art_Ft.WorthTXMeacham1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Ft.WorthTXMeacham1Member" xlink:to="lab_art_Ft.WorthTXMeacham1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VinelandNJNorthMill2Member_019e1743-aa65-7fb1-9e67-7d812b7e3bc4_terseLabel_en-US" xlink:label="lab_art_VinelandNJNorthMill2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vineland, NJ (North Mill)</link:label>
    <link:label id="lab_art_VinelandNJNorthMill2Member_label_en-US" xlink:label="lab_art_VinelandNJNorthMill2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vineland, NJ (North Mill) 2 [Member]</link:label>
    <link:label id="lab_art_VinelandNJNorthMill2Member_documentation_en-US" xlink:label="lab_art_VinelandNJNorthMill2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vineland, NJ (North Mill) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VinelandNJNorthMill2Member" xlink:href="art-20260806.xsd#art_VinelandNJNorthMill2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VinelandNJNorthMill2Member" xlink:to="lab_art_VinelandNJNorthMill2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FremontNE2Member_019e1743-ab7d-7ec7-b234-4880377aab2b_terseLabel_en-US" xlink:label="lab_art_FremontNE2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fremont, NE</link:label>
    <link:label id="lab_art_FremontNE2Member_label_en-US" xlink:label="lab_art_FremontNE2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fremont, NE 2 [Member]</link:label>
    <link:label id="lab_art_FremontNE2Member_documentation_en-US" xlink:label="lab_art_FremontNE2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fremont, NE 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FremontNE2Member" xlink:href="art-20260806.xsd#art_FremontNE2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FremontNE2Member" xlink:to="lab_art_FremontNE2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaSkygateGA2Member_019e1743-ab7d-7f41-87d8-26680b8d2c6b_terseLabel_en-US" xlink:label="lab_art_AtlantaSkygateGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Skygate, GA</link:label>
    <link:label id="lab_art_AtlantaSkygateGA2Member_label_en-US" xlink:label="lab_art_AtlantaSkygateGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Skygate, GA 2 [Member]</link:label>
    <link:label id="lab_art_AtlantaSkygateGA2Member_documentation_en-US" xlink:label="lab_art_AtlantaSkygateGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Skygate, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaSkygateGA2Member" xlink:href="art-20260806.xsd#art_AtlantaSkygateGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaSkygateGA2Member" xlink:to="lab_art_AtlantaSkygateGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillLineItems_019e1743-a9d5-7776-8473-328d81c6de37_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill [Line Items]</link:label>
    <link:label id="lab_us-gaap_GoodwillLineItems_label_en-US" xlink:label="lab_us-gaap_GoodwillLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillLineItems" xlink:to="lab_us-gaap_GoodwillLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage_019e1743-a9d5-7cb8-b903-b3b7217d94b1_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal early repayment, percentage</link:label>
    <link:label id="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage_label_en-US" xlink:label="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Principal Early Repayment, Percentage</link:label>
    <link:label id="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage_documentation_en-US" xlink:label="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Principal Early Repayment, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentPrincipalEarlyRepaymentPercentage" xlink:href="art-20260806.xsd#art_DebtInstrumentPrincipalEarlyRepaymentPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentPrincipalEarlyRepaymentPercentage" xlink:to="lab_art_DebtInstrumentPrincipalEarlyRepaymentPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_019e1743-aa65-7244-b3a6-d0a0f979dd2a_verboseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Gross amount, Buildings and Improvements</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_019e1743-aa65-7b6a-95d5-11a847dfe170_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total per Schedule III</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Building and Improvements, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale_019e1743-a921-7abd-8c48-960d29100a57_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Purchase option transferred</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Net Book Value Before Sale</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Net Book Value Before Sale</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionNetBookValueBeforeSale" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionNetBookValueBeforeSale"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionNetBookValueBeforeSale" xlink:to="lab_art_SaleLeasebackTransactionNetBookValueBeforeSale" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ColumbiaSC2Member_019e1743-aaf8-75f9-8c3a-c5e7ce5864fe_terseLabel_en-US" xlink:label="lab_art_ColumbiaSC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Columbia, SC</link:label>
    <link:label id="lab_art_ColumbiaSC2Member_label_en-US" xlink:label="lab_art_ColumbiaSC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Columbia, SC 2 [Member]</link:label>
    <link:label id="lab_art_ColumbiaSC2Member_documentation_en-US" xlink:label="lab_art_ColumbiaSC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Columbia, SC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ColumbiaSC2Member" xlink:href="art-20260806.xsd#art_ColumbiaSC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ColumbiaSC2Member" xlink:to="lab_art_ColumbiaSC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VictorvilleCA1Member_019e1743-a9d5-7d3e-99f5-97c52afe1036_terseLabel_en-US" xlink:label="lab_art_VictorvilleCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Victorville, CA</link:label>
    <link:label id="lab_art_VictorvilleCA1Member_label_en-US" xlink:label="lab_art_VictorvilleCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Victorville, CA 1 [Member]</link:label>
    <link:label id="lab_art_VictorvilleCA1Member_documentation_en-US" xlink:label="lab_art_VictorvilleCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Victorville, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VictorvilleCA1Member" xlink:href="art-20260806.xsd#art_VictorvilleCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VictorvilleCA1Member" xlink:to="lab_art_VictorvilleCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefit_019e1743-a922-7c79-ba54-2b37cf78db67_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Current income tax</link:label>
    <link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefit_019e1743-a922-7d8d-ba29-2e0a4710ae07_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xml:lang="en-US">Total current income tax</link:label>
    <link:label id="lab_us-gaap_CurrentIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019e1743-a921-7b45-b7d7-7677465a79e5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: unamortized deferred financing costs</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019e1743-a921-7f21-820c-07a90e41ba00_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unamortized deferred financing costs related to revolving credit facility</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019e1743-a921-7ac7-9cdb-657d62f896db_negatedLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: unamortized deferred financing costs(2)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:to="lab_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_019e1743-aa65-7d12-afc7-1fe42020e247_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Other Operating Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WarehouseSegmentMember_019e1743-a9d5-77b1-8995-cfdfcb987218_verboseLabel_en-US" xlink:label="lab_art_WarehouseSegmentMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Rent, storage, and warehouse services</link:label>
    <link:label id="lab_art_WarehouseSegmentMember_019e1743-a9d5-725e-bff6-b79610c8ec5f_terseLabel_en-US" xlink:label="lab_art_WarehouseSegmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Warehouse</link:label>
    <link:label id="lab_art_WarehouseSegmentMember_label_en-US" xlink:label="lab_art_WarehouseSegmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Warehouse Segment [Member]</link:label>
    <link:label id="lab_art_WarehouseSegmentMember_documentation_en-US" xlink:label="lab_art_WarehouseSegmentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Warehouse Segment [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WarehouseSegmentMember" xlink:href="art-20260806.xsd#art_WarehouseSegmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WarehouseSegmentMember" xlink:to="lab_art_WarehouseSegmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TrancheA1Member_019e1743-ab7d-791a-8a17-b04d60459642_terseLabel_en-US" xlink:label="lab_art_TrancheA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tranche A-1</link:label>
    <link:label id="lab_art_TrancheA1Member_label_en-US" xlink:label="lab_art_TrancheA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tranche A-1 [Member]</link:label>
    <link:label id="lab_art_TrancheA1Member_documentation_en-US" xlink:label="lab_art_TrancheA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tranche A-1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TrancheA1Member" xlink:href="art-20260806.xsd#art_TrancheA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TrancheA1Member" xlink:to="lab_art_TrancheA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TarboroNC2Member_019e1743-a9d5-7401-adc8-6471d59c7e92_terseLabel_en-US" xlink:label="lab_art_TarboroNC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tarboro, NC</link:label>
    <link:label id="lab_art_TarboroNC2Member_label_en-US" xlink:label="lab_art_TarboroNC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tarboro, NC 2 [Member]</link:label>
    <link:label id="lab_art_TarboroNC2Member_documentation_en-US" xlink:label="lab_art_TarboroNC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tarboro, NC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TarboroNC2Member" xlink:href="art-20260806.xsd#art_TarboroNC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TarboroNC2Member" xlink:to="lab_art_TarboroNC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_019e1743-a922-7a06-bdac-8bb631924949_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Percent [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_StrasburgVA2Member_019e1743-ab7d-7690-9200-3873e72bdf1d_terseLabel_en-US" xlink:label="lab_art_StrasburgVA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Strasburg, VA</link:label>
    <link:label id="lab_art_StrasburgVA2Member_label_en-US" xlink:label="lab_art_StrasburgVA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Strasburg, VA 2 [Member]</link:label>
    <link:label id="lab_art_StrasburgVA2Member_documentation_en-US" xlink:label="lab_art_StrasburgVA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Strasburg, VA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_StrasburgVA2Member" xlink:href="art-20260806.xsd#art_StrasburgVA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_StrasburgVA2Member" xlink:to="lab_art_StrasburgVA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquity_019e1743-aaf8-7174-9ce1-e9519087a0ea_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total stockholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="lab_us-gaap_StockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_019e1743-aaf8-7de8-b073-dcfbaeca14d8_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingInformationRevenueAbstract_019e1743-ab7d-7553-84b3-b33b9b4b34d9_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationRevenueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment revenues:</link:label>
    <link:label id="lab_us-gaap_SegmentReportingInformationRevenueAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationRevenueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Information, Revenue for Reportable Segment [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationRevenueAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationRevenueAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingInformationRevenueAbstract" xlink:to="lab_us-gaap_SegmentReportingInformationRevenueAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TurlockCA11Member_019e1743-a922-7aac-aa28-e817c7734d08_terseLabel_en-US" xlink:label="lab_art_TurlockCA11Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Turlock, CA (#1)</link:label>
    <link:label id="lab_art_TurlockCA11Member_label_en-US" xlink:label="lab_art_TurlockCA11Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Turlock, CA (#1) 1 [Member]</link:label>
    <link:label id="lab_art_TurlockCA11Member_documentation_en-US" xlink:label="lab_art_TurlockCA11Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Turlock, CA (#1) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TurlockCA11Member" xlink:href="art-20260806.xsd#art_TurlockCA11Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TurlockCA11Member" xlink:to="lab_art_TurlockCA11Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ForestMS1Member_019e1743-ab7d-7eb1-9cda-6f67bfff9ce9_terseLabel_en-US" xlink:label="lab_art_ForestMS1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Forest, MS</link:label>
    <link:label id="lab_art_ForestMS1Member_label_en-US" xlink:label="lab_art_ForestMS1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Forest, MS 1 [Member]</link:label>
    <link:label id="lab_art_ForestMS1Member_documentation_en-US" xlink:label="lab_art_ForestMS1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Forest, MS 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ForestMS1Member" xlink:href="art-20260806.xsd#art_ForestMS1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ForestMS1Member" xlink:to="lab_art_ForestMS1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementsRecurringMember_019e1743-aaf8-7fa4-9d87-d2dc2f85abe8_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsRecurringMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measured at fair value on a recurring basis</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsRecurringMember_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsRecurringMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Recurring [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsRecurringMember" xlink:to="lab_us-gaap_FairValueMeasurementsRecurringMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SalemOR2Member_019e1743-a9d5-7355-abf4-5380b34e874e_terseLabel_en-US" xlink:label="lab_art_SalemOR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Salem, OR</link:label>
    <link:label id="lab_art_SalemOR2Member_label_en-US" xlink:label="lab_art_SalemOR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Salem, OR 2 [Member]</link:label>
    <link:label id="lab_art_SalemOR2Member_documentation_en-US" xlink:label="lab_art_SalemOR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Salem, OR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SalemOR2Member" xlink:href="art-20260806.xsd#art_SalemOR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SalemOR2Member" xlink:to="lab_art_SalemOR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StateAndLocalJurisdictionMember_019e1743-aaf8-7b60-bcf4-1798a144bf84_terseLabel_en-US" xlink:label="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">State:</link:label>
    <link:label id="lab_us-gaap_StateAndLocalJurisdictionMember_label_en-US" xlink:label="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">State and Local Jurisdiction [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StateAndLocalJurisdictionMember" xlink:to="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CoverAbstract_019e1743-aa65-73ce-a889-36e509cad928_terseLabel_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:label id="lab_dei_CoverAbstract_label_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CoverAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CoverAbstract" xlink:to="lab_dei_CoverAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MaximumMember_019e1743-a9d5-7964-b13b-2074aec55608_terseLabel_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum</link:label>
    <link:label id="lab_srt_MaximumMember_label_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MaximumMember" xlink:to="lab_srt_MaximumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019e1743-aa65-7088-b67e-63be009772d1_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Useful lives of finite-lived intangible assets</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Useful Life</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_019e1743-aa65-7f69-b235-771cce8de767_totalLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net Carrying Amount</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxContingencyLineItems_019e1743-a921-7a31-851c-d7eb59059218_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxContingencyLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Tax Contingency [Line Items]</link:label>
    <link:label id="lab_us-gaap_IncomeTaxContingencyLineItems_label_en-US" xlink:label="lab_us-gaap_IncomeTaxContingencyLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Contingency [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxContingencyLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems" xlink:to="lab_us-gaap_IncomeTaxContingencyLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TwoThousandandTenEquityIncentivePlanMember_019e1743-a9d5-7eeb-b557-065713323801_terseLabel_en-US" xlink:label="lab_art_TwoThousandandTenEquityIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2010 Plan</link:label>
    <link:label id="lab_art_TwoThousandandTenEquityIncentivePlanMember_label_en-US" xlink:label="lab_art_TwoThousandandTenEquityIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Two Thousand and Ten Equity Incentive Plan [Member]</link:label>
    <link:label id="lab_art_TwoThousandandTenEquityIncentivePlanMember_documentation_en-US" xlink:label="lab_art_TwoThousandandTenEquityIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Two Thousand and Ten Equity Incentive Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TwoThousandandTenEquityIncentivePlanMember" xlink:href="art-20260806.xsd#art_TwoThousandandTenEquityIncentivePlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TwoThousandandTenEquityIncentivePlanMember" xlink:to="lab_art_TwoThousandandTenEquityIncentivePlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts_019e1743-ab7d-72f1-bb5b-e4b0cba97e18_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Costs Capitalized Subsequent to Acquisition</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts" xlink:to="lab_us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ProjectOrionMember_019e1743-aa64-71e7-9656-23d55955b2f0_terseLabel_en-US" xlink:label="lab_art_ProjectOrionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Project Orion</link:label>
    <link:label id="lab_art_ProjectOrionMember_label_en-US" xlink:label="lab_art_ProjectOrionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Project Orion [Member]</link:label>
    <link:label id="lab_art_ProjectOrionMember_documentation_en-US" xlink:label="lab_art_ProjectOrionMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Project Orion</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ProjectOrionMember" xlink:href="art-20260806.xsd#art_ProjectOrionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ProjectOrionMember" xlink:to="lab_art_ProjectOrionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019e1743-aa64-76f1-9713-fc6b83399049_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Loss from continuing operations before income taxes</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GoldsboroCommercePA1Member_019e1743-aa65-7dd6-b01c-cd624cf592b9_terseLabel_en-US" xlink:label="lab_art_GoldsboroCommercePA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goldsboro Commerce, PA</link:label>
    <link:label id="lab_art_GoldsboroCommercePA1Member_label_en-US" xlink:label="lab_art_GoldsboroCommercePA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goldsboro Commerce, PA 1 [Member]</link:label>
    <link:label id="lab_art_GoldsboroCommercePA1Member_documentation_en-US" xlink:label="lab_art_GoldsboroCommercePA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Goldsboro Commerce, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GoldsboroCommercePA1Member" xlink:href="art-20260806.xsd#art_GoldsboroCommercePA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GoldsboroCommercePA1Member" xlink:to="lab_art_GoldsboroCommercePA1Member" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentTable_019e1743-aaf8-71bd-a7fb-3fe402c773e6_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTable_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Long-Term Debt Instruments [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentTable" xlink:to="lab_us-gaap_DebtInstrumentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LossContingenciesByNatureOfContingencyAxis_019e1743-aa65-722e-b8a3-23cfbc985b4b_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss Contingency Nature [Axis]</link:label>
    <link:label id="lab_us-gaap_LossContingenciesByNatureOfContingencyAxis_label_en-US" xlink:label="lab_us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency Nature [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:to="lab_us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_019e1743-a9d5-7cbd-8e5d-8427610eceaa_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingSegmentsMember_019e1743-a9d5-7bf0-a07c-6c3461b61593_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Segments</link:label>
    <link:label id="lab_us-gaap_OperatingSegmentsMember_label_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Segments [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingSegmentsMember" xlink:to="lab_us-gaap_OperatingSegmentsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock_019e1743-a921-7a8e-a649-924e7e85b92c_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Cash Flow, Supplemental Disclosures</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_019e1743-aa65-79cb-95b8-f567996a1d15_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other comprehensive (loss) income attributable to noncontrolling interests</link:label>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest"/>
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    <link:label id="lab_art_GaffneySC1Member_019e1743-aaf8-7e52-b1c5-ab2c365fdbca_terseLabel_en-US" xlink:label="lab_art_GaffneySC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gaffney, SC</link:label>
    <link:label id="lab_art_GaffneySC1Member_label_en-US" xlink:label="lab_art_GaffneySC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gaffney, SC 1 [Member]</link:label>
    <link:label id="lab_art_GaffneySC1Member_documentation_en-US" xlink:label="lab_art_GaffneySC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gaffney, SC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GaffneySC1Member" xlink:href="art-20260806.xsd#art_GaffneySC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GaffneySC1Member" xlink:to="lab_art_GaffneySC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityTable_019e1743-aaf8-7466-94e6-67c23a28fe1f_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Table]</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityTable_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityTable" xlink:to="lab_us-gaap_LineOfCreditFacilityTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ReclassificationsPolicyTextBlock_019e1743-aa64-77e3-80e6-e4895d8975a0_terseLabel_en-US" xlink:label="lab_art_ReclassificationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reclassifications</link:label>
    <link:label id="lab_art_ReclassificationsPolicyTextBlock_label_en-US" xlink:label="lab_art_ReclassificationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reclassifications [Policy Text Block]</link:label>
    <link:label id="lab_art_ReclassificationsPolicyTextBlock_documentation_en-US" xlink:label="lab_art_ReclassificationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reclassifications</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ReclassificationsPolicyTextBlock" xlink:href="art-20260806.xsd#art_ReclassificationsPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ReclassificationsPolicyTextBlock" xlink:to="lab_art_ReclassificationsPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BirminghamAL2Member_019e1743-a9d5-71d2-8ea6-dfb449b1b775_terseLabel_en-US" xlink:label="lab_art_BirminghamAL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Birmingham, AL</link:label>
    <link:label id="lab_art_BirminghamAL2Member_label_en-US" xlink:label="lab_art_BirminghamAL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Birmingham, AL 2 [Member]</link:label>
    <link:label id="lab_art_BirminghamAL2Member_documentation_en-US" xlink:label="lab_art_BirminghamAL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Birmingham, AL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BirminghamAL2Member" xlink:href="art-20260806.xsd#art_BirminghamAL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BirminghamAL2Member" xlink:to="lab_art_BirminghamAL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges_019e1743-a921-7cfd-a348-4933472ce61a_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Internal restructuring</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Restructuring Charges, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges" xlink:to="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherReceivables_019e1743-aa65-70ca-84c0-504d40a0f3c2_terseLabel_en-US" xlink:label="lab_us-gaap_OtherReceivables" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_OtherReceivables_label_en-US" xlink:label="lab_us-gaap_OtherReceivables" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Receivables</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivables" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherReceivables"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherReceivables" xlink:to="lab_us-gaap_OtherReceivables" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_019e1743-aaf8-757c-b35e-bdcc4846dfcc_negatedTerseLabel_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOfDisposalGroupIncludingDiscontinuedOperation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Liabilities of discontinued operations - held for sale</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOfDisposalGroupIncludingDiscontinuedOperation" xlink:to="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOfDisposalGroupIncludingDiscontinuedOperation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAbstract_019e1743-a922-7099-86ce-9751ff72f568_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nontaxable or Nondeductible Items</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseAbstract"/>
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    <link:label id="lab_art_LoganTownshipNJ2Member_019e1743-aaf8-71d8-896c-d2dc790aaeac_terseLabel_en-US" xlink:label="lab_art_LoganTownshipNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Logan Township, NJ</link:label>
    <link:label id="lab_art_LoganTownshipNJ2Member_label_en-US" xlink:label="lab_art_LoganTownshipNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Logan Township, NJ 2 [Member]</link:label>
    <link:label id="lab_art_LoganTownshipNJ2Member_documentation_en-US" xlink:label="lab_art_LoganTownshipNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Logan Township, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LoganTownshipNJ2Member" xlink:href="art-20260806.xsd#art_LoganTownshipNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LoganTownshipNJ2Member" xlink:to="lab_art_LoganTownshipNJ2Member" xlink:type="arc" order="1"/>
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    <link:label id="lab_art_PerryvilleMD1Member_label_en-US" xlink:label="lab_art_PerryvilleMD1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Perryville, MD 1 [Member]</link:label>
    <link:label id="lab_art_PerryvilleMD1Member_documentation_en-US" xlink:label="lab_art_PerryvilleMD1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Perryville, MD 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PerryvilleMD1Member" xlink:href="art-20260806.xsd#art_PerryvilleMD1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PerryvilleMD1Member" xlink:to="lab_art_PerryvilleMD1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member_019e1743-aaf8-7848-993a-d8d731d3bc1f_terseLabel_en-US" xlink:label="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Bridge Loan Agreement With RSA Joint Venture, Phase 2</link:label>
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    <link:label id="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member_documentation_en-US" xlink:label="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bridge Loan Agreement With RSA Joint Venture, Phase 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member" xlink:href="art-20260806.xsd#art_BridgeLoanAgreementWithRSAJointVenturePhase2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member" xlink:to="lab_art_BridgeLoanAgreementWithRSAJointVenturePhase2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseInterestExpense_019e1743-aa65-708a-a8a3-c1c4ccb8bca7_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest on lease liabilities</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseInterestExpense_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Interest Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseInterestExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseInterestExpense" xlink:to="lab_us-gaap_FinanceLeaseInterestExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_019e1743-a9d5-7bc3-9eed-689fe5d04791_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
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    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_019e1743-aaf8-7a41-9671-eaa414b03ce4_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss per common share from continuing operations - basic (in USD per share)</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations, Per Basic Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract_019e1743-a921-7943-973e-512d074ecfba_terseLabel_en-US" xlink:label="lab_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Attributable to Noncontrolling Interest [Abstract]</link:label>
    <link:label id="lab_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract_label_en-US" xlink:label="lab_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Attributable to Noncontrolling Interest [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract" xlink:to="lab_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SebreeKY1Member_019e1743-a9d5-7251-812f-54164fa302a0_terseLabel_en-US" xlink:label="lab_art_SebreeKY1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sebree, KY</link:label>
    <link:label id="lab_art_SebreeKY1Member_label_en-US" xlink:label="lab_art_SebreeKY1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sebree, KY 1 [Member]</link:label>
    <link:label id="lab_art_SebreeKY1Member_documentation_en-US" xlink:label="lab_art_SebreeKY1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sebree, KY 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SebreeKY1Member" xlink:href="art-20260806.xsd#art_SebreeKY1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SebreeKY1Member" xlink:to="lab_art_SebreeKY1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AwardTypeAxis_019e1743-a9d5-7fe4-9284-de7fe32775a7_terseLabel_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:label id="lab_us-gaap_AwardTypeAxis_label_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AwardTypeAxis" xlink:to="lab_us-gaap_AwardTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Rockmart2Member_019e1743-a9d5-706e-9863-18c434db8d0d_terseLabel_en-US" xlink:label="lab_art_Rockmart2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rockmart</link:label>
    <link:label id="lab_art_Rockmart2Member_label_en-US" xlink:label="lab_art_Rockmart2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rockmart 2 [Member]</link:label>
    <link:label id="lab_art_Rockmart2Member_documentation_en-US" xlink:label="lab_art_Rockmart2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rockmart 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Rockmart2Member" xlink:href="art-20260806.xsd#art_Rockmart2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Rockmart2Member" xlink:to="lab_art_Rockmart2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DividendsCommonStockPercentage_019e1743-aaf8-7817-a72c-1c9831d41e88_totalLabel_en-US" xlink:label="lab_art_DividendsCommonStockPercentage" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_art_DividendsCommonStockPercentage_label_en-US" xlink:label="lab_art_DividendsCommonStockPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Percentage</link:label>
    <link:label id="lab_art_DividendsCommonStockPercentage_documentation_en-US" xlink:label="lab_art_DividendsCommonStockPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DividendsCommonStockPercentage" xlink:href="art-20260806.xsd#art_DividendsCommonStockPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DividendsCommonStockPercentage" xlink:to="lab_art_DividendsCommonStockPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LakevilleMN1Member_019e1743-ab7d-70a8-8267-d2477bd1e60b_terseLabel_en-US" xlink:label="lab_art_LakevilleMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lakeville, MN</link:label>
    <link:label id="lab_art_LakevilleMN1Member_label_en-US" xlink:label="lab_art_LakevilleMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lakeville, MN 1 [Member]</link:label>
    <link:label id="lab_art_LakevilleMN1Member_documentation_en-US" xlink:label="lab_art_LakevilleMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lakeville, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LakevilleMN1Member" xlink:href="art-20260806.xsd#art_LakevilleMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LakevilleMN1Member" xlink:to="lab_art_LakevilleMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionNameDomain_019e1743-aa64-716b-920f-6641cf935595_terseLabel_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionNameDomain_label_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleLeasebackTransactionNameDomain" xlink:to="lab_us-gaap_SaleLeasebackTransactionNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_EquityMethodInvesteeNameDomain_019e1743-a9d5-7ca1-b0c3-ead6bcb7aea3_terseLabel_en-US" xlink:label="lab_srt_EquityMethodInvesteeNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment, Name [Domain]</link:label>
    <link:label id="lab_srt_EquityMethodInvesteeNameDomain_label_en-US" xlink:label="lab_srt_EquityMethodInvesteeNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_EquityMethodInvesteeNameDomain" xlink:to="lab_srt_EquityMethodInvesteeNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_019e1743-a9d5-7411-9867-e4c11a2e5e17_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value, nonvested</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested"/>
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    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member_019e1743-ab7d-79cc-9d2d-0b0703f72ea0_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 2</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 2 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member" xlink:to="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_019e1743-a921-7bdc-9480-07675ea4619d_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Changes in Valuation Allowance</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance"/>
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    <link:label id="lab_us-gaap_OperatingLossCarryforwardsTable_019e1743-ab7d-7df5-b506-df740dde1d5f_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards [Table]</link:label>
    <link:label id="lab_us-gaap_OperatingLossCarryforwardsTable_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwardsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable" xlink:to="lab_us-gaap_OperatingLossCarryforwardsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy_019e1743-aaf8-76c0-9aad-df8bd33a7377_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Identifiable Intangible Assets</link:label>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets, Intangible Assets, Indefinite-Lived, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsIndefiniteLivedPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressCityOrTown_019e1743-aaf8-7fd0-83b1-8fe295fe951a_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:label id="lab_dei_EntityAddressCityOrTown_label_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
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    <link:label id="lab_us-gaap_ShortTermDebtTypeDomain_019e1743-ab7d-7986-b467-483779d3c267_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Short-Term Debt, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ShortTermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Short-Term Debt, Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain" xlink:to="lab_us-gaap_ShortTermDebtTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_019e1743-a9d5-7719-a552-6683f366bf4e_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finance leases</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Weighted Average Discount Rate, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:to="lab_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementLocationDomain_019e1743-aa65-7b06-a630-d9aeaf73b841_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Income Location, Balance [Domain]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementLocationDomain_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Income Location, Balance [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementLocationDomain" xlink:to="lab_us-gaap_IncomeStatementLocationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Oxford1Member_019e1743-aaf8-7c89-a730-74fcce070fa1_terseLabel_en-US" xlink:label="lab_art_Oxford1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Oxford</link:label>
    <link:label id="lab_art_Oxford1Member_label_en-US" xlink:label="lab_art_Oxford1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Oxford 1 [Member]</link:label>
    <link:label id="lab_art_Oxford1Member_documentation_en-US" xlink:label="lab_art_Oxford1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Oxford 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Oxford1Member" xlink:href="art-20260806.xsd#art_Oxford1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Oxford1Member" xlink:to="lab_art_Oxford1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityEmergingGrowthCompany_019e1743-aa65-7927-a79c-69db3507c9a0_terseLabel_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Emerging Growth Company</link:label>
    <link:label id="lab_dei_EntityEmergingGrowthCompany_label_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Emerging Growth Company</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityEmergingGrowthCompany" xlink:to="lab_dei_EntityEmergingGrowthCompany" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_019e1743-aa65-7189-a70a-a3c8c16a3c94_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finance leases</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Weighted Average Remaining Lease Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:to="lab_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_019e1743-aaf8-7ffc-9600-1ddda76974bd_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unamortized debt issuance cost</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsNet" xlink:to="lab_us-gaap_DeferredFinanceCostsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_019e1743-a9d5-7854-9a57-15870b00f1ed_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average assumptions used to determine obligations (balance sheet):</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract"/>
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    <link:label id="lab_us-gaap_OtherAssetsFairValueDisclosure_019e1743-a9d5-796e-9181-7bb9d9a8409d_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Certain previously impaired real estate assets</link:label>
    <link:label id="lab_us-gaap_OtherAssetsFairValueDisclosure_label_en-US" xlink:label="lab_us-gaap_OtherAssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets, Fair Value Disclosure</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsFairValueDisclosure" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsFairValueDisclosure"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsFairValueDisclosure" xlink:to="lab_us-gaap_OtherAssetsFairValueDisclosure" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueTableTextBlock_019e1743-aa65-76e7-ade5-636432310d23_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Disaggregated Revenues</link:label>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueTableTextBlock_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disaggregation of Revenue [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTableTextBlock"/>
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    <link:label id="lab_art_GrandPrairieTX1Member_019e1743-ab7d-7919-a789-ec8e50357905_terseLabel_en-US" xlink:label="lab_art_GrandPrairieTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Grand Prairie, TX</link:label>
    <link:label id="lab_art_GrandPrairieTX1Member_label_en-US" xlink:label="lab_art_GrandPrairieTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Grand Prairie, TX 1 [Member]</link:label>
    <link:label id="lab_art_GrandPrairieTX1Member_documentation_en-US" xlink:label="lab_art_GrandPrairieTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Grand Prairie, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GrandPrairieTX1Member" xlink:href="art-20260806.xsd#art_GrandPrairieTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GrandPrairieTX1Member" xlink:to="lab_art_GrandPrairieTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements_019e1743-aa65-7487-a149-38f4d94e2c13_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Initial Costs, Buildings and Improvements</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost of Building and Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements"/>
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    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsOfDisposalGroupIncludingDiscontinuedOperation_019e1743-aa65-7dbd-9f23-131ece674c9c_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsOfDisposalGroupIncludingDiscontinuedOperation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets of discontinued operations - held for sale</link:label>
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    <link:label id="lab_art_MountvillePA1Member_019e1743-aa65-7f8e-8f23-01ad39edf6a4_terseLabel_en-US" xlink:label="lab_art_MountvillePA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mountville, PA</link:label>
    <link:label id="lab_art_MountvillePA1Member_label_en-US" xlink:label="lab_art_MountvillePA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mountville, PA 1 [Member]</link:label>
    <link:label id="lab_art_MountvillePA1Member_documentation_en-US" xlink:label="lab_art_MountvillePA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mountville, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MountvillePA1Member" xlink:href="art-20260806.xsd#art_MountvillePA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MountvillePA1Member" xlink:to="lab_art_MountvillePA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfProductInformationTable_019e1743-a921-79ea-85a8-1b928f9bc24e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfProductInformationTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nature of Operation, Product Information, Concentration of Risk [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfProductInformationTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfProductInformationTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nature of Operation, Product Information, Concentration of Risk [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfProductInformationTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfProductInformationTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfProductInformationTable" xlink:to="lab_us-gaap_ScheduleOfProductInformationTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IntangibleAssetsFiniteLivedPolicy_019e1743-aa65-7cae-8034-31268e908fc5_terseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsFiniteLivedPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets</link:label>
    <link:label id="lab_us-gaap_IntangibleAssetsFiniteLivedPolicy_label_en-US" xlink:label="lab_us-gaap_IntangibleAssetsFiniteLivedPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Assets, Finite-Lived, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsFiniteLivedPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsFiniteLivedPolicy"/>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_019e1743-a9d5-702d-9441-943dd357d222_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in benefit obligation:</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward"/>
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    <link:label id="lab_dei_EntityAddressPostalZipCode_019e1743-a921-7528-9bb6-3ef5ce65067f_terseLabel_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:label id="lab_dei_EntityAddressPostalZipCode_label_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressPostalZipCode" xlink:to="lab_dei_EntityAddressPostalZipCode" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SeniorUnsecuredNotesMember_019e1743-aaf8-7703-8745-5a9e95f3e369_terseLabel_en-US" xlink:label="lab_art_SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes</link:label>
    <link:label id="lab_art_SeniorUnsecuredNotesMember_019e1743-aaf8-7ed7-a2f8-445ba389aee9_verboseLabel_en-US" xlink:label="lab_art_SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total Senior Unsecured Notes</link:label>
    <link:label id="lab_art_SeniorUnsecuredNotesMember_label_en-US" xlink:label="lab_art_SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes [Member]</link:label>
    <link:label id="lab_art_SeniorUnsecuredNotesMember_documentation_en-US" xlink:label="lab_art_SeniorUnsecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Senior Unsecured Notes [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SeniorUnsecuredNotesMember" xlink:href="art-20260806.xsd#art_SeniorUnsecuredNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SeniorUnsecuredNotesMember" xlink:to="lab_art_SeniorUnsecuredNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MonmouthIL2Member_019e1743-aaf8-7be0-8842-a1767e8b733a_terseLabel_en-US" xlink:label="lab_art_MonmouthIL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Monmouth, IL</link:label>
    <link:label id="lab_art_MonmouthIL2Member_label_en-US" xlink:label="lab_art_MonmouthIL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Monmouth, IL 2 [Member]</link:label>
    <link:label id="lab_art_MonmouthIL2Member_documentation_en-US" xlink:label="lab_art_MonmouthIL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Monmouth, IL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MonmouthIL2Member" xlink:href="art-20260806.xsd#art_MonmouthIL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MonmouthIL2Member" xlink:to="lab_art_MonmouthIL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SalinasCA1Member_019e1743-aaf8-7920-b196-cdba44f48ab4_terseLabel_en-US" xlink:label="lab_art_SalinasCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Salinas, CA</link:label>
    <link:label id="lab_art_SalinasCA1Member_label_en-US" xlink:label="lab_art_SalinasCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Salinas, CA 1 [Member]</link:label>
    <link:label id="lab_art_SalinasCA1Member_documentation_en-US" xlink:label="lab_art_SalinasCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Salinas, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SalinasCA1Member" xlink:href="art-20260806.xsd#art_SalinasCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SalinasCA1Member" xlink:to="lab_art_SalinasCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1_019e1743-ab7d-7cec-b4bc-445f564adada_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Life on which depreciation is calculated</link:label>
    <link:label id="lab_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1_label_en-US" xlink:label="lab_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Life Used for Depreciation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1"/>
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    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_019e1743-aaf8-7b05-9967-a9e79f38f5b6_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss per common share from discontinued operations - basic (in USD per share)</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare"/>
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    <link:label id="lab_us-gaap_OtherAssets_019e1743-aaf8-7740-9c7b-cfaf39762f9c_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_us-gaap_OtherAssets_019e1743-aaf8-7d24-a763-28afb8673f30_totalLabel_en-US" xlink:label="lab_us-gaap_OtherAssets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total other assets</link:label>
    <link:label id="lab_us-gaap_OtherAssets_label_en-US" xlink:label="lab_us-gaap_OtherAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssets" xlink:to="lab_us-gaap_OtherAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BankBillReferenceRateMember_019e1743-ab7d-7c38-a0f6-21c9f4fc88ea_terseLabel_en-US" xlink:label="lab_art_BankBillReferenceRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">BKBM</link:label>
    <link:label id="lab_art_BankBillReferenceRateMember_label_en-US" xlink:label="lab_art_BankBillReferenceRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Bank Bill Reference Rate [Member]</link:label>
    <link:label id="lab_art_BankBillReferenceRateMember_documentation_en-US" xlink:label="lab_art_BankBillReferenceRateMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Bank Bill Reference Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BankBillReferenceRateMember" xlink:href="art-20260806.xsd#art_BankBillReferenceRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BankBillReferenceRateMember" xlink:to="lab_art_BankBillReferenceRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Dalgety2Member_019e1743-a921-785c-b128-c9d90dd6a521_terseLabel_en-US" xlink:label="lab_art_Dalgety2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dalgety</link:label>
    <link:label id="lab_art_Dalgety2Member_label_en-US" xlink:label="lab_art_Dalgety2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dalgety 2 [Member]</link:label>
    <link:label id="lab_art_Dalgety2Member_documentation_en-US" xlink:label="lab_art_Dalgety2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dalgety 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Dalgety2Member" xlink:href="art-20260806.xsd#art_Dalgety2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Dalgety2Member" xlink:to="lab_art_Dalgety2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DesignatedAsHedgingInstrumentMember_019e1743-ab7d-76b4-9dce-b288932c0ac8_terseLabel_en-US" xlink:label="lab_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Designated as Hedging Instrument</link:label>
    <link:label id="lab_us-gaap_DesignatedAsHedgingInstrumentMember_label_en-US" xlink:label="lab_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Designated as Hedging Instrument [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:to="lab_us-gaap_DesignatedAsHedgingInstrumentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_019e1743-a9d5-769f-8380-15a73589bbbd_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019e1743-a921-7f6e-9de8-b47bb139d2b0_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hedging Relationship [Axis]</link:label>
    <link:label id="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hedging Relationship [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="lab_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_019e1743-a9d5-7781-a095-ab831eaa2850_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unrealized net (loss) gain on cash flow hedges</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax"/>
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    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedWeightedAverageGrantDateFairValue_019e1743-a9d5-7b8a-a2a9-304b0a9288f0_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vested awards, weighted average grant date fair value (in USD per share)</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Weighted Average Grant Date Fair Value</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedWeightedAverageGrantDateFairValue_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Weighted Average Grant Date Fair Value</link:label>
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    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEquipment_019e1743-ab7d-7e9f-ab33-7013d51ef2b2_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Machinery and equipment</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEquipment_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEquipment"/>
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    <link:label id="lab_us-gaap_GoodwillAcquiredDuringPeriod_019e1743-a921-7b0d-9a42-64e35b8fc407_verboseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAcquiredDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Goodwill acquired</link:label>
    <link:label id="lab_us-gaap_GoodwillAcquiredDuringPeriod_label_en-US" xlink:label="lab_us-gaap_GoodwillAcquiredDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Acquired During Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAcquiredDuringPeriod" xlink:to="lab_us-gaap_GoodwillAcquiredDuringPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_019e1743-a921-7cad-a2e5-eab6c5e8347c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Total accumulated depreciation per consolidated balance sheet (property, buildings and equipment)</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization</link:label>
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    <link:label id="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock_019e1743-a9d5-72e5-a605-1b024dcef191_terseLabel_en-US" xlink:label="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combinations, Asset Acquisitions and Discontinued Operations</link:label>
    <link:label id="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mergers, Acquisitions and Dispositions Disclosures [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:to="lab_us-gaap_MergersAcquisitionsAndDispositionsDisclosuresTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairfieldOH2Member_019e1743-aaf8-74d1-afa5-7c1592386165_terseLabel_en-US" xlink:label="lab_art_FairfieldOH2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fairfield, OH</link:label>
    <link:label id="lab_art_FairfieldOH2Member_label_en-US" xlink:label="lab_art_FairfieldOH2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fairfield, OH 2 [Member]</link:label>
    <link:label id="lab_art_FairfieldOH2Member_documentation_en-US" xlink:label="lab_art_FairfieldOH2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fairfield, OH 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairfieldOH2Member" xlink:href="art-20260806.xsd#art_FairfieldOH2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairfieldOH2Member" xlink:to="lab_art_FairfieldOH2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SanfordNC1Member_019e1743-a9d5-7f83-a710-b63332f03113_terseLabel_en-US" xlink:label="lab_art_SanfordNC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sanford, NC</link:label>
    <link:label id="lab_art_SanfordNC1Member_label_en-US" xlink:label="lab_art_SanfordNC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sanford, NC 1 [Member]</link:label>
    <link:label id="lab_art_SanfordNC1Member_documentation_en-US" xlink:label="lab_art_SanfordNC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sanford, NC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SanfordNC1Member" xlink:href="art-20260806.xsd#art_SanfordNC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SanfordNC1Member" xlink:to="lab_art_SanfordNC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome_019e1743-a922-7724-a390-e46f1df5ec14_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Earnings from REIT - not subject to tax</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e1743-a9d5-7b1a-9f8b-d8a54d8ff5eb_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning balance (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019e1743-a9d5-7d9f-8676-5035cfe05349_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending balance (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA1Member_019e1743-aaf8-78af-af81-aa613c23c045_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tranche A-1</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA1Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A-1 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanA1Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A-1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredTermLoanA1Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredTermLoanA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredTermLoanA1Member" xlink:to="lab_art_A20222020SeniorUnsecuredTermLoanA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_019e1743-aaf8-76c7-826e-5321afbc0f8a_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_019e1743-a9d5-71e1-beeb-01fe271cadc3_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amounts recognized on the consolidated balance sheet:</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract"/>
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    <link:label id="lab_us-gaap_DebtInstrumentTerm_019e1743-aaf8-7d49-a5a8-db9538fcca8f_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Term of debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTerm_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentTerm" xlink:to="lab_us-gaap_DebtInstrumentTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_019e1743-aa64-7748-93ce-610c9bf038e1_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues from External Customers and Long-Lived Assets [Line Items]</link:label>
    <link:label id="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_label_en-US" xlink:label="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues from External Customers and Long-Lived Assets [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="lab_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019e1743-a9d5-70df-a2c2-8f028f2fc3bf_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Equity Method Investments [Line Items]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Equity Method Investments [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
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    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_019e1743-aaf8-7ef8-b0e2-2b5da1e0c093_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-term Debt, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
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    <link:label id="lab_us-gaap_Depreciation_label_en-US" xlink:label="lab_us-gaap_Depreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Depreciation"/>
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    <link:label id="lab_us-gaap_MoneyMarketFundsMember_019e1743-aaf8-71a3-b5d2-c2d681a26ef9_terseLabel_en-US" xlink:label="lab_us-gaap_MoneyMarketFundsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Money markets</link:label>
    <link:label id="lab_us-gaap_MoneyMarketFundsMember_label_en-US" xlink:label="lab_us-gaap_MoneyMarketFundsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Money Market Funds [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MoneyMarketFundsMember" xlink:to="lab_us-gaap_MoneyMarketFundsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_019e1743-ab7d-738f-adc2-04a1b4dd1e42_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HalwynDr2Member_019e1743-a9d5-723b-b6ae-6416e6daadb9_terseLabel_en-US" xlink:label="lab_art_HalwynDr2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Halwyn Dr</link:label>
    <link:label id="lab_art_HalwynDr2Member_label_en-US" xlink:label="lab_art_HalwynDr2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Halwyn Dr 2 [Member]</link:label>
    <link:label id="lab_art_HalwynDr2Member_documentation_en-US" xlink:label="lab_art_HalwynDr2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Halwyn Dr 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HalwynDr2Member" xlink:href="art-20260806.xsd#art_HalwynDr2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HalwynDr2Member" xlink:to="lab_art_HalwynDr2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_019e1743-a9d5-74b0-8885-8115781d2a77_terseLabel_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_label_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementEquityComponentsAxis" xlink:to="lab_us-gaap_StatementEquityComponentsAxis" xlink:type="arc" order="1"/>
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    <link:label id="lab_art_RochelleILCaron1Member_label_en-US" xlink:label="lab_art_RochelleILCaron1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Caron) 1 [Member]</link:label>
    <link:label id="lab_art_RochelleILCaron1Member_documentation_en-US" xlink:label="lab_art_RochelleILCaron1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Caron) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RochelleILCaron1Member" xlink:href="art-20260806.xsd#art_RochelleILCaron1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RochelleILCaron1Member" xlink:to="lab_art_RochelleILCaron1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum_019e1743-aaf8-7b6b-af08-b9977f13b2c9_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum secured leverage ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Secured Leverage Ratio, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Secured Leverage Ratio, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantSecuredLeverageRatioMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum" xlink:to="lab_art_DebtInstrumentCovenantSecuredLeverageRatioMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortWorthSamuelsTX1Member_019e1743-aaf8-7b7d-a59c-b78b48f916ad_terseLabel_en-US" xlink:label="lab_art_FortWorthSamuelsTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Worth-Samuels, TX</link:label>
    <link:label id="lab_art_FortWorthSamuelsTX1Member_label_en-US" xlink:label="lab_art_FortWorthSamuelsTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Worth-Samuels, TX 1 [Member]</link:label>
    <link:label id="lab_art_FortWorthSamuelsTX1Member_documentation_en-US" xlink:label="lab_art_FortWorthSamuelsTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Worth-Samuels, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortWorthSamuelsTX1Member" xlink:href="art-20260806.xsd#art_FortWorthSamuelsTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortWorthSamuelsTX1Member" xlink:to="lab_art_FortWorthSamuelsTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AllentownPA2Member_019e1743-aaf8-76ef-9f29-df37efea6410_terseLabel_en-US" xlink:label="lab_art_AllentownPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Allentown, PA</link:label>
    <link:label id="lab_art_AllentownPA2Member_label_en-US" xlink:label="lab_art_AllentownPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Allentown, PA 2 [Member]</link:label>
    <link:label id="lab_art_AllentownPA2Member_documentation_en-US" xlink:label="lab_art_AllentownPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Allentown, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AllentownPA2Member" xlink:href="art-20260806.xsd#art_AllentownPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AllentownPA2Member" xlink:to="lab_art_AllentownPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NorthLittleRockAR2Member_019e1743-ab7d-729e-aa59-212bf3bee253_terseLabel_en-US" xlink:label="lab_art_NorthLittleRockAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">North Little Rock, AR</link:label>
    <link:label id="lab_art_NorthLittleRockAR2Member_label_en-US" xlink:label="lab_art_NorthLittleRockAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">North Little Rock, AR 2 [Member]</link:label>
    <link:label id="lab_art_NorthLittleRockAR2Member_documentation_en-US" xlink:label="lab_art_NorthLittleRockAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">North Little Rock, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NorthLittleRockAR2Member" xlink:href="art-20260806.xsd#art_NorthLittleRockAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NorthLittleRockAR2Member" xlink:to="lab_art_NorthLittleRockAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GadsdenAL1Member_019e1743-a9d5-775f-9961-570cc094f262_terseLabel_en-US" xlink:label="lab_art_GadsdenAL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gadsden, AL</link:label>
    <link:label id="lab_art_GadsdenAL1Member_label_en-US" xlink:label="lab_art_GadsdenAL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gadsden, AL 1 [Member]</link:label>
    <link:label id="lab_art_GadsdenAL1Member_documentation_en-US" xlink:label="lab_art_GadsdenAL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gadsden, AL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GadsdenAL1Member" xlink:href="art-20260806.xsd#art_GadsdenAL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GadsdenAL1Member" xlink:to="lab_art_GadsdenAL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_IndianapolisIN1Member_019e1743-aa65-7998-8e69-e0e387b71e70_terseLabel_en-US" xlink:label="lab_art_IndianapolisIN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indianapolis, IN</link:label>
    <link:label id="lab_art_IndianapolisIN1Member_label_en-US" xlink:label="lab_art_IndianapolisIN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Indianapolis, IN 1 [Member]</link:label>
    <link:label id="lab_art_IndianapolisIN1Member_documentation_en-US" xlink:label="lab_art_IndianapolisIN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Indianapolis, IN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_IndianapolisIN1Member" xlink:href="art-20260806.xsd#art_IndianapolisIN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_IndianapolisIN1Member" xlink:to="lab_art_IndianapolisIN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredIndebtedness_019e1743-aa64-7c7f-ab61-1cd303a28704_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredIndebtedness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, secured indebtedness</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredIndebtedness_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredIndebtedness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Secured Indebtedness</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantSecuredIndebtedness_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantSecuredIndebtedness" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Secured Indebtedness</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantSecuredIndebtedness" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantSecuredIndebtedness"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantSecuredIndebtedness" xlink:to="lab_art_DebtInstrumentCovenantSecuredIndebtedness" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CollectiveBargainingArrangementDomain_019e1743-aaf8-795a-a746-a7de3b32def2_terseLabel_en-US" xlink:label="lab_us-gaap_CollectiveBargainingArrangementDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement [Domain]</link:label>
    <link:label id="lab_us-gaap_CollectiveBargainingArrangementDomain_label_en-US" xlink:label="lab_us-gaap_CollectiveBargainingArrangementDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollectiveBargainingArrangementDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CollectiveBargainingArrangementDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CollectiveBargainingArrangementDomain" xlink:to="lab_us-gaap_CollectiveBargainingArrangementDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_019e1743-ab7d-775e-9812-ef489750ba2c_negatedLabel_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Repayment of financing lease obligations</link:label>
    <link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_019e1743-ab7d-7107-a9da-13b9dbdef500_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Financing cash flows from finance leases</link:label>
    <link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_label_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Principal Payments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeasePrincipalPayments" xlink:to="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions_019e1743-a922-7538-8e00-fae5424a3ae7_terseLabel_en-US" xlink:label="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating loss carryforwards obtained through acquisitions</link:label>
    <link:label id="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions_label_en-US" xlink:label="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards, Acquired Through Acquisitions</link:label>
    <link:label id="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions_documentation_en-US" xlink:label="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards, Acquired Through Acquisitions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions" xlink:href="art-20260806.xsd#art_OperatingLossCarryforwardsAcquiredThroughAcquisitions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions" xlink:to="lab_art_OperatingLossCarryforwardsAcquiredThroughAcquisitions" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DerivativeInstrumentNameAxis_019e1743-aaf8-72f1-ae76-d8ac0a8e5cd6_terseLabel_en-US" xlink:label="lab_art_DerivativeInstrumentNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Instrument, Name [Axis]</link:label>
    <link:label id="lab_art_DerivativeInstrumentNameAxis_label_en-US" xlink:label="lab_art_DerivativeInstrumentNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Instrument, Name [Axis]</link:label>
    <link:label id="lab_art_DerivativeInstrumentNameAxis_documentation_en-US" xlink:label="lab_art_DerivativeInstrumentNameAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Derivative Instrument, Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DerivativeInstrumentNameAxis" xlink:href="art-20260806.xsd#art_DerivativeInstrumentNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DerivativeInstrumentNameAxis" xlink:to="lab_art_DerivativeInstrumentNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedContributionPlanCostRecognized_019e1743-ab7d-7289-8c1e-6ef2cb04dc90_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanCostRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined contribution plan expense</link:label>
    <link:label id="lab_us-gaap_DefinedContributionPlanCostRecognized_label_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanCostRecognized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedContributionPlanCostRecognized" xlink:to="lab_us-gaap_DefinedContributionPlanCostRecognized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019e1743-a921-789d-ac79-06e41c0e1a18_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Leases</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxAuthorityDomain_019e1743-aaf8-78da-8e3e-c7147f865de2_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Tax Jurisdiction [Domain]</link:label>
    <link:label id="lab_us-gaap_IncomeTaxAuthorityDomain_label_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Jurisdiction [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain" xlink:to="lab_us-gaap_IncomeTaxAuthorityDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OntarioOR2Member_019e1743-a9d5-7e3d-91d4-a488548c9d9d_terseLabel_en-US" xlink:label="lab_art_OntarioOR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ontario, OR</link:label>
    <link:label id="lab_art_OntarioOR2Member_label_en-US" xlink:label="lab_art_OntarioOR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ontario, OR 2 [Member]</link:label>
    <link:label id="lab_art_OntarioOR2Member_documentation_en-US" xlink:label="lab_art_OntarioOR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ontario, OR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OntarioOR2Member" xlink:href="art-20260806.xsd#art_OntarioOR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OntarioOR2Member" xlink:to="lab_art_OntarioOR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_019e1743-aaf8-752c-a352-31ac6cba8eab_verboseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Finance leases</link:label>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_019e1743-aaf8-7330-9852-80fb9cfc2112_terseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finance leases</link:label>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_label_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Right-of-Use Asset Obtained in Exchange for Finance Lease Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:to="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BarcelonaSpainMember_019e1743-ab7d-77be-bb36-95d106e33d29_terseLabel_en-US" xlink:label="lab_art_BarcelonaSpainMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Barcelona, Spain</link:label>
    <link:label id="lab_art_BarcelonaSpainMember_label_en-US" xlink:label="lab_art_BarcelonaSpainMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Barcelona, Spain [Member]</link:label>
    <link:label id="lab_art_BarcelonaSpainMember_documentation_en-US" xlink:label="lab_art_BarcelonaSpainMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Barcelona, Spain</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BarcelonaSpainMember" xlink:href="art-20260806.xsd#art_BarcelonaSpainMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BarcelonaSpainMember" xlink:to="lab_art_BarcelonaSpainMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember_019e1743-a9d5-7c70-99d4-dda4e94abd0b_terseLabel_en-US" xlink:label="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unionized Employees, Under Renegotiation Concentration Risk</link:label>
    <link:label id="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember_label_en-US" xlink:label="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unionized Employees, Under Renegotiation Concentration Risk [Member]</link:label>
    <link:label id="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember_documentation_en-US" xlink:label="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Unionized Employees, Under Renegotiation Concentration Risk</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember" xlink:href="art-20260806.xsd#art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember" xlink:to="lab_art_UnionizedEmployeesUnderRenegotiationConcentrationRiskMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList_019e1743-aa65-7a95-9751-9abfc314c94b_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_019e1743-aa65-7bc3-8652-3b8144267893_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SOFR</link:label>
    <link:label id="lab_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_label_en-US" xlink:label="lab_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" xlink:to="lab_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WoodburnOR1Member_019e1743-a9d5-7c99-84e8-0f8c4c901e4c_terseLabel_en-US" xlink:label="lab_art_WoodburnOR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Woodburn, OR</link:label>
    <link:label id="lab_art_WoodburnOR1Member_label_en-US" xlink:label="lab_art_WoodburnOR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Woodburn, OR 1 [Member]</link:label>
    <link:label id="lab_art_WoodburnOR1Member_documentation_en-US" xlink:label="lab_art_WoodburnOR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Woodburn, OR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WoodburnOR1Member" xlink:href="art-20260806.xsd#art_WoodburnOR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WoodburnOR1Member" xlink:to="lab_art_WoodburnOR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DividendsCommonStockOrdinaryIncomePercentage_019e1743-ab7d-7a98-8d13-68a8b487c4e0_terseLabel_en-US" xlink:label="lab_art_DividendsCommonStockOrdinaryIncomePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ordinary income</link:label>
    <link:label id="lab_art_DividendsCommonStockOrdinaryIncomePercentage_label_en-US" xlink:label="lab_art_DividendsCommonStockOrdinaryIncomePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Ordinary Income, Percentage</link:label>
    <link:label id="lab_art_DividendsCommonStockOrdinaryIncomePercentage_documentation_en-US" xlink:label="lab_art_DividendsCommonStockOrdinaryIncomePercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Ordinary Income, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DividendsCommonStockOrdinaryIncomePercentage" xlink:href="art-20260806.xsd#art_DividendsCommonStockOrdinaryIncomePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DividendsCommonStockOrdinaryIncomePercentage" xlink:to="lab_art_DividendsCommonStockOrdinaryIncomePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WallaWallaWA2Member_019e1743-aa65-7aec-9011-6f51c987686b_terseLabel_en-US" xlink:label="lab_art_WallaWallaWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Walla Walla, WA</link:label>
    <link:label id="lab_art_WallaWallaWA2Member_label_en-US" xlink:label="lab_art_WallaWallaWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Walla Walla, WA 2 [Member]</link:label>
    <link:label id="lab_art_WallaWallaWA2Member_documentation_en-US" xlink:label="lab_art_WallaWallaWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Walla Walla, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WallaWallaWA2Member" xlink:href="art-20260806.xsd#art_WallaWallaWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WallaWallaWA2Member" xlink:to="lab_art_WallaWallaWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HermistonOR2Member_019e1743-a9d5-79ee-8af3-87977df6768e_terseLabel_en-US" xlink:label="lab_art_HermistonOR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hermiston, OR</link:label>
    <link:label id="lab_art_HermistonOR2Member_label_en-US" xlink:label="lab_art_HermistonOR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hermiston, OR 2 [Member]</link:label>
    <link:label id="lab_art_HermistonOR2Member_documentation_en-US" xlink:label="lab_art_HermistonOR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Hermiston, OR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HermistonOR2Member" xlink:href="art-20260806.xsd#art_HermistonOR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HermistonOR2Member" xlink:to="lab_art_HermistonOR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LossContingencyNatureDomain_019e1743-a9d5-7e56-b3d9-cd9b3a764c65_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyNatureDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss Contingency, Nature [Domain]</link:label>
    <link:label id="lab_us-gaap_LossContingencyNatureDomain_label_en-US" xlink:label="lab_us-gaap_LossContingencyNatureDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency, Nature [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyNatureDomain" xlink:to="lab_us-gaap_LossContingencyNatureDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_YorkWillowSpringsPA1Member_019e1743-aaf8-7291-b24d-d8c502e1b4f2_terseLabel_en-US" xlink:label="lab_art_YorkWillowSpringsPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">York-Willow Springs, PA</link:label>
    <link:label id="lab_art_YorkWillowSpringsPA1Member_label_en-US" xlink:label="lab_art_YorkWillowSpringsPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">York-Willow Springs, PA 1 [Member]</link:label>
    <link:label id="lab_art_YorkWillowSpringsPA1Member_documentation_en-US" xlink:label="lab_art_YorkWillowSpringsPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">York-Willow Springs, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_YorkWillowSpringsPA1Member" xlink:href="art-20260806.xsd#art_YorkWillowSpringsPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_YorkWillowSpringsPA1Member" xlink:to="lab_art_YorkWillowSpringsPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_019e1743-aa64-7b0d-b4be-59981a1198c8_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalization of Costs and Revenue Recognition</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SavannahPoolerGA2Member_019e1743-a922-7f52-8671-4e9f238b65f7_terseLabel_en-US" xlink:label="lab_art_SavannahPoolerGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Savannah Pooler, GA</link:label>
    <link:label id="lab_art_SavannahPoolerGA2Member_label_en-US" xlink:label="lab_art_SavannahPoolerGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Savannah Pooler, GA 2 [Member]</link:label>
    <link:label id="lab_art_SavannahPoolerGA2Member_documentation_en-US" xlink:label="lab_art_SavannahPoolerGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Savannah Pooler, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SavannahPoolerGA2Member" xlink:href="art-20260806.xsd#art_SavannahPoolerGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SavannahPoolerGA2Member" xlink:to="lab_art_SavannahPoolerGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness_019e1743-a9d5-75a1-89c2-b6f396475329_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, unsecured indebtedness</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Indebtedness</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Indebtedness</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantUnsecuredIndebtedness" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantUnsecuredIndebtedness"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantUnsecuredIndebtedness" xlink:to="lab_art_DebtInstrumentCovenantUnsecuredIndebtedness" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Calgary2Member_019e1743-ab7d-7e70-bfe2-4d90a73a7fc7_terseLabel_en-US" xlink:label="lab_art_Calgary2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Calgary</link:label>
    <link:label id="lab_art_Calgary2Member_label_en-US" xlink:label="lab_art_Calgary2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Calgary 2 [Member]</link:label>
    <link:label id="lab_art_Calgary2Member_documentation_en-US" xlink:label="lab_art_Calgary2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Calgary 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Calgary2Member" xlink:href="art-20260806.xsd#art_Calgary2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Calgary2Member" xlink:to="lab_art_Calgary2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1_019e1743-aaf8-796f-87c5-914e9c8df707_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remaining useful life</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Remaining Amortization Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WeightedAverageRemainingLeaseTermAbstract_019e1743-aaf8-72e5-a5b1-10090d42f0ce_terseLabel_en-US" xlink:label="lab_art_WeightedAverageRemainingLeaseTermAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average remaining lease term (years)</link:label>
    <link:label id="lab_art_WeightedAverageRemainingLeaseTermAbstract_label_en-US" xlink:label="lab_art_WeightedAverageRemainingLeaseTermAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Remaining Lease Term [Abstract]</link:label>
    <link:label id="lab_art_WeightedAverageRemainingLeaseTermAbstract_documentation_en-US" xlink:label="lab_art_WeightedAverageRemainingLeaseTermAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Weighted Average Remaining Lease Term [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WeightedAverageRemainingLeaseTermAbstract" xlink:href="art-20260806.xsd#art_WeightedAverageRemainingLeaseTermAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WeightedAverageRemainingLeaseTermAbstract" xlink:to="lab_art_WeightedAverageRemainingLeaseTermAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_OwnershipDomain_019e1743-aa65-7f8b-8761-0a9c5ff96857_terseLabel_en-US" xlink:label="lab_srt_OwnershipDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ownership [Domain]</link:label>
    <link:label id="lab_srt_OwnershipDomain_label_en-US" xlink:label="lab_srt_OwnershipDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ownership [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_OwnershipDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_OwnershipDomain" xlink:to="lab_srt_OwnershipDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock_019e1743-aaf8-7b25-8a88-61effc6b6e68_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Future Minimum Lease Payments Due from Customers</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Maturity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_019e1743-ab7d-712d-981e-bc5a82e632b9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentDiscountRatePercentage_019e1743-aa65-7ac6-a010-7e493aa159e0_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentDiscountRatePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discount rate, percentage</link:label>
    <link:label id="lab_art_DebtInstrumentDiscountRatePercentage_label_en-US" xlink:label="lab_art_DebtInstrumentDiscountRatePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Discount Rate, Percentage</link:label>
    <link:label id="lab_art_DebtInstrumentDiscountRatePercentage_documentation_en-US" xlink:label="lab_art_DebtInstrumentDiscountRatePercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Discount Rate, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentDiscountRatePercentage" xlink:href="art-20260806.xsd#art_DebtInstrumentDiscountRatePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentDiscountRatePercentage" xlink:to="lab_art_DebtInstrumentDiscountRatePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_019e1743-aa65-70e0-ad3e-aca7e550a2d5_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Aggregate Future Repayments of Indebtedness</link:label>
    <link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Maturities of Long-Term Debt [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AnaheimCA1Member_019e1743-aa65-7299-a268-49475e2b2491_terseLabel_en-US" xlink:label="lab_art_AnaheimCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Anaheim, CA</link:label>
    <link:label id="lab_art_AnaheimCA1Member_label_en-US" xlink:label="lab_art_AnaheimCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Anaheim, CA 1 [Member]</link:label>
    <link:label id="lab_art_AnaheimCA1Member_documentation_en-US" xlink:label="lab_art_AnaheimCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anaheim, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AnaheimCA1Member" xlink:href="art-20260806.xsd#art_AnaheimCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AnaheimCA1Member" xlink:to="lab_art_AnaheimCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessAcquisitionsMember_019e1743-aaf8-7037-a05d-8e8153484ed1_terseLabel_en-US" xlink:label="lab_art_BusinessAcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Acquisitions</link:label>
    <link:label id="lab_art_BusinessAcquisitionsMember_label_en-US" xlink:label="lab_art_BusinessAcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Acquisitions [Member]</link:label>
    <link:label id="lab_art_BusinessAcquisitionsMember_documentation_en-US" xlink:label="lab_art_BusinessAcquisitionsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Acquisitions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessAcquisitionsMember" xlink:href="art-20260806.xsd#art_BusinessAcquisitionsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessAcquisitionsMember" xlink:to="lab_art_BusinessAcquisitionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_019e1743-aa65-72d0-a97e-bf039f4a5740_terseLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other comprehensive income (loss) - net of tax:</link:label>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:to="lab_us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_019e1743-aa65-73cd-9590-87edb80befa8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="lab_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract_019e1743-a9d5-7add-b29c-edcd4a305b5c_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reconciliation of total accumulated depreciation to consolidated balance sheet caption as of December&#160;31, 2025:</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Amortization, Reconciliation [Abstract]</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Amortization, Reconciliation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateAccumulatedAmortizationReconciliationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AustralianIntercompanyLoanMember_019e1743-aaf8-7fad-9218-3ec08283b604_terseLabel_en-US" xlink:label="lab_art_AustralianIntercompanyLoanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Australian Intercompany Loan</link:label>
    <link:label id="lab_art_AustralianIntercompanyLoanMember_label_en-US" xlink:label="lab_art_AustralianIntercompanyLoanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Australian Intercompany Loan [Member]</link:label>
    <link:label id="lab_art_AustralianIntercompanyLoanMember_documentation_en-US" xlink:label="lab_art_AustralianIntercompanyLoanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Australian Intercompany Loan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AustralianIntercompanyLoanMember" xlink:href="art-20260806.xsd#art_AustralianIntercompanyLoanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AustralianIntercompanyLoanMember" xlink:to="lab_art_AustralianIntercompanyLoanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ColdLatamLimitedMember_019e1743-aaf8-72cf-a1cb-5154de0aee5c_terseLabel_en-US" xlink:label="lab_art_ColdLatamLimitedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cold Latam Limited</link:label>
    <link:label id="lab_art_ColdLatamLimitedMember_label_en-US" xlink:label="lab_art_ColdLatamLimitedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cold Latam Limited [Member]</link:label>
    <link:label id="lab_art_ColdLatamLimitedMember_documentation_en-US" xlink:label="lab_art_ColdLatamLimitedMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cold Latam Limited</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ColdLatamLimitedMember" xlink:href="art-20260806.xsd#art_ColdLatamLimitedMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ColdLatamLimitedMember" xlink:to="lab_art_ColdLatamLimitedMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_019e1743-a9d5-771d-b83b-abd708e3aa23_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Benefits paid</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Benefits Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_019e1743-a921-792c-9f51-869559a3b56e_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income taxes from continuing operations at the statutory rate</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SiouxFallsSD1Member_019e1743-a9d5-7a1e-ac2b-bd5a92503021_terseLabel_en-US" xlink:label="lab_art_SiouxFallsSD1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sioux Falls, SD</link:label>
    <link:label id="lab_art_SiouxFallsSD1Member_label_en-US" xlink:label="lab_art_SiouxFallsSD1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sioux Falls, SD 1 [Member]</link:label>
    <link:label id="lab_art_SiouxFallsSD1Member_documentation_en-US" xlink:label="lab_art_SiouxFallsSD1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sioux Falls, SD 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SiouxFallsSD1Member" xlink:href="art-20260806.xsd#art_SiouxFallsSD1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SiouxFallsSD1Member" xlink:to="lab_art_SiouxFallsSD1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ManchesterPA2Member_019e1743-aaf8-7fad-a2b3-06c9daade539_terseLabel_en-US" xlink:label="lab_art_ManchesterPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Manchester, PA</link:label>
    <link:label id="lab_art_ManchesterPA2Member_label_en-US" xlink:label="lab_art_ManchesterPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Manchester, PA 2 [Member]</link:label>
    <link:label id="lab_art_ManchesterPA2Member_documentation_en-US" xlink:label="lab_art_ManchesterPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Manchester, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ManchesterPA2Member" xlink:href="art-20260806.xsd#art_ManchesterPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ManchesterPA2Member" xlink:to="lab_art_ManchesterPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PublicDebtIssuance5.600NotesMember_019e1743-a921-70da-bcaa-7df39e406931_terseLabel_en-US" xlink:label="lab_art_PublicDebtIssuance5.600NotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Public 5.600% Notes</link:label>
    <link:label id="lab_art_PublicDebtIssuance5.600NotesMember_label_en-US" xlink:label="lab_art_PublicDebtIssuance5.600NotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Public Debt Issuance, 5.600% Notes [Member]</link:label>
    <link:label id="lab_art_PublicDebtIssuance5.600NotesMember_documentation_en-US" xlink:label="lab_art_PublicDebtIssuance5.600NotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Public Debt Issuance, 5.600% Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PublicDebtIssuance5.600NotesMember" xlink:href="art-20260806.xsd#art_PublicDebtIssuance5.600NotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PublicDebtIssuance5.600NotesMember" xlink:to="lab_art_PublicDebtIssuance5.600NotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TauntonMA2Member_019e1743-a9d5-77b3-8e27-4ebd01956af0_terseLabel_en-US" xlink:label="lab_art_TauntonMA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Taunton, MA</link:label>
    <link:label id="lab_art_TauntonMA2Member_label_en-US" xlink:label="lab_art_TauntonMA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Taunton, MA 2 [Member]</link:label>
    <link:label id="lab_art_TauntonMA2Member_documentation_en-US" xlink:label="lab_art_TauntonMA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Taunton, MA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TauntonMA2Member" xlink:href="art-20260806.xsd#art_TauntonMA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TauntonMA2Member" xlink:to="lab_art_TauntonMA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionTable_019e1743-ab7d-7755-b7d3-3e6cb3282177_terseLabel_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction [Table]</link:label>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionTable_label_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable" xlink:to="lab_us-gaap_SaleLeasebackTransactionTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsGross_019e1743-a9d5-7e1a-89fe-8cb66a1ab0d1_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gross Carrying Amount</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsGross_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressAddressLine1_019e1743-a9d5-77b6-b50a-3c6c59ce3d06_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line One</link:label>
    <link:label id="lab_dei_EntityAddressAddressLine1_label_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressAddressLine1" xlink:to="lab_dei_EntityAddressAddressLine1" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressAddressLine2_019e1743-aa64-7257-b54a-c678226cb791_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line Two</link:label>
    <link:label id="lab_dei_EntityAddressAddressLine2_label_en-US" xlink:label="lab_dei_EntityAddressAddressLine2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Address, Address Line Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressAddressLine2" xlink:to="lab_dei_EntityAddressAddressLine2" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaWestgateGA2Member_019e1743-aa65-7f97-9ebd-4ad6ec37f1d9_terseLabel_en-US" xlink:label="lab_art_AtlantaWestgateGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Westgate, GA</link:label>
    <link:label id="lab_art_AtlantaWestgateGA2Member_label_en-US" xlink:label="lab_art_AtlantaWestgateGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Westgate, GA 2 [Member]</link:label>
    <link:label id="lab_art_AtlantaWestgateGA2Member_documentation_en-US" xlink:label="lab_art_AtlantaWestgateGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Westgate, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaWestgateGA2Member" xlink:href="art-20260806.xsd#art_AtlantaWestgateGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaWestgateGA2Member" xlink:to="lab_art_AtlantaWestgateGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1743-a9d5-7136-aac5-a8d1f622bdc8_verboseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Loss</link:label>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019e1743-a9d5-7442-8862-c6fac19f6dfd_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated other comprehensive loss</link:label>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AOCI Attributable to Parent [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LebanonTN2Member_019e1743-aaf8-707d-aac8-919506f97e5a_terseLabel_en-US" xlink:label="lab_art_LebanonTN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lebanon, TN</link:label>
    <link:label id="lab_art_LebanonTN2Member_label_en-US" xlink:label="lab_art_LebanonTN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lebanon, TN 2 [Member]</link:label>
    <link:label id="lab_art_LebanonTN2Member_documentation_en-US" xlink:label="lab_art_LebanonTN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lebanon, TN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LebanonTN2Member" xlink:href="art-20260806.xsd#art_LebanonTN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LebanonTN2Member" xlink:to="lab_art_LebanonTN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BensonHodgesNC1Member_019e1743-aa65-74af-9d05-468ebf9bf9c2_terseLabel_en-US" xlink:label="lab_art_BensonHodgesNC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Benson Hodges, NC</link:label>
    <link:label id="lab_art_BensonHodgesNC1Member_label_en-US" xlink:label="lab_art_BensonHodgesNC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Benson Hodges, NC 1 [Member]</link:label>
    <link:label id="lab_art_BensonHodgesNC1Member_documentation_en-US" xlink:label="lab_art_BensonHodgesNC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benson Hodges, NC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BensonHodgesNC1Member" xlink:href="art-20260806.xsd#art_BensonHodgesNC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BensonHodgesNC1Member" xlink:to="lab_art_BensonHodgesNC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationAndAssetAcquisitionAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:to="lab_us-gaap_BusinessCombinationAndAssetAcquisitionAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_OwnershipAxis_019e1743-a9d5-7e6d-b19e-ffe818118964_terseLabel_en-US" xlink:label="lab_srt_OwnershipAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ownership [Axis]</link:label>
    <link:label id="lab_srt_OwnershipAxis_label_en-US" xlink:label="lab_srt_OwnershipAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ownership [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_OwnershipAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_OwnershipAxis" xlink:to="lab_srt_OwnershipAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_UrkNetherlandsMember_019e1743-a9d5-70bc-88a9-ced199290475_terseLabel_en-US" xlink:label="lab_art_UrkNetherlandsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Urk, Netherlands</link:label>
    <link:label id="lab_art_UrkNetherlandsMember_label_en-US" xlink:label="lab_art_UrkNetherlandsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Urk, Netherlands [Member]</link:label>
    <link:label id="lab_art_UrkNetherlandsMember_documentation_en-US" xlink:label="lab_art_UrkNetherlandsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Urk, Netherlands</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_UrkNetherlandsMember" xlink:href="art-20260806.xsd#art_UrkNetherlandsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_UrkNetherlandsMember" xlink:to="lab_art_UrkNetherlandsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairmontMN1Member_019e1743-aa65-70ed-baed-49c302d65243_terseLabel_en-US" xlink:label="lab_art_FairmontMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fairmont, MN</link:label>
    <link:label id="lab_art_FairmontMN1Member_label_en-US" xlink:label="lab_art_FairmontMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fairmont, MN 1 [Member]</link:label>
    <link:label id="lab_art_FairmontMN1Member_documentation_en-US" xlink:label="lab_art_FairmontMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fairmont, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairmontMN1Member" xlink:href="art-20260806.xsd#art_FairmontMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairmontMN1Member" xlink:to="lab_art_FairmontMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CarsonCA2Member_019e1743-aaf8-7462-a243-9f02f0d2bf80_terseLabel_en-US" xlink:label="lab_art_CarsonCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carson, CA</link:label>
    <link:label id="lab_art_CarsonCA2Member_label_en-US" xlink:label="lab_art_CarsonCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Carson, CA 2 [Member]</link:label>
    <link:label id="lab_art_CarsonCA2Member_documentation_en-US" xlink:label="lab_art_CarsonCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carson, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CarsonCA2Member" xlink:href="art-20260806.xsd#art_CarsonCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CarsonCA2Member" xlink:to="lab_art_CarsonCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization_019e1743-a921-782b-b1fd-a6e3e9f45850_terseLabel_en-US" xlink:label="lab_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Implementation cost</link:label>
    <link:label id="lab_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization_label_en-US" xlink:label="lab_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization" xlink:to="lab_us-gaap_HostingArrangementServiceContractImplementationCostCapitalizedAfterAccumulatedAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLossCarryforwards_019e1743-aa65-7964-9303-7d4e95ee9909_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating loss carryforwards</link:label>
    <link:label id="lab_us-gaap_OperatingLossCarryforwards_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLossCarryforwards" xlink:to="lab_us-gaap_OperatingLossCarryforwards" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_019e1743-a922-70fc-93c4-f95e07bf34ee_verboseLabel_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Dilutive effect of share-based awards (in shares)</link:label>
    <link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_label_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:to="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e1743-aaf8-7ffd-94c0-d9631573d274_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e1743-aaf8-791f-9a8d-82e5ec27d072_netLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:type="resource" xml:lang="en-US">Number of Restricted Stock Units Granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019e1743-aaf8-725c-9af0-41135727a7d7_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Number of units granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain_019e1743-aaf8-701c-93b7-6e9e08916957_terseLabel_en-US" xlink:label="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Title and Position [Domain]</link:label>
    <link:label id="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain_label_en-US" xlink:label="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Title and Position [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="lab_srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities_019e1743-aaf8-7aa2-8589-67a8ab222f09_negatedLabel_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and accrued expenses</link:label>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities_label_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Accounts Payable And Accrued Liabilities</link:label>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities_documentation_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Accounts Payable And Accrued Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities" xlink:href="art-20260806.xsd#art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities" xlink:to="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndAccruedLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_019e1743-a9d5-7864-8d6d-2a21e4df88ba_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unrecognized stock-based compensation expense</link:label>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionDescriptionAxis_019e1743-ab7d-76d3-83bb-5ad1fc609352_terseLabel_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionDescriptionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Description [Axis]</link:label>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionDescriptionAxis_label_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionDescriptionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Description [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionDescriptionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionDescriptionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleLeasebackTransactionDescriptionAxis" xlink:to="lab_us-gaap_SaleLeasebackTransactionDescriptionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WarehouseServicesMember_019e1743-a9d5-7630-a0bd-bacb20b1223b_terseLabel_en-US" xlink:label="lab_art_WarehouseServicesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Warehouse Services</link:label>
    <link:label id="lab_art_WarehouseServicesMember_label_en-US" xlink:label="lab_art_WarehouseServicesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Warehouse Services [Member]</link:label>
    <link:label id="lab_art_WarehouseServicesMember_documentation_en-US" xlink:label="lab_art_WarehouseServicesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Warehouse Services [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WarehouseServicesMember" xlink:href="art-20260806.xsd#art_WarehouseServicesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WarehouseServicesMember" xlink:to="lab_art_WarehouseServicesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MilwaukieOR2Member_019e1743-a9d5-710d-8465-fd1461042358_terseLabel_en-US" xlink:label="lab_art_MilwaukieOR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Milwaukie, OR</link:label>
    <link:label id="lab_art_MilwaukieOR2Member_label_en-US" xlink:label="lab_art_MilwaukieOR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Milwaukie, OR 2 [Member]</link:label>
    <link:label id="lab_art_MilwaukieOR2Member_documentation_en-US" xlink:label="lab_art_MilwaukieOR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Milwaukie, OR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MilwaukieOR2Member" xlink:href="art-20260806.xsd#art_MilwaukieOR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MilwaukieOR2Member" xlink:to="lab_art_MilwaukieOR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RussellvilleARCloverleafRt.3241Member_019e1743-aa65-7bd0-bce8-18f2ec1a057e_terseLabel_en-US" xlink:label="lab_art_RussellvilleARCloverleafRt.3241Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Russellville, AR - Cloverleaf (Rt. 324)</link:label>
    <link:label id="lab_art_RussellvilleARCloverleafRt.3241Member_label_en-US" xlink:label="lab_art_RussellvilleARCloverleafRt.3241Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Russellville, AR - Cloverleaf (Rt. 324) 1 [Member]</link:label>
    <link:label id="lab_art_RussellvilleARCloverleafRt.3241Member_documentation_en-US" xlink:label="lab_art_RussellvilleARCloverleafRt.3241Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Russellville, AR - Cloverleaf (Rt. 324) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RussellvilleARCloverleafRt.3241Member" xlink:href="art-20260806.xsd#art_RussellvilleARCloverleafRt.3241Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RussellvilleARCloverleafRt.3241Member" xlink:to="lab_art_RussellvilleARCloverleafRt.3241Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_019e1743-aaf8-752b-8f96-e1e1641ae618_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_019e1743-aa65-77b4-9ecc-fd1de6311e01_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Outstanding</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock_019e1743-ab7d-72e6-ae39-f90ae06f7a9d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Accounts Payable and Accrued Liabilities</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NumberOfPartiesReceivedRegulatoryApproval_019e1743-aaf8-7fdf-91ab-30d673f68680_terseLabel_en-US" xlink:label="lab_art_NumberOfPartiesReceivedRegulatoryApproval" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of parties received regulatory approval</link:label>
    <link:label id="lab_art_NumberOfPartiesReceivedRegulatoryApproval_label_en-US" xlink:label="lab_art_NumberOfPartiesReceivedRegulatoryApproval" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Parties Received Regulatory Approval</link:label>
    <link:label id="lab_art_NumberOfPartiesReceivedRegulatoryApproval_documentation_en-US" xlink:label="lab_art_NumberOfPartiesReceivedRegulatoryApproval" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number of Parties Received Regulatory Approval</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NumberOfPartiesReceivedRegulatoryApproval" xlink:href="art-20260806.xsd#art_NumberOfPartiesReceivedRegulatoryApproval"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NumberOfPartiesReceivedRegulatoryApproval" xlink:to="lab_art_NumberOfPartiesReceivedRegulatoryApproval" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock_019e1743-ab7d-7c05-8b6e-9575c55e4b09_terseLabel_en-US" xlink:label="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Actuarial Information</link:label>
    <link:label id="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:to="lab_us-gaap_ChangesInProjectedBenefitObligationsFairValueOfPlanAssetsAndFundedStatusOfPlanTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Spearwood2Member_019e1743-a9d5-772c-8014-7eab7e057e1b_terseLabel_en-US" xlink:label="lab_art_Spearwood2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Spearwood</link:label>
    <link:label id="lab_art_Spearwood2Member_label_en-US" xlink:label="lab_art_Spearwood2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Spearwood 2 [Member]</link:label>
    <link:label id="lab_art_Spearwood2Member_documentation_en-US" xlink:label="lab_art_Spearwood2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Spearwood 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Spearwood2Member" xlink:href="art-20260806.xsd#art_Spearwood2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Spearwood2Member" xlink:to="lab_art_Spearwood2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MontgomeryAL2Member_019e1743-ab7d-70d6-a84c-e6a8469c49c8_terseLabel_en-US" xlink:label="lab_art_MontgomeryAL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Montgomery, AL</link:label>
    <link:label id="lab_art_MontgomeryAL2Member_label_en-US" xlink:label="lab_art_MontgomeryAL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Montgomery, AL 2 [Member]</link:label>
    <link:label id="lab_art_MontgomeryAL2Member_documentation_en-US" xlink:label="lab_art_MontgomeryAL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Montgomery, AL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MontgomeryAL2Member" xlink:href="art-20260806.xsd#art_MontgomeryAL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MontgomeryAL2Member" xlink:to="lab_art_MontgomeryAL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_019e1743-a9d5-79c8-bf57-9cd6994334de_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment of indefinite and long-lived assets</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_label_en-US" xlink:label="lab_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Long-Lived Assets to be Disposed of</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:to="lab_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_019e1743-aaf8-7a07-87ac-a18b2afc1bcc_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock issuance related to employee stock purchase plan</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, Employee Stock Purchase Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_019e1743-a921-7660-af30-3516eaf99758_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_label_en-US" xlink:label="lab_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:to="lab_us-gaap_GoodwillImpairmentLossStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_019e1743-aa65-7793-9d82-53864dadb4a1_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss) [Line Items]</link:label>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss) [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HatfieldPA1Member_019e1743-ab7d-7d5e-a614-b9afaccebf11_terseLabel_en-US" xlink:label="lab_art_HatfieldPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hatfield, PA</link:label>
    <link:label id="lab_art_HatfieldPA1Member_label_en-US" xlink:label="lab_art_HatfieldPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hatfield, PA 1 [Member]</link:label>
    <link:label id="lab_art_HatfieldPA1Member_documentation_en-US" xlink:label="lab_art_HatfieldPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Hatfield, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HatfieldPA1Member" xlink:href="art-20260806.xsd#art_HatfieldPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HatfieldPA1Member" xlink:to="lab_art_HatfieldPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignCurrencyGainLossMember_019e1743-aa65-768b-a676-bc0d85c04084_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyGainLossMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign currency exchange loss, net</link:label>
    <link:label id="lab_us-gaap_ForeignCurrencyGainLossMember_label_en-US" xlink:label="lab_us-gaap_ForeignCurrencyGainLossMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Currency Gain (Loss) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyGainLossMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignCurrencyGainLossMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCurrencyGainLossMember" xlink:to="lab_us-gaap_ForeignCurrencyGainLossMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019e1743-a9d5-7dc7-baa9-72f4b093b71c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Award Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Award Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MinorityInterest_019e1743-a9d5-776d-9d4d-ae3e24903c2e_terseLabel_en-US" xlink:label="lab_us-gaap_MinorityInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Noncontrolling interests</link:label>
    <link:label id="lab_us-gaap_MinorityInterest_label_en-US" xlink:label="lab_us-gaap_MinorityInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity, Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MinorityInterest" xlink:to="lab_us-gaap_MinorityInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_country_CA_019e1743-a921-756e-9ca1-83c7ed4b6bca_terseLabel_en-US" xlink:label="lab_country_CA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Canada</link:label>
    <link:label id="lab_country_CA_label_en-US" xlink:label="lab_country_CA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">CANADA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_CA"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_CA" xlink:to="lab_country_CA" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BurlingtonWA2Member_019e1743-aaf8-7004-82b0-b3c90ad6f00e_terseLabel_en-US" xlink:label="lab_art_BurlingtonWA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Burlington, WA</link:label>
    <link:label id="lab_art_BurlingtonWA2Member_label_en-US" xlink:label="lab_art_BurlingtonWA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Burlington, WA 2 [Member]</link:label>
    <link:label id="lab_art_BurlingtonWA2Member_documentation_en-US" xlink:label="lab_art_BurlingtonWA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Burlington, WA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BurlingtonWA2Member" xlink:href="art-20260806.xsd#art_BurlingtonWA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BurlingtonWA2Member" xlink:to="lab_art_BurlingtonWA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsegmentsDomain_019e1743-aaf8-7b56-b817-ce4777812961_terseLabel_en-US" xlink:label="lab_us-gaap_SubsegmentsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsegments [Domain]</link:label>
    <link:label id="lab_us-gaap_SubsegmentsDomain_label_en-US" xlink:label="lab_us-gaap_SubsegmentsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsegments [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsegmentsDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsegmentsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsegmentsDomain" xlink:to="lab_us-gaap_SubsegmentsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent_019e1743-a921-7082-912d-4ccae821f151_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_019e1743-a9d5-7dd2-910a-088494282364_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="lab_us-gaap_DebtInstrumentNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignExchangeContractMember_019e1743-a9d5-71a1-88cb-610f322b3e42_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignExchangeContractMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign exchange contracts</link:label>
    <link:label id="lab_us-gaap_ForeignExchangeContractMember_label_en-US" xlink:label="lab_us-gaap_ForeignExchangeContractMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Exchange Contract [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignExchangeContractMember" xlink:to="lab_us-gaap_ForeignExchangeContractMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber_019e1743-ab7d-706f-b040-12bbb3c96425_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Shares vested, but not released (in shares)</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Number</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Vested, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber" xlink:to="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsVestedNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_country_AR_019e1743-ab7d-7cea-916e-add643db64d7_terseLabel_en-US" xlink:label="lab_country_AR" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Argentina</link:label>
    <link:label id="lab_country_AR_label_en-US" xlink:label="lab_country_AR" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">ARGENTINA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_AR" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_AR"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_AR" xlink:to="lab_country_AR" xlink:type="arc" order="1"/>
    <link:label id="lab_country_AU_019e1743-a921-7cbb-9715-17a4c7a9a203_terseLabel_en-US" xlink:label="lab_country_AU" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Australia</link:label>
    <link:label id="lab_country_AU_label_en-US" xlink:label="lab_country_AU" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AUSTRALIA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_AU" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_AU"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_AU" xlink:to="lab_country_AU" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract_019e1743-a9d5-75c0-ab42-810b517a778e_terseLabel_en-US" xlink:label="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measured at fair value on a recurring basis:</link:label>
    <link:label id="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract_label_en-US" xlink:label="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Measurements, Recurring Value Measurement [Abstract]</link:label>
    <link:label id="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract_documentation_en-US" xlink:label="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fair Value Measurements, Recurring Value Measurement [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairValueMeasurementsRecurringValueMeasurementAbstract" xlink:href="art-20260806.xsd#art_FairValueMeasurementsRecurringValueMeasurementAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairValueMeasurementsRecurringValueMeasurementAbstract" xlink:to="lab_art_FairValueMeasurementsRecurringValueMeasurementAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_country_AT_019e1743-a921-75b0-a8af-d1556764e1ea_terseLabel_en-US" xlink:label="lab_country_AT" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Austria</link:label>
    <link:label id="lab_country_AT_label_en-US" xlink:label="lab_country_AT" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AUSTRIA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_AT" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_AT"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_AT" xlink:to="lab_country_AT" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances_019e1743-aaf8-7c1f-a5cd-448a71ad5f51_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Encumbrances</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Amount of Encumbrances</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TransportationSegmentMember_019e1743-a921-7628-a994-df452009a217_verboseLabel_en-US" xlink:label="lab_art_TransportationSegmentMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Transportation services</link:label>
    <link:label id="lab_art_TransportationSegmentMember_019e1743-a921-759c-b219-e1882b217a55_terseLabel_en-US" xlink:label="lab_art_TransportationSegmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transportation</link:label>
    <link:label id="lab_art_TransportationSegmentMember_label_en-US" xlink:label="lab_art_TransportationSegmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Transportation Segment [Member]</link:label>
    <link:label id="lab_art_TransportationSegmentMember_documentation_en-US" xlink:label="lab_art_TransportationSegmentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Transportation Segment [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TransportationSegmentMember" xlink:href="art-20260806.xsd#art_TransportationSegmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TransportationSegmentMember" xlink:to="lab_art_TransportationSegmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CastleblayneyMember_019e1743-aaf8-70c8-b115-21c1627ec18f_terseLabel_en-US" xlink:label="lab_art_CastleblayneyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Castleblayney</link:label>
    <link:label id="lab_art_CastleblayneyMember_label_en-US" xlink:label="lab_art_CastleblayneyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Castleblayney [Member]</link:label>
    <link:label id="lab_art_CastleblayneyMember_documentation_en-US" xlink:label="lab_art_CastleblayneyMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Castleblayney</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CastleblayneyMember" xlink:href="art-20260806.xsd#art_CastleblayneyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CastleblayneyMember" xlink:to="lab_art_CastleblayneyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_019e1743-a9d5-78ff-a953-abe7c1936e8f_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Information for plans with accumulated benefit obligation in excess of plan assets:</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:to="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019e1743-aa65-713f-869d-ca7c9077ae76_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated other comprehensive loss</link:label>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss), Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WivenhoeTasmania2Member_019e1743-a921-7470-8343-d6f5a96b39c2_terseLabel_en-US" xlink:label="lab_art_WivenhoeTasmania2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wivenhoe - Tasmania</link:label>
    <link:label id="lab_art_WivenhoeTasmania2Member_label_en-US" xlink:label="lab_art_WivenhoeTasmania2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wivenhoe - Tasmania 2 [Member]</link:label>
    <link:label id="lab_art_WivenhoeTasmania2Member_documentation_en-US" xlink:label="lab_art_WivenhoeTasmania2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Wivenhoe - Tasmania 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WivenhoeTasmania2Member" xlink:href="art-20260806.xsd#art_WivenhoeTasmania2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WivenhoeTasmania2Member" xlink:to="lab_art_WivenhoeTasmania2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019e1743-aaf8-7904-a60d-78afb6c1c5f6_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense_019e1743-a921-78b2-ab2b-9d5ad5aa62b7_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Orion - transformation related costs (non-capitalizable costs)</link:label>
    <link:label id="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense_label_en-US" xlink:label="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Cyber Incident-Related Costs, Expense</link:label>
    <link:label id="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense_documentation_en-US" xlink:label="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Cyber Incident-Related Costs, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationCyberIncidentRelatedCostsExpense" xlink:href="art-20260806.xsd#art_BusinessCombinationCyberIncidentRelatedCostsExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationCyberIncidentRelatedCostsExpense" xlink:to="lab_art_BusinessCombinationCyberIncidentRelatedCostsExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Piscataway120NJ2Member_019e1743-aa65-77f8-a45f-17b24f1fecd3_terseLabel_en-US" xlink:label="lab_art_Piscataway120NJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Piscataway 120, NJ</link:label>
    <link:label id="lab_art_Piscataway120NJ2Member_label_en-US" xlink:label="lab_art_Piscataway120NJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Piscataway 120, NJ 2 [Member]</link:label>
    <link:label id="lab_art_Piscataway120NJ2Member_documentation_en-US" xlink:label="lab_art_Piscataway120NJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Piscataway 120, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Piscataway120NJ2Member" xlink:href="art-20260806.xsd#art_Piscataway120NJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Piscataway120NJ2Member" xlink:to="lab_art_Piscataway120NJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GdyniaMember_019e1743-ab7d-785f-a3f8-37ef99a0e73a_terseLabel_en-US" xlink:label="lab_art_GdyniaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gdynia</link:label>
    <link:label id="lab_art_GdyniaMember_label_en-US" xlink:label="lab_art_GdyniaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gdynia [Member]</link:label>
    <link:label id="lab_art_GdyniaMember_documentation_en-US" xlink:label="lab_art_GdyniaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gdynia</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GdyniaMember" xlink:href="art-20260806.xsd#art_GdyniaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GdyniaMember" xlink:to="lab_art_GdyniaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SumterSC1Member_019e1743-a9d5-77b5-81f7-28e850641426_terseLabel_en-US" xlink:label="lab_art_SumterSC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sumter, SC</link:label>
    <link:label id="lab_art_SumterSC1Member_label_en-US" xlink:label="lab_art_SumterSC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sumter, SC 1 [Member]</link:label>
    <link:label id="lab_art_SumterSC1Member_documentation_en-US" xlink:label="lab_art_SumterSC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sumter, SC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SumterSC1Member" xlink:href="art-20260806.xsd#art_SumterSC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SumterSC1Member" xlink:to="lab_art_SumterSC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther_019e1743-a921-731b-97a6-3bd0bbce2d90_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:to="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:type="arc" order="1"/>
    <link:label id="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member_019e1743-a9d5-7994-9984-e31b7156e53f_terseLabel_en-US" xlink:label="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 2 Maturing December 31 2027</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member_label_en-US" xlink:label="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 2 Maturing December 31 2027 [Member]</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member_documentation_en-US" xlink:label="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 2 Maturing December 31 2027</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_InterestRateSwapAgreement2MaturingDecember312027Member" xlink:href="art-20260806.xsd#art_InterestRateSwapAgreement2MaturingDecember312027Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_InterestRateSwapAgreement2MaturingDecember312027Member" xlink:to="lab_art_InterestRateSwapAgreement2MaturingDecember312027Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InventoryNet_019e1743-aa65-7f40-b601-ccf051daf62c_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Inventory and supplies</link:label>
    <link:label id="lab_us-gaap_InventoryNet_label_en-US" xlink:label="lab_us-gaap_InventoryNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryNet" xlink:to="lab_us-gaap_InventoryNet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax_019e1743-aa65-79a7-9dfb-8fc4d821336d_negatedTerseLabel_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Effect of tax</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax_label_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Effect Of Tax</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax_documentation_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Effect Of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax" xlink:href="art-20260806.xsd#art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax" xlink:to="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanEffectOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement_019e1743-aa65-789c-ab5b-5acd5930b9bd_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Recognition of a settlement loss</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Payment for Settlement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligationPaymentForSettlement" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract_019e1743-a921-7c17-a3bb-8c99c6a344dd_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Adjustments</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercentAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019e1743-ab7d-7c93-809b-c9702c773933_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ArndellPark1Member_019e1743-ab7d-7980-befc-b88afe4e8015_terseLabel_en-US" xlink:label="lab_art_ArndellPark1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Arndell Park</link:label>
    <link:label id="lab_art_ArndellPark1Member_label_en-US" xlink:label="lab_art_ArndellPark1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Arndell Park 1 [Member]</link:label>
    <link:label id="lab_art_ArndellPark1Member_documentation_en-US" xlink:label="lab_art_ArndellPark1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Arndell Park 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ArndellPark1Member" xlink:href="art-20260806.xsd#art_ArndellPark1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ArndellPark1Member" xlink:to="lab_art_ArndellPark1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlanBenefitObligationServiceCost_019e1743-a9d5-77f1-9f3c-0778ce9f79a7_negatedTerseLabel_en-US" xlink:label="lab_art_DefinedBenefitPlanBenefitObligationServiceCost" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Service cost</link:label>
    <link:label id="lab_art_DefinedBenefitPlanBenefitObligationServiceCost_label_en-US" xlink:label="lab_art_DefinedBenefitPlanBenefitObligationServiceCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Service Cost</link:label>
    <link:label id="lab_art_DefinedBenefitPlanBenefitObligationServiceCost_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlanBenefitObligationServiceCost" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Service Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlanBenefitObligationServiceCost" xlink:href="art-20260806.xsd#art_DefinedBenefitPlanBenefitObligationServiceCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlanBenefitObligationServiceCost" xlink:to="lab_art_DefinedBenefitPlanBenefitObligationServiceCost" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MinimumMember_019e1743-ab7d-7e41-96c3-7792b4af766d_terseLabel_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum</link:label>
    <link:label id="lab_srt_MinimumMember_label_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MinimumMember" xlink:to="lab_srt_MinimumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GardenCityKS1Member_019e1743-a9d5-7874-82a5-51ea6f235585_terseLabel_en-US" xlink:label="lab_art_GardenCityKS1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Garden City, KS</link:label>
    <link:label id="lab_art_GardenCityKS1Member_label_en-US" xlink:label="lab_art_GardenCityKS1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Garden City, KS 1 [Member]</link:label>
    <link:label id="lab_art_GardenCityKS1Member_documentation_en-US" xlink:label="lab_art_GardenCityKS1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Garden City, KS 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GardenCityKS1Member" xlink:href="art-20260806.xsd#art_GardenCityKS1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GardenCityKS1Member" xlink:to="lab_art_GardenCityKS1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Paisley1Member_019e1743-aa65-7e7b-8d6e-3104a447d5ef_terseLabel_en-US" xlink:label="lab_art_Paisley1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Paisley</link:label>
    <link:label id="lab_art_Paisley1Member_label_en-US" xlink:label="lab_art_Paisley1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Paisley 1 [Member]</link:label>
    <link:label id="lab_art_Paisley1Member_documentation_en-US" xlink:label="lab_art_Paisley1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Paisley 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Paisley1Member" xlink:href="art-20260806.xsd#art_Paisley1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Paisley1Member" xlink:to="lab_art_Paisley1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ScheduleofDividendTypeTableTextBlock_019e1743-a9d5-786c-b826-251806da4f44_terseLabel_en-US" xlink:label="lab_art_ScheduleofDividendTypeTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Distributions Per Common Share</link:label>
    <link:label id="lab_art_ScheduleofDividendTypeTableTextBlock_label_en-US" xlink:label="lab_art_ScheduleofDividendTypeTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Dividend Type [Table Text Block]</link:label>
    <link:label id="lab_art_ScheduleofDividendTypeTableTextBlock_documentation_en-US" xlink:label="lab_art_ScheduleofDividendTypeTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Schedule of Dividend Type [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ScheduleofDividendTypeTableTextBlock" xlink:href="art-20260806.xsd#art_ScheduleofDividendTypeTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ScheduleofDividendTypeTableTextBlock" xlink:to="lab_art_ScheduleofDividendTypeTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_country_AE_019e1743-aa65-737c-a33c-105ef74bc74a_terseLabel_en-US" xlink:label="lab_country_AE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">United Arab Emirates</link:label>
    <link:label id="lab_country_AE_label_en-US" xlink:label="lab_country_AE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">UNITED ARAB EMIRATES</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_AE" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_AE"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_AE" xlink:to="lab_country_AE" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueAfterYearFive_019e1743-aa65-7425-aad8-1f12974ccaab_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueAfterYearFive_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due After Year Five</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueAfterYearFive_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due After Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDueAfterYearFive" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDueAfterYearFive" xlink:to="lab_art_LeaseLiabilityPaymentsDueAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract_019e1743-aa65-70b8-9be2-1aa9a0ea6b22_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred tax liabilities:</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Net [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxLiabilitiesNetAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeasePayments_019e1743-aa64-7288-821f-602b3029bb65_negatedLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasePayments" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Operating cash flows from operating leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeasePayments_label_en-US" xlink:label="lab_us-gaap_OperatingLeasePayments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Payments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeasePayments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasePayments" xlink:to="lab_us-gaap_OperatingLeasePayments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_019e1743-aa65-708a-9919-1df371a3ff8c_terseLabel_en-US" xlink:label="lab_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ownership of partnership</link:label>
    <link:label id="lab_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_label_en-US" xlink:label="lab_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:to="lab_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WestlandRotterdamMember_019e1743-aaf8-717b-a80c-fd22cde18628_terseLabel_en-US" xlink:label="lab_art_WestlandRotterdamMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Westland - Rotterdam</link:label>
    <link:label id="lab_art_WestlandRotterdamMember_label_en-US" xlink:label="lab_art_WestlandRotterdamMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Westland - Rotterdam [Member]</link:label>
    <link:label id="lab_art_WestlandRotterdamMember_documentation_en-US" xlink:label="lab_art_WestlandRotterdamMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Westland - Rotterdam</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WestlandRotterdamMember" xlink:href="art-20260806.xsd#art_WestlandRotterdamMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WestlandRotterdamMember" xlink:to="lab_art_WestlandRotterdamMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CurrentForeignTaxExpenseBenefit_019e1743-ab7d-7a67-bd08-5b0fafe8ab0f_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CurrentForeignTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Foreign</link:label>
    <link:label id="lab_us-gaap_CurrentForeignTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_CurrentForeignTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Foreign Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentForeignTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentForeignTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentForeignTaxExpenseBenefit" xlink:to="lab_us-gaap_CurrentForeignTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MarshallMO1Member_019e1743-ab7d-7d65-bea8-7eaf2f1851fe_terseLabel_en-US" xlink:label="lab_art_MarshallMO1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Marshall, MO</link:label>
    <link:label id="lab_art_MarshallMO1Member_label_en-US" xlink:label="lab_art_MarshallMO1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Marshall, MO 1 [Member]</link:label>
    <link:label id="lab_art_MarshallMO1Member_documentation_en-US" xlink:label="lab_art_MarshallMO1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Marshall, MO 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MarshallMO1Member" xlink:href="art-20260806.xsd#art_MarshallMO1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MarshallMO1Member" xlink:to="lab_art_MarshallMO1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillRollForward_019e1743-a921-72b1-b5c5-aa31e388dd1d_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill [Roll Forward]</link:label>
    <link:label id="lab_us-gaap_GoodwillRollForward_label_en-US" xlink:label="lab_us-gaap_GoodwillRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillRollForward" xlink:to="lab_us-gaap_GoodwillRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction_019e1743-a921-7ba4-841f-ac8e5f683c66_terseLabel_en-US" xlink:label="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from settlement of treasury lock hedge transactions</link:label>
    <link:label id="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction_label_en-US" xlink:label="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From Settlement Of Treasury Lock Hedge Transaction</link:label>
    <link:label id="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction_documentation_en-US" xlink:label="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From Settlement Of Treasury Lock Hedge Transaction</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction" xlink:href="art-20260806.xsd#art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction" xlink:to="lab_art_ProceedsFromSettlementOfTreasuryLockHedgeTransaction" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_019e1743-aaf8-7e80-8e8c-85ec362486a7_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Conversion of OP units to common stock (in shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Shares, Conversion of Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PascoWA1Member_019e1743-aa65-7e4e-ae19-2c952a5f2fd7_terseLabel_en-US" xlink:label="lab_art_PascoWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pasco, WA</link:label>
    <link:label id="lab_art_PascoWA1Member_label_en-US" xlink:label="lab_art_PascoWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pasco, WA 1 [Member]</link:label>
    <link:label id="lab_art_PascoWA1Member_documentation_en-US" xlink:label="lab_art_PascoWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pasco, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PascoWA1Member" xlink:href="art-20260806.xsd#art_PascoWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PascoWA1Member" xlink:to="lab_art_PascoWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member_019e1743-ab7d-79d3-8400-79e2a6ca4a3f_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 5</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 5 [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facilities, Tranche 5</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member" xlink:to="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilitiesTranche5Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ProspectASCCorporate2Member_019e1743-a9d5-730b-8447-820b8adc5095_terseLabel_en-US" xlink:label="lab_art_ProspectASCCorporate2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prospect/ASC Corporate</link:label>
    <link:label id="lab_art_ProspectASCCorporate2Member_label_en-US" xlink:label="lab_art_ProspectASCCorporate2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prospect/ASC Corporate 2 [Member]</link:label>
    <link:label id="lab_art_ProspectASCCorporate2Member_documentation_en-US" xlink:label="lab_art_ProspectASCCorporate2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Prospect/ASC Corporate 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ProspectASCCorporate2Member" xlink:href="art-20260806.xsd#art_ProspectASCCorporate2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ProspectASCCorporate2Member" xlink:to="lab_art_ProspectASCCorporate2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LondonMember_019e1743-ab7d-7e74-a29b-a25555e57db4_terseLabel_en-US" xlink:label="lab_art_LondonMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">London</link:label>
    <link:label id="lab_art_LondonMember_label_en-US" xlink:label="lab_art_LondonMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">London [Member]</link:label>
    <link:label id="lab_art_LondonMember_documentation_en-US" xlink:label="lab_art_LondonMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">London</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LondonMember" xlink:href="art-20260806.xsd#art_LondonMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LondonMember" xlink:to="lab_art_LondonMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearThree_019e1743-aa65-77bb-b435-a4d5f2f2b105_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Three</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearThree_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDueYearThree" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDueYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDueYearThree" xlink:to="lab_art_LeaseLiabilityPaymentsDueYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_019e1743-a9d5-7b4c-9ce4-aa83a3ce99eb_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Tax Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract" xlink:to="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LondonCanadaMember_019e1743-a922-71af-93ad-bfdccfebd116_terseLabel_en-US" xlink:label="lab_art_LondonCanadaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">London, Canada</link:label>
    <link:label id="lab_art_LondonCanadaMember_label_en-US" xlink:label="lab_art_LondonCanadaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">London, Canada [Member]</link:label>
    <link:label id="lab_art_LondonCanadaMember_documentation_en-US" xlink:label="lab_art_LondonCanadaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">London, Canada</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LondonCanadaMember" xlink:href="art-20260806.xsd#art_LondonCanadaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LondonCanadaMember" xlink:to="lab_art_LondonCanadaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_019e1743-a9d5-73b2-8383-b8878a6374a5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">State</link:label>
    <link:label id="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current State and Local Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:to="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ZumbrotaMN2Member_019e1743-aaf8-7c1b-ad68-3c9b65b629b3_terseLabel_en-US" xlink:label="lab_art_ZumbrotaMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Zumbrota, MN</link:label>
    <link:label id="lab_art_ZumbrotaMN2Member_label_en-US" xlink:label="lab_art_ZumbrotaMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Zumbrota, MN 2 [Member]</link:label>
    <link:label id="lab_art_ZumbrotaMN2Member_documentation_en-US" xlink:label="lab_art_ZumbrotaMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Zumbrota, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ZumbrotaMN2Member" xlink:href="art-20260806.xsd#art_ZumbrotaMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ZumbrotaMN2Member" xlink:to="lab_art_ZumbrotaMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod_019e1743-aaf8-7e22-b936-d77b74eda400_terseLabel_en-US" xlink:label="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue satisfaction of monthly storage and handling services</link:label>
    <link:label id="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod_label_en-US" xlink:label="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue Remaining Performance Obligation Satisfaction Period</link:label>
    <link:label id="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod_documentation_en-US" xlink:label="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Revenue Remaining Performance Obligation Satisfaction Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RevenueRemainingPerformanceObligationSatisfactionPeriod" xlink:href="art-20260806.xsd#art_RevenueRemainingPerformanceObligationSatisfactionPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RevenueRemainingPerformanceObligationSatisfactionPeriod" xlink:to="lab_art_RevenueRemainingPerformanceObligationSatisfactionPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityComponentDomain_019e1743-aaf8-7fc7-85dd-efdacd76c50d_terseLabel_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:label id="lab_us-gaap_EquityComponentDomain_label_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityComponentDomain" xlink:to="lab_us-gaap_EquityComponentDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent_019e1743-ab7d-7b42-b97f-de66d172204e_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued payroll and employee benefits</link:label>
    <link:label id="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Salaries</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedSalariesCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:to="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxDisclosureTextBlock_019e1743-ab7d-71f4-ad8f-462c2311cd3e_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Taxes</link:label>
    <link:label id="lab_us-gaap_IncomeTaxDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxDisclosureTextBlock" xlink:to="lab_us-gaap_IncomeTaxDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GovernmentSponsoredPlansContributions_019e1743-aaf8-7f95-926e-255216e06b2a_terseLabel_en-US" xlink:label="lab_art_GovernmentSponsoredPlansContributions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contributions to government sponsored plan</link:label>
    <link:label id="lab_art_GovernmentSponsoredPlansContributions_label_en-US" xlink:label="lab_art_GovernmentSponsoredPlansContributions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Government Sponsored Plans, Contributions</link:label>
    <link:label id="lab_art_GovernmentSponsoredPlansContributions_documentation_en-US" xlink:label="lab_art_GovernmentSponsoredPlansContributions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Government Sponsored Plans, Contributions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GovernmentSponsoredPlansContributions" xlink:href="art-20260806.xsd#art_GovernmentSponsoredPlansContributions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GovernmentSponsoredPlansContributions" xlink:to="lab_art_GovernmentSponsoredPlansContributions" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SavannahGA2Member_019e1743-aa65-7c24-816a-b3406e173e1f_terseLabel_en-US" xlink:label="lab_art_SavannahGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Savannah, GA</link:label>
    <link:label id="lab_art_SavannahGA2Member_label_en-US" xlink:label="lab_art_SavannahGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Savannah GA 2 [Member]</link:label>
    <link:label id="lab_art_SavannahGA2Member_documentation_en-US" xlink:label="lab_art_SavannahGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Savannah GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SavannahGA2Member" xlink:href="art-20260806.xsd#art_SavannahGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SavannahGA2Member" xlink:to="lab_art_SavannahGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BensonNC2Member_019e1743-a9d5-771b-bd8b-00219b3f4725_terseLabel_en-US" xlink:label="lab_art_BensonNC2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Benson, NC</link:label>
    <link:label id="lab_art_BensonNC2Member_label_en-US" xlink:label="lab_art_BensonNC2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Benson, NC 2 [Member]</link:label>
    <link:label id="lab_art_BensonNC2Member_documentation_en-US" xlink:label="lab_art_BensonNC2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Benson, NC 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BensonNC2Member" xlink:href="art-20260806.xsd#art_BensonNC2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BensonNC2Member" xlink:to="lab_art_BensonNC2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember_019e1743-aa65-7c11-928c-227a019b293c_terseLabel_en-US" xlink:label="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">I.U.O.E Stationary Engineers Local 39 Pension Fund</link:label>
    <link:label id="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember_label_en-US" xlink:label="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">I.U.O.E Stationary Engineers Local 39 Pension Fund [Member]</link:label>
    <link:label id="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember_documentation_en-US" xlink:label="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">I.U.O.E Stationary Engineers Local 39 Pension Fund [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_I.U.O.EStationaryEngineersLocal39PensionFundMember" xlink:href="art-20260806.xsd#art_I.U.O.EStationaryEngineersLocal39PensionFundMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_I.U.O.EStationaryEngineersLocal39PensionFundMember" xlink:to="lab_art_I.U.O.EStationaryEngineersLocal39PensionFundMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_019e1743-aaf8-7abf-926f-961d7e314ff9_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercisable</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_UrkMember_019e1743-aaf8-76d7-93bb-665d228c9019_terseLabel_en-US" xlink:label="lab_art_UrkMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Urk</link:label>
    <link:label id="lab_art_UrkMember_label_en-US" xlink:label="lab_art_UrkMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Urk [Member]</link:label>
    <link:label id="lab_art_UrkMember_documentation_en-US" xlink:label="lab_art_UrkMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Urk</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_UrkMember" xlink:href="art-20260806.xsd#art_UrkMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_UrkMember" xlink:to="lab_art_UrkMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentType_019e1743-aa65-7889-9e92-e3db2404ff6c_terseLabel_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Document Type</link:label>
    <link:label id="lab_dei_DocumentType_label_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document Type</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentType" xlink:to="lab_dei_DocumentType" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueInputsLevel3Member_019e1743-aa65-7af7-9db6-21942f2def88_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Level 3</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel3Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 3 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel3Member" xlink:to="lab_us-gaap_FairValueInputsLevel3Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LossContingenciesTable_019e1743-ab7d-76cf-a010-dfaa68121537_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingenciesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss Contingencies [Table]</link:label>
    <link:label id="lab_us-gaap_LossContingenciesTable_label_en-US" xlink:label="lab_us-gaap_LossContingenciesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingencies [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesTable" xlink:to="lab_us-gaap_LossContingenciesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentNumberOfExtensions_019e1743-aaf8-7c02-88c0-23d65fc110a8_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentNumberOfExtensions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of extensions</link:label>
    <link:label id="lab_art_DebtInstrumentNumberOfExtensions_label_en-US" xlink:label="lab_art_DebtInstrumentNumberOfExtensions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Number of Extensions</link:label>
    <link:label id="lab_art_DebtInstrumentNumberOfExtensions_documentation_en-US" xlink:label="lab_art_DebtInstrumentNumberOfExtensions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Number of Extensions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentNumberOfExtensions" xlink:href="art-20260806.xsd#art_DebtInstrumentNumberOfExtensions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentNumberOfExtensions" xlink:to="lab_art_DebtInstrumentNumberOfExtensions" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetAcquisitionDomain_019e1743-a9d5-7bd8-b6b5-562ba4ab8263_terseLabel_en-US" xlink:label="lab_us-gaap_AssetAcquisitionDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset Acquisition [Domain]</link:label>
    <link:label id="lab_us-gaap_AssetAcquisitionDomain_label_en-US" xlink:label="lab_us-gaap_AssetAcquisitionDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Acquisition [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetAcquisitionDomain" xlink:to="lab_us-gaap_AssetAcquisitionDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_country_ES_019e1743-a921-75f9-81f3-2404d5adaf15_terseLabel_en-US" xlink:label="lab_country_ES" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Spain</link:label>
    <link:label id="lab_country_ES_label_en-US" xlink:label="lab_country_ES" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SPAIN</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_ES" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_ES"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_ES" xlink:to="lab_country_ES" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019e1743-aaf8-75e9-8da6-6d94c4aab46f_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total revenues</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue from Contract with Customer, Excluding Assessed Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility_019fcf5a-a0b4-775a-9659-22bdaf84e3cb_terseLabel_en-US" xlink:label="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of cold storage facilities contributed</link:label>
    <link:label id="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility_label_en-US" xlink:label="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment In Joint Venture, Contribution, Number Of Cold Storage Facility</link:label>
    <link:label id="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility_documentation_en-US" xlink:label="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Equity Method Investment In Joint Venture, Contribution, Number Of Cold Storage Facility</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility" xlink:href="art-20260806.xsd#art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility" xlink:to="lab_art_EquityMethodInvestmentInJointVentureContributionNumberOfColdStorageFacility" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_019e1743-aaf8-7de6-a6a6-285b780047e5_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity method investment, realized gain on disposal</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Realized Gain (Loss) on Disposal</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:to="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EastDubuqueIL2Member_019e1743-a9d5-7a0e-9a18-5a443296d117_terseLabel_en-US" xlink:label="lab_art_EastDubuqueIL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">East Dubuque, IL</link:label>
    <link:label id="lab_art_EastDubuqueIL2Member_label_en-US" xlink:label="lab_art_EastDubuqueIL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">East Dubuque, IL 2 [Member]</link:label>
    <link:label id="lab_art_EastDubuqueIL2Member_documentation_en-US" xlink:label="lab_art_EastDubuqueIL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">East Dubuque, IL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EastDubuqueIL2Member" xlink:href="art-20260806.xsd#art_EastDubuqueIL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EastDubuqueIL2Member" xlink:to="lab_art_EastDubuqueIL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TampaPlantCityFL2Member_019e1743-a9d5-7d5a-bfb7-b1a8c085e4fe_terseLabel_en-US" xlink:label="lab_art_TampaPlantCityFL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tampa Plant City, FL</link:label>
    <link:label id="lab_art_TampaPlantCityFL2Member_label_en-US" xlink:label="lab_art_TampaPlantCityFL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tampa Plant City, FL 2 [Member]</link:label>
    <link:label id="lab_art_TampaPlantCityFL2Member_documentation_en-US" xlink:label="lab_art_TampaPlantCityFL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tampa Plant City, FL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TampaPlantCityFL2Member" xlink:href="art-20260806.xsd#art_TampaPlantCityFL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TampaPlantCityFL2Member" xlink:to="lab_art_TampaPlantCityFL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_019e1743-aaf8-725e-af65-e98bd43ddda2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Remittance of withholding taxes related to employee stock-based transactions</link:label>
    <link:label id="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payment, Tax Withholding, Share-Based Payment Arrangement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:to="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfOtherAssetsTableTextBlock_019e1743-ab7d-7162-8041-117425d881de_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Other Assets</link:label>
    <link:label id="lab_us-gaap_ScheduleOfOtherAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Other Assets [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfOtherAssetsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget_019e1743-ab7d-7ca1-8c3b-41d75e73947c_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Target Level</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Target</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Target</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget" xlink:to="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageTarget" xlink:type="arc" order="1"/>
    <link:label id="lab_art_KansasCityMOMember_019e1743-a9d5-7787-bb68-d1a37596f83b_terseLabel_en-US" xlink:label="lab_art_KansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Kansas City, MO</link:label>
    <link:label id="lab_art_KansasCityMOMember_label_en-US" xlink:label="lab_art_KansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Kansas City, MO [Member]</link:label>
    <link:label id="lab_art_KansasCityMOMember_documentation_en-US" xlink:label="lab_art_KansasCityMOMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Kansas City, MO</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_KansasCityMOMember" xlink:href="art-20260806.xsd#art_KansasCityMOMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_KansasCityMOMember" xlink:to="lab_art_KansasCityMOMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_019e1743-aaf8-71e1-b5d9-0ddfbb811029_totalLabel_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Pre-tax loss</link:label>
    <link:label id="lab_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_label_en-US" xlink:label="lab_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:to="lab_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock_019e1743-a9d5-7e1a-a81e-82a18acafb80_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summary of Derivative Results</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Instruments, Gain (Loss) [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:to="lab_us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaGatewayGA1Member_019e1743-a922-7023-ad29-d23eaf4535d2_terseLabel_en-US" xlink:label="lab_art_AtlantaGatewayGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Gateway, GA</link:label>
    <link:label id="lab_art_AtlantaGatewayGA1Member_label_en-US" xlink:label="lab_art_AtlantaGatewayGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Gateway, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaGatewayGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaGatewayGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Gateway, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaGatewayGA1Member" xlink:href="art-20260806.xsd#art_AtlantaGatewayGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaGatewayGA1Member" xlink:to="lab_art_AtlantaGatewayGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RussellvilleARValleyMember_019e1743-ab7d-7278-ba5f-128a0c962bbc_terseLabel_en-US" xlink:label="lab_art_RussellvilleARValleyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Russellville, AR - Valley</link:label>
    <link:label id="lab_art_RussellvilleARValleyMember_label_en-US" xlink:label="lab_art_RussellvilleARValleyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Russellville, AR - Valley [Member]</link:label>
    <link:label id="lab_art_RussellvilleARValleyMember_documentation_en-US" xlink:label="lab_art_RussellvilleARValleyMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Russellville, AR - Valley [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RussellvilleARValleyMember" xlink:href="art-20260806.xsd#art_RussellvilleARValleyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RussellvilleARValleyMember" xlink:to="lab_art_RussellvilleARValleyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAssetsAbstract_label_en-US" xlink:label="lab_us-gaap_OtherAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsAbstract" xlink:to="lab_us-gaap_OtherAssetsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum_019e1743-ab7d-70b3-af6b-85158bc764ce_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Threshold Level</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Maximum</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum" xlink:to="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CashFlowLesseeAbstract_019e1743-aaf8-74fa-8bb2-7d12cf611ef7_terseLabel_en-US" xlink:label="lab_art_CashFlowLesseeAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash paid for amounts included in the measurement of lease liabilities</link:label>
    <link:label id="lab_art_CashFlowLesseeAbstract_label_en-US" xlink:label="lab_art_CashFlowLesseeAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flow, Lessee [Abstract]</link:label>
    <link:label id="lab_art_CashFlowLesseeAbstract_documentation_en-US" xlink:label="lab_art_CashFlowLesseeAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash Flow, Lessee [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CashFlowLesseeAbstract" xlink:href="art-20260806.xsd#art_CashFlowLesseeAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CashFlowLesseeAbstract" xlink:to="lab_art_CashFlowLesseeAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_019e1743-aa65-762b-b364-d3005bbec585_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations_019e1743-aa65-75e9-97be-4003c6392809_terseLabel_en-US" xlink:label="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of facility purchased</link:label>
    <link:label id="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations_label_en-US" xlink:label="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Facilities Purchased From Failed Lease-back Financing Obligations</link:label>
    <link:label id="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations_documentation_en-US" xlink:label="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number of Facilities Purchased From Failed Lease-back Financing Obligations</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations" xlink:href="art-20260806.xsd#art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations" xlink:to="lab_art_NumberOfFacilitiesPurchasedFromFailedLeaseBackFinancingObligations" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_019e1743-a922-7500-96ec-4a7a8a696d76_terseLabel_en-US" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Supplemental disclosures of non-cash investing and financing activities:</link:label>
    <link:label id="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MansfieldTX1Member_019e1743-aa65-77b9-bff4-4d864919c333_terseLabel_en-US" xlink:label="lab_art_MansfieldTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mansfield, TX</link:label>
    <link:label id="lab_art_MansfieldTX1Member_label_en-US" xlink:label="lab_art_MansfieldTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mansfield, TX 1 [Member]</link:label>
    <link:label id="lab_art_MansfieldTX1Member_documentation_en-US" xlink:label="lab_art_MansfieldTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mansfield, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MansfieldTX1Member" xlink:href="art-20260806.xsd#art_MansfieldTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MansfieldTX1Member" xlink:to="lab_art_MansfieldTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_019e1743-ab7d-725d-80f2-c96cc22c32b5_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Weighted Average Assumptions Used To Determine Benefit Obligations and Net Period Benefit Costs</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Assumptions [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAssumptionsUsedTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ConsolidationItemsDomain_019e1743-a9d5-74e7-8d79-22f50ff0487b_terseLabel_en-US" xlink:label="lab_srt_ConsolidationItemsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidation Items [Domain]</link:label>
    <link:label id="lab_srt_ConsolidationItemsDomain_label_en-US" xlink:label="lab_srt_ConsolidationItemsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation Items [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidationItemsDomain" xlink:to="lab_srt_ConsolidationItemsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GenevaLakesWI2Member_019e1743-a9d5-713a-92ce-ff1ca84a3bfc_terseLabel_en-US" xlink:label="lab_art_GenevaLakesWI2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geneva Lakes, WI</link:label>
    <link:label id="lab_art_GenevaLakesWI2Member_label_en-US" xlink:label="lab_art_GenevaLakesWI2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geneva Lakes, WI 2 [Member]</link:label>
    <link:label id="lab_art_GenevaLakesWI2Member_documentation_en-US" xlink:label="lab_art_GenevaLakesWI2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Geneva Lakes, WI 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GenevaLakesWI2Member" xlink:href="art-20260806.xsd#art_GenevaLakesWI2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GenevaLakesWI2Member" xlink:to="lab_art_GenevaLakesWI2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_019e1743-aa65-7d03-97a8-020ee99ea613_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss from discontinued operations, net of tax</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_019e1743-aa65-7b4e-ae1d-3a661edb32e0_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Loss from discontinued operations, net of tax</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:to="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionTermofLease_019e1743-a9d5-746f-aa4e-b29cac44416e_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionTermofLease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease agreement term</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionTermofLease_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionTermofLease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Term of Lease</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionTermofLease_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionTermofLease" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Term of Lease</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionTermofLease" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionTermofLease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionTermofLease" xlink:to="lab_art_SaleLeasebackTransactionTermofLease" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MiddleboroMA1Member_019e1743-aa65-750a-825b-2f16a019714f_terseLabel_en-US" xlink:label="lab_art_MiddleboroMA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Middleboro, MA</link:label>
    <link:label id="lab_art_MiddleboroMA1Member_label_en-US" xlink:label="lab_art_MiddleboroMA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Middleboro, MA 1 [Member]</link:label>
    <link:label id="lab_art_MiddleboroMA1Member_documentation_en-US" xlink:label="lab_art_MiddleboroMA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Middleboro, MA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MiddleboroMA1Member" xlink:href="art-20260806.xsd#art_MiddleboroMA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MiddleboroMA1Member" xlink:to="lab_art_MiddleboroMA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiability_019e1743-a9d5-7094-b50c-fca94e1ba3dc_totalLabel_en-US" xlink:label="lab_art_LeaseLiability" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total future minimum lease payments less interest</link:label>
    <link:label id="lab_art_LeaseLiability_label_en-US" xlink:label="lab_art_LeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability</link:label>
    <link:label id="lab_art_LeaseLiability_documentation_en-US" xlink:label="lab_art_LeaseLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiability" xlink:href="art-20260806.xsd#art_LeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiability" xlink:to="lab_art_LeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsDisclosureTextBlock_019e1743-ab7d-70a6-a8bf-3927a6dc3da4_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investments in and Advances to Partially Owned Entities</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments and Joint Ventures Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentsDisclosureTextBlock" xlink:to="lab_us-gaap_EquityMethodInvestmentsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember_019e1743-ab7d-7075-976f-acb121000730_terseLabel_en-US" xlink:label="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">General Partner And Two Minority Shareholders</link:label>
    <link:label id="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember_label_en-US" xlink:label="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">General Partner And Two Minority Shareholders [Member]</link:label>
    <link:label id="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember_documentation_en-US" xlink:label="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">General Partner And Two Minority Shareholders</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GeneralPartnerAndTwoMinorityShareholdersMember" xlink:href="art-20260806.xsd#art_GeneralPartnerAndTwoMinorityShareholdersMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GeneralPartnerAndTwoMinorityShareholdersMember" xlink:to="lab_art_GeneralPartnerAndTwoMinorityShareholdersMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember_019e1743-ab7d-74bf-8602-dae43286e4d5_terseLabel_en-US" xlink:label="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Public Senior Unsecured Four Percent Coupon Notes</link:label>
    <link:label id="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember_label_en-US" xlink:label="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Public Senior Unsecured Four Percent Coupon Notes [Member]</link:label>
    <link:label id="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember_documentation_en-US" xlink:label="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Public Senior Unsecured Four Percent Coupon Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PublicSeniorUnsecuredFourPercentCouponNotesMember" xlink:href="art-20260806.xsd#art_PublicSeniorUnsecuredFourPercentCouponNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PublicSeniorUnsecuredFourPercentCouponNotesMember" xlink:to="lab_art_PublicSeniorUnsecuredFourPercentCouponNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant_019e1743-a9d5-790d-bbd3-10daf63d8467_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Plan participants&#8217; contributions</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OrmeauColdStoreMember_019e1743-aaf8-7184-8c3b-50c7c7fefba7_terseLabel_en-US" xlink:label="lab_art_OrmeauColdStoreMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ormeau Cold Store</link:label>
    <link:label id="lab_art_OrmeauColdStoreMember_label_en-US" xlink:label="lab_art_OrmeauColdStoreMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ormeau Cold Store [Member]</link:label>
    <link:label id="lab_art_OrmeauColdStoreMember_documentation_en-US" xlink:label="lab_art_OrmeauColdStoreMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ormeau Cold Store</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OrmeauColdStoreMember" xlink:href="art-20260806.xsd#art_OrmeauColdStoreMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OrmeauColdStoreMember" xlink:to="lab_art_OrmeauColdStoreMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock_019e1743-a9d5-7d37-9ed2-2b66b668da69_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts Payable and Accrued Expenses</link:label>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable and Accrued Liabilities Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:to="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember_019e1743-a921-752e-a34b-854cd75aa595_terseLabel_en-US" xlink:label="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New England Teamsters &amp; Trucking Industry Pension Plan</link:label>
    <link:label id="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember_label_en-US" xlink:label="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New England Teamsters and Trucking Industry Pension Plan [Member]</link:label>
    <link:label id="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember_documentation_en-US" xlink:label="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">New England Teamsters and Trucking Industry Pension Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember" xlink:href="art-20260806.xsd#art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember" xlink:to="lab_art_NewEnglandTeamstersandTruckingIndustryPensionPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities_019e1743-aaf8-7c56-b285-1e661948dd89_negatedTerseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Repayment of sale-leaseback financing obligations</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Repayment, Financing Activities</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Repayment, Financing Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionRepaymentFinancingActivities" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionRepaymentFinancingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionRepaymentFinancingActivities" xlink:to="lab_art_SaleLeasebackTransactionRepaymentFinancingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned_019e1743-aaf8-7641-8d69-e7db873ed10b_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Conversion of leased assets to owned</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Conversion of Leased Assets to Owned</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Conversion of Leased Assets to Owned</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesConversionofLeasedAssetstoOwned" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_019e1743-aaf8-7616-9ff5-5d80ba089dc2_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income taxes paid &#8211; net of refunds</link:label>
    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_019e1743-aaf8-7b77-bbbe-e1823fce7ed3_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_label_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Taxes Paid, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesPaidNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxesPaidNet" xlink:to="lab_us-gaap_IncomeTaxesPaidNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_019e1743-a921-704c-b4e6-625613674818_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_019e1743-a9d5-7ebd-9ba6-aca7f118e5a8_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total principal amount of indebtedness</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_019e1743-a9d5-7672-9982-553e5d879f76_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Carrying Amount (USD)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_019e1743-a9d5-77e9-9b24-7987171e375c_totalLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total principal amount of indebtedness</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:to="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019e1743-aa65-7def-8ffa-1f779ee418d9_negatedLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accumulated Depreciation</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019e1743-aa65-7a3e-90e7-c3d04bd11484_negatedPeriodStartLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning Balance</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019e1743-aa65-7de2-b9d2-7c5bf1e32dab_negatedPeriodEndLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:type="resource" xml:lang="en-US">Ending Balance</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_019e1743-aa65-7b5e-bb7b-a76b66291c84_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Accumulated depreciation per Schedule III</link:label>
    <link:label id="lab_us-gaap_RealEstateAccumulatedDepreciation_label_en-US" xlink:label="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateAccumulatedDepreciation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateAccumulatedDepreciation" xlink:to="lab_us-gaap_RealEstateAccumulatedDepreciation" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance_019e1743-a921-742c-b157-1e6b2feaa242_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Closed site costs, excluding severance</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance_label_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition Related Expenses, Closed Site Cost, Excluding Severance</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance_documentation_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition Related Expenses, Closed Site Cost, Excluding Severance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance" xlink:href="art-20260806.xsd#art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance" xlink:to="lab_art_BusinessCombinationAcquisitionRelatedExpensesClosedSiteCostExcludingSeverance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges_019e1743-a921-703e-b9e4-c75835b8d2a6_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Internal restructuring</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Restructuring Charges, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PendergrassGA2Member_019e1743-a9d5-7369-bc5a-537b942d6dbe_terseLabel_en-US" xlink:label="lab_art_PendergrassGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pendergrass, GA</link:label>
    <link:label id="lab_art_PendergrassGA2Member_label_en-US" xlink:label="lab_art_PendergrassGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pendergrass, GA 2 [Member]</link:label>
    <link:label id="lab_art_PendergrassGA2Member_documentation_en-US" xlink:label="lab_art_PendergrassGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pendergrass, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PendergrassGA2Member" xlink:href="art-20260806.xsd#art_PendergrassGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PendergrassGA2Member" xlink:to="lab_art_PendergrassGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WichitaKS1Member_019e1743-aaf8-7580-8e80-ed6627d73a2a_terseLabel_en-US" xlink:label="lab_art_WichitaKS1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wichita, KS</link:label>
    <link:label id="lab_art_WichitaKS1Member_label_en-US" xlink:label="lab_art_WichitaKS1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wichita, KS 1 [Member]</link:label>
    <link:label id="lab_art_WichitaKS1Member_documentation_en-US" xlink:label="lab_art_WichitaKS1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Wichita, KS 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WichitaKS1Member" xlink:href="art-20260806.xsd#art_WichitaKS1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WichitaKS1Member" xlink:to="lab_art_WichitaKS1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember_019e1743-aaf8-7b23-ab5f-eb41551ecdf3_terseLabel_en-US" xlink:label="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Central Pension Fund of the International Union of Operating Engineers and Participating Employers</link:label>
    <link:label id="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember_label_en-US" xlink:label="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Central Pension Fund of the International Union of Operating Engineers and Participating Employers [Member]</link:label>
    <link:label id="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember_documentation_en-US" xlink:label="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Central Pension Fund of the International Union of Operating Engineers and Participating Employers [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember" xlink:href="art-20260806.xsd#art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember" xlink:to="lab_art_CentralPensionFundoftheInternationalUnionofOperatingEngineersandParticipatingEmployersMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract_019e1743-a922-7df6-a5bb-414680415d14_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reconciliation of the Company&#8217;s real estate activity to Schedule III:</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross Reconciliation [Abstract]</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross Reconciliation [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesInvestmentinRealEstateGrossReconciliationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaSouthgateGA1Member_019e1743-a9d5-735d-b49c-2c5c75e1562f_terseLabel_en-US" xlink:label="lab_art_AtlantaSouthgateGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Southgate, GA</link:label>
    <link:label id="lab_art_AtlantaSouthgateGA1Member_label_en-US" xlink:label="lab_art_AtlantaSouthgateGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Southgate, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaSouthgateGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaSouthgateGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Southgate, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaSouthgateGA1Member" xlink:href="art-20260806.xsd#art_AtlantaSouthgateGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaSouthgateGA1Member" xlink:to="lab_art_AtlantaSouthgateGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeLineItems_019e1743-aaf8-75cd-9be4-8bb0d243f6cf_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative [Line Items]</link:label>
    <link:label id="lab_us-gaap_DerivativeLineItems_label_en-US" xlink:label="lab_us-gaap_DerivativeLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLineItems" xlink:to="lab_us-gaap_DerivativeLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignExchangeForwardMember_019e1743-a9d5-7fd7-8aa0-0cc33fe5b8de_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignExchangeForwardMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign currency exchange forwards</link:label>
    <link:label id="lab_us-gaap_ForeignExchangeForwardMember_label_en-US" xlink:label="lab_us-gaap_ForeignExchangeForwardMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Exchange Forward [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignExchangeForwardMember" xlink:to="lab_us-gaap_ForeignExchangeForwardMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MultiemployerPlansWithdrawalObligation_019e1743-a921-7f9a-a720-e9a9b9fee52b_terseLabel_en-US" xlink:label="lab_us-gaap_MultiemployerPlansWithdrawalObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other liabilities</link:label>
    <link:label id="lab_us-gaap_MultiemployerPlansWithdrawalObligation_label_en-US" xlink:label="lab_us-gaap_MultiemployerPlansWithdrawalObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plans, Withdrawal Obligation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlansWithdrawalObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlansWithdrawalObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MultiemployerPlansWithdrawalObligation" xlink:to="lab_us-gaap_MultiemployerPlansWithdrawalObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionDisclosureTextBlock_019e1743-a9d5-7fb4-96b5-de4729a531b1_terseLabel_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale-Leasebacks of Real Estate</link:label>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transactions [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleLeasebackTransactionDisclosureTextBlock" xlink:to="lab_us-gaap_SaleLeasebackTransactionDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrooklynParkMN1Member_019e1743-aa65-7b54-ac76-55e5cdd5070f_terseLabel_en-US" xlink:label="lab_art_BrooklynParkMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brooklyn Park, MN</link:label>
    <link:label id="lab_art_BrooklynParkMN1Member_label_en-US" xlink:label="lab_art_BrooklynParkMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brooklyn Park, MN 1 [Member]</link:label>
    <link:label id="lab_art_BrooklynParkMN1Member_documentation_en-US" xlink:label="lab_art_BrooklynParkMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brooklyn Park, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrooklynParkMN1Member" xlink:href="art-20260806.xsd#art_BrooklynParkMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrooklynParkMN1Member" xlink:to="lab_art_BrooklynParkMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NapoleonOH2Member_019e1743-aa64-771d-9aa0-699df1846ec9_terseLabel_en-US" xlink:label="lab_art_NapoleonOH2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Napoleon, OH</link:label>
    <link:label id="lab_art_NapoleonOH2Member_label_en-US" xlink:label="lab_art_NapoleonOH2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Napoleon, OH 2 [Member]</link:label>
    <link:label id="lab_art_NapoleonOH2Member_documentation_en-US" xlink:label="lab_art_NapoleonOH2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Napoleon, OH 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NapoleonOH2Member" xlink:href="art-20260806.xsd#art_NapoleonOH2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NapoleonOH2Member" xlink:to="lab_art_NapoleonOH2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DecreaseInDerivativeAmountOfHedgedLiability_019e1743-aa65-7f2d-a12c-d068cc79288a_terseLabel_en-US" xlink:label="lab_art_DecreaseInDerivativeAmountOfHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in amount of hedged loan</link:label>
    <link:label id="lab_art_DecreaseInDerivativeAmountOfHedgedLiability_label_en-US" xlink:label="lab_art_DecreaseInDerivativeAmountOfHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Decrease in Derivative, Amount of Hedged Liability</link:label>
    <link:label id="lab_art_DecreaseInDerivativeAmountOfHedgedLiability_documentation_en-US" xlink:label="lab_art_DecreaseInDerivativeAmountOfHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Decrease in Derivative, Amount of Hedged Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DecreaseInDerivativeAmountOfHedgedLiability" xlink:href="art-20260806.xsd#art_DecreaseInDerivativeAmountOfHedgedLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DecreaseInDerivativeAmountOfHedgedLiability" xlink:to="lab_art_DecreaseInDerivativeAmountOfHedgedLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_019e1743-a9d5-7705-b30d-9d4c7b3f29b8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Activity of Allowance for Doubtful Accounts</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeLiabilities_019e1743-a922-7989-85dd-29a4ed45fb2a_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Liabilities</link:label>
    <link:label id="lab_us-gaap_DerivativeLiabilities_019e1743-a922-7f08-9d96-8966670abbfb_verboseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilities" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap liabilities</link:label>
    <link:label id="lab_us-gaap_DerivativeLiabilities_label_en-US" xlink:label="lab_us-gaap_DerivativeLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilities" xlink:to="lab_us-gaap_DerivativeLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AmortizationOfSoftwareDeferredCosts_019e1743-a921-7541-bec1-268826e58bdd_terseLabel_en-US" xlink:label="lab_art_AmortizationOfSoftwareDeferredCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Project Orion and other software related deferred costs amortization</link:label>
    <link:label id="lab_art_AmortizationOfSoftwareDeferredCosts_label_en-US" xlink:label="lab_art_AmortizationOfSoftwareDeferredCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization Of Software Deferred Costs</link:label>
    <link:label id="lab_art_AmortizationOfSoftwareDeferredCosts_documentation_en-US" xlink:label="lab_art_AmortizationOfSoftwareDeferredCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amortization Of Software Deferred Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmortizationOfSoftwareDeferredCosts" xlink:href="art-20260806.xsd#art_AmortizationOfSoftwareDeferredCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmortizationOfSoftwareDeferredCosts" xlink:to="lab_art_AmortizationOfSoftwareDeferredCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_019e1743-aaf8-7f45-a1ad-e25bb0622a32_verboseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Operating expenses</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Operating Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentDividendsOrDistributions_019e1743-a921-7804-9fe3-93b919efd5a1_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Obligation to receive</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentDividendsOrDistributions_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Equity Method Investment, Distribution</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:to="lab_us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DividendsCommonStockReturnOfCapitalPercentage_019e1743-a9d5-7841-8668-35d1c76cba01_terseLabel_en-US" xlink:label="lab_art_DividendsCommonStockReturnOfCapitalPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Return of capital</link:label>
    <link:label id="lab_art_DividendsCommonStockReturnOfCapitalPercentage_label_en-US" xlink:label="lab_art_DividendsCommonStockReturnOfCapitalPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Return Of Capital, Percentage</link:label>
    <link:label id="lab_art_DividendsCommonStockReturnOfCapitalPercentage_documentation_en-US" xlink:label="lab_art_DividendsCommonStockReturnOfCapitalPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Return Of Capital, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DividendsCommonStockReturnOfCapitalPercentage" xlink:href="art-20260806.xsd#art_DividendsCommonStockReturnOfCapitalPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DividendsCommonStockReturnOfCapitalPercentage" xlink:to="lab_art_DividendsCommonStockReturnOfCapitalPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities_019e1743-a921-70be-8efb-e6cc4c7feb4c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Payment for foreign currency exchange forwards settlement</link:label>
    <link:label id="lab_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities_label_en-US" xlink:label="lab_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Derivative Instrument, Investing Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForDerivativeInstrumentInvestingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities" xlink:to="lab_us-gaap_PaymentsForDerivativeInstrumentInvestingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount_019fcf95-63bd-7ead-a6c1-cc2b882fa5d6_terseLabel_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount_label_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other, Amount</link:label>
    <link:label id="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount_documentation_en-US" xlink:label="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EffectiveIncomeTaxRateReconciliationOtherAmount" xlink:href="art-20260806.xsd#art_EffectiveIncomeTaxRateReconciliationOtherAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EffectiveIncomeTaxRateReconciliationOtherAmount" xlink:to="lab_art_EffectiveIncomeTaxRateReconciliationOtherAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_019e1743-ab7d-7762-b650-9cc06cc811ab_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by (used in) financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ChesapeakeVA2Member_019e1743-aaf8-7a0a-b7d3-78e0d8bd27c0_terseLabel_en-US" xlink:label="lab_art_ChesapeakeVA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chesapeake, VA</link:label>
    <link:label id="lab_art_ChesapeakeVA2Member_label_en-US" xlink:label="lab_art_ChesapeakeVA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chesapeake, VA 2 [Member]</link:label>
    <link:label id="lab_art_ChesapeakeVA2Member_documentation_en-US" xlink:label="lab_art_ChesapeakeVA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chesapeake, VA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ChesapeakeVA2Member" xlink:href="art-20260806.xsd#art_ChesapeakeVA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ChesapeakeVA2Member" xlink:to="lab_art_ChesapeakeVA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember_019e1743-ab7d-7b82-98e9-055206699b4c_terseLabel_en-US" xlink:label="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020 Senior Unsecured Revolving Credit Facility</link:label>
    <link:label id="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember_label_en-US" xlink:label="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Twenty Twenty Senior Unsecured Revolving Credit Facilities [Member]</link:label>
    <link:label id="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember_documentation_en-US" xlink:label="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Twenty Twenty Senior Unsecured Revolving Credit Facilities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:href="art-20260806.xsd#art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:to="lab_art_TwentyTwentySeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ValueAddedTaxReceivable_019e1743-aaf8-72d1-9e4b-a9a39e7e2c8a_terseLabel_en-US" xlink:label="lab_us-gaap_ValueAddedTaxReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Value added tax receivable</link:label>
    <link:label id="lab_us-gaap_ValueAddedTaxReceivable_label_en-US" xlink:label="lab_us-gaap_ValueAddedTaxReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Value Added Tax Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValueAddedTaxReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValueAddedTaxReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ValueAddedTaxReceivable" xlink:to="lab_us-gaap_ValueAddedTaxReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_019e1743-aa65-7d06-89a6-087caa965578_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-Lived Tangible Asset [Domain]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Lived Tangible Asset [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_019e1743-aa65-77fa-aa37-4737e62c30d4_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net gain (loss) arising during period</link:label>
    <link:label id="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:to="lab_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PortlandME1Member_019e1743-ab7d-7793-bc1c-a9a2327dcb76_terseLabel_en-US" xlink:label="lab_art_PortlandME1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Portland, ME</link:label>
    <link:label id="lab_art_PortlandME1Member_label_en-US" xlink:label="lab_art_PortlandME1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Portland, ME 1 [Member]</link:label>
    <link:label id="lab_art_PortlandME1Member_documentation_en-US" xlink:label="lab_art_PortlandME1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Portland, ME 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PortlandME1Member" xlink:href="art-20260806.xsd#art_PortlandME1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PortlandME1Member" xlink:to="lab_art_PortlandME1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum_019e1743-ab7d-76df-8990-66e5e9e4d9e3_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum unsecured interest coverage ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Interest Coverage Ratio, Minimum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Interest Coverage Ratio, Minimum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum" xlink:to="lab_art_DebtInstrumentCovenantUnsecuredInterestCoverageRatioMinimum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainesvilleGA1Member_019e1743-aaf8-7408-9ddb-310cf133f609_terseLabel_en-US" xlink:label="lab_art_GainesvilleGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gainesville, GA</link:label>
    <link:label id="lab_art_GainesvilleGA1Member_label_en-US" xlink:label="lab_art_GainesvilleGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gainesville, GA 1 [Member]</link:label>
    <link:label id="lab_art_GainesvilleGA1Member_documentation_en-US" xlink:label="lab_art_GainesvilleGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gainesville, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainesvilleGA1Member" xlink:href="art-20260806.xsd#art_GainesvilleGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainesvilleGA1Member" xlink:to="lab_art_GainesvilleGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AlbertvilleAL2Member_019e1743-aaf8-7769-bc88-4387574b6063_terseLabel_en-US" xlink:label="lab_art_AlbertvilleAL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Albertville, AL</link:label>
    <link:label id="lab_art_AlbertvilleAL2Member_label_en-US" xlink:label="lab_art_AlbertvilleAL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Albertville, AL 2 [Member]</link:label>
    <link:label id="lab_art_AlbertvilleAL2Member_documentation_en-US" xlink:label="lab_art_AlbertvilleAL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Albertville, AL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AlbertvilleAL2Member" xlink:href="art-20260806.xsd#art_AlbertvilleAL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AlbertvilleAL2Member" xlink:to="lab_art_AlbertvilleAL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_019e1743-aaf8-7e73-9bb8-97df5b7aa3e5_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Risk-Free Interest Rate</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityTaxIdentificationNumber_019e1743-aaf8-744c-9d66-deece7a5dcc6_terseLabel_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Tax Identification Number</link:label>
    <link:label id="lab_dei_EntityTaxIdentificationNumber_label_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Tax Identification Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityTaxIdentificationNumber" xlink:to="lab_dei_EntityTaxIdentificationNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GenevaLakesWI1Member_019e1743-a9d5-700f-9169-687f4e9016cd_terseLabel_en-US" xlink:label="lab_art_GenevaLakesWI1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geneva Lakes, WI</link:label>
    <link:label id="lab_art_GenevaLakesWI1Member_label_en-US" xlink:label="lab_art_GenevaLakesWI1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geneva Lakes, WI 1 [Member]</link:label>
    <link:label id="lab_art_GenevaLakesWI1Member_documentation_en-US" xlink:label="lab_art_GenevaLakesWI1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Geneva Lakes, WI 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GenevaLakesWI1Member" xlink:href="art-20260806.xsd#art_GenevaLakesWI1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GenevaLakesWI1Member" xlink:to="lab_art_GenevaLakesWI1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSoldCarryingAmount_019e1743-a921-7b2e-83b6-7cbc39a1f37b_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSoldCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity method investment, amount sold</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSoldCarryingAmount_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSoldCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Amount Sold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentSoldCarryingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentSoldCarryingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSoldCarryingAmount" xlink:to="lab_us-gaap_EquityMethodInvestmentSoldCarryingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetAcquisitionAxis_019e1743-aa65-768c-b1ab-2d79a4763d8f_terseLabel_en-US" xlink:label="lab_us-gaap_AssetAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset Acquisition [Axis]</link:label>
    <link:label id="lab_us-gaap_AssetAcquisitionAxis_label_en-US" xlink:label="lab_us-gaap_AssetAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Acquisition [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetAcquisitionAxis" xlink:to="lab_us-gaap_AssetAcquisitionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member_019e1743-a9d5-7c67-b9e3-79f39913e26e_terseLabel_en-US" xlink:label="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 2 Maturing July 30 2027</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member_label_en-US" xlink:label="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 2 Maturing July 30 2027 [Member]</link:label>
    <link:label id="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member_documentation_en-US" xlink:label="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Agreement 2 Maturing July 30 2027</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_InterestRateSwapAgreement2MaturingJuly302027Member" xlink:href="art-20260806.xsd#art_InterestRateSwapAgreement2MaturingJuly302027Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_InterestRateSwapAgreement2MaturingJuly302027Member" xlink:to="lab_art_InterestRateSwapAgreement2MaturingJuly302027Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlanBenefitObligationInterestCost_019e1743-a9d5-7346-b230-2a6b52615eff_negatedTerseLabel_en-US" xlink:label="lab_art_DefinedBenefitPlanBenefitObligationInterestCost" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Interest cost</link:label>
    <link:label id="lab_art_DefinedBenefitPlanBenefitObligationInterestCost_label_en-US" xlink:label="lab_art_DefinedBenefitPlanBenefitObligationInterestCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Interest Cost</link:label>
    <link:label id="lab_art_DefinedBenefitPlanBenefitObligationInterestCost_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlanBenefitObligationInterestCost" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Interest Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlanBenefitObligationInterestCost" xlink:href="art-20260806.xsd#art_DefinedBenefitPlanBenefitObligationInterestCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlanBenefitObligationInterestCost" xlink:to="lab_art_DefinedBenefitPlanBenefitObligationInterestCost" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount_019e1743-a921-7a04-8463-eea98a08b75c_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal amount, percent</link:label>
    <link:label id="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount_label_en-US" xlink:label="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Percentage of Principal Amount of Issuance In Discount</link:label>
    <link:label id="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount_documentation_en-US" xlink:label="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Percentage of Principal Amount of Issuance In Discount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount" xlink:href="art-20260806.xsd#art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount" xlink:to="lab_art_DebtInstrumentPercentageOfPrincipalAmountOfIssuanceInDiscount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_019e1743-aaf8-77fc-979f-e337114b9ec6_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Basic and Diluted Weighted-Average Common Stock Outstanding</link:label>
    <link:label id="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Weighted Average Number of Shares [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019e1743-a9d5-7d4a-94ad-61b1ab9fab69_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CharlotteNC1Member_019e1743-aa65-747d-88e3-9f2a7f7e5454_terseLabel_en-US" xlink:label="lab_art_CharlotteNC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Charlotte, NC</link:label>
    <link:label id="lab_art_CharlotteNC1Member_label_en-US" xlink:label="lab_art_CharlotteNC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Charlotte, NC 1 [Member]</link:label>
    <link:label id="lab_art_CharlotteNC1Member_documentation_en-US" xlink:label="lab_art_CharlotteNC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Charlotte, NC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CharlotteNC1Member" xlink:href="art-20260806.xsd#art_CharlotteNC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CharlotteNC1Member" xlink:to="lab_art_CharlotteNC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths_019e1743-aaf8-76e5-b51b-d59990fc8b4d_terseLabel_en-US" xlink:label="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of collective bargaining agreements expiring in next twelve months</link:label>
    <link:label id="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths_label_en-US" xlink:label="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement, Number Of Agreements Which Are Expiring, Next Twelve Months</link:label>
    <link:label id="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths_documentation_en-US" xlink:label="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Collective-Bargaining Arrangement, Number Of Agreements Which Are Expiring, Next Twelve Months</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths" xlink:href="art-20260806.xsd#art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths" xlink:to="lab_art_CollectiveBargainingArrangementNumberOfAgreementsWhichAreExpiringNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaltLakeCityUT1Member_019e1743-aaf8-7e17-89ba-3fa5c4837590_terseLabel_en-US" xlink:label="lab_art_SaltLakeCityUT1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Salt Lake City, UT</link:label>
    <link:label id="lab_art_SaltLakeCityUT1Member_label_en-US" xlink:label="lab_art_SaltLakeCityUT1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Salt Lake City, UT 1 [Member]</link:label>
    <link:label id="lab_art_SaltLakeCityUT1Member_documentation_en-US" xlink:label="lab_art_SaltLakeCityUT1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Salt Lake City, UT 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaltLakeCityUT1Member" xlink:href="art-20260806.xsd#art_SaltLakeCityUT1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaltLakeCityUT1Member" xlink:to="lab_art_SaltLakeCityUT1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_019e1743-a9d5-7373-a4e7-6bc3a051d91e_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets</link:label>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortWorthBlueMoundTX1Member_019e1743-aa64-7873-a0b6-3a53998dfb59_terseLabel_en-US" xlink:label="lab_art_FortWorthBlueMoundTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Worth-Blue Mound, TX</link:label>
    <link:label id="lab_art_FortWorthBlueMoundTX1Member_label_en-US" xlink:label="lab_art_FortWorthBlueMoundTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Worth-Blue Mound, TX 1 [Member]</link:label>
    <link:label id="lab_art_FortWorthBlueMoundTX1Member_documentation_en-US" xlink:label="lab_art_FortWorthBlueMoundTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Worth-Blue Mound, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortWorthBlueMoundTX1Member" xlink:href="art-20260806.xsd#art_FortWorthBlueMoundTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortWorthBlueMoundTX1Member" xlink:to="lab_art_FortWorthBlueMoundTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfGoodwillTextBlock_019e1743-a9d5-703b-b285-a5c7b6f1d8e0_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Changes in Goodwill</link:label>
    <link:label id="lab_us-gaap_ScheduleOfGoodwillTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Goodwill [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGoodwillTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfGoodwillTextBlock" xlink:to="lab_us-gaap_ScheduleOfGoodwillTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_019e1743-a9d5-77c8-b83e-93e59937b153_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Net (gain) loss</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:to="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_country_NL_019e1743-a921-72cf-a363-e1c7151c1cee_terseLabel_en-US" xlink:label="lab_country_NL" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Netherlands</link:label>
    <link:label id="lab_country_NL_label_en-US" xlink:label="lab_country_NL" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">NETHERLANDS</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_NL" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_NL"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_NL" xlink:to="lab_country_NL" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TomahWI1Member_019e1743-aa65-788f-8d44-f9bbf56654ad_terseLabel_en-US" xlink:label="lab_art_TomahWI1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tomah, WI</link:label>
    <link:label id="lab_art_TomahWI1Member_label_en-US" xlink:label="lab_art_TomahWI1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tomah, WI 1 [Member]</link:label>
    <link:label id="lab_art_TomahWI1Member_documentation_en-US" xlink:label="lab_art_TomahWI1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tomah, WI 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TomahWI1Member" xlink:href="art-20260806.xsd#art_TomahWI1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TomahWI1Member" xlink:to="lab_art_TomahWI1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpense_019e1743-aaf8-7aab-9a60-81fe84f80a09_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Non-deductible expenses</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpense_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpense" xlink:to="lab_us-gaap_IncomeTaxReconciliationNondeductibleExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_country_NZ_019e1743-a922-7d6b-b831-3ac15e0c3d19_terseLabel_en-US" xlink:label="lab_country_NZ" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New Zealand</link:label>
    <link:label id="lab_country_NZ_label_en-US" xlink:label="lab_country_NZ" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">NEW ZEALAND</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_country_NZ" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_NZ"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_NZ" xlink:to="lab_country_NZ" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RussellvilleARElmira1Member_019e1743-ab7d-7638-beec-f007a4a0be25_terseLabel_en-US" xlink:label="lab_art_RussellvilleARElmira1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Russellville, AR - Elmira</link:label>
    <link:label id="lab_art_RussellvilleARElmira1Member_label_en-US" xlink:label="lab_art_RussellvilleARElmira1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Russellville, AR - Elmira 1 [Member]</link:label>
    <link:label id="lab_art_RussellvilleARElmira1Member_documentation_en-US" xlink:label="lab_art_RussellvilleARElmira1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Russellville, AR - Elmira 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RussellvilleARElmira1Member" xlink:href="art-20260806.xsd#art_RussellvilleARElmira1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RussellvilleARElmira1Member" xlink:to="lab_art_RussellvilleARElmira1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss_019e1743-ab7d-71c7-a95d-b279b2d3e374_negatedTerseLabel_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Foreign currency translation loss</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss_label_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Foreign Currency Translation Gain (Loss)</link:label>
    <link:label id="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss_documentation_en-US" xlink:label="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Foreign Currency Translation Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss" xlink:href="art-20260806.xsd#art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss" xlink:to="lab_art_OtherComprehensiveIncomeLossDefinedBenefitPlanForeignCurrencyTranslationGainLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionNumberofExtensions_019e1743-aaf8-78c9-bb6c-5c84009c45a2_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberofExtensions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of extensions under sale-leaseback transaction</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberofExtensions_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberofExtensions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number of Extensions</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberofExtensions_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberofExtensions" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number of Extensions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionNumberofExtensions" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionNumberofExtensions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionNumberofExtensions" xlink:to="lab_art_SaleLeasebackTransactionNumberofExtensions" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019e1743-a9d5-72fe-8451-24336afd29e3_terseLabel_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indefinite-lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_label_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Indefinite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="lab_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingExpensesAbstract_019e1743-aa65-7808-ab66-b450f2a63df8_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating expenses:</link:label>
    <link:label id="lab_us-gaap_OperatingExpensesAbstract_label_en-US" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Expenses [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingExpensesAbstract" xlink:to="lab_us-gaap_OperatingExpensesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BrightonDenver2CO2Member_019e1743-aaf8-7c1d-a55b-c852cc09ffaa_terseLabel_en-US" xlink:label="lab_art_BrightonDenver2CO2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Brighton (Denver 2), CO</link:label>
    <link:label id="lab_art_BrightonDenver2CO2Member_label_en-US" xlink:label="lab_art_BrightonDenver2CO2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Brighton (Denver 2), CO 2 [Member]</link:label>
    <link:label id="lab_art_BrightonDenver2CO2Member_documentation_en-US" xlink:label="lab_art_BrightonDenver2CO2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Brighton (Denver 2), CO 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BrightonDenver2CO2Member" xlink:href="art-20260806.xsd#art_BrightonDenver2CO2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BrightonDenver2CO2Member" xlink:to="lab_art_BrightonDenver2CO2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_019e1743-aa65-77c2-883d-4b47779509cd_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discount rate</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:to="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SmartsRd2Member_019e1743-aaf8-7d8c-8ad5-d1a58df03bb4_terseLabel_en-US" xlink:label="lab_art_SmartsRd2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Smarts Rd</link:label>
    <link:label id="lab_art_SmartsRd2Member_label_en-US" xlink:label="lab_art_SmartsRd2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Smarts Rd 2 [Member]</link:label>
    <link:label id="lab_art_SmartsRd2Member_documentation_en-US" xlink:label="lab_art_SmartsRd2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Smarts Rd 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SmartsRd2Member" xlink:href="art-20260806.xsd#art_SmartsRd2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SmartsRd2Member" xlink:to="lab_art_SmartsRd2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventLineItems_019fcf58-32c6-7d85-859f-6bd479e703d9_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsequent Event [Line Items]</link:label>
    <link:label id="lab_us-gaap_SubsequentEventLineItems_label_en-US" xlink:label="lab_us-gaap_SubsequentEventLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Event [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventLineItems" xlink:to="lab_us-gaap_SubsequentEventLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PlainvilleCTMember_019e1743-ab7d-7bfe-b70b-5306a28d55d5_terseLabel_en-US" xlink:label="lab_art_PlainvilleCTMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plainville, CT</link:label>
    <link:label id="lab_art_PlainvilleCTMember_label_en-US" xlink:label="lab_art_PlainvilleCTMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plainville, CT [Member]</link:label>
    <link:label id="lab_art_PlainvilleCTMember_documentation_en-US" xlink:label="lab_art_PlainvilleCTMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Plainville, CT</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PlainvilleCTMember" xlink:href="art-20260806.xsd#art_PlainvilleCTMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PlainvilleCTMember" xlink:to="lab_art_PlainvilleCTMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_019e1743-aa65-790d-bf7d-02ad77ecc295_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage_019e1743-aa65-785f-97df-dafaabab81a3_terseLabel_en-US" xlink:label="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable consideration, percentage constrained</link:label>
    <link:label id="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage_label_en-US" xlink:label="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Performance Obligation Satisfied Over Time, Variable Consideration Constrained, Percentage</link:label>
    <link:label id="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage_documentation_en-US" xlink:label="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Revenue, Performance Obligation Satisfied Over Time, Variable Consideration Constrained, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage" xlink:href="art-20260806.xsd#art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage" xlink:to="lab_art_RevenuePerformanceObligationSatisfiedOverTimeVariableConsiderationConstrainedPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_019e1743-a9d5-7e12-88b6-8d0d00c4defd_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]</link:label>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_label_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:to="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeasesAbstract_019e1743-ab7d-720d-ad28-f0688fa31365_terseLabel_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Leases [Abstract]</link:label>
    <link:label id="lab_us-gaap_LeasesAbstract_label_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Leases [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeasesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeasesAbstract" xlink:to="lab_us-gaap_LeasesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Piscataway5AccessNJMember_019e1743-aaf8-7f5e-956d-40f97456d0e7_terseLabel_en-US" xlink:label="lab_art_Piscataway5AccessNJMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Piscataway 5 Access, NJ</link:label>
    <link:label id="lab_art_Piscataway5AccessNJMember_label_en-US" xlink:label="lab_art_Piscataway5AccessNJMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Piscataway 5 Access, NJ [Member]</link:label>
    <link:label id="lab_art_Piscataway5AccessNJMember_documentation_en-US" xlink:label="lab_art_Piscataway5AccessNJMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Piscataway 5 Access, NJ</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Piscataway5AccessNJMember" xlink:href="art-20260806.xsd#art_Piscataway5AccessNJMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Piscataway5AccessNJMember" xlink:to="lab_art_Piscataway5AccessNJMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ArndellPark2Member_019e1743-aaf8-7fae-be51-0d50966f7ec9_terseLabel_en-US" xlink:label="lab_art_ArndellPark2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Arndell Park</link:label>
    <link:label id="lab_art_ArndellPark2Member_label_en-US" xlink:label="lab_art_ArndellPark2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Arndell Park 2 [Member]</link:label>
    <link:label id="lab_art_ArndellPark2Member_documentation_en-US" xlink:label="lab_art_ArndellPark2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Arndell Park 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ArndellPark2Member" xlink:href="art-20260806.xsd#art_ArndellPark2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ArndellPark2Member" xlink:to="lab_art_ArndellPark2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainesvilleCandlerGA1Member_019e1743-a921-73f3-a565-7dec3bcd4ddd_terseLabel_en-US" xlink:label="lab_art_GainesvilleCandlerGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gainesville Candler, GA</link:label>
    <link:label id="lab_art_GainesvilleCandlerGA1Member_label_en-US" xlink:label="lab_art_GainesvilleCandlerGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gainesville Candler, GA 1 [Member]</link:label>
    <link:label id="lab_art_GainesvilleCandlerGA1Member_documentation_en-US" xlink:label="lab_art_GainesvilleCandlerGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gainesville Candler, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainesvilleCandlerGA1Member" xlink:href="art-20260806.xsd#art_GainesvilleCandlerGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainesvilleCandlerGA1Member" xlink:to="lab_art_GainesvilleCandlerGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Laverton1Member_019e1743-ab7d-7778-b29c-40338e0248e8_terseLabel_en-US" xlink:label="lab_art_Laverton1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Laverton</link:label>
    <link:label id="lab_art_Laverton1Member_label_en-US" xlink:label="lab_art_Laverton1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Laverton 1 [Member]</link:label>
    <link:label id="lab_art_Laverton1Member_documentation_en-US" xlink:label="lab_art_Laverton1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Laverton 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Laverton1Member" xlink:href="art-20260806.xsd#art_Laverton1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Laverton1Member" xlink:to="lab_art_Laverton1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock_019e1743-aa65-7335-8e06-11edaea739dd_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Components of Loss From Discontinued Operations</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Groups, Including Discontinued Operations [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:to="lab_us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RealEstateUnderConstructionNettingMember_019e1743-ab7d-7c70-9751-d5888f0a6643_terseLabel_en-US" xlink:label="lab_art_RealEstateUnderConstructionNettingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets Under Construction</link:label>
    <link:label id="lab_art_RealEstateUnderConstructionNettingMember_label_en-US" xlink:label="lab_art_RealEstateUnderConstructionNettingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Under Construction, Netting [Member]</link:label>
    <link:label id="lab_art_RealEstateUnderConstructionNettingMember_documentation_en-US" xlink:label="lab_art_RealEstateUnderConstructionNettingMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Real Estate Under Construction, Netting [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RealEstateUnderConstructionNettingMember" xlink:href="art-20260806.xsd#art_RealEstateUnderConstructionNettingMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RealEstateUnderConstructionNettingMember" xlink:to="lab_art_RealEstateUnderConstructionNettingMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanNameAxis_019e1743-aa65-7d87-8ed9-4c8e706e496a_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Plan Name [Axis]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanNameAxis_label_en-US" xlink:label="lab_us-gaap_RetirementPlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanNameAxis" xlink:to="lab_us-gaap_RetirementPlanNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MultiemployerPlanEmployerContributionCost_019e1743-a922-7583-8ff1-d8d617fe7370_terseLabel_en-US" xlink:label="lab_us-gaap_MultiemployerPlanEmployerContributionCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Americold Contributions</link:label>
    <link:label id="lab_us-gaap_MultiemployerPlanEmployerContributionCost_label_en-US" xlink:label="lab_us-gaap_MultiemployerPlanEmployerContributionCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Multiemployer Plan, Employer Contribution, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanEmployerContributionCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanEmployerContributionCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MultiemployerPlanEmployerContributionCost" xlink:to="lab_us-gaap_MultiemployerPlanEmployerContributionCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareBasic_019e1743-a922-7959-aa15-f971ae1b1108_totalLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Basic loss per share (in USD per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareBasic_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasic" xlink:to="lab_us-gaap_EarningsPerShareBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_019e1743-aa65-7ef8-acc4-03636be8dce2_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and accrued expenses</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accounts Payable and Accrued Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DeferredTaxAssetsLeasingObligations_019e1743-aa65-7c74-8c93-f30b7f0d9d6e_terseLabel_en-US" xlink:label="lab_art_DeferredTaxAssetsLeasingObligations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease obligations</link:label>
    <link:label id="lab_art_DeferredTaxAssetsLeasingObligations_label_en-US" xlink:label="lab_art_DeferredTaxAssetsLeasingObligations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Leasing Obligations</link:label>
    <link:label id="lab_art_DeferredTaxAssetsLeasingObligations_documentation_en-US" xlink:label="lab_art_DeferredTaxAssetsLeasingObligations" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Leasing Obligations</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DeferredTaxAssetsLeasingObligations" xlink:href="art-20260806.xsd#art_DeferredTaxAssetsLeasingObligations"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DeferredTaxAssetsLeasingObligations" xlink:to="lab_art_DeferredTaxAssetsLeasingObligations" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TimeBasedOPUnitsMember_019e1743-ab7d-7535-8ed8-97c0b98fabc1_terseLabel_en-US" xlink:label="lab_art_TimeBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Time-Based OP Units</link:label>
    <link:label id="lab_art_TimeBasedOPUnitsMember_label_en-US" xlink:label="lab_art_TimeBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Time-Based OP Units [Member]</link:label>
    <link:label id="lab_art_TimeBasedOPUnitsMember_documentation_en-US" xlink:label="lab_art_TimeBasedOPUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Time-Based OP Units [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TimeBasedOPUnitsMember" xlink:href="art-20260806.xsd#art_TimeBasedOPUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TimeBasedOPUnitsMember" xlink:to="lab_art_TimeBasedOPUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_019e1743-ab7d-744d-ba13-fc4da4cd7328_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of shares authorized (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_label_en-US" xlink:label="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Capital Shares Reserved for Future Issuance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:to="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_019e1743-a9d5-717a-8ceb-f26c1831ce85_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of plan assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_019e1743-ab7d-7f63-964a-a7a75b5739ec_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discount rate</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate"/>
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    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_019e1743-ab7d-76ac-98e2-949418100b9f_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net loss per common share from discontinued operations - diluted (in USD per share)</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare"/>
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    <link:label id="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember_019e1743-ab7d-7de7-b802-1a4dc6f6c095_terseLabel_en-US" xlink:label="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Alternative New England Teamsters &amp; Trucking Industry Pension Plan</link:label>
    <link:label id="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember_label_en-US" xlink:label="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Alternative New England Teamsters &amp; Trucking Industry Pension Plan [Member]</link:label>
    <link:label id="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember_documentation_en-US" xlink:label="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Alternative New England Teamsters &amp; Trucking Industry Pension Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember" xlink:href="art-20260806.xsd#art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember" xlink:to="lab_art_AlternativeNewEnglandTeamstersTruckingIndustryPensionPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember_019e1743-aa65-7650-bb7e-e1f8d3bde19a_terseLabel_en-US" xlink:label="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020 Senior Unsecured Term Loan A Facility and Senior Unsecured Credit Facility</link:label>
    <link:label id="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember_label_en-US" xlink:label="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Twenty Twenty Senior Secured Credit Facilities and Senior Unsecured Term Loan A Facility [Member]</link:label>
    <link:label id="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember_documentation_en-US" xlink:label="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Twenty Twenty Senior Secured Credit Facilities and Senior Unsecured Term Loan A Facility [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember" xlink:href="art-20260806.xsd#art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember" xlink:to="lab_art_TwentyTwentySeniorSecuredCreditFacilitiesandSeniorUnsecuredTermLoanAFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligation_019e1743-aaf8-722a-9d8d-23df2a3efb9a_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unsatisfied performance obligation</link:label>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligation_label_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligation" xlink:to="lab_us-gaap_RevenueRemainingPerformanceObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_019e1743-a9d5-7510-ace0-bb1aa31d3541_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2028</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_art_JohnsonAR2Member_019e1743-aaf8-7561-ba2f-3535f2ddb890_terseLabel_en-US" xlink:label="lab_art_JohnsonAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Johnson, AR</link:label>
    <link:label id="lab_art_JohnsonAR2Member_label_en-US" xlink:label="lab_art_JohnsonAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Johnson, AR 2 [Member]</link:label>
    <link:label id="lab_art_JohnsonAR2Member_documentation_en-US" xlink:label="lab_art_JohnsonAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Johnson, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_JohnsonAR2Member" xlink:href="art-20260806.xsd#art_JohnsonAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_JohnsonAR2Member" xlink:to="lab_art_JohnsonAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SouthPlainfieldNJ2Member_019e1743-aaf8-73c7-9951-b7b482743107_terseLabel_en-US" xlink:label="lab_art_SouthPlainfieldNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">South Plainfield, NJ</link:label>
    <link:label id="lab_art_SouthPlainfieldNJ2Member_label_en-US" xlink:label="lab_art_SouthPlainfieldNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">South Plainfield, NJ 2 [Member]</link:label>
    <link:label id="lab_art_SouthPlainfieldNJ2Member_documentation_en-US" xlink:label="lab_art_SouthPlainfieldNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">South Plainfield, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SouthPlainfieldNJ2Member" xlink:href="art-20260806.xsd#art_SouthPlainfieldNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SouthPlainfieldNJ2Member" xlink:to="lab_art_SouthPlainfieldNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireEquityMethodInvestments_019e1743-aaf8-7e66-ada6-27e7a239d24b_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireEquityMethodInvestments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Investments in and advances to partially owned entities and other, net</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireEquityMethodInvestments_019e1743-aaf8-74bf-b5dc-c8a79c28696f_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash investments in joint venture</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireEquityMethodInvestments_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireEquityMethodInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Equity Method Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
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    <link:label id="lab_us-gaap_HedgingDesignationDomain_019e1743-aaf8-7204-8f20-88be47ab1b81_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingDesignationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hedging Designation [Domain]</link:label>
    <link:label id="lab_us-gaap_HedgingDesignationDomain_label_en-US" xlink:label="lab_us-gaap_HedgingDesignationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hedging Designation [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HedgingDesignationDomain" xlink:to="lab_us-gaap_HedgingDesignationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewportMN1Member_019e1743-ab7d-720c-9690-a018d643cdd5_terseLabel_en-US" xlink:label="lab_art_NewportMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Newport, MN</link:label>
    <link:label id="lab_art_NewportMN1Member_label_en-US" xlink:label="lab_art_NewportMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Newport, MN 1 [Member]</link:label>
    <link:label id="lab_art_NewportMN1Member_documentation_en-US" xlink:label="lab_art_NewportMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Newport, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewportMN1Member" xlink:href="art-20260806.xsd#art_NewportMN1Member"/>
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    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_019e1743-aa65-7850-a16d-affab6972e60_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill and Intangible Assets Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract"/>
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    <link:label id="lab_art_MullicaHill.NJ2Member_019e1743-ab7d-7830-9f72-ff26c5a6b16c_terseLabel_en-US" xlink:label="lab_art_MullicaHill.NJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mullica Hill. NJ</link:label>
    <link:label id="lab_art_MullicaHill.NJ2Member_label_en-US" xlink:label="lab_art_MullicaHill.NJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mullica Hill. NJ 2 [Member]</link:label>
    <link:label id="lab_art_MullicaHill.NJ2Member_documentation_en-US" xlink:label="lab_art_MullicaHill.NJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mullica Hill. NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MullicaHill.NJ2Member" xlink:href="art-20260806.xsd#art_MullicaHill.NJ2Member"/>
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    <link:label id="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock_019e1743-aa65-79dd-b6d8-1ae94c149f49_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign Currency Related Transactions and Foreign Currency Gains and Losses</link:label>
    <link:label id="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Currency Transactions and Translations Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanOtherChanges_019e1743-a921-7898-be2f-84c6b5437958_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanOtherChanges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash annuity payment</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanOtherChanges_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanOtherChanges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanOtherChanges" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanOtherChanges"/>
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    <link:label id="lab_us-gaap_ConcentrationRiskByBenchmarkAxis_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Benchmark [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="lab_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_019e1743-ab7d-7b0f-9553-47da5c84d3dd_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Options</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_019e1743-aa65-7cd1-8192-72a773e6cde2_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsOther_019e1743-aa65-702d-9706-ceef318f0733_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsOther_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Assets, Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOther" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsOther" xlink:to="lab_us-gaap_DeferredTaxAssetsOther" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019e1743-aa65-7bf5-b1c1-0d496826355e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method Investment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CarthageWarehouseDistMO1Member_019e1743-a9d5-7945-be3a-ae75886b016c_terseLabel_en-US" xlink:label="lab_art_CarthageWarehouseDistMO1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carthage Warehouse Dist, MO</link:label>
    <link:label id="lab_art_CarthageWarehouseDistMO1Member_label_en-US" xlink:label="lab_art_CarthageWarehouseDistMO1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Carthage Warehouse Dist, MO 1 [Member]</link:label>
    <link:label id="lab_art_CarthageWarehouseDistMO1Member_documentation_en-US" xlink:label="lab_art_CarthageWarehouseDistMO1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carthage Warehouse Dist, MO 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CarthageWarehouseDistMO1Member" xlink:href="art-20260806.xsd#art_CarthageWarehouseDistMO1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CarthageWarehouseDistMO1Member" xlink:to="lab_art_CarthageWarehouseDistMO1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SanAntonioHEBTXMember_019e1743-aa65-7cd2-926a-94ce7e709bff_terseLabel_en-US" xlink:label="lab_art_SanAntonioHEBTXMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">San Antonio - HEB, TX</link:label>
    <link:label id="lab_art_SanAntonioHEBTXMember_label_en-US" xlink:label="lab_art_SanAntonioHEBTXMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">San Antonio - HEB, TX [Member]</link:label>
    <link:label id="lab_art_SanAntonioHEBTXMember_documentation_en-US" xlink:label="lab_art_SanAntonioHEBTXMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">San Antonio - HEB, TX</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SanAntonioHEBTXMember" xlink:href="art-20260806.xsd#art_SanAntonioHEBTXMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SanAntonioHEBTXMember" xlink:to="lab_art_SanAntonioHEBTXMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_019e1743-aaf8-789a-b543-373ff77cfa2f_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Future Minimum Operating Lease Payments</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskTypeDomain_019e1743-ab7d-7472-9590-e30dc55a3b80_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskTypeDomain_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain" xlink:to="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ColumbusOH2Member_019e1743-a9d5-7e57-ab69-939dcc3c7927_terseLabel_en-US" xlink:label="lab_art_ColumbusOH2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Columbus, OH</link:label>
    <link:label id="lab_art_ColumbusOH2Member_label_en-US" xlink:label="lab_art_ColumbusOH2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Columbus, OH 2 [Member]</link:label>
    <link:label id="lab_art_ColumbusOH2Member_documentation_en-US" xlink:label="lab_art_ColumbusOH2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Columbus, OH 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ColumbusOH2Member" xlink:href="art-20260806.xsd#art_ColumbusOH2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ColumbusOH2Member" xlink:to="lab_art_ColumbusOH2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLiability_019e1743-aa65-72ea-92c1-54f8c4e18995_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Operating lease obligations</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiability_019e1743-aa65-7b36-a2e7-2713456e8d05_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total future minimum lease payments less interest</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiability" xlink:to="lab_us-gaap_OperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaEmpireGA1Member_019e1743-ab7d-750a-a4e8-5754bfd7a4c3_terseLabel_en-US" xlink:label="lab_art_AtlantaEmpireGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Empire, GA</link:label>
    <link:label id="lab_art_AtlantaEmpireGA1Member_label_en-US" xlink:label="lab_art_AtlantaEmpireGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Empire, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaEmpireGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaEmpireGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Empire, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaEmpireGA1Member" xlink:href="art-20260806.xsd#art_AtlantaEmpireGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaEmpireGA1Member" xlink:to="lab_art_AtlantaEmpireGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesAbstract_019e1743-a9d5-7e3c-9e62-c8f9a1106f00_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="lab_us-gaap_LiabilitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed_019e1743-a9d5-78ed-86f9-dd36632a7184_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Repayment percentage of principal amount</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed" xlink:to="lab_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis_019e1743-aaf8-7554-99fe-43f07b9521fd_terseLabel_en-US" xlink:label="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Financial Statement Location of Deconsolidated Items [Axis]</link:label>
    <link:label id="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis_label_en-US" xlink:label="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Financial Statement Location Of Deconsolidated Items [Axis]</link:label>
    <link:label id="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis_documentation_en-US" xlink:label="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Financial Statement Location Of Deconsolidated Items</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FinancialStatementLocationOfDeconsolidatedItemsAxis" xlink:href="art-20260806.xsd#art_FinancialStatementLocationOfDeconsolidatedItemsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FinancialStatementLocationOfDeconsolidatedItemsAxis" xlink:to="lab_art_FinancialStatementLocationOfDeconsolidatedItemsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent_019e1743-ab7d-7161-ab68-09277ed37707_terseLabel_en-US" xlink:label="lab_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued workers' compensation expenses</link:label>
    <link:label id="lab_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Workers' Compensation Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent" xlink:to="lab_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward_019e1743-a9d5-78e5-a625-91c10d5bd6ae_terseLabel_en-US" xlink:label="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Facilities, at Cost:</link:label>
    <link:label id="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:to="lab_us-gaap_ReconciliationOfCarryingAmountOfRealEstateInvestmentsRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionLineItems_019e1743-a9d5-75e6-bb50-b98bb5f670a1_terseLabel_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction [Line Items]</link:label>
    <link:label id="lab_us-gaap_SaleLeasebackTransactionLineItems_label_en-US" xlink:label="lab_us-gaap_SaleLeasebackTransactionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems" xlink:to="lab_us-gaap_SaleLeasebackTransactionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MansfieldTX2Member_019e1743-aaf8-7fb1-8540-60fa4b0604b4_terseLabel_en-US" xlink:label="lab_art_MansfieldTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mansfield, TX</link:label>
    <link:label id="lab_art_MansfieldTX2Member_label_en-US" xlink:label="lab_art_MansfieldTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mansfield, TX 2 [Member]</link:label>
    <link:label id="lab_art_MansfieldTX2Member_documentation_en-US" xlink:label="lab_art_MansfieldTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mansfield, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MansfieldTX2Member" xlink:href="art-20260806.xsd#art_MansfieldTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MansfieldTX2Member" xlink:to="lab_art_MansfieldTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_019e1743-aaf8-712e-90f7-52794f2dc83b_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_019e1743-a921-7f3e-9367-de41596db4ee_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Deferred financing costs</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_019e1743-a921-77f5-aaa4-b78a56a3f275_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred financing costs</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsGross" xlink:to="lab_us-gaap_DeferredFinanceCostsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairmontCityIL2Member_019e1743-a922-703a-9f3f-d58c36f21919_terseLabel_en-US" xlink:label="lab_art_FairmontCityIL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fairmont City, IL</link:label>
    <link:label id="lab_art_FairmontCityIL2Member_label_en-US" xlink:label="lab_art_FairmontCityIL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fairmont City, IL 2 [Member]</link:label>
    <link:label id="lab_art_FairmontCityIL2Member_documentation_en-US" xlink:label="lab_art_FairmontCityIL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fairmont City, IL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairmontCityIL2Member" xlink:href="art-20260806.xsd#art_FairmontCityIL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairmontCityIL2Member" xlink:to="lab_art_FairmontCityIL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Spearwood1Member_019e1743-a922-7ddf-84bd-dd4a1eb14409_terseLabel_en-US" xlink:label="lab_art_Spearwood1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Spearwood</link:label>
    <link:label id="lab_art_Spearwood1Member_label_en-US" xlink:label="lab_art_Spearwood1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Spearwood 1 [Member]</link:label>
    <link:label id="lab_art_Spearwood1Member_documentation_en-US" xlink:label="lab_art_Spearwood1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Spearwood 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Spearwood1Member" xlink:href="art-20260806.xsd#art_Spearwood1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Spearwood1Member" xlink:to="lab_art_Spearwood1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MilwaukieOR1Member_019e1743-a9d5-79a2-a294-c21c16357893_terseLabel_en-US" xlink:label="lab_art_MilwaukieOR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Milwaukie, OR</link:label>
    <link:label id="lab_art_MilwaukieOR1Member_label_en-US" xlink:label="lab_art_MilwaukieOR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Milwaukie, OR 1 [Member]</link:label>
    <link:label id="lab_art_MilwaukieOR1Member_documentation_en-US" xlink:label="lab_art_MilwaukieOR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Milwaukie, OR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MilwaukieOR1Member" xlink:href="art-20260806.xsd#art_MilwaukieOR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MilwaukieOR1Member" xlink:to="lab_art_MilwaukieOR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GloucesterRoweMA1Member_019e1743-aaf8-729d-b6f2-9e563cf8666d_terseLabel_en-US" xlink:label="lab_art_GloucesterRoweMA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gloucester - Rowe, MA</link:label>
    <link:label id="lab_art_GloucesterRoweMA1Member_label_en-US" xlink:label="lab_art_GloucesterRoweMA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gloucester - Rowe, MA 1 [Member]</link:label>
    <link:label id="lab_art_GloucesterRoweMA1Member_documentation_en-US" xlink:label="lab_art_GloucesterRoweMA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gloucester - Rowe, MA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GloucesterRoweMA1Member" xlink:href="art-20260806.xsd#art_GloucesterRoweMA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GloucesterRoweMA1Member" xlink:to="lab_art_GloucesterRoweMA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlanAverageFutureServicePeriod_019e1743-aaf8-7b11-a3d7-36421038c817_terseLabel_en-US" xlink:label="lab_art_DefinedBenefitPlanAverageFutureServicePeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Average future service period</link:label>
    <link:label id="lab_art_DefinedBenefitPlanAverageFutureServicePeriod_label_en-US" xlink:label="lab_art_DefinedBenefitPlanAverageFutureServicePeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Average Future Service Period</link:label>
    <link:label id="lab_art_DefinedBenefitPlanAverageFutureServicePeriod_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlanAverageFutureServicePeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Average Future Service Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlanAverageFutureServicePeriod" xlink:href="art-20260806.xsd#art_DefinedBenefitPlanAverageFutureServicePeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlanAverageFutureServicePeriod" xlink:to="lab_art_DefinedBenefitPlanAverageFutureServicePeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_LegalEntityAxis_019e1743-a9d5-72da-b77f-3386e7d0cbda_terseLabel_en-US" xlink:label="lab_dei_LegalEntityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Legal Entity [Axis]</link:label>
    <link:label id="lab_dei_LegalEntityAxis_label_en-US" xlink:label="lab_dei_LegalEntityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Legal Entity [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_LegalEntityAxis" xlink:to="lab_dei_LegalEntityAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RSAMember_019e1743-ab7d-71f0-bf63-c070846f2929_terseLabel_en-US" xlink:label="lab_art_RSAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">RSA</link:label>
    <link:label id="lab_art_RSAMember_label_en-US" xlink:label="lab_art_RSAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">RSA [Member]</link:label>
    <link:label id="lab_art_RSAMember_documentation_en-US" xlink:label="lab_art_RSAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">RSA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RSAMember" xlink:href="art-20260806.xsd#art_RSAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RSAMember" xlink:to="lab_art_RSAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock_019e1743-aa65-76e0-a923-ffd739663bc5_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Restricted Stock Units Activity</link:label>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_019e1743-ab7d-7dfc-935f-94d2abf9b451_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2026</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019e1743-a9d5-7e93-8313-ca1383402830_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vested, grant date fair value (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PedricktownNJ1Member_019e1743-aa65-7fc2-86fa-7ebd896e043b_terseLabel_en-US" xlink:label="lab_art_PedricktownNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pedricktown, NJ</link:label>
    <link:label id="lab_art_PedricktownNJ1Member_label_en-US" xlink:label="lab_art_PedricktownNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pedricktown, NJ 1 [Member]</link:label>
    <link:label id="lab_art_PedricktownNJ1Member_documentation_en-US" xlink:label="lab_art_PedricktownNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pedricktown, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PedricktownNJ1Member" xlink:href="art-20260806.xsd#art_PedricktownNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PedricktownNJ1Member" xlink:to="lab_art_PedricktownNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment_019e1743-a922-72f7-bdba-f0ea02df4d2a_terseLabel_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capital expenditures for Expansion and Development</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment_label_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Capital Expenditures for Expansion And Development</link:label>
    <link:label id="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment_documentation_en-US" xlink:label="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">SEC Schedule 12-28, Real Estate Companies, Capital Expenditures for Expansion And Development</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment" xlink:href="art-20260806.xsd#art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment" xlink:to="lab_art_SECSchedule1228RealEstateCompaniesCapitalExpendituresForExpansionAndDevelopment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense_019e1743-a9d5-71bf-8412-b9e856b3d97e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Depreciation expense</link:label>
    <link:label id="lab_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense_label_en-US" xlink:label="lab_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Depreciation Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense" xlink:to="lab_us-gaap_SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskByTypeAxis_019e1743-a9d5-7e70-9cf0-9fe38a2ed9cc_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskByTypeAxis_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis" xlink:to="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SiouxCityIA2640MurraySt2Member_019e1743-aaf8-78b9-8fa3-3a1a392df1a2_terseLabel_en-US" xlink:label="lab_art_SiouxCityIA2640MurraySt2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2640 Murray St</link:label>
    <link:label id="lab_art_SiouxCityIA2640MurraySt2Member_label_en-US" xlink:label="lab_art_SiouxCityIA2640MurraySt2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2640 Murray St 2 [Member]</link:label>
    <link:label id="lab_art_SiouxCityIA2640MurraySt2Member_documentation_en-US" xlink:label="lab_art_SiouxCityIA2640MurraySt2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2640 Murray St 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SiouxCityIA2640MurraySt2Member" xlink:href="art-20260806.xsd#art_SiouxCityIA2640MurraySt2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SiouxCityIA2640MurraySt2Member" xlink:to="lab_art_SiouxCityIA2640MurraySt2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract_019e1743-a921-7d2a-93ca-425182583551_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Significant Segment Expenses:</link:label>
    <link:label id="lab_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment, Reconciliation of Other Items from Segments to Consolidated [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract" xlink:to="lab_us-gaap_SegmentReportingOtherSignificantReconcilingItemConsolidatedAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OklahomaCityOK1Member_019e1743-aa65-7cb5-93f5-b3272b920a1c_terseLabel_en-US" xlink:label="lab_art_OklahomaCityOK1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Oklahoma City, OK</link:label>
    <link:label id="lab_art_OklahomaCityOK1Member_label_en-US" xlink:label="lab_art_OklahomaCityOK1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Oklahoma City, OK 1 [Member]</link:label>
    <link:label id="lab_art_OklahomaCityOK1Member_documentation_en-US" xlink:label="lab_art_OklahomaCityOK1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Oklahoma City, OK 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OklahomaCityOK1Member" xlink:href="art-20260806.xsd#art_OklahomaCityOK1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OklahomaCityOK1Member" xlink:to="lab_art_OklahomaCityOK1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_019e1743-aaf8-72c3-ae58-0a70de589ebf_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2029</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_019e1743-a921-7ec5-8152-bff18d6491ce_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment of indefinite and long-lived assets</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_019e1743-a921-7e30-9a94-ebb2529db1f9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Impairment of indefinite and long-lived assets</link:label>
    <link:label id="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_label_en-US" xlink:label="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment, Long-Lived Asset, Held-for-Use</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:to="lab_us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueInputsLevel2Member_019e1743-a9d5-73da-aa8a-1788aae902d9_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Level 2</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel2Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 2 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel2Member" xlink:to="lab_us-gaap_FairValueInputsLevel2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_019e1743-a921-7b6c-b8b2-b6bdba3878a2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">State income taxes, net of federal income tax benefit</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:to="lab_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HoustonWarehouseAcquisitionMember_019e1743-a921-7bcf-a66b-021771814794_terseLabel_en-US" xlink:label="lab_art_HoustonWarehouseAcquisitionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Houston Warehouse Acquisition</link:label>
    <link:label id="lab_art_HoustonWarehouseAcquisitionMember_label_en-US" xlink:label="lab_art_HoustonWarehouseAcquisitionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Houston Warehouse Acquisition [Member]</link:label>
    <link:label id="lab_art_HoustonWarehouseAcquisitionMember_documentation_en-US" xlink:label="lab_art_HoustonWarehouseAcquisitionMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Houston Warehouse Acquisition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HoustonWarehouseAcquisitionMember" xlink:href="art-20260806.xsd#art_HoustonWarehouseAcquisitionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HoustonWarehouseAcquisitionMember" xlink:to="lab_art_HoustonWarehouseAcquisitionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_019e1743-a921-731c-8941-152482270cb6_terseLabel_en-US" xlink:label="lab_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Removal of hedge designation [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_label_en-US" xlink:label="lab_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">OCI, Cash Flow Hedge, Reclassification for Discontinuance, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:to="lab_us-gaap_OciCashFlowHedgeReclassificationForDiscontinuanceStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ReimbursementReceivable_019e1743-aaf8-75d5-859b-0c9874bec0f5_terseLabel_en-US" xlink:label="lab_art_ReimbursementReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reimbursement receivable</link:label>
    <link:label id="lab_art_ReimbursementReceivable_label_en-US" xlink:label="lab_art_ReimbursementReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reimbursement Receivable</link:label>
    <link:label id="lab_art_ReimbursementReceivable_documentation_en-US" xlink:label="lab_art_ReimbursementReceivable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reimbursement Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ReimbursementReceivable" xlink:href="art-20260806.xsd#art_ReimbursementReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ReimbursementReceivable" xlink:to="lab_art_ReimbursementReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessAcquisitionAcquireeDomain_019e1743-aa65-7767-86a8-4b5c46e90a53_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combination [Domain]</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionAcquireeDomain_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="lab_us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_019e1743-aa65-78ad-a869-946659bef9b9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss on classification of Comfrio as held for sale</link:label>
    <link:label id="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_019e1743-aa65-7eee-95b9-0ef20c9223ed_negatedLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Gain from sale of Comfrio</link:label>
    <link:label id="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_label_en-US" xlink:label="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:to="lab_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AssetAcquisitionAssetsLiabilitiesOther_019e1743-aa64-743f-8f48-e052ad892573_terseLabel_en-US" xlink:label="lab_art_AssetAcquisitionAssetsLiabilitiesOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other assets and liabilities, net</link:label>
    <link:label id="lab_art_AssetAcquisitionAssetsLiabilitiesOther_label_en-US" xlink:label="lab_art_AssetAcquisitionAssetsLiabilitiesOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Acquisition, Assets (Liabilities), Other</link:label>
    <link:label id="lab_art_AssetAcquisitionAssetsLiabilitiesOther_documentation_en-US" xlink:label="lab_art_AssetAcquisitionAssetsLiabilitiesOther" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Asset Acquisition, Assets (Liabilities), Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AssetAcquisitionAssetsLiabilitiesOther" xlink:href="art-20260806.xsd#art_AssetAcquisitionAssetsLiabilitiesOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AssetAcquisitionAssetsLiabilitiesOther" xlink:to="lab_art_AssetAcquisitionAssetsLiabilitiesOther" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_019e1743-a9d5-7133-bf43-684f56750c1a_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in plan assets:</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:to="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MontgomeryAL1Member_019e1743-aa64-7390-b935-5e11d6968f75_terseLabel_en-US" xlink:label="lab_art_MontgomeryAL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Montgomery, AL</link:label>
    <link:label id="lab_art_MontgomeryAL1Member_label_en-US" xlink:label="lab_art_MontgomeryAL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Montgomery, AL 1 [Member]</link:label>
    <link:label id="lab_art_MontgomeryAL1Member_documentation_en-US" xlink:label="lab_art_MontgomeryAL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Montgomery, AL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MontgomeryAL1Member" xlink:href="art-20260806.xsd#art_MontgomeryAL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MontgomeryAL1Member" xlink:to="lab_art_MontgomeryAL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LancasterPA1Member_019e1743-aa65-7257-8b5d-1b79eb6286fd_terseLabel_en-US" xlink:label="lab_art_LancasterPA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lancaster, PA</link:label>
    <link:label id="lab_art_LancasterPA1Member_label_en-US" xlink:label="lab_art_LancasterPA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lancaster, PA 1 [Member]</link:label>
    <link:label id="lab_art_LancasterPA1Member_documentation_en-US" xlink:label="lab_art_LancasterPA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lancaster, PA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LancasterPA1Member" xlink:href="art-20260806.xsd#art_LancasterPA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LancasterPA1Member" xlink:to="lab_art_LancasterPA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityNumberOfEmployees_019e1743-aa64-745d-a7d9-f24c7cb6784e_terseLabel_en-US" xlink:label="lab_dei_EntityNumberOfEmployees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of employees</link:label>
    <link:label id="lab_dei_EntityNumberOfEmployees_label_en-US" xlink:label="lab_dei_EntityNumberOfEmployees" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Number of Employees</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityNumberOfEmployees" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityNumberOfEmployees"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityNumberOfEmployees" xlink:to="lab_dei_EntityNumberOfEmployees" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Ormeau1Member_019e1743-aa65-7d7a-8359-b0f8baa72fca_terseLabel_en-US" xlink:label="lab_art_Ormeau1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ormeau</link:label>
    <link:label id="lab_art_Ormeau1Member_label_en-US" xlink:label="lab_art_Ormeau1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ormeau 1 [Member]</link:label>
    <link:label id="lab_art_Ormeau1Member_documentation_en-US" xlink:label="lab_art_Ormeau1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ormeau 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Ormeau1Member" xlink:href="art-20260806.xsd#art_Ormeau1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Ormeau1Member" xlink:to="lab_art_Ormeau1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_019e1743-a9d5-7b14-a6e0-12e4f9142691_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Changes in operating assets and liabilities:</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MobileAL1Member_019e1743-a9d5-7216-a6d3-611952835116_terseLabel_en-US" xlink:label="lab_art_MobileAL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mobile, AL</link:label>
    <link:label id="lab_art_MobileAL1Member_label_en-US" xlink:label="lab_art_MobileAL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mobile, AL 1 [Member]</link:label>
    <link:label id="lab_art_MobileAL1Member_documentation_en-US" xlink:label="lab_art_MobileAL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mobile, AL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MobileAL1Member" xlink:href="art-20260806.xsd#art_MobileAL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MobileAL1Member" xlink:to="lab_art_MobileAL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance_019e1743-a9d5-7a28-af10-c5012c24587f_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Changes in Valuation Allowance</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:to="lab_us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_019e1743-ab7d-71b3-935c-286e808fad26_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expected Stock Price Volatility</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxAuthorityAxis_019e1743-aa65-7009-b355-17fe2dfb8bc9_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Tax Jurisdiction [Axis]</link:label>
    <link:label id="lab_us-gaap_IncomeTaxAuthorityAxis_label_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Jurisdiction [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis" xlink:to="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_019e1743-aaf8-773b-8314-b1510f9b0643_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Payment Arrangement [Abstract]</link:label>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_label_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementAbstract_019e1743-a9d5-7b58-9a12-f5b522683bd8_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="lab_us-gaap_IncomeStatementAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FairmontMN2Member_019e1743-a922-7870-a9bb-7a9e3f575d64_terseLabel_en-US" xlink:label="lab_art_FairmontMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fairmont, MN</link:label>
    <link:label id="lab_art_FairmontMN2Member_label_en-US" xlink:label="lab_art_FairmontMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fairmont, MN 2 [Member]</link:label>
    <link:label id="lab_art_FairmontMN2Member_documentation_en-US" xlink:label="lab_art_FairmontMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fairmont, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FairmontMN2Member" xlink:href="art-20260806.xsd#art_FairmontMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FairmontMN2Member" xlink:to="lab_art_FairmontMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EaganMN1Member_019e1743-aa64-705d-9766-849c087a6c44_terseLabel_en-US" xlink:label="lab_art_EaganMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Eagan, MN</link:label>
    <link:label id="lab_art_EaganMN1Member_label_en-US" xlink:label="lab_art_EaganMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Eagan, MN 1 [Member]</link:label>
    <link:label id="lab_art_EaganMN1Member_documentation_en-US" xlink:label="lab_art_EaganMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Eagan, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EaganMN1Member" xlink:href="art-20260806.xsd#art_EaganMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EaganMN1Member" xlink:to="lab_art_EaganMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductsAndServicesDomain_019e1743-a9d5-7455-8370-168509cdc66f_terseLabel_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:label id="lab_srt_ProductsAndServicesDomain_label_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductsAndServicesDomain" xlink:to="lab_srt_ProductsAndServicesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019e1743-aa65-7e46-b749-c9216663545e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combination [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AmarilloTX2Member_019e1743-aa65-75d0-a842-d1e4e37b4a38_terseLabel_en-US" xlink:label="lab_art_AmarilloTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amarillo, TX</link:label>
    <link:label id="lab_art_AmarilloTX2Member_label_en-US" xlink:label="lab_art_AmarilloTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amarillo, TX 2 [Member]</link:label>
    <link:label id="lab_art_AmarilloTX2Member_documentation_en-US" xlink:label="lab_art_AmarilloTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amarillo, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmarilloTX2Member" xlink:href="art-20260806.xsd#art_AmarilloTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmarilloTX2Member" xlink:to="lab_art_AmarilloTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LowellAR1Member_019e1743-aaf8-74a0-a2dd-af91a3224e45_terseLabel_en-US" xlink:label="lab_art_LowellAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lowell, AR</link:label>
    <link:label id="lab_art_LowellAR1Member_label_en-US" xlink:label="lab_art_LowellAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lowell, AR 1 [Member]</link:label>
    <link:label id="lab_art_LowellAR1Member_documentation_en-US" xlink:label="lab_art_LowellAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lowell, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LowellAR1Member" xlink:href="art-20260806.xsd#art_LowellAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LowellAR1Member" xlink:to="lab_art_LowellAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeNotionalAmount_019e1743-a9d5-764d-9ed8-5511ec440270_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeNotionalAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Notional</link:label>
    <link:label id="lab_us-gaap_DerivativeNotionalAmount_label_en-US" xlink:label="lab_us-gaap_DerivativeNotionalAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Notional Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeNotionalAmount" xlink:to="lab_us-gaap_DerivativeNotionalAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AppletonWIMember_019e1743-a9d5-735c-8a67-362073ef4ccb_terseLabel_en-US" xlink:label="lab_art_AppletonWIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Appleton, WI</link:label>
    <link:label id="lab_art_AppletonWIMember_label_en-US" xlink:label="lab_art_AppletonWIMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Appleton, WI [Member]</link:label>
    <link:label id="lab_art_AppletonWIMember_documentation_en-US" xlink:label="lab_art_AppletonWIMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Appleton, WI [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AppletonWIMember" xlink:href="art-20260806.xsd#art_AppletonWIMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AppletonWIMember" xlink:to="lab_art_AppletonWIMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationTaxExemptIncome_019e1743-aa65-7e38-a580-b899509dbe88_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Earnings from REIT - not subject to tax</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationTaxExemptIncome_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationTaxExemptIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:to="lab_us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList_019e1743-aaf8-778c-a792-ce45b67fed08_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList" xlink:to="lab_us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WestMemphisAR2Member_019e1743-ab7d-758a-9dc5-245075704d4c_terseLabel_en-US" xlink:label="lab_art_WestMemphisAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">West Memphis, AR</link:label>
    <link:label id="lab_art_WestMemphisAR2Member_label_en-US" xlink:label="lab_art_WestMemphisAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">West Memphis, AR 2 [Member]</link:label>
    <link:label id="lab_art_WestMemphisAR2Member_documentation_en-US" xlink:label="lab_art_WestMemphisAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">West Memphis, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WestMemphisAR2Member" xlink:href="art-20260806.xsd#art_WestMemphisAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WestMemphisAR2Member" xlink:to="lab_art_WestMemphisAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration_019e1743-aaf8-7648-a970-aec3099561ed_terseLabel_en-US" xlink:label="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating loss carryforwards, not subject to expiration</link:label>
    <link:label id="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration_label_en-US" xlink:label="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards, Not Subject To Expiration</link:label>
    <link:label id="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration_documentation_en-US" xlink:label="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards, Not Subject To Expiration</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OperatingLossCarryforwardsNotSubjectToExpiration" xlink:href="art-20260806.xsd#art_OperatingLossCarryforwardsNotSubjectToExpiration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OperatingLossCarryforwardsNotSubjectToExpiration" xlink:to="lab_art_OperatingLossCarryforwardsNotSubjectToExpiration" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RochelleILAmericoldDrive1Member_019e1743-a921-7e21-b048-32cf9390f688_terseLabel_en-US" xlink:label="lab_art_RochelleILAmericoldDrive1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Americold Drive)</link:label>
    <link:label id="lab_art_RochelleILAmericoldDrive1Member_label_en-US" xlink:label="lab_art_RochelleILAmericoldDrive1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Americold Drive) 1 [Member]</link:label>
    <link:label id="lab_art_RochelleILAmericoldDrive1Member_documentation_en-US" xlink:label="lab_art_RochelleILAmericoldDrive1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Americold Drive) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RochelleILAmericoldDrive1Member" xlink:href="art-20260806.xsd#art_RochelleILAmericoldDrive1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RochelleILAmericoldDrive1Member" xlink:to="lab_art_RochelleILAmericoldDrive1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantLeverageRatioMaximum_019e1743-ab7d-7ce9-8c0d-7b20382600e4_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum leverage ratio</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantLeverageRatioMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Leverage Ratio, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantLeverageRatioMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantLeverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Leverage Ratio, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantLeverageRatioMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantLeverageRatioMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantLeverageRatioMaximum" xlink:to="lab_art_DebtInstrumentCovenantLeverageRatioMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_019e1743-a922-76a6-b447-3d42ef0225b0_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from revolving line of credit</link:label>
    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_label_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Long-Term Lines of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:to="lab_us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RochelleILCaron2Member_019e1743-aaf8-778c-99a8-69ea04379a5b_terseLabel_en-US" xlink:label="lab_art_RochelleILCaron2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Caron)</link:label>
    <link:label id="lab_art_RochelleILCaron2Member_label_en-US" xlink:label="lab_art_RochelleILCaron2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Caron) 2 [Member]</link:label>
    <link:label id="lab_art_RochelleILCaron2Member_documentation_en-US" xlink:label="lab_art_RochelleILCaron2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Caron) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RochelleILCaron2Member" xlink:href="art-20260806.xsd#art_RochelleILCaron2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RochelleILCaron2Member" xlink:to="lab_art_RochelleILCaron2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherCapitalizedOperatingAssets_019e1743-aa65-72c5-b978-e598af787836_terseLabel_en-US" xlink:label="lab_art_OtherCapitalizedOperatingAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalized costs related to Project Orion, net of accumulated amortization</link:label>
    <link:label id="lab_art_OtherCapitalizedOperatingAssets_label_en-US" xlink:label="lab_art_OtherCapitalizedOperatingAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Capitalized Operating Assets</link:label>
    <link:label id="lab_art_OtherCapitalizedOperatingAssets_documentation_en-US" xlink:label="lab_art_OtherCapitalizedOperatingAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Capitalized Operating Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherCapitalizedOperatingAssets" xlink:href="art-20260806.xsd#art_OtherCapitalizedOperatingAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherCapitalizedOperatingAssets" xlink:to="lab_art_OtherCapitalizedOperatingAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PowerMember_019e1743-aaf8-7ca1-8e2f-796b16921211_terseLabel_en-US" xlink:label="lab_art_PowerMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Power</link:label>
    <link:label id="lab_art_PowerMember_label_en-US" xlink:label="lab_art_PowerMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Power [Member]</link:label>
    <link:label id="lab_art_PowerMember_documentation_en-US" xlink:label="lab_art_PowerMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Power</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PowerMember" xlink:href="art-20260806.xsd#art_PowerMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PowerMember" xlink:to="lab_art_PowerMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OtherAcquisitionLitigationIncomeExpenseNet_019e1743-aa65-7d88-a80a-98a265608e44_negatedLabel_en-US" xlink:label="lab_art_OtherAcquisitionLitigationIncomeExpenseNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other, net</link:label>
    <link:label id="lab_art_OtherAcquisitionLitigationIncomeExpenseNet_label_en-US" xlink:label="lab_art_OtherAcquisitionLitigationIncomeExpenseNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Acquisition, Litigation Income (Expense), Net</link:label>
    <link:label id="lab_art_OtherAcquisitionLitigationIncomeExpenseNet_documentation_en-US" xlink:label="lab_art_OtherAcquisitionLitigationIncomeExpenseNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Acquisition, Litigation Income (Expense), Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OtherAcquisitionLitigationIncomeExpenseNet" xlink:href="art-20260806.xsd#art_OtherAcquisitionLitigationIncomeExpenseNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OtherAcquisitionLitigationIncomeExpenseNet" xlink:to="lab_art_OtherAcquisitionLitigationIncomeExpenseNet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember_019e1743-aaf8-7c36-9ded-141789c7debf_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction Accounted for as a Financing Lease</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction Accounted for as a Financing Lease [Member]</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction Accounted for as a Financing Lease [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember" xlink:to="lab_art_SaleLeasebackTransactionAccountedforasaFinancingLeaseMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MonaghanIrelandMember_019e1743-a9d5-7c1e-a6d7-ae7863f5b161_terseLabel_en-US" xlink:label="lab_art_MonaghanIrelandMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Monaghan, Ireland</link:label>
    <link:label id="lab_art_MonaghanIrelandMember_label_en-US" xlink:label="lab_art_MonaghanIrelandMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Monaghan, Ireland [Member]</link:label>
    <link:label id="lab_art_MonaghanIrelandMember_documentation_en-US" xlink:label="lab_art_MonaghanIrelandMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Monaghan, Ireland</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MonaghanIrelandMember" xlink:href="art-20260806.xsd#art_MonaghanIrelandMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MonaghanIrelandMember" xlink:to="lab_art_MonaghanIrelandMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OntarioCA1Member_019e1743-ab7d-70b3-bb1c-6a8b9adc961b_terseLabel_en-US" xlink:label="lab_art_OntarioCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ontario, CA</link:label>
    <link:label id="lab_art_OntarioCA1Member_label_en-US" xlink:label="lab_art_OntarioCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ontario, CA 1 [Member]</link:label>
    <link:label id="lab_art_OntarioCA1Member_documentation_en-US" xlink:label="lab_art_OntarioCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ontario, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OntarioCA1Member" xlink:href="art-20260806.xsd#art_OntarioCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OntarioCA1Member" xlink:to="lab_art_OntarioCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DefinedBenefitPlansNumberOfPlans_019e1743-aaf8-7312-aa87-5c29232da8d7_terseLabel_en-US" xlink:label="lab_art_DefinedBenefitPlansNumberOfPlans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of plans</link:label>
    <link:label id="lab_art_DefinedBenefitPlansNumberOfPlans_label_en-US" xlink:label="lab_art_DefinedBenefitPlansNumberOfPlans" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans, Number of Plans</link:label>
    <link:label id="lab_art_DefinedBenefitPlansNumberOfPlans_documentation_en-US" xlink:label="lab_art_DefinedBenefitPlansNumberOfPlans" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Defined Benefit Plans, Number of Plans</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DefinedBenefitPlansNumberOfPlans" xlink:href="art-20260806.xsd#art_DefinedBenefitPlansNumberOfPlans"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DefinedBenefitPlansNumberOfPlans" xlink:to="lab_art_DefinedBenefitPlansNumberOfPlans" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_019e1743-a9d5-7e99-8b6e-15bf8487693b_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Amortization of net (gain) loss</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Amortization of Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:to="lab_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_019e1743-a921-7d57-a899-6b35ca8ac477_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation [Line Items]</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeaseCost_019e1743-aaf8-7d24-a090-33862d2a6ac4_totalLabel_en-US" xlink:label="lab_us-gaap_LeaseCost" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net lease expense</link:label>
    <link:label id="lab_us-gaap_LeaseCost_label_en-US" xlink:label="lab_us-gaap_LeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCost" xlink:to="lab_us-gaap_LeaseCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherLiabilities_019e1743-aaf8-705a-848c-5e1c2d83ffb7_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other liabilities</link:label>
    <link:label id="lab_us-gaap_OtherLiabilities_label_en-US" xlink:label="lab_us-gaap_OtherLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilities" xlink:to="lab_us-gaap_OtherLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Goodwill_019e1743-aa65-79a9-b42b-fa3bcaa6cf20_terseLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:label id="lab_us-gaap_Goodwill_019e1743-aa65-70ec-bb15-5e10a9c5af63_verboseLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:label id="lab_us-gaap_Goodwill_019e1743-aa65-77fa-8f4b-f65eb99dc130_periodStartLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning balance</link:label>
    <link:label id="lab_us-gaap_Goodwill_019e1743-aa65-7a43-8e12-59aa810ecfc5_periodEndLabel_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending balance</link:label>
    <link:label id="lab_us-gaap_Goodwill_label_en-US" xlink:label="lab_us-gaap_Goodwill" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Goodwill" xlink:to="lab_us-gaap_Goodwill" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeaseCostTableTextBlock_019e1743-aaf8-7a78-a592-c811b6dc12b9_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Components of Lease Expense and Other Information Related To Leases</link:label>
    <link:label id="lab_us-gaap_LeaseCostTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Cost [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseCostTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCostTableTextBlock" xlink:to="lab_us-gaap_LeaseCostTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DouglasGA1Member_019e1743-aa65-71cf-9ec7-014b3905ac30_terseLabel_en-US" xlink:label="lab_art_DouglasGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Douglas, GA</link:label>
    <link:label id="lab_art_DouglasGA1Member_label_en-US" xlink:label="lab_art_DouglasGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Douglas, GA 1 [Member]</link:label>
    <link:label id="lab_art_DouglasGA1Member_documentation_en-US" xlink:label="lab_art_DouglasGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Douglas, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DouglasGA1Member" xlink:href="art-20260806.xsd#art_DouglasGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DouglasGA1Member" xlink:to="lab_art_DouglasGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BarcelonaMember_019e1743-aa64-7ddc-b6bf-8276788dd1b3_terseLabel_en-US" xlink:label="lab_art_BarcelonaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Barcelona</link:label>
    <link:label id="lab_art_BarcelonaMember_label_en-US" xlink:label="lab_art_BarcelonaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Barcelona [Member]</link:label>
    <link:label id="lab_art_BarcelonaMember_documentation_en-US" xlink:label="lab_art_BarcelonaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Barcelona</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BarcelonaMember" xlink:href="art-20260806.xsd#art_BarcelonaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BarcelonaMember" xlink:to="lab_art_BarcelonaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NumberOfFacilitiesAcquired_019e1743-aaf8-71fd-b73c-8c68e8b0ec18_terseLabel_en-US" xlink:label="lab_art_NumberOfFacilitiesAcquired" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of facilities acquired</link:label>
    <link:label id="lab_art_NumberOfFacilitiesAcquired_label_en-US" xlink:label="lab_art_NumberOfFacilitiesAcquired" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Facilities Acquired</link:label>
    <link:label id="lab_art_NumberOfFacilitiesAcquired_documentation_en-US" xlink:label="lab_art_NumberOfFacilitiesAcquired" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number of Facilities Acquired</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NumberOfFacilitiesAcquired" xlink:href="art-20260806.xsd#art_NumberOfFacilitiesAcquired"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NumberOfFacilitiesAcquired" xlink:to="lab_art_NumberOfFacilitiesAcquired" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFederalIncomeTaxExpenseBenefit_019e1743-aa65-78dd-96a5-da66341ab241_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">U.S. federal</link:label>
    <link:label id="lab_us-gaap_DeferredFederalIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Federal Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CarthageWarehouseDistMO2Member_019e1743-aa65-7db4-bfd8-f24d48cce916_terseLabel_en-US" xlink:label="lab_art_CarthageWarehouseDistMO2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carthage Warehouse Dist, MO</link:label>
    <link:label id="lab_art_CarthageWarehouseDistMO2Member_label_en-US" xlink:label="lab_art_CarthageWarehouseDistMO2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Carthage Warehouse Dist, MO 2 [Member]</link:label>
    <link:label id="lab_art_CarthageWarehouseDistMO2Member_documentation_en-US" xlink:label="lab_art_CarthageWarehouseDistMO2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carthage Warehouse Dist, MO 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CarthageWarehouseDistMO2Member" xlink:href="art-20260806.xsd#art_CarthageWarehouseDistMO2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CarthageWarehouseDistMO2Member" xlink:to="lab_art_CarthageWarehouseDistMO2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract_019e1743-ab7d-70ea-bde3-687b0a36e27e_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, buildings, and equipment:</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Net, Excluding Capital Leased Assets [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssetsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ColumbusOH1Member_019e1743-a9d5-74af-b38a-49366d263843_terseLabel_en-US" xlink:label="lab_art_ColumbusOH1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Columbus, OH</link:label>
    <link:label id="lab_art_ColumbusOH1Member_label_en-US" xlink:label="lab_art_ColumbusOH1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Columbus, OH 1 [Member]</link:label>
    <link:label id="lab_art_ColumbusOH1Member_documentation_en-US" xlink:label="lab_art_ColumbusOH1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Columbus, OH 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ColumbusOH1Member" xlink:href="art-20260806.xsd#art_ColumbusOH1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ColumbusOH1Member" xlink:to="lab_art_ColumbusOH1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_019e1743-aaf8-7a75-bf07-5487d2b687b5_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of net gain</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_USTreasuryAndGovernmentMember_019e1743-aa64-7c6c-89b7-ff8dbe64b2ef_terseLabel_en-US" xlink:label="lab_us-gaap_USTreasuryAndGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">U.S. bonds</link:label>
    <link:label id="lab_us-gaap_USTreasuryAndGovernmentMember_label_en-US" xlink:label="lab_us-gaap_USTreasuryAndGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">US Treasury and Government [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasuryAndGovernmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_USTreasuryAndGovernmentMember" xlink:to="lab_us-gaap_USTreasuryAndGovernmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_019e1743-a921-7c6f-a898-6c6e2f95b680_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net gain on sale</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WitchurchUKMember_019e1743-a9d5-7904-9bb3-9a66a912f6e3_terseLabel_en-US" xlink:label="lab_art_WitchurchUKMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Witchurch, UK</link:label>
    <link:label id="lab_art_WitchurchUKMember_label_en-US" xlink:label="lab_art_WitchurchUKMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Witchurch, UK [Member]</link:label>
    <link:label id="lab_art_WitchurchUKMember_documentation_en-US" xlink:label="lab_art_WitchurchUKMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Witchurch, UK</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WitchurchUKMember" xlink:href="art-20260806.xsd#art_WitchurchUKMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WitchurchUKMember" xlink:to="lab_art_WitchurchUKMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes_019e1743-aaf8-74ed-829d-d8ce3204203e_terseLabel_en-US" xlink:label="lab_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment, tax basis, cost</link:label>
    <link:label id="lab_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes_label_en-US" xlink:label="lab_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Tax Basis, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes" xlink:to="lab_us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EaganMN2Member_019e1743-aaf8-7404-8c85-01335f4ae044_terseLabel_en-US" xlink:label="lab_art_EaganMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Eagan, MN</link:label>
    <link:label id="lab_art_EaganMN2Member_label_en-US" xlink:label="lab_art_EaganMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Eagan, MN 2 [Member]</link:label>
    <link:label id="lab_art_EaganMN2Member_documentation_en-US" xlink:label="lab_art_EaganMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Eagan, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EaganMN2Member" xlink:href="art-20260806.xsd#art_EaganMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EaganMN2Member" xlink:to="lab_art_EaganMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementPlansPolicy_019e1743-aaf8-79ee-916b-d332efecfe60_terseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementPlansPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension and Post-Retirement Benefits</link:label>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementPlansPolicy_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementPlansPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pension and Other Postretirement Plans, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementPlansPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionAndOtherPostretirementPlansPolicy" xlink:to="lab_us-gaap_PensionAndOtherPostretirementPlansPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PloverWI1Member_019e1743-aaf8-729a-b371-5a3b649b3dc3_terseLabel_en-US" xlink:label="lab_art_PloverWI1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plover, WI</link:label>
    <link:label id="lab_art_PloverWI1Member_label_en-US" xlink:label="lab_art_PloverWI1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plover, WI 1 [Member]</link:label>
    <link:label id="lab_art_PloverWI1Member_documentation_en-US" xlink:label="lab_art_PloverWI1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Plover, WI 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PloverWI1Member" xlink:href="art-20260806.xsd#art_PloverWI1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PloverWI1Member" xlink:to="lab_art_PloverWI1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealEstateMember_019e1743-aaf8-7472-9298-4f618cd7cd16_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate</link:label>
    <link:label id="lab_us-gaap_RealEstateMember_label_en-US" xlink:label="lab_us-gaap_RealEstateMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateMember" xlink:to="lab_us-gaap_RealEstateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_019e1743-a921-7308-91ef-31b2a22761f2_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount (In thousands)</link:label>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OntarioCA2Member_019e1743-a9d5-7a34-a6fc-ed59e78593b7_terseLabel_en-US" xlink:label="lab_art_OntarioCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ontario, CA</link:label>
    <link:label id="lab_art_OntarioCA2Member_label_en-US" xlink:label="lab_art_OntarioCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ontario, CA 2 [Member]</link:label>
    <link:label id="lab_art_OntarioCA2Member_documentation_en-US" xlink:label="lab_art_OntarioCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ontario, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OntarioCA2Member" xlink:href="art-20260806.xsd#art_OntarioCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OntarioCA2Member" xlink:to="lab_art_OntarioCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MassillonErieOH1Member_019e1743-aa65-762e-a2e2-5789bc32bca2_terseLabel_en-US" xlink:label="lab_art_MassillonErieOH1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Massillon Erie, OH</link:label>
    <link:label id="lab_art_MassillonErieOH1Member_label_en-US" xlink:label="lab_art_MassillonErieOH1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Massillon Erie, OH 1 [Member]</link:label>
    <link:label id="lab_art_MassillonErieOH1Member_documentation_en-US" xlink:label="lab_art_MassillonErieOH1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Massillon Erie, OH 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MassillonErieOH1Member" xlink:href="art-20260806.xsd#art_MassillonErieOH1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MassillonErieOH1Member" xlink:to="lab_art_MassillonErieOH1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeInstrumentRiskAxis_019e1743-aa65-7ca2-9425-c9123c346fda_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Derivative Instrument [Axis]</link:label>
    <link:label id="lab_us-gaap_DerivativeInstrumentRiskAxis_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Instrument [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis" xlink:to="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WallaWallaWA1Member_019e1743-aaf8-72af-a922-940fcc5a8604_terseLabel_en-US" xlink:label="lab_art_WallaWallaWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Walla Walla, WA</link:label>
    <link:label id="lab_art_WallaWallaWA1Member_label_en-US" xlink:label="lab_art_WallaWallaWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Walla Walla, WA 1 [Member]</link:label>
    <link:label id="lab_art_WallaWallaWA1Member_documentation_en-US" xlink:label="lab_art_WallaWallaWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Walla Walla, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WallaWallaWA1Member" xlink:href="art-20260806.xsd#art_WallaWallaWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WallaWallaWA1Member" xlink:to="lab_art_WallaWallaWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_019e1743-aaf8-7fd9-8591-4b3d49d42013_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Benefits paid</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Benefits Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:to="lab_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeFinanceLeasesTextBlock_019e1743-a9d5-78c5-a37b-bf9944588d92_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeFinanceLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease Accounting</link:label>
    <link:label id="lab_us-gaap_LesseeFinanceLeasesTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeFinanceLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Finance Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeFinanceLeasesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeFinanceLeasesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeFinanceLeasesTextBlock" xlink:to="lab_us-gaap_LesseeFinanceLeasesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_PreCommencementIssuerTenderOffer_019fcfa7-2be1-7db7-9895-58241fb618f1_terseLabel_en-US" xlink:label="lab_dei_PreCommencementIssuerTenderOffer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pre-commencement Issuer Tender Offer</link:label>
    <link:label id="lab_dei_PreCommencementIssuerTenderOffer_label_en-US" xlink:label="lab_dei_PreCommencementIssuerTenderOffer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pre-commencement Issuer Tender Offer</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_PreCommencementIssuerTenderOffer" xlink:to="lab_dei_PreCommencementIssuerTenderOffer" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LowellAR2Member_019e1743-a9d5-7386-9637-2dac3ceebf4d_terseLabel_en-US" xlink:label="lab_art_LowellAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lowell, AR</link:label>
    <link:label id="lab_art_LowellAR2Member_label_en-US" xlink:label="lab_art_LowellAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lowell, AR 2 [Member]</link:label>
    <link:label id="lab_art_LowellAR2Member_documentation_en-US" xlink:label="lab_art_LowellAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lowell, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LowellAR2Member" xlink:href="art-20260806.xsd#art_LowellAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LowellAR2Member" xlink:to="lab_art_LowellAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue_019e1743-a921-7189-9779-d253f2b14981_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred revenue</link:label>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue_label_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Revenue</link:label>
    <link:label id="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue_documentation_en-US" xlink:label="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Revenue</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue" xlink:href="art-20260806.xsd#art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue" xlink:to="lab_art_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredRevenue" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityDomain_019e1743-aaf8-7b4b-bff9-8e8c6d7a5848_terseLabel_en-US" xlink:label="lab_dei_EntityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity [Domain]</link:label>
    <link:label id="lab_dei_EntityDomain_label_en-US" xlink:label="lab_dei_EntityDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityDomain" xlink:to="lab_dei_EntityDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_019e1743-aa65-7c0b-9ab6-1d39e4378795_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Settlement loss</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_019e1743-aa65-7725-9c2e-c018b07e2de4_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Effect of settlement</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Payment for Settlement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanSettlementsPlanAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanSettlementsPlanAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_019e1743-a9d5-782b-bf98-0541071925ea_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash used in investing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_019e1743-a9d5-7e09-99e0-d6220748b3eb_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance obligation, period for recognition</link:label>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_label_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:to="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MosesLakeWA1Member_019e1743-aaf8-7e77-9fff-25473ff3771c_terseLabel_en-US" xlink:label="lab_art_MosesLakeWA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Moses Lake, WA</link:label>
    <link:label id="lab_art_MosesLakeWA1Member_label_en-US" xlink:label="lab_art_MosesLakeWA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Moses Lake, WA 1 [Member]</link:label>
    <link:label id="lab_art_MosesLakeWA1Member_documentation_en-US" xlink:label="lab_art_MosesLakeWA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Moses Lake, WA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MosesLakeWA1Member" xlink:href="art-20260806.xsd#art_MosesLakeWA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MosesLakeWA1Member" xlink:to="lab_art_MosesLakeWA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts_019e1743-aa65-7e25-a187-9516b8db8208_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Orion - Oracle related costs (non-capitalizable costs)</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition-Related Cost, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:to="lab_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_019e1743-aa65-75a2-b982-f75f164da3e9_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unrecognized stock-based compensation expense, period for recognition</link:label>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WestMemphisAR1Member_019e1743-a922-72fa-adf4-723b4df65fbf_terseLabel_en-US" xlink:label="lab_art_WestMemphisAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">West Memphis, AR</link:label>
    <link:label id="lab_art_WestMemphisAR1Member_label_en-US" xlink:label="lab_art_WestMemphisAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">West Memphis, AR 1 [Member]</link:label>
    <link:label id="lab_art_WestMemphisAR1Member_documentation_en-US" xlink:label="lab_art_WestMemphisAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">West Memphis, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WestMemphisAR1Member" xlink:href="art-20260806.xsd#art_WestMemphisAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WestMemphisAR1Member" xlink:to="lab_art_WestMemphisAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_NorthAmericaMember_019e1743-aa65-7d3d-b6b2-294b63ca6f7c_terseLabel_en-US" xlink:label="lab_srt_NorthAmericaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">North America</link:label>
    <link:label id="lab_srt_NorthAmericaMember_label_en-US" xlink:label="lab_srt_NorthAmericaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">North America [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NorthAmericaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_NorthAmericaMember" xlink:to="lab_srt_NorthAmericaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HatfieldPA2Member_019e1743-a9d5-72c6-846b-dd7c422ff193_terseLabel_en-US" xlink:label="lab_art_HatfieldPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hatfield, PA</link:label>
    <link:label id="lab_art_HatfieldPA2Member_label_en-US" xlink:label="lab_art_HatfieldPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hatfield, PA 2 [Member]</link:label>
    <link:label id="lab_art_HatfieldPA2Member_documentation_en-US" xlink:label="lab_art_HatfieldPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Hatfield, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HatfieldPA2Member" xlink:href="art-20260806.xsd#art_HatfieldPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HatfieldPA2Member" xlink:to="lab_art_HatfieldPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_019e1743-aaf8-730f-b17d-34c814d035fa_verboseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Geographic Concentrations</link:label>
    <link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_019e1743-aaf8-72b1-8376-b4ced9c58c60_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment Information</link:label>
    <link:label id="lab_us-gaap_SegmentReportingDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingDisclosureTextBlock" xlink:to="lab_us-gaap_SegmentReportingDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember_019e1743-a9d5-7eab-b3e6-eb9a01c50c48_terseLabel_en-US" xlink:label="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022 Senior Unsecured Revolving Credit Facilities</link:label>
    <link:label id="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember_label_en-US" xlink:label="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Twenty Twenty Two Senior Unsecured Revolving Credit Facilities [Member]</link:label>
    <link:label id="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember_documentation_en-US" xlink:label="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Twenty Twenty Two Senior Unsecured Revolving Credit Facilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:href="art-20260806.xsd#art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:to="lab_art_TwentyTwentyTwoSeniorUnsecuredRevolvingCreditFacilitiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfGoodwillTable_019e1743-aaf8-78d7-a98c-7365955ce5bf_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfGoodwillTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable" xlink:to="lab_us-gaap_ScheduleOfGoodwillTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019e1743-ab7d-755b-8eb5-0395b1671534_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_019e1743-aaf8-7353-b2f4-83857ddf16ae_periodStartLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Fair value of plan assets&#160;&#8211; beginning of year</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_019e1743-aaf8-7e6e-9b08-67981b809d5d_periodEndLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Fair value of plan assets&#160;&#8211; end of year</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_019e1743-aaf8-735f-bfbb-611eb34de1f9_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_019e1743-aaf8-7216-be70-c7439aa072d5_terseLabel_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements or Change in Accounting Principle [Line Items]</link:label>
    <link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_label_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements or Change in Accounting Principle [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:to="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanSponsorLocationAxis_019e1743-aa65-7182-b89d-825192fb3f72_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Plan Sponsor Location [Axis]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanSponsorLocationAxis_label_en-US" xlink:label="lab_us-gaap_RetirementPlanSponsorLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Sponsor Location [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanSponsorLocationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis" xlink:to="lab_us-gaap_RetirementPlanSponsorLocationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems_019e1743-a9d5-7b72-b841-57cbfbb035f4_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets [Line Items]</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DividendsCommonStockCapitalGainsPercentage_019e1743-aaf8-7798-b1bc-d5c80e14b520_terseLabel_en-US" xlink:label="lab_art_DividendsCommonStockCapitalGainsPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capital gains</link:label>
    <link:label id="lab_art_DividendsCommonStockCapitalGainsPercentage_label_en-US" xlink:label="lab_art_DividendsCommonStockCapitalGainsPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Capital Gains, Percentage</link:label>
    <link:label id="lab_art_DividendsCommonStockCapitalGainsPercentage_documentation_en-US" xlink:label="lab_art_DividendsCommonStockCapitalGainsPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Capital Gains, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DividendsCommonStockCapitalGainsPercentage" xlink:href="art-20260806.xsd#art_DividendsCommonStockCapitalGainsPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DividendsCommonStockCapitalGainsPercentage" xlink:to="lab_art_DividendsCommonStockCapitalGainsPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019e1743-aaf8-7dc9-a4b6-d17cc2397d44_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value, Recurring and Nonrecurring [Table]</link:label>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Recurring and Nonrecurring [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_019e1743-aa64-7751-8c42-7d07ff1391e3_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of finite-lived intangible assets</link:label>
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_label_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Intangible Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AmortizationOfIntangibleAssets" xlink:to="lab_us-gaap_AmortizationOfIntangibleAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeLeasesPolicyTextBlock_019e1743-a921-7763-8834-acaa870c19ec_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeLeasesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease Accounting Arrangements wherein we are the lessee</link:label>
    <link:label id="lab_us-gaap_LesseeLeasesPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeLeasesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Leases [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeasesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeasesPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeLeasesPolicyTextBlock" xlink:to="lab_us-gaap_LesseeLeasesPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DepreciationDepletionAndAmortization_019e1743-aa65-77bd-951d-50a1f6c9e579_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DepreciationDepletionAndAmortization" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:label id="lab_us-gaap_DepreciationDepletionAndAmortization_label_en-US" xlink:label="lab_us-gaap_DepreciationDepletionAndAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion and Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DepreciationDepletionAndAmortization" xlink:to="lab_us-gaap_DepreciationDepletionAndAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_019e1743-aa65-761d-8226-a7915ef869c8_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Effect of settlement</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1"/>
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    <link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_019e1743-aa65-79dc-a866-994b02f8287a_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Revenues from External Customers and Long-Lived Assets [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Revenues from External Customers and Long-Lived Assets [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
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    <link:label id="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment_019e1743-a922-7180-9967-6fd4f5b3cc6d_negatedLabel_en-US" xlink:label="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Performance adjustment (in shares)</link:label>
    <link:label id="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment_label_en-US" xlink:label="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Market-Performance Adjustment</link:label>
    <link:label id="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment_documentation_en-US" xlink:label="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Performance Adjustment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment" xlink:href="art-20260806.xsd#art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment" xlink:to="lab_art_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsMarketPerformanceAdjustment" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet_019e1743-a9d5-7fed-93da-d8411a3690d9_totalLabel_en-US" xlink:label="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Cash paid for acquisitions of property, buildings, equipment, and other assets, net</link:label>
    <link:label id="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet_label_en-US" xlink:label="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Acquisition, Assets Acquired And Liabilities Assumed, Net</link:label>
    <link:label id="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet_documentation_en-US" xlink:label="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Asset Acquisition, Assets Acquired And Liabilities Assumed, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet" xlink:href="art-20260806.xsd#art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet" xlink:to="lab_art_AssetAcquisitionAssetsAcquiredAndLiabilitiesAssumedNet" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember_019e1743-ab7d-7311-af3c-a8e0fd853448_terseLabel_en-US" xlink:label="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Americold Realty Trust 2017 Equity Incentive Plan</link:label>
    <link:label id="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember_label_en-US" xlink:label="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Americold Realty Trust 2017 Equity Incentive Plan [Member]</link:label>
    <link:label id="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember_documentation_en-US" xlink:label="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Americold Realty Trust 2017 Equity Incentive Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmericoldRealtyTrust2017EquityIncentivePlanMember" xlink:href="art-20260806.xsd#art_AmericoldRealtyTrust2017EquityIncentivePlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmericoldRealtyTrust2017EquityIncentivePlanMember" xlink:to="lab_art_AmericoldRealtyTrust2017EquityIncentivePlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevolvingCreditFacilityMember_019e1743-a9d5-7383-87a3-ebe4df7f1aa8_terseLabel_en-US" xlink:label="lab_us-gaap_RevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolving Credit Facility</link:label>
    <link:label id="lab_us-gaap_RevolvingCreditFacilityMember_label_en-US" xlink:label="lab_us-gaap_RevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revolving Credit Facility [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevolvingCreditFacilityMember" xlink:to="lab_us-gaap_RevolvingCreditFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy_019e1743-aa65-7739-836b-e0e34dfc3603_terseLabel_en-US" xlink:label="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts Receivable</link:label>
    <link:label id="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy_label_en-US" xlink:label="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeAndOtherAccountsReceivablePolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:to="lab_us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiability_019e1743-ab7d-7f99-803f-88e8a3629040_verboseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Financing lease obligations</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiability_019e1743-ab7d-7e9a-acd0-0137ab033334_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Present value of net minimum payments</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiability_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiability" xlink:to="lab_us-gaap_FinanceLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MassillonErieOH2Member_019e1743-aa65-7a60-8396-6b91cf1b270f_terseLabel_en-US" xlink:label="lab_art_MassillonErieOH2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Massillon Erie, OH</link:label>
    <link:label id="lab_art_MassillonErieOH2Member_label_en-US" xlink:label="lab_art_MassillonErieOH2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Massillon Erie, OH 2 [Member]</link:label>
    <link:label id="lab_art_MassillonErieOH2Member_documentation_en-US" xlink:label="lab_art_MassillonErieOH2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Massillon Erie, OH 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MassillonErieOH2Member" xlink:href="art-20260806.xsd#art_MassillonErieOH2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MassillonErieOH2Member" xlink:to="lab_art_MassillonErieOH2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementBusinessSegmentsAxis_019e1743-a9d5-7a83-9072-2a00e1842a2c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementBusinessSegmentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segments [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementBusinessSegmentsAxis_label_en-US" xlink:label="lab_us-gaap_StatementBusinessSegmentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segments [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis" xlink:to="lab_us-gaap_StatementBusinessSegmentsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LimitedPartnerMember_019e1743-aa65-7807-8e6d-6b989dd39e37_terseLabel_en-US" xlink:label="lab_us-gaap_LimitedPartnerMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Limited Partner</link:label>
    <link:label id="lab_us-gaap_LimitedPartnerMember_label_en-US" xlink:label="lab_us-gaap_LimitedPartnerMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Limited Partner [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LimitedPartnerMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LimitedPartnerMember" xlink:to="lab_us-gaap_LimitedPartnerMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_LocalPhoneNumber_019e1743-aa65-7e16-a1d6-90af7a6eebcf_terseLabel_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Local Phone Number</link:label>
    <link:label id="lab_dei_LocalPhoneNumber_label_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Local Phone Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_LocalPhoneNumber" xlink:to="lab_dei_LocalPhoneNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_019e1743-aa65-7d78-8e0f-5aaab3bf83c4_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Maturity, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_SouthAmericaMember_019e1743-a9d5-7a57-8a2c-055456863c55_terseLabel_en-US" xlink:label="lab_srt_SouthAmericaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">South America</link:label>
    <link:label id="lab_srt_SouthAmericaMember_label_en-US" xlink:label="lab_srt_SouthAmericaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">South America [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SouthAmericaMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SouthAmericaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SouthAmericaMember" xlink:to="lab_srt_SouthAmericaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock_019e1743-a9d5-7a11-b899-ec41585220ca_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Failed Sale-Leaseback Financing Obligations and Future Minimum Lease Payments</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transactions [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock" xlink:to="lab_us-gaap_ScheduleOfSaleLeasebackTransactionsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DunkirkNY2Member_019e1743-aa64-7567-bc55-de3a1fe887f5_terseLabel_en-US" xlink:label="lab_art_DunkirkNY2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dunkirk, NY</link:label>
    <link:label id="lab_art_DunkirkNY2Member_label_en-US" xlink:label="lab_art_DunkirkNY2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dunkirk, NY 2 [Member]</link:label>
    <link:label id="lab_art_DunkirkNY2Member_documentation_en-US" xlink:label="lab_art_DunkirkNY2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dunkirk, NY 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DunkirkNY2Member" xlink:href="art-20260806.xsd#art_DunkirkNY2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DunkirkNY2Member" xlink:to="lab_art_DunkirkNY2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ThreeFacilities2007Member_019e1743-a9d5-7175-b6e2-19a256f519a7_terseLabel_en-US" xlink:label="lab_art_ThreeFacilities2007Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1 facility - 2007 (Agro)</link:label>
    <link:label id="lab_art_ThreeFacilities2007Member_label_en-US" xlink:label="lab_art_ThreeFacilities2007Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Three Facilities, 2007 [Member]</link:label>
    <link:label id="lab_art_ThreeFacilities2007Member_documentation_en-US" xlink:label="lab_art_ThreeFacilities2007Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Three Facilities, 2007</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ThreeFacilities2007Member" xlink:href="art-20260806.xsd#art_ThreeFacilities2007Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ThreeFacilities2007Member" xlink:to="lab_art_ThreeFacilities2007Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CreditFacilityAxis_019e1743-aaf8-70e8-9f74-6d9b8c191cda_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityAxis_label_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CreditFacilityAxis" xlink:to="lab_us-gaap_CreditFacilityAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TimeBasedRestrictedStockUnitsMember_019e1743-a9d5-7901-96bb-7f9535450212_terseLabel_en-US" xlink:label="lab_art_TimeBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Time-based Restricted Stock Units</link:label>
    <link:label id="lab_art_TimeBasedRestrictedStockUnitsMember_label_en-US" xlink:label="lab_art_TimeBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Time-Based Restricted Stock Units [Member]</link:label>
    <link:label id="lab_art_TimeBasedRestrictedStockUnitsMember_documentation_en-US" xlink:label="lab_art_TimeBasedRestrictedStockUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Time-Based Restricted Stock Units [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TimeBasedRestrictedStockUnitsMember" xlink:href="art-20260806.xsd#art_TimeBasedRestrictedStockUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TimeBasedRestrictedStockUnitsMember" xlink:to="lab_art_TimeBasedRestrictedStockUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentAxis_019e1743-aa64-7754-b60b-c1cd9e6f9fb9_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument [Axis]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentAxis_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentAxis" xlink:to="lab_us-gaap_DebtInstrumentAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_019e1743-a9d5-7d62-b91e-a5bf18a36f89_terseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employee Benefit Plans</link:label>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Benefits [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:to="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_019e1743-aaf8-767f-b979-64ed55b1b430_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Measurements</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Disclosures [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosuresTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:to="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_019e1743-ab7d-7669-bef2-a01cf516bc02_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Extinguishment of Debt</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
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    <link:label id="lab_us-gaap_CreditFacilityDomain_019e1743-aaf8-745a-8065-93a07bd49bf9_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility [Domain]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityDomain_label_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CreditFacilityDomain" xlink:to="lab_us-gaap_CreditFacilityDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_019e1743-aa65-708f-ba3a-6295a760e9b4_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stockholders' equity:</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity, Attributable to Parent [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityAbstract" xlink:to="lab_us-gaap_StockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_019e1743-aaf8-7d88-832e-5c2b07da2736_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vesting percentage</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
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    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1743-aa65-766f-94a5-49b4d03a13a0_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Interest rate</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_019e1743-aa65-76ab-88ae-9df2cbf3e34c_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contractual Interest Rate</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Stated Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
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    <link:label id="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019e1743-aa65-703b-bdfd-279ee9f76419_terseLabel_en-US" xlink:label="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:label id="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_label_en-US" xlink:label="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DunkirkNY1Member_019e1743-a9d5-7784-9947-6f0dfa1268f6_terseLabel_en-US" xlink:label="lab_art_DunkirkNY1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dunkirk, NY</link:label>
    <link:label id="lab_art_DunkirkNY1Member_label_en-US" xlink:label="lab_art_DunkirkNY1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dunkirk, NY 1 [Member]</link:label>
    <link:label id="lab_art_DunkirkNY1Member_documentation_en-US" xlink:label="lab_art_DunkirkNY1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dunkirk, NY 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DunkirkNY1Member" xlink:href="art-20260806.xsd#art_DunkirkNY1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DunkirkNY1Member" xlink:to="lab_art_DunkirkNY1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SyracuseNY1Member_019e1743-aaf8-7331-9bb0-d1abfaf14baa_terseLabel_en-US" xlink:label="lab_art_SyracuseNY1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Syracuse, NY</link:label>
    <link:label id="lab_art_SyracuseNY1Member_label_en-US" xlink:label="lab_art_SyracuseNY1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Syracuse, NY 1 [Member]</link:label>
    <link:label id="lab_art_SyracuseNY1Member_documentation_en-US" xlink:label="lab_art_SyracuseNY1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Syracuse, NY 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SyracuseNY1Member" xlink:href="art-20260806.xsd#art_SyracuseNY1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SyracuseNY1Member" xlink:to="lab_art_SyracuseNY1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueOutstandingVested_019e1743-ab7d-7ce5-86a2-81168e6cca72_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueOutstandingVested" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value, shares vested but not released</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueOutstandingVested" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueOutstandingVested"/>
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    <link:label id="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember_019e1743-a921-79b2-b046-f3824f9c85bb_terseLabel_en-US" xlink:label="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Public Senior Unsecured 5.600% Coupon Notes</link:label>
    <link:label id="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember_label_en-US" xlink:label="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Public Senior Unsecured Five Point Six Zero Percent Coupon Notes [Member]</link:label>
    <link:label id="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember_documentation_en-US" xlink:label="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Public Senior Unsecured Five Point Six Zero Percent Coupon Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember" xlink:href="art-20260806.xsd#art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember" xlink:to="lab_art_PublicSeniorUnsecuredFivePointSixZeroPercentCouponNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum_019e1743-aa64-7794-b599-db7d22bb0770_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">High Level</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Minimum</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Total Shareholder Return Payout Percentage, Minimum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum" xlink:to="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardTotalShareholderReturnPayoutPercentageMinimum" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountsPayableTradeCurrentAndNoncurrent_019e1743-a9d5-7d36-9ebe-a3545ce5c420_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableTradeCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trade payables</link:label>
    <link:label id="lab_us-gaap_AccountsPayableTradeCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_AccountsPayableTradeCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable, Trade</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableTradeCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableTradeCurrentAndNoncurrent"/>
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    <link:label id="lab_art_AmarilloTX1Member_019e1743-aa65-7d89-ab47-c4620ae008bb_terseLabel_en-US" xlink:label="lab_art_AmarilloTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amarillo, TX</link:label>
    <link:label id="lab_art_AmarilloTX1Member_label_en-US" xlink:label="lab_art_AmarilloTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amarillo, TX 1 [Member]</link:label>
    <link:label id="lab_art_AmarilloTX1Member_documentation_en-US" xlink:label="lab_art_AmarilloTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amarillo, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmarilloTX1Member" xlink:href="art-20260806.xsd#art_AmarilloTX1Member"/>
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    <link:label id="lab_us-gaap_AccountsReceivableNet_019e1743-aaf8-7106-9759-939bf312ab13_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable - net of allowance of $16,396 and $24,426 at December&#160;31, 2025 and 2024, respectively</link:label>
    <link:label id="lab_us-gaap_AccountsReceivableNet_label_en-US" xlink:label="lab_us-gaap_AccountsReceivableNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, after Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsReceivableNet" xlink:to="lab_us-gaap_AccountsReceivableNet" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityRegistrantName_019e1743-aaf8-7be9-b25f-fb402ea285c2_terseLabel_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:label id="lab_dei_EntityRegistrantName_label_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
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    <link:label id="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_019e1743-ab7d-7707-b5bd-29e029dd7340_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss to be reclassified in next twelve months</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
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    <link:label id="lab_art_PersonalPropertyAssetsUnderConstructionMember_019e1743-ab7d-7ba6-908d-2815ec01bccb_terseLabel_en-US" xlink:label="lab_art_PersonalPropertyAssetsUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Personal property assets under construction</link:label>
    <link:label id="lab_art_PersonalPropertyAssetsUnderConstructionMember_label_en-US" xlink:label="lab_art_PersonalPropertyAssetsUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Personal Property Assets Under Construction [Member]</link:label>
    <link:label id="lab_art_PersonalPropertyAssetsUnderConstructionMember_documentation_en-US" xlink:label="lab_art_PersonalPropertyAssetsUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Personal Property Assets Under Construction [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PersonalPropertyAssetsUnderConstructionMember" xlink:href="art-20260806.xsd#art_PersonalPropertyAssetsUnderConstructionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PersonalPropertyAssetsUnderConstructionMember" xlink:to="lab_art_PersonalPropertyAssetsUnderConstructionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GloucesterRogersMA2Member_019e1743-a921-7da9-884f-271f852c7ec8_terseLabel_en-US" xlink:label="lab_art_GloucesterRogersMA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gloucester - Rogers, MA</link:label>
    <link:label id="lab_art_GloucesterRogersMA2Member_label_en-US" xlink:label="lab_art_GloucesterRogersMA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gloucester - Rogers, MA 2 [Member]</link:label>
    <link:label id="lab_art_GloucesterRogersMA2Member_documentation_en-US" xlink:label="lab_art_GloucesterRogersMA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gloucester - Rogers, MA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GloucesterRogersMA2Member" xlink:href="art-20260806.xsd#art_GloucesterRogersMA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GloucesterRogersMA2Member" xlink:to="lab_art_GloucesterRogersMA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_019e1743-ab7d-741f-961b-319c8d700587_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net pension benefit (income) cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit Cost (Credit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DelayedDrawFacilityMember_019e1743-aa65-7db0-a878-570766f8ddad_terseLabel_en-US" xlink:label="lab_art_DelayedDrawFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Delayed Draw Facility</link:label>
    <link:label id="lab_art_DelayedDrawFacilityMember_label_en-US" xlink:label="lab_art_DelayedDrawFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Delayed Draw Facility [Member]</link:label>
    <link:label id="lab_art_DelayedDrawFacilityMember_documentation_en-US" xlink:label="lab_art_DelayedDrawFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Delayed Draw Facility</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DelayedDrawFacilityMember" xlink:href="art-20260806.xsd#art_DelayedDrawFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DelayedDrawFacilityMember" xlink:to="lab_art_DelayedDrawFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TreasuryLockMember_019e1743-a921-7baf-9350-a57752b62eb4_terseLabel_en-US" xlink:label="lab_us-gaap_TreasuryLockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Treasury locks</link:label>
    <link:label id="lab_us-gaap_TreasuryLockMember_label_en-US" xlink:label="lab_us-gaap_TreasuryLockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Treasury Lock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryLockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryLockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryLockMember" xlink:to="lab_us-gaap_TreasuryLockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CapitalizedComputerSoftwareAmortization1_019e1743-aa65-7b90-a513-1811d956c215_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalizedComputerSoftwareAmortization1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization expense</link:label>
    <link:label id="lab_us-gaap_CapitalizedComputerSoftwareAmortization1_label_en-US" xlink:label="lab_us-gaap_CapitalizedComputerSoftwareAmortization1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Computer Software, Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedComputerSoftwareAmortization1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CapitalizedComputerSoftwareAmortization1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedComputerSoftwareAmortization1" xlink:to="lab_us-gaap_CapitalizedComputerSoftwareAmortization1" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag_019e1743-aaf8-7034-b5bc-80a9c1a150ac_terseLabel_en-US" xlink:label="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment Of Intangible Asset Finite Lived Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag</link:label>
    <link:label id="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag_label_en-US" xlink:label="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment Of Intangible Asset Finite Lived Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag</link:label>
    <link:label id="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag_documentation_en-US" xlink:label="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Impairment Of Intangible Asset Finite Lived Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" xlink:href="art-20260806.xsd#art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" xlink:to="lab_art_ImpairmentOfIntangibleAssetFiniteLivedStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MullicaHill.NJ1Member_019e1743-ab7d-7646-bb6c-d6df32a53225_terseLabel_en-US" xlink:label="lab_art_MullicaHill.NJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mullica Hill, NJ</link:label>
    <link:label id="lab_art_MullicaHill.NJ1Member_label_en-US" xlink:label="lab_art_MullicaHill.NJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mullica Hill. NJ 1 [Member]</link:label>
    <link:label id="lab_art_MullicaHill.NJ1Member_documentation_en-US" xlink:label="lab_art_MullicaHill.NJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mullica Hill. NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MullicaHill.NJ1Member" xlink:href="art-20260806.xsd#art_MullicaHill.NJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MullicaHill.NJ1Member" xlink:to="lab_art_MullicaHill.NJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GloucesterRoweMA2Member_019e1743-aaf8-7d14-a99b-ffb6bb4582c3_terseLabel_en-US" xlink:label="lab_art_GloucesterRoweMA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gloucester - Rowe, MA</link:label>
    <link:label id="lab_art_GloucesterRoweMA2Member_label_en-US" xlink:label="lab_art_GloucesterRoweMA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gloucester - Rowe, MA 2 [Member]</link:label>
    <link:label id="lab_art_GloucesterRoweMA2Member_documentation_en-US" xlink:label="lab_art_GloucesterRoweMA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gloucester - Rowe, MA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GloucesterRoweMA2Member" xlink:href="art-20260806.xsd#art_GloucesterRoweMA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GloucesterRoweMA2Member" xlink:to="lab_art_GloucesterRoweMA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProvisionForLoanLeaseAndOtherLosses_019e1743-aa65-774e-a7c2-9503563f6ccb_terseLabel_en-US" xlink:label="lab_us-gaap_ProvisionForLoanLeaseAndOtherLosses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment of related party loan receivable</link:label>
    <link:label id="lab_us-gaap_ProvisionForLoanLeaseAndOtherLosses_label_en-US" xlink:label="lab_us-gaap_ProvisionForLoanLeaseAndOtherLosses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Provision for Loan, Lease, and Other Losses</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForLoanLeaseAndOtherLosses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProvisionForLoanLeaseAndOtherLosses" xlink:to="lab_us-gaap_ProvisionForLoanLeaseAndOtherLosses" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DominguezHillsCA2Member_019e1743-a9d5-7642-b468-b4aaf7330ae8_terseLabel_en-US" xlink:label="lab_art_DominguezHillsCA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dominguez Hills, CA</link:label>
    <link:label id="lab_art_DominguezHillsCA2Member_label_en-US" xlink:label="lab_art_DominguezHillsCA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dominguez Hills, CA 2 [Member]</link:label>
    <link:label id="lab_art_DominguezHillsCA2Member_documentation_en-US" xlink:label="lab_art_DominguezHillsCA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dominguez Hills, CA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DominguezHillsCA2Member" xlink:href="art-20260806.xsd#art_DominguezHillsCA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DominguezHillsCA2Member" xlink:to="lab_art_DominguezHillsCA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SyracuseNY2Member_019e1743-aaf8-7a1a-8d5e-936103541359_terseLabel_en-US" xlink:label="lab_art_SyracuseNY2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Syracuse, NY</link:label>
    <link:label id="lab_art_SyracuseNY2Member_label_en-US" xlink:label="lab_art_SyracuseNY2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Syracuse, NY 2 [Member]</link:label>
    <link:label id="lab_art_SyracuseNY2Member_documentation_en-US" xlink:label="lab_art_SyracuseNY2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Syracuse, NY 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SyracuseNY2Member" xlink:href="art-20260806.xsd#art_SyracuseNY2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SyracuseNY2Member" xlink:to="lab_art_SyracuseNY2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_CityOfIndustryCAMember_019e1743-aa65-7bea-bd00-5e9b1456152f_terseLabel_en-US" xlink:label="lab_art_CityOfIndustryCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">City of Industry, CA</link:label>
    <link:label id="lab_art_CityOfIndustryCAMember_label_en-US" xlink:label="lab_art_CityOfIndustryCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">City of Industry, CA [Member]</link:label>
    <link:label id="lab_art_CityOfIndustryCAMember_documentation_en-US" xlink:label="lab_art_CityOfIndustryCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">City of Industry, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_CityOfIndustryCAMember" xlink:href="art-20260806.xsd#art_CityOfIndustryCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_CityOfIndustryCAMember" xlink:to="lab_art_CityOfIndustryCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MachineryAndEquipmentMember_019e1743-a9d5-7901-a77a-e08170d98903_terseLabel_en-US" xlink:label="lab_us-gaap_MachineryAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Machinery and equipment</link:label>
    <link:label id="lab_us-gaap_MachineryAndEquipmentMember_label_en-US" xlink:label="lab_us-gaap_MachineryAndEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Machinery and Equipment [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MachineryAndEquipmentMember" xlink:to="lab_us-gaap_MachineryAndEquipmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanInterestCost_019e1743-ab7d-791a-a29a-39bfc5ca0c68_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanInterestCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanInterestCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanInterestCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Interest Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanInterestCost" xlink:to="lab_us-gaap_DefinedBenefitPlanInterestCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019e1743-aaf8-7549-bf53-d8c08a0cc860_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Granted, grant date fair value (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_019e1743-aa65-7388-9766-3064c9ee9107_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Related Party [Axis]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Related and Nonrelated Parties [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ChambersburgPA2Member_019e1743-aaf8-7548-ba0d-8d80edde2fba_terseLabel_en-US" xlink:label="lab_art_ChambersburgPA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Chambersburg, PA</link:label>
    <link:label id="lab_art_ChambersburgPA2Member_label_en-US" xlink:label="lab_art_ChambersburgPA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Chambersburg, PA 2 [Member]</link:label>
    <link:label id="lab_art_ChambersburgPA2Member_documentation_en-US" xlink:label="lab_art_ChambersburgPA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Chambersburg, PA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ChambersburgPA2Member" xlink:href="art-20260806.xsd#art_ChambersburgPA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ChambersburgPA2Member" xlink:to="lab_art_ChambersburgPA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_019e1743-a9d5-7f1f-a388-380f8f9c8775_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Repayment on revolving line of credit</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-Term Lines of Credit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:to="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NationalServiceRelatedPensionPlanMember_019e1743-aa65-741d-a101-cd12e76bd1c4_terseLabel_en-US" xlink:label="lab_art_NationalServiceRelatedPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">National Service-Related Pension Plan (NSRPP)</link:label>
    <link:label id="lab_art_NationalServiceRelatedPensionPlanMember_019e1743-aa65-754e-940a-53b66605178f_verboseLabel_en-US" xlink:label="lab_art_NationalServiceRelatedPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">National Service-Related Pension Plan (NSRPP)</link:label>
    <link:label id="lab_art_NationalServiceRelatedPensionPlanMember_label_en-US" xlink:label="lab_art_NationalServiceRelatedPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">National Service-Related Pension Plan [Member]</link:label>
    <link:label id="lab_art_NationalServiceRelatedPensionPlanMember_documentation_en-US" xlink:label="lab_art_NationalServiceRelatedPensionPlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">National Service-Related Pension Plan [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NationalServiceRelatedPensionPlanMember" xlink:href="art-20260806.xsd#art_NationalServiceRelatedPensionPlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NationalServiceRelatedPensionPlanMember" xlink:to="lab_art_NationalServiceRelatedPensionPlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019e1743-a9d5-7863-a7f6-b8f6c7a1d73a_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stock issuance related to stock-based payment plans, net of shares withheld for employee taxes</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredForeignIncomeTaxExpenseBenefit_019e1743-aa65-7a50-8039-f064a85e7920_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Foreign</link:label>
    <link:label id="lab_us-gaap_DeferredForeignIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Foreign Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredForeignIncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock_019e1743-a921-777f-9908-8e18074ef3d6_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Interest Rate Derivatives</link:label>
    <link:label id="lab_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Interest Rate Derivatives [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfInterestRateDerivativesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreaseTerm_019e1743-aa65-7383-8aff-f46de1b5672f_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreaseTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rent increase term</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreaseTerm_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreaseTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Rent Increase, Term</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionRentIncreaseTerm_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionRentIncreaseTerm" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Rent Increase, Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionRentIncreaseTerm" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionRentIncreaseTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionRentIncreaseTerm" xlink:to="lab_art_SaleLeasebackTransactionRentIncreaseTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_019e1743-a9d5-73af-8574-babaeceef244_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Amount being reclassified</link:label>
    <link:label id="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_label_en-US" xlink:label="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:to="lab_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_JohnsonAR1Member_019e1743-a9d5-7d8f-8e9b-50c0de916294_terseLabel_en-US" xlink:label="lab_art_JohnsonAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Johnson, AR</link:label>
    <link:label id="lab_art_JohnsonAR1Member_label_en-US" xlink:label="lab_art_JohnsonAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Johnson, AR 1 [Member]</link:label>
    <link:label id="lab_art_JohnsonAR1Member_documentation_en-US" xlink:label="lab_art_JohnsonAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Johnson, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_JohnsonAR1Member" xlink:href="art-20260806.xsd#art_JohnsonAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_JohnsonAR1Member" xlink:to="lab_art_JohnsonAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_currency_AllCurrenciesDomain_019e1743-a9d5-7c7e-b09a-7ce128700afd_terseLabel_en-US" xlink:label="lab_currency_AllCurrenciesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All Currencies [Domain]</link:label>
    <link:label id="lab_currency_AllCurrenciesDomain_label_en-US" xlink:label="lab_currency_AllCurrenciesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">All Currencies [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain" xlink:href="https://xbrl.sec.gov/currency/2025/currency-2025.xsd#currency_AllCurrenciesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_currency_AllCurrenciesDomain" xlink:to="lab_currency_AllCurrenciesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LesseeLeaseRenewalTerm_019e1743-a9d5-7b5a-b39f-d51352a92ca0_terseLabel_en-US" xlink:label="lab_art_LesseeLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Extended lease term</link:label>
    <link:label id="lab_art_LesseeLeaseRenewalTerm_label_en-US" xlink:label="lab_art_LesseeLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Renewal Term</link:label>
    <link:label id="lab_art_LesseeLeaseRenewalTerm_documentation_en-US" xlink:label="lab_art_LesseeLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Renewal Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LesseeLeaseRenewalTerm" xlink:href="art-20260806.xsd#art_LesseeLeaseRenewalTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LesseeLeaseRenewalTerm" xlink:to="lab_art_LesseeLeaseRenewalTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits_019e1743-aa65-77ca-a39b-887047d78967_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Conversion of OP units to common stock</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, Conversion of Units</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfUnits"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentFaceAmount_019e1743-aaf8-7fd3-ad38-de0777f3fdd4_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Borrowing Currency</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentFaceAmount_019e1743-aaf8-789b-bfc7-68de20320921_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, face amount</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentFaceAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentFaceAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Face Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentFaceAmount" xlink:to="lab_us-gaap_DebtInstrumentFaceAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_019e1743-a921-718f-b71e-f5b64a8e594c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Comprehensive Income [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Comprehensive Income [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:to="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_StrasburgVA1Member_019e1743-a9d5-73b1-87ff-97fce3b0fe9d_terseLabel_en-US" xlink:label="lab_art_StrasburgVA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Strasburg, VA</link:label>
    <link:label id="lab_art_StrasburgVA1Member_label_en-US" xlink:label="lab_art_StrasburgVA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Strasburg, VA 1 [Member]</link:label>
    <link:label id="lab_art_StrasburgVA1Member_documentation_en-US" xlink:label="lab_art_StrasburgVA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Strasburg, VA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_StrasburgVA1Member" xlink:href="art-20260806.xsd#art_StrasburgVA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_StrasburgVA1Member" xlink:to="lab_art_StrasburgVA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent_019e1743-aaf8-7847-8d46-caa585616901_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other accrued expenses</link:label>
    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Accrued Liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" xlink:to="lab_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019e1743-aa64-74ab-aa05-1eeb0171658e_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Outstanding, grant date fair value (in USD per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Laverton2Member_019e1743-aa65-7113-9507-796b2f2ac31f_terseLabel_en-US" xlink:label="lab_art_Laverton2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Laverton</link:label>
    <link:label id="lab_art_Laverton2Member_label_en-US" xlink:label="lab_art_Laverton2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Laverton 2 [Member]</link:label>
    <link:label id="lab_art_Laverton2Member_documentation_en-US" xlink:label="lab_art_Laverton2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Laverton 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Laverton2Member" xlink:href="art-20260806.xsd#art_Laverton2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Laverton2Member" xlink:to="lab_art_Laverton2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax_019e1743-a9d5-7718-8f8a-626dc7195ec9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Fee for termination of derivative instruments remaining in accumulated other comprehensive income</link:label>
    <link:label id="lab_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax_label_en-US" xlink:label="lab_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax" xlink:to="lab_us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TampaMapleFL1Member_019e1743-aa65-75f4-8456-643ce35ce665_terseLabel_en-US" xlink:label="lab_art_TampaMapleFL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tampa Maple, FL</link:label>
    <link:label id="lab_art_TampaMapleFL1Member_label_en-US" xlink:label="lab_art_TampaMapleFL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tampa Maple, FL 1 [Member]</link:label>
    <link:label id="lab_art_TampaMapleFL1Member_documentation_en-US" xlink:label="lab_art_TampaMapleFL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tampa Maple, FL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TampaMapleFL1Member" xlink:href="art-20260806.xsd#art_TampaMapleFL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TampaMapleFL1Member" xlink:to="lab_art_TampaMapleFL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_019e1743-aaf8-7dd3-af39-ea1a5637bbde_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Future Minimum Finance Lease Payments</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Maturity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:to="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PiedmontSC1Member_019e1743-a922-7015-adb3-93981dd3f2ee_terseLabel_en-US" xlink:label="lab_art_PiedmontSC1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Piedmont, SC</link:label>
    <link:label id="lab_art_PiedmontSC1Member_label_en-US" xlink:label="lab_art_PiedmontSC1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Piedmont, SC 1 [Member]</link:label>
    <link:label id="lab_art_PiedmontSC1Member_documentation_en-US" xlink:label="lab_art_PiedmontSC1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Piedmont, SC 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PiedmontSC1Member" xlink:href="art-20260806.xsd#art_PiedmontSC1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PiedmontSC1Member" xlink:to="lab_art_PiedmontSC1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RefrigerationEquipmentMember_019e1743-aaf8-7a02-a6bb-40441f7a1da3_terseLabel_en-US" xlink:label="lab_art_RefrigerationEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Refrigeration Equipment</link:label>
    <link:label id="lab_art_RefrigerationEquipmentMember_label_en-US" xlink:label="lab_art_RefrigerationEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Refrigeration Equipment [Member]</link:label>
    <link:label id="lab_art_RefrigerationEquipmentMember_documentation_en-US" xlink:label="lab_art_RefrigerationEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Refrigeration Equipment [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RefrigerationEquipmentMember" xlink:href="art-20260806.xsd#art_RefrigerationEquipmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RefrigerationEquipmentMember" xlink:to="lab_art_RefrigerationEquipmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaSkygateGA1Member_019e1743-a9d5-7ffc-b2c0-4e9101b6a297_terseLabel_en-US" xlink:label="lab_art_AtlantaSkygateGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta - Skygate, GA</link:label>
    <link:label id="lab_art_AtlantaSkygateGA1Member_label_en-US" xlink:label="lab_art_AtlantaSkygateGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta - Skygate, GA 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaSkygateGA1Member_documentation_en-US" xlink:label="lab_art_AtlantaSkygateGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta - Skygate, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaSkygateGA1Member" xlink:href="art-20260806.xsd#art_AtlantaSkygateGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaSkygateGA1Member" xlink:to="lab_art_AtlantaSkygateGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignCountryMember_019e1743-a921-792b-99d6-b6882e4910dc_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignCountryMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign:</link:label>
    <link:label id="lab_us-gaap_ForeignCountryMember_label_en-US" xlink:label="lab_us-gaap_ForeignCountryMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Tax Jurisdiction [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignCountryMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCountryMember" xlink:to="lab_us-gaap_ForeignCountryMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementLocationAxis_019e1743-aa64-7435-b100-39d3d0d2d86a_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement of Income Location, Balance [Axis]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementLocationAxis_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Income Location, Balance [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementLocationAxis" xlink:to="lab_us-gaap_IncomeStatementLocationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_019e1743-a9d5-7263-83e7-ceba9a2e38c5_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Foreign</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations before Income Taxes, Foreign</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_019e1743-aaf8-7a4d-b118-b5cff6d51250_negatedPeriodStartLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:role="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:type="resource" xml:lang="en-US">Benefit obligation&#160;&#8211; beginning of year</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_019e1743-aaf8-7637-91db-e37ae902c223_negatedPeriodEndLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:role="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:type="resource" xml:lang="en-US">Benefit obligation&#160;&#8211; end of year</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019e1743-aaf8-7e60-92f5-20aec5e0ac8c_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MurfreesboroTN2Member_019e1743-aa65-72c1-ae98-10d9942a427e_terseLabel_en-US" xlink:label="lab_art_MurfreesboroTN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Murfreesboro, TN</link:label>
    <link:label id="lab_art_MurfreesboroTN2Member_label_en-US" xlink:label="lab_art_MurfreesboroTN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Murfreesboro, TN 2 [Member]</link:label>
    <link:label id="lab_art_MurfreesboroTN2Member_documentation_en-US" xlink:label="lab_art_MurfreesboroTN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Murfreesboro, TN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MurfreesboroTN2Member" xlink:href="art-20260806.xsd#art_MurfreesboroTN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MurfreesboroTN2Member" xlink:to="lab_art_MurfreesboroTN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PublicDebtIssuance5.409NotesMember_019e1743-a921-7af5-8516-018f6e6599cf_terseLabel_en-US" xlink:label="lab_art_PublicDebtIssuance5.409NotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Public 5.409% Notes</link:label>
    <link:label id="lab_art_PublicDebtIssuance5.409NotesMember_label_en-US" xlink:label="lab_art_PublicDebtIssuance5.409NotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Public Debt Issuance, 5.409% Notes [Member]</link:label>
    <link:label id="lab_art_PublicDebtIssuance5.409NotesMember_documentation_en-US" xlink:label="lab_art_PublicDebtIssuance5.409NotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Public Debt Issuance, 5.409% Notes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PublicDebtIssuance5.409NotesMember" xlink:href="art-20260806.xsd#art_PublicDebtIssuance5.409NotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PublicDebtIssuance5.409NotesMember" xlink:to="lab_art_PublicDebtIssuance5.409NotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HattiesburgMS1Member_019e1743-aa65-7942-aaa7-9fc94baddd20_terseLabel_en-US" xlink:label="lab_art_HattiesburgMS1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Hattiesburg, MS</link:label>
    <link:label id="lab_art_HattiesburgMS1Member_label_en-US" xlink:label="lab_art_HattiesburgMS1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Hattiesburg, MS 1 [Member]</link:label>
    <link:label id="lab_art_HattiesburgMS1Member_documentation_en-US" xlink:label="lab_art_HattiesburgMS1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Hattiesburg, MS 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HattiesburgMS1Member" xlink:href="art-20260806.xsd#art_HattiesburgMS1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HattiesburgMS1Member" xlink:to="lab_art_HattiesburgMS1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewarkNJ2Member_019e1743-ab7d-762c-9343-79dc31b21db9_terseLabel_en-US" xlink:label="lab_art_NewarkNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Newark, NJ</link:label>
    <link:label id="lab_art_NewarkNJ2Member_label_en-US" xlink:label="lab_art_NewarkNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Newark, NJ 2 [Member]</link:label>
    <link:label id="lab_art_NewarkNJ2Member_documentation_en-US" xlink:label="lab_art_NewarkNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Newark, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewarkNJ2Member" xlink:href="art-20260806.xsd#art_NewarkNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewarkNJ2Member" xlink:to="lab_art_NewarkNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019e1743-aa65-7555-a1c4-decd43c392d2_negatedLabel_en-US" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accumulated depreciation</link:label>
    <link:label id="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestPayableCurrentAndNoncurrent_019e1743-a9d5-77d9-8d26-7e60ee51d10e_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPayableCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued interest</link:label>
    <link:label id="lab_us-gaap_InterestPayableCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_InterestPayableCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Payable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPayableCurrentAndNoncurrent" xlink:to="lab_us-gaap_InterestPayableCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromStockPlans_019e1743-aaf8-7660-9f21-79af0db960c4_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromStockPlans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from employee stock purchase plan</link:label>
    <link:label id="lab_us-gaap_ProceedsFromStockPlans_label_en-US" xlink:label="lab_us-gaap_ProceedsFromStockPlans" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Stock Plans</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockPlans" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromStockPlans"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromStockPlans" xlink:to="lab_us-gaap_ProceedsFromStockPlans" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_019e1743-a9d5-7dd7-a6b4-d2e693d021de_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Final asset fair values associated with acquisition</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Recognized Liability Assumed, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_art_VinelandNJNorthMill1Member_019e1743-aaf8-79f3-bee1-d856a5a7e47f_terseLabel_en-US" xlink:label="lab_art_VinelandNJNorthMill1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vineland, NJ (North Mill)</link:label>
    <link:label id="lab_art_VinelandNJNorthMill1Member_label_en-US" xlink:label="lab_art_VinelandNJNorthMill1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vineland, NJ (North Mill) 1 [Member]</link:label>
    <link:label id="lab_art_VinelandNJNorthMill1Member_documentation_en-US" xlink:label="lab_art_VinelandNJNorthMill1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vineland, NJ (North Mill) 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_VinelandNJNorthMill1Member" xlink:href="art-20260806.xsd#art_VinelandNJNorthMill1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_VinelandNJNorthMill1Member" xlink:to="lab_art_VinelandNJNorthMill1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_019e1743-aa65-76f8-9640-53d483b53dcc_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Financing leases - net</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Right-of-Use Asset, after Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAsset" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OperatingLossCarryforwardsSubjectToExpiration_019e1743-aaf8-7fb5-a23e-65bb6bf675ab_terseLabel_en-US" xlink:label="lab_art_OperatingLossCarryforwardsSubjectToExpiration" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating loss carryforwards, subject to expiration</link:label>
    <link:label id="lab_art_OperatingLossCarryforwardsSubjectToExpiration_label_en-US" xlink:label="lab_art_OperatingLossCarryforwardsSubjectToExpiration" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards, Subject To Expiration</link:label>
    <link:label id="lab_art_OperatingLossCarryforwardsSubjectToExpiration_documentation_en-US" xlink:label="lab_art_OperatingLossCarryforwardsSubjectToExpiration" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Operating Loss Carryforwards, Subject To Expiration</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OperatingLossCarryforwardsSubjectToExpiration" xlink:href="art-20260806.xsd#art_OperatingLossCarryforwardsSubjectToExpiration"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OperatingLossCarryforwardsSubjectToExpiration" xlink:to="lab_art_OperatingLossCarryforwardsSubjectToExpiration" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationIntegrationRelatedCosts_019e1743-aaf8-7cb7-b1b9-30bea3c657fb_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquisition and integration related costs</link:label>
    <link:label id="lab_us-gaap_BusinessCombinationIntegrationRelatedCosts_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Integration-Related Cost, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationIntegrationRelatedCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:to="lab_us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommitmentsAndContingencies_019e1743-aa65-78f2-a443-660e79a1ad7e_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commitments and contingencies (Note 17 - Commitments and Contingencies)</link:label>
    <link:label id="lab_us-gaap_CommitmentsAndContingencies_label_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Commitments and Contingencies</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsAndContingencies" xlink:to="lab_us-gaap_CommitmentsAndContingencies" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PloverWI2Member_019e1743-aaf8-7a8b-a842-07ecdc57a0c9_terseLabel_en-US" xlink:label="lab_art_PloverWI2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Plover, WI</link:label>
    <link:label id="lab_art_PloverWI2Member_label_en-US" xlink:label="lab_art_PloverWI2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plover, WI 2 [Member]</link:label>
    <link:label id="lab_art_PloverWI2Member_documentation_en-US" xlink:label="lab_art_PloverWI2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Plover, WI 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PloverWI2Member" xlink:href="art-20260806.xsd#art_PloverWI2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PloverWI2Member" xlink:to="lab_art_PloverWI2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessAcquisitionAxis_019e1743-aaf8-767e-aa97-646838a5451a_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Combination [Axis]</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionAxis_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionAxis" xlink:to="lab_us-gaap_BusinessAcquisitionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_019e1743-a9d5-7858-aaee-a8be367dc2bb_terseLabel_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements or Change in Accounting Principle [Table]</link:label>
    <link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_label_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Standards Update and Change in Accounting Principle [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:to="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Ormeau2Member_019e1743-aa65-7aeb-83c7-d4d5fe88fbbf_terseLabel_en-US" xlink:label="lab_art_Ormeau2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ormeau</link:label>
    <link:label id="lab_art_Ormeau2Member_label_en-US" xlink:label="lab_art_Ormeau2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ormeau 2 [Member]</link:label>
    <link:label id="lab_art_Ormeau2Member_documentation_en-US" xlink:label="lab_art_Ormeau2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ormeau 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Ormeau2Member" xlink:href="art-20260806.xsd#art_Ormeau2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Ormeau2Member" xlink:to="lab_art_Ormeau2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_019e1743-a921-7838-b9a1-6c541f79ddd6_terseLabel_en-US" xlink:label="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage in sale of equity interest</link:label>
    <link:label id="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_label_en-US" xlink:label="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Ownership Percentage in Disposed Asset</link:label>
    <link:label id="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset_documentation_en-US" xlink:label="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Ownership Percentage in Disposed Asset</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset" xlink:href="art-20260806.xsd#art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset" xlink:to="lab_art_DisposalGroupIncludingDiscontinuedOperationOwnershipPercentageInDisposedAsset" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NoncontrollingInterestMember_019e1743-aa65-76c2-b687-7c2942bc5496_terseLabel_en-US" xlink:label="lab_us-gaap_NoncontrollingInterestMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Noncontrolling Interests in Operating Partnership</link:label>
    <link:label id="lab_us-gaap_NoncontrollingInterestMember_label_en-US" xlink:label="lab_us-gaap_NoncontrollingInterestMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncontrolling Interest [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NoncontrollingInterestMember" xlink:to="lab_us-gaap_NoncontrollingInterestMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited_019e1743-a921-7a68-9d19-5ca4437ca933_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of facilities exited</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number Of Facilities Exited</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Number Of Facilities Exited</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionNumberOfFacilitiesExited" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionNumberOfFacilitiesExited"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionNumberOfFacilitiesExited" xlink:to="lab_art_SaleLeasebackTransactionNumberOfFacilitiesExited" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RochelleILAmericoldDrive2Member_019e1743-aa65-7b62-b1f1-fdc3aea72767_terseLabel_en-US" xlink:label="lab_art_RochelleILAmericoldDrive2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Americold Drive)</link:label>
    <link:label id="lab_art_RochelleILAmericoldDrive2Member_label_en-US" xlink:label="lab_art_RochelleILAmericoldDrive2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Americold Drive) 2 [Member]</link:label>
    <link:label id="lab_art_RochelleILAmericoldDrive2Member_documentation_en-US" xlink:label="lab_art_RochelleILAmericoldDrive2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rochelle, IL (Americold Drive) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RochelleILAmericoldDrive2Member" xlink:href="art-20260806.xsd#art_RochelleILAmericoldDrive2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RochelleILAmericoldDrive2Member" xlink:to="lab_art_RochelleILAmericoldDrive2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_019e1743-aa65-7d4b-be9c-43faec2f02e8_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Payment to be Received, after Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:to="lab_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements_019e1743-a9d5-7184-ac70-bf6c782a4361_terseLabel_en-US" xlink:label="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consideration to be used toward improvements</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements_label_en-US" xlink:label="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Consideration Received for Improvements</link:label>
    <link:label id="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements_documentation_en-US" xlink:label="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction, Consideration Received for Improvements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SaleLeasebackTransactionConsiderationReceivedforImprovements" xlink:href="art-20260806.xsd#art_SaleLeasebackTransactionConsiderationReceivedforImprovements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SaleLeasebackTransactionConsiderationReceivedforImprovements" xlink:to="lab_art_SaleLeasebackTransactionConsiderationReceivedforImprovements" xlink:type="arc" order="1"/>
    <link:label id="lab_art_Dalgety1Member_019e1743-aa65-733f-a3c6-03a028481e7b_terseLabel_en-US" xlink:label="lab_art_Dalgety1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dalgety</link:label>
    <link:label id="lab_art_Dalgety1Member_label_en-US" xlink:label="lab_art_Dalgety1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dalgety 1 [Member]</link:label>
    <link:label id="lab_art_Dalgety1Member_documentation_en-US" xlink:label="lab_art_Dalgety1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dalgety 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_Dalgety1Member" xlink:href="art-20260806.xsd#art_Dalgety1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_Dalgety1Member" xlink:to="lab_art_Dalgety1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GainesvilleCandlerGA2Member_019e1743-aa65-710c-aabe-4af03a9a7d8b_terseLabel_en-US" xlink:label="lab_art_GainesvilleCandlerGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gainesville Candler, GA</link:label>
    <link:label id="lab_art_GainesvilleCandlerGA2Member_label_en-US" xlink:label="lab_art_GainesvilleCandlerGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gainesville Candler, GA 2 [Member]</link:label>
    <link:label id="lab_art_GainesvilleCandlerGA2Member_documentation_en-US" xlink:label="lab_art_GainesvilleCandlerGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gainesville Candler, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GainesvilleCandlerGA2Member" xlink:href="art-20260806.xsd#art_GainesvilleCandlerGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GainesvilleCandlerGA2Member" xlink:to="lab_art_GainesvilleCandlerGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_EquityMethodInvestmentNetSettledCashOutflow_019e1743-a921-70d0-bf68-1fd47b6af9b5_terseLabel_en-US" xlink:label="lab_art_EquityMethodInvestmentNetSettledCashOutflow" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net settled cash outflow</link:label>
    <link:label id="lab_art_EquityMethodInvestmentNetSettledCashOutflow_label_en-US" xlink:label="lab_art_EquityMethodInvestmentNetSettledCashOutflow" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Net Settled Cash Outflow</link:label>
    <link:label id="lab_art_EquityMethodInvestmentNetSettledCashOutflow_documentation_en-US" xlink:label="lab_art_EquityMethodInvestmentNetSettledCashOutflow" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Net Settled Cash Outflow</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_EquityMethodInvestmentNetSettledCashOutflow" xlink:href="art-20260806.xsd#art_EquityMethodInvestmentNetSettledCashOutflow"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_EquityMethodInvestmentNetSettledCashOutflow" xlink:to="lab_art_EquityMethodInvestmentNetSettledCashOutflow" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortSmithHwy45ARCL2Member_019e1743-aaf8-7e3b-92f9-320eb295d51f_terseLabel_en-US" xlink:label="lab_art_FortSmithHwy45ARCL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Smith (Hwy 45), AR CL</link:label>
    <link:label id="lab_art_FortSmithHwy45ARCL2Member_label_en-US" xlink:label="lab_art_FortSmithHwy45ARCL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Smith (Hwy 45), AR CL 2 [Member]</link:label>
    <link:label id="lab_art_FortSmithHwy45ARCL2Member_documentation_en-US" xlink:label="lab_art_FortSmithHwy45ARCL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Smith (Hwy 45), AR CL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortSmithHwy45ARCL2Member" xlink:href="art-20260806.xsd#art_FortSmithHwy45ARCL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortSmithHwy45ARCL2Member" xlink:to="lab_art_FortSmithHwy45ARCL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember_019e1743-ab7d-735c-82ec-34801a4c4117_terseLabel_en-US" xlink:label="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Time-based Restricted Stock Units, Awarded As Part of Annual Compensation</link:label>
    <link:label id="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember_label_en-US" xlink:label="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Time-based Restricted Stock Units, Awarded As Part of Annual Compensation [Member]</link:label>
    <link:label id="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember_documentation_en-US" xlink:label="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Time-based Restricted Stock Units, Awarded As Part of Annual Compensation [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember" xlink:href="art-20260806.xsd#art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember" xlink:to="lab_art_TimebasedRestrictedStockUnitsAwardedAsPartofAnnualCompensationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TurlockCA12Member_019e1743-aa65-7a6c-8b12-e3cc74dca57a_terseLabel_en-US" xlink:label="lab_art_TurlockCA12Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Turlock, CA (#1)</link:label>
    <link:label id="lab_art_TurlockCA12Member_label_en-US" xlink:label="lab_art_TurlockCA12Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Turlock, CA (#1) 2 [Member]</link:label>
    <link:label id="lab_art_TurlockCA12Member_documentation_en-US" xlink:label="lab_art_TurlockCA12Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Turlock, CA (#1) 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TurlockCA12Member" xlink:href="art-20260806.xsd#art_TurlockCA12Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TurlockCA12Member" xlink:to="lab_art_TurlockCA12Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation_019e1743-aaf8-7625-87b5-231af8cf55ee_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Projected benefit obligation</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SiouxCityIA2640MurraySt1Member_019e1743-a9d5-70d4-af7e-a5bed95eab85_terseLabel_en-US" xlink:label="lab_art_SiouxCityIA2640MurraySt1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2640 Murray St</link:label>
    <link:label id="lab_art_SiouxCityIA2640MurraySt1Member_label_en-US" xlink:label="lab_art_SiouxCityIA2640MurraySt1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2640 Murray St 1 [Member]</link:label>
    <link:label id="lab_art_SiouxCityIA2640MurraySt1Member_documentation_en-US" xlink:label="lab_art_SiouxCityIA2640MurraySt1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sioux City, IA-2640 Murray St 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SiouxCityIA2640MurraySt1Member" xlink:href="art-20260806.xsd#art_SiouxCityIA2640MurraySt1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SiouxCityIA2640MurraySt1Member" xlink:to="lab_art_SiouxCityIA2640MurraySt1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetInvestmentHedgingMember_019e1743-a921-79e8-ba4b-a34097ce91ac_terseLabel_en-US" xlink:label="lab_us-gaap_NetInvestmentHedgingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net Investment Hedging</link:label>
    <link:label id="lab_us-gaap_NetInvestmentHedgingMember_label_en-US" xlink:label="lab_us-gaap_NetInvestmentHedgingMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Investment Hedging [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetInvestmentHedgingMember" xlink:to="lab_us-gaap_NetInvestmentHedgingMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeaseTermOfContract_019e1743-aaf8-72be-9204-e2a094f9e98e_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeaseTermOfContract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remaining term</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeaseTermOfContract_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeaseTermOfContract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Term of Contract</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseTermOfContract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeaseTermOfContract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeaseTermOfContract" xlink:to="lab_us-gaap_LessorOperatingLeaseTermOfContract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet_019e1743-ab7d-7797-84bc-3b196a3da571_terseLabel_en-US" xlink:label="lab_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Real Estate Facilities, Net at December 31</link:label>
    <link:label id="lab_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet_label_en-US" xlink:label="lab_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet" xlink:to="lab_us-gaap_SECScheduleIIIRealEstateInvestmentPropertyNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongtermDebtTypeDomain_019e1743-a9d5-7ae2-83f8-08aaf521fbf3_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-term Debt, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_LongtermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Term Debt, Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtTypeDomain" xlink:to="lab_us-gaap_LongtermDebtTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TexarkanaAR1Member_019e1743-ab7d-7fe7-bd02-143bd158a406_terseLabel_en-US" xlink:label="lab_art_TexarkanaAR1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Texarkana, AR</link:label>
    <link:label id="lab_art_TexarkanaAR1Member_label_en-US" xlink:label="lab_art_TexarkanaAR1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Texarkana, AR 1 [Member]</link:label>
    <link:label id="lab_art_TexarkanaAR1Member_documentation_en-US" xlink:label="lab_art_TexarkanaAR1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Texarkana, AR 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TexarkanaAR1Member" xlink:href="art-20260806.xsd#art_TexarkanaAR1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TexarkanaAR1Member" xlink:to="lab_art_TexarkanaAR1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosuresAbstract_019e1743-aaf8-79d2-b3a0-026b956e915a_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosuresAbstract_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract" xlink:to="lab_us-gaap_FairValueDisclosuresAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases_019e1743-aa65-7076-b759-ac148ff6e5b7_terseLabel_en-US" xlink:label="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:label id="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases_label_en-US" xlink:label="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion And Amortization, Excluding Amortization Of Debt Issuance Costs And Discounts And Below Market Leases</link:label>
    <link:label id="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases_documentation_en-US" xlink:label="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion And Amortization, Excluding Amortization Of Debt Issuance Costs And Discounts And Below Market Leases</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases" xlink:href="art-20260806.xsd#art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases" xlink:to="lab_art_DepreciationDepletionAndAmortizationExcludingAmortizationOfDebtIssuanceCostsAndDiscountsAndBelowMarketLeases" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAssetImpairmentCharges_019e1743-aa64-7aba-a4d2-aa244f6ac6b0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetImpairmentCharges" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Impairment of related party loan receivable</link:label>
    <link:label id="lab_us-gaap_OtherAssetImpairmentCharges_label_en-US" xlink:label="lab_us-gaap_OtherAssetImpairmentCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Asset Impairment Charges</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetImpairmentCharges" xlink:to="lab_us-gaap_OtherAssetImpairmentCharges" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupClassificationAxis_019e1743-ab7d-7909-a2c5-4200f7e6f549_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Axis]</link:label>
    <link:label id="lab_us-gaap_DisposalGroupClassificationAxis_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis" xlink:to="lab_us-gaap_DisposalGroupClassificationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MobileAL2Member_019e1743-a9d5-761b-a855-15ce178184b6_terseLabel_en-US" xlink:label="lab_art_MobileAL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mobile, AL</link:label>
    <link:label id="lab_art_MobileAL2Member_label_en-US" xlink:label="lab_art_MobileAL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mobile, AL 2 [Member]</link:label>
    <link:label id="lab_art_MobileAL2Member_documentation_en-US" xlink:label="lab_art_MobileAL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mobile, AL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MobileAL2Member" xlink:href="art-20260806.xsd#art_MobileAL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MobileAL2Member" xlink:to="lab_art_MobileAL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PilarBuenosAiresARGMember_019e1743-a9d5-7994-8975-d2731a0b47ca_terseLabel_en-US" xlink:label="lab_art_PilarBuenosAiresARGMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pilar - Buenos Aires, ARG</link:label>
    <link:label id="lab_art_PilarBuenosAiresARGMember_label_en-US" xlink:label="lab_art_PilarBuenosAiresARGMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pilar - Buenos Aires, ARG [Member]</link:label>
    <link:label id="lab_art_PilarBuenosAiresARGMember_documentation_en-US" xlink:label="lab_art_PilarBuenosAiresARGMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pilar - Buenos Aires, ARG [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PilarBuenosAiresARGMember" xlink:href="art-20260806.xsd#art_PilarBuenosAiresARGMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PilarBuenosAiresARGMember" xlink:to="lab_art_PilarBuenosAiresARGMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanAMember_019e1743-aaf8-7e84-9969-31c95a383d1f_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Unsecured Term Loans</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanAMember_019e1743-aaf8-7d31-b5c8-134ea16b1261_verboseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total Senior Unsecured Term Loans</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanAMember_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredTermLoanAMember_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Term Loan A</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredTermLoanAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:to="lab_art_A20222020SeniorUnsecuredTermLoanAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum_019e1743-aaf8-74e3-9ba9-8dc75ea40580_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, unsecured debt service ratio, maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Debt Service Ratio, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Unsecured Debt Service Ratio, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum" xlink:to="lab_art_DebtInstrumentCovenantUnsecuredDebtServiceRatioMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TexarkanaAR2Member_019e1743-a9d5-776d-9996-3fde00f0d2d0_terseLabel_en-US" xlink:label="lab_art_TexarkanaAR2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Texarkana, AR</link:label>
    <link:label id="lab_art_TexarkanaAR2Member_label_en-US" xlink:label="lab_art_TexarkanaAR2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Texarkana, AR 2 [Member]</link:label>
    <link:label id="lab_art_TexarkanaAR2Member_documentation_en-US" xlink:label="lab_art_TexarkanaAR2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Texarkana, AR 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TexarkanaAR2Member" xlink:href="art-20260806.xsd#art_TexarkanaAR2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TexarkanaAR2Member" xlink:to="lab_art_TexarkanaAR2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019e1743-aa65-76b8-9fa3-9169652de950_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intangible Asset, Finite-Lived [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Asset, Finite-Lived [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="lab_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_art_GrandIslandNE2Member_019e1743-ab7d-7bc1-a9e6-e404077dd484_terseLabel_en-US" xlink:label="lab_art_GrandIslandNE2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Grand Island, NE</link:label>
    <link:label id="lab_art_GrandIslandNE2Member_label_en-US" xlink:label="lab_art_GrandIslandNE2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Grand Island, NE 2 [Member]</link:label>
    <link:label id="lab_art_GrandIslandNE2Member_documentation_en-US" xlink:label="lab_art_GrandIslandNE2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Grand Island, NE 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_GrandIslandNE2Member" xlink:href="art-20260806.xsd#art_GrandIslandNE2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_GrandIslandNE2Member" xlink:to="lab_art_GrandIslandNE2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_019e1743-ab7d-7ea1-b7ab-6346cb695aee_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Line Items]</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems" xlink:to="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_StatementGeographicalAxis_019e1743-aa65-7287-b152-9239b61089c0_terseLabel_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:label id="lab_srt_StatementGeographicalAxis_label_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_StatementGeographicalAxis" xlink:to="lab_srt_StatementGeographicalAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionLineItems_019e1743-aaf8-783f-8785-7ee5150827cd_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Line Items]</link:label>
    <link:label id="lab_us-gaap_LesseeLeaseDescriptionLineItems_label_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessee, Lease, Description [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="lab_us-gaap_LesseeLeaseDescriptionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_019e1743-aaf8-740f-b601-8a8c76c4ffd1_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other, net</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Other Operating Assets and Liabilities, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_019e1743-aa65-7509-a99a-4e9d82e330bc_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total recognized in other comprehensive (income) loss</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AlgecirasMember_019e1743-a9d5-7cc8-a84f-99740f0ba8b1_terseLabel_en-US" xlink:label="lab_art_AlgecirasMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Algeciras</link:label>
    <link:label id="lab_art_AlgecirasMember_label_en-US" xlink:label="lab_art_AlgecirasMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Algeciras [Member]</link:label>
    <link:label id="lab_art_AlgecirasMember_documentation_en-US" xlink:label="lab_art_AlgecirasMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Algeciras</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AlgecirasMember" xlink:href="art-20260806.xsd#art_AlgecirasMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AlgecirasMember" xlink:to="lab_art_AlgecirasMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_AsiaPacificMember_019e1743-aaf8-71bc-87de-098909462365_terseLabel_en-US" xlink:label="lab_srt_AsiaPacificMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asia-Pacific</link:label>
    <link:label id="lab_srt_AsiaPacificMember_label_en-US" xlink:label="lab_srt_AsiaPacificMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asia Pacific [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_AsiaPacificMember" xlink:to="lab_srt_AsiaPacificMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019e1743-aa65-7cbd-9767-a9e3433cb77c_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Groups, Including Discontinued Operations [Table]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_label_en-US" xlink:label="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Groups, Including Discontinued Operations [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItems_019e1743-a921-73f5-b2ff-f13eef1129cd_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItems_label_en-US" xlink:label="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationOtherReconcilingItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:to="lab_us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum_019e1743-a922-7a26-9353-334ecc0f3018_terseLabel_en-US" xlink:label="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt instrument, covenant, fixed charge coverage ratio, maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum_label_en-US" xlink:label="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Fixed Charge Coverage Ratio, Maximum</link:label>
    <link:label id="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum_documentation_en-US" xlink:label="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Covenant, Fixed Charge Coverage Ratio, Maximum</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum" xlink:href="art-20260806.xsd#art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum" xlink:to="lab_art_DebtInstrumentCovenantFixedChargeCoverageRatioMaximum" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A501KentileNJ2Member_019e1743-a9d5-74e8-85c7-7cdb3a8c1a1c_terseLabel_en-US" xlink:label="lab_art_A501KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">501 Kentile, NJ</link:label>
    <link:label id="lab_art_A501KentileNJ2Member_label_en-US" xlink:label="lab_art_A501KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">501 Kentile, NJ 2 [Member]</link:label>
    <link:label id="lab_art_A501KentileNJ2Member_documentation_en-US" xlink:label="lab_art_A501KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">501 Kentile, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A501KentileNJ2Member" xlink:href="art-20260806.xsd#art_A501KentileNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A501KentileNJ2Member" xlink:to="lab_art_A501KentileNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies_019e1743-aaf8-7c6c-9a18-5feda0f76114_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Environmental liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies_label_en-US" xlink:label="lab_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities Subject to Compromise, Environmental Contingencies</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies" xlink:to="lab_us-gaap_LiabilitiesSubjectToCompromiseEnvironmentalContingencies" xlink:type="arc" order="1"/>
    <link:label id="lab_art_OklahomaCityOK2Member_019e1743-ab7d-7e2d-b594-8e849d274fbb_terseLabel_en-US" xlink:label="lab_art_OklahomaCityOK2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Oklahoma City, OK</link:label>
    <link:label id="lab_art_OklahomaCityOK2Member_label_en-US" xlink:label="lab_art_OklahomaCityOK2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Oklahoma City, OK 2 [Member]</link:label>
    <link:label id="lab_art_OklahomaCityOK2Member_documentation_en-US" xlink:label="lab_art_OklahomaCityOK2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Oklahoma City, OK 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_OklahomaCityOK2Member" xlink:href="art-20260806.xsd#art_OklahomaCityOK2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_OklahomaCityOK2Member" xlink:to="lab_art_OklahomaCityOK2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability_019e1743-a921-7c9e-89a9-0ae4e12fe4a5_terseLabel_en-US" xlink:label="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount of hedged loan</link:label>
    <link:label id="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability_label_en-US" xlink:label="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Designated Non-Derivative, Amount of Investment Hedged Liability</link:label>
    <link:label id="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability_documentation_en-US" xlink:label="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Designated Non-Derivative, Amount of Investment Hedged Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability" xlink:href="art-20260806.xsd#art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability" xlink:to="lab_art_DesignatedNonDerivativeAmountOfInvestmentHedgedLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MaasvlakteRotterdamMember_019e1743-aa65-75f1-a35c-3bbbae90224e_terseLabel_en-US" xlink:label="lab_art_MaasvlakteRotterdamMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maasvlakte - Rotterdam</link:label>
    <link:label id="lab_art_MaasvlakteRotterdamMember_label_en-US" xlink:label="lab_art_MaasvlakteRotterdamMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maasvlakte - Rotterdam [Member]</link:label>
    <link:label id="lab_art_MaasvlakteRotterdamMember_documentation_en-US" xlink:label="lab_art_MaasvlakteRotterdamMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Maasvlakte - Rotterdam</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MaasvlakteRotterdamMember" xlink:href="art-20260806.xsd#art_MaasvlakteRotterdamMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MaasvlakteRotterdamMember" xlink:to="lab_art_MaasvlakteRotterdamMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetUnderConstructionMember_019e1743-aa65-7bdb-97bd-842eb061fc5b_terseLabel_en-US" xlink:label="lab_us-gaap_AssetUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets under construction</link:label>
    <link:label id="lab_us-gaap_AssetUnderConstructionMember_label_en-US" xlink:label="lab_us-gaap_AssetUnderConstructionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset under Construction [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetUnderConstructionMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetUnderConstructionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetUnderConstructionMember" xlink:to="lab_us-gaap_AssetUnderConstructionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_019e1743-a9d5-776e-bd66-230539de2776_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList" xlink:type="arc" order="1"/>
    <link:label id="lab_art_JeffersonWI1Member_019e1743-a9d5-7fbe-ba59-2fdca9807fce_terseLabel_en-US" xlink:label="lab_art_JeffersonWI1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Jefferson, WI</link:label>
    <link:label id="lab_art_JeffersonWI1Member_label_en-US" xlink:label="lab_art_JeffersonWI1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Jefferson, WI 1 [Member]</link:label>
    <link:label id="lab_art_JeffersonWI1Member_documentation_en-US" xlink:label="lab_art_JeffersonWI1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Jefferson, WI 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_JeffersonWI1Member" xlink:href="art-20260806.xsd#art_JeffersonWI1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_JeffersonWI1Member" xlink:to="lab_art_JeffersonWI1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A401KentileNJ2Member_019e1743-a9d5-759d-acc7-e95b34d13e3e_terseLabel_en-US" xlink:label="lab_art_A401KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">401 Kentile, NJ</link:label>
    <link:label id="lab_art_A401KentileNJ2Member_label_en-US" xlink:label="lab_art_A401KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">401 Kentile, NJ 2 [Member]</link:label>
    <link:label id="lab_art_A401KentileNJ2Member_documentation_en-US" xlink:label="lab_art_A401KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">401 Kentile, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A401KentileNJ2Member" xlink:href="art-20260806.xsd#art_A401KentileNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A401KentileNJ2Member" xlink:to="lab_art_A401KentileNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewUlmMN1Member_019e1743-aa64-768f-ad0d-ece4a40096a1_terseLabel_en-US" xlink:label="lab_art_NewUlmMN1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New Ulm, MN</link:label>
    <link:label id="lab_art_NewUlmMN1Member_label_en-US" xlink:label="lab_art_NewUlmMN1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Ulm, MN 1 [Member]</link:label>
    <link:label id="lab_art_NewUlmMN1Member_documentation_en-US" xlink:label="lab_art_NewUlmMN1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">New Ulm, MN 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewUlmMN1Member" xlink:href="art-20260806.xsd#art_NewUlmMN1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewUlmMN1Member" xlink:to="lab_art_NewUlmMN1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_019e1743-a922-7dfb-8255-a60398d47ecb_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Service cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Service Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanServiceCost" xlink:to="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementFrequencyDomain_019e1743-a9d5-7867-9d1a-ccf1875e6bfa_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Measurement Frequency [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementFrequencyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Measurement Frequency [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_019e1743-ab7d-785d-ae46-f1393b9875d4_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net gain (loss) arising during period</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), before Reclassifications, Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_019e1743-aaf8-7725-a291-3f71db8f001c_terseLabel_en-US" xlink:label="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Partner Type [Axis]</link:label>
    <link:label id="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_label_en-US" xlink:label="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Partner Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:to="lab_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateDuringPeriod_019e1743-a921-7c82-81d9-6f56c5f75bbf_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateDuringPeriod_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate During Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:to="lab_us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventTable_019fcf58-32c6-79ea-9c26-92902e047d9f_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsequent Event [Table]</link:label>
    <link:label id="lab_us-gaap_SubsequentEventTable_label_en-US" xlink:label="lab_us-gaap_SubsequentEventTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Event [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTable" xlink:to="lab_us-gaap_SubsequentEventTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019e1743-a9d5-77be-b634-5bbc8ec27732_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Allowance for Credit Loss [Roll Forward]</link:label>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Allowance for Credit Loss [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:to="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_019e1743-a921-7843-8d66-fd0d7d8fc2a5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Other Adjustments, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A601KentileNJ1Member_019e1743-ab7d-7569-9e21-16f0aee5fd39_terseLabel_en-US" xlink:label="lab_art_A601KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">601 Kentile, NJ</link:label>
    <link:label id="lab_art_A601KentileNJ1Member_label_en-US" xlink:label="lab_art_A601KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">601 Kentile, NJ 1 [Member]</link:label>
    <link:label id="lab_art_A601KentileNJ1Member_documentation_en-US" xlink:label="lab_art_A601KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">601 Kentile, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A601KentileNJ1Member" xlink:href="art-20260806.xsd#art_A601KentileNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A601KentileNJ1Member" xlink:to="lab_art_A601KentileNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingInformationLineItems_019e1743-aa65-7eba-85db-d76be4148f49_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment Reporting Information [Line Items]</link:label>
    <link:label id="lab_us-gaap_SegmentReportingInformationLineItems_label_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Information [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems" xlink:to="lab_us-gaap_SegmentReportingInformationLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_art_HalifaxDartmouthMember_019e1743-a9d5-77f2-8dd9-6d3f510e7dc3_terseLabel_en-US" xlink:label="lab_art_HalifaxDartmouthMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Halifax Dartmouth</link:label>
    <link:label id="lab_art_HalifaxDartmouthMember_label_en-US" xlink:label="lab_art_HalifaxDartmouthMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Halifax - Dartmouth [Member]</link:label>
    <link:label id="lab_art_HalifaxDartmouthMember_documentation_en-US" xlink:label="lab_art_HalifaxDartmouthMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Halifax - Dartmouth</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_HalifaxDartmouthMember" xlink:href="art-20260806.xsd#art_HalifaxDartmouthMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_HalifaxDartmouthMember" xlink:to="lab_art_HalifaxDartmouthMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets_019e1743-a9d5-72a4-94f3-7c73a1001f4b_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Intangible assets and goodwill</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Goodwill and Intangible Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CustomerRelationshipsMember_019e1743-aa65-7307-babd-36d6e095a652_terseLabel_en-US" xlink:label="lab_us-gaap_CustomerRelationshipsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Customer relationships</link:label>
    <link:label id="lab_us-gaap_CustomerRelationshipsMember_019e1743-aa65-76d1-94ae-2e52052edf5b_verboseLabel_en-US" xlink:label="lab_us-gaap_CustomerRelationshipsMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Customer relationships</link:label>
    <link:label id="lab_us-gaap_CustomerRelationshipsMember_label_en-US" xlink:label="lab_us-gaap_CustomerRelationshipsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer Relationships [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CustomerRelationshipsMember" xlink:to="lab_us-gaap_CustomerRelationshipsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditMember_019e1743-ab7d-71d3-a615-623f261804a3_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility</link:label>
    <link:label id="lab_us-gaap_LineOfCreditMember_label_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditMember" xlink:to="lab_us-gaap_LineOfCreditMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_FortSmithHwy45ARCL1Member_019e1743-aa65-7a44-b8e6-726c999584ad_terseLabel_en-US" xlink:label="lab_art_FortSmithHwy45ARCL1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fort Smith (Hwy 45), AR CL</link:label>
    <link:label id="lab_art_FortSmithHwy45ARCL1Member_label_en-US" xlink:label="lab_art_FortSmithHwy45ARCL1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fort Smith (Hwy 45), AR CL 1 [Member]</link:label>
    <link:label id="lab_art_FortSmithHwy45ARCL1Member_documentation_en-US" xlink:label="lab_art_FortSmithHwy45ARCL1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fort Smith (Hwy 45), AR CL 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_FortSmithHwy45ARCL1Member" xlink:href="art-20260806.xsd#art_FortSmithHwy45ARCL1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_FortSmithHwy45ARCL1Member" xlink:to="lab_art_FortSmithHwy45ARCL1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019e1743-aa65-799e-9202-6580c31ddffd_terseLabel_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Name of Property [Axis]</link:label>
    <link:label id="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_label_en-US" xlink:label="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Name of Property [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:to="lab_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember_019e1743-aa65-7a9e-a869-43fb64bf4e1a_terseLabel_en-US" xlink:label="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Agrofundo Brazil II Fundode Investimento em Participacoes</link:label>
    <link:label id="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember_label_en-US" xlink:label="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Agrofundo Brazil II Fundode Investimento em Participacoes [Member]</link:label>
    <link:label id="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember_documentation_en-US" xlink:label="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Agrofundo Brazil II Fundode Investimento em Participacoes</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember" xlink:href="art-20260806.xsd#art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember" xlink:to="lab_art_AgrofundoBrazilIIFundodeInvestimentoEmParticipacoesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AmericoldLATAMHoldingsLtdMember_019e1743-aa65-7849-ba55-742546d833b5_terseLabel_en-US" xlink:label="lab_art_AmericoldLATAMHoldingsLtdMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Americold LATAM Holdings Ltd</link:label>
    <link:label id="lab_art_AmericoldLATAMHoldingsLtdMember_label_en-US" xlink:label="lab_art_AmericoldLATAMHoldingsLtdMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Americold LATAM Holdings Ltd [Member]</link:label>
    <link:label id="lab_art_AmericoldLATAMHoldingsLtdMember_documentation_en-US" xlink:label="lab_art_AmericoldLATAMHoldingsLtdMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Americold LATAM Holdings Ltd</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AmericoldLATAMHoldingsLtdMember" xlink:href="art-20260806.xsd#art_AmericoldLATAMHoldingsLtdMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AmericoldLATAMHoldingsLtdMember" xlink:to="lab_art_AmericoldLATAMHoldingsLtdMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SanAntonioTX2Member_019e1743-ab7d-7683-9236-6c4778fe73cc_terseLabel_en-US" xlink:label="lab_art_SanAntonioTX2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">San Antonio, TX</link:label>
    <link:label id="lab_art_SanAntonioTX2Member_label_en-US" xlink:label="lab_art_SanAntonioTX2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">San Antonio, TX 2 [Member]</link:label>
    <link:label id="lab_art_SanAntonioTX2Member_documentation_en-US" xlink:label="lab_art_SanAntonioTX2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">San Antonio, TX 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SanAntonioTX2Member" xlink:href="art-20260806.xsd#art_SanAntonioTX2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SanAntonioTX2Member" xlink:to="lab_art_SanAntonioTX2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_MercadoCentralBuenosAiresARGMember_019e1743-a9d5-7c17-9879-cecd376fae11_terseLabel_en-US" xlink:label="lab_art_MercadoCentralBuenosAiresARGMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mercado Central - Buenos Aires, ARG</link:label>
    <link:label id="lab_art_MercadoCentralBuenosAiresARGMember_label_en-US" xlink:label="lab_art_MercadoCentralBuenosAiresARGMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mercado Central - Buenos Aires, ARG [Member]</link:label>
    <link:label id="lab_art_MercadoCentralBuenosAiresARGMember_documentation_en-US" xlink:label="lab_art_MercadoCentralBuenosAiresARGMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Mercado Central - Buenos Aires, ARG [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_MercadoCentralBuenosAiresARGMember" xlink:href="art-20260806.xsd#art_MercadoCentralBuenosAiresARGMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_MercadoCentralBuenosAiresARGMember" xlink:to="lab_art_MercadoCentralBuenosAiresARGMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_TampaMapleFL2Member_019e1743-aaf8-78c0-9981-93dc00a88a59_terseLabel_en-US" xlink:label="lab_art_TampaMapleFL2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tampa Maple, FL</link:label>
    <link:label id="lab_art_TampaMapleFL2Member_label_en-US" xlink:label="lab_art_TampaMapleFL2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tampa Maple, FL 2 [Member]</link:label>
    <link:label id="lab_art_TampaMapleFL2Member_documentation_en-US" xlink:label="lab_art_TampaMapleFL2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tampa Maple, FL 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_TampaMapleFL2Member" xlink:href="art-20260806.xsd#art_TampaMapleFL2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_TampaMapleFL2Member" xlink:to="lab_art_TampaMapleFL2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock_019e1743-aa65-7f92-87d5-0c2c93881792_terseLabel_en-US" xlink:label="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Acquisition, Cyber Incident and Other, Net</link:label>
    <link:label id="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock_label_en-US" xlink:label="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Business Combination, Acquisition Related Cost, Cyber Incident And Other Special Charges [Table Text Block]</link:label>
    <link:label id="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock_documentation_en-US" xlink:label="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Schedule of Business Combination, Acquisition Related Cost, Cyber Incident And Other Special Charges [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock" xlink:href="art-20260806.xsd#art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock" xlink:to="lab_art_ScheduleOfBusinessCombinationAcquisitionRelatedCostCyberIncidentAndOtherSpecialChargesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewUlmMN2Member_019e1743-aa65-7995-ba0b-136635872cf4_terseLabel_en-US" xlink:label="lab_art_NewUlmMN2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">New Ulm, MN</link:label>
    <link:label id="lab_art_NewUlmMN2Member_label_en-US" xlink:label="lab_art_NewUlmMN2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Ulm, MN 2 [Member]</link:label>
    <link:label id="lab_art_NewUlmMN2Member_documentation_en-US" xlink:label="lab_art_NewUlmMN2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">New Ulm, MN 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewUlmMN2Member" xlink:href="art-20260806.xsd#art_NewUlmMN2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewUlmMN2Member" xlink:to="lab_art_NewUlmMN2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesOther_019e1743-aaf8-787a-a0c9-7f65f8817266_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesOther" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other liabilities</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesOther_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Tax Liabilities, Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesOther" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxLiabilitiesOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesOther" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesOther" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanTypeAxis_019e1743-a921-76c2-bfcd-ba2367ce89ab_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Retirement Plan Type [Axis]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanTypeAxis_label_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Plan Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanTypeAxis" xlink:to="lab_us-gaap_RetirementPlanTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PayablesAndAccrualsAbstract_019e1743-aaf8-7f3b-924c-be413a610103_terseLabel_en-US" xlink:label="lab_us-gaap_PayablesAndAccrualsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payables and Accruals [Abstract]</link:label>
    <link:label id="lab_us-gaap_PayablesAndAccrualsAbstract_label_en-US" xlink:label="lab_us-gaap_PayablesAndAccrualsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payables and Accruals [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PayablesAndAccrualsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PayablesAndAccrualsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PayablesAndAccrualsAbstract" xlink:to="lab_us-gaap_PayablesAndAccrualsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_019e1743-a9d5-7482-8355-97585f05dbee_terseLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other, net</link:label>
    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_019e1743-a9d5-7d14-aa0a-a9c5bf1a3c5d_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other, net</link:label>
    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_label_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Nonoperating Income (Expense)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense" xlink:to="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementTable_019e1743-a9d5-77f3-8f2c-97da08b4ea5c_terseLabel_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement [Table]</link:label>
    <link:label id="lab_us-gaap_StatementTable_label_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementTable" xlink:to="lab_us-gaap_StatementTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_019e1743-a921-7259-8719-7a05f1856354_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Actual return on plan assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_019e1743-a9d5-73ed-a417-6542fd41ae07_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustments to reconcile net loss to net cash provided by operating activities:</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_019e1743-aa65-7968-8960-4a5e7abd80cf_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Deferred income tax</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_019e1743-aa65-7d83-a4a2-c4ad87fc5144_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred income tax benefit</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_019e1743-aa65-745c-9e23-70d67fc53c1a_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xml:lang="en-US">Total deferred income tax</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:to="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A601KentileNJ2Member_019e1743-aaf8-7a30-9272-c45444b95a14_terseLabel_en-US" xlink:label="lab_art_A601KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">601 Kentile, NJ</link:label>
    <link:label id="lab_art_A601KentileNJ2Member_label_en-US" xlink:label="lab_art_A601KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">601 Kentile, NJ 2 [Member]</link:label>
    <link:label id="lab_art_A601KentileNJ2Member_documentation_en-US" xlink:label="lab_art_A601KentileNJ2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">601 Kentile, NJ 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A601KentileNJ2Member" xlink:href="art-20260806.xsd#art_A601KentileNJ2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A601KentileNJ2Member" xlink:to="lab_art_A601KentileNJ2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignTaxJurisdictionOtherMember_019e1743-a921-7058-b7d9-667459f3c487_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignTaxJurisdictionOtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Foreign Jurisdictions</link:label>
    <link:label id="lab_us-gaap_ForeignTaxJurisdictionOtherMember_label_en-US" xlink:label="lab_us-gaap_ForeignTaxJurisdictionOtherMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Foreign Tax Jurisdiction, Other [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignTaxJurisdictionOtherMember" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignTaxJurisdictionOtherMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignTaxJurisdictionOtherMember" xlink:to="lab_us-gaap_ForeignTaxJurisdictionOtherMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityUndiscountedExcessAmount_019e1743-aaf8-7620-9636-a3f233f28cb0_negatedTotalLabel_en-US" xlink:label="lab_art_LeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xml:lang="en-US">Less: Interest</link:label>
    <link:label id="lab_art_LeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_art_LeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:label id="lab_art_LeaseLiabilityUndiscountedExcessAmount_documentation_en-US" xlink:label="lab_art_LeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityUndiscountedExcessAmount" xlink:href="art-20260806.xsd#art_LeaseLiabilityUndiscountedExcessAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_art_LeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A401KentileNJ1Member_019e1743-aa64-79d7-820c-5ed3b1613d91_terseLabel_en-US" xlink:label="lab_art_A401KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">401 Kentile, NJ</link:label>
    <link:label id="lab_art_A401KentileNJ1Member_label_en-US" xlink:label="lab_art_A401KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">401 Kentile, NJ 1 [Member]</link:label>
    <link:label id="lab_art_A401KentileNJ1Member_documentation_en-US" xlink:label="lab_art_A401KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">401 Kentile, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A401KentileNJ1Member" xlink:href="art-20260806.xsd#art_A401KentileNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A401KentileNJ1Member" xlink:to="lab_art_A401KentileNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SanAntonioTX1Member_019e1743-a9d5-7459-af7e-032e5045f7b1_terseLabel_en-US" xlink:label="lab_art_SanAntonioTX1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">San Antonio, TX</link:label>
    <link:label id="lab_art_SanAntonioTX1Member_label_en-US" xlink:label="lab_art_SanAntonioTX1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">San Antonio, TX 1 [Member]</link:label>
    <link:label id="lab_art_SanAntonioTX1Member_documentation_en-US" xlink:label="lab_art_SanAntonioTX1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">San Antonio, TX 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SanAntonioTX1Member" xlink:href="art-20260806.xsd#art_SanAntonioTX1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SanAntonioTX1Member" xlink:to="lab_art_SanAntonioTX1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorLeasesPolicyTextBlock_019e1743-a9d5-77a5-9cad-d09978ca70a9_terseLabel_en-US" xlink:label="lab_us-gaap_LessorLeasesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease Accounting Arrangements wherein we are the lessor</link:label>
    <link:label id="lab_us-gaap_LessorLeasesPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_LessorLeasesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Leases [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeasesPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorLeasesPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorLeasesPolicyTextBlock" xlink:to="lab_us-gaap_LessorLeasesPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_019e1743-aaf8-7132-8db0-a7740d004c7b_terseLabel_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Description of the Business</link:label>
    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_NewarkNJ1Member_019e1743-ab7d-776d-8630-3d9e046c44fa_terseLabel_en-US" xlink:label="lab_art_NewarkNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Newark, NJ</link:label>
    <link:label id="lab_art_NewarkNJ1Member_label_en-US" xlink:label="lab_art_NewarkNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Newark, NJ 1 [Member]</link:label>
    <link:label id="lab_art_NewarkNJ1Member_documentation_en-US" xlink:label="lab_art_NewarkNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Newark, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_NewarkNJ1Member" xlink:href="art-20260806.xsd#art_NewarkNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_NewarkNJ1Member" xlink:to="lab_art_NewarkNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AmendmentFlag_019e1743-aaf8-70e3-9d83-bc6033c5a9f0_terseLabel_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amendment Flag</link:label>
    <link:label id="lab_dei_AmendmentFlag_label_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amendment Flag</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AmendmentFlag" xlink:to="lab_dei_AmendmentFlag" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock_019e1743-ab7d-77d1-a58d-f82dfb469fbf_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Pension Plan Assets By Category</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Allocation of Plan Assets [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AgroAcquisitionMember_019e1743-ab7d-74d1-93e6-36c0e0b1653a_terseLabel_en-US" xlink:label="lab_art_AgroAcquisitionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Agro Acquisition</link:label>
    <link:label id="lab_art_AgroAcquisitionMember_label_en-US" xlink:label="lab_art_AgroAcquisitionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Agro Acquisition [Member]</link:label>
    <link:label id="lab_art_AgroAcquisitionMember_documentation_en-US" xlink:label="lab_art_AgroAcquisitionMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Agro Acquisition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AgroAcquisitionMember" xlink:href="art-20260806.xsd#art_AgroAcquisitionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AgroAcquisitionMember" xlink:to="lab_art_AgroAcquisitionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_019e1743-a9d5-757d-82bb-83f73ae2a3a1_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Lease, Weighted Average Discount Rate, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:to="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:type="arc" order="1"/>
    <link:label id="lab_art_RSAColdHoldingsLimitedMember_019e1743-a9d5-7f6d-81e2-0d0c2205aaeb_terseLabel_en-US" xlink:label="lab_art_RSAColdHoldingsLimitedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investment in RSA</link:label>
    <link:label id="lab_art_RSAColdHoldingsLimitedMember_label_en-US" xlink:label="lab_art_RSAColdHoldingsLimitedMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">RSA Cold Holdings Limited [Member]</link:label>
    <link:label id="lab_art_RSAColdHoldingsLimitedMember_documentation_en-US" xlink:label="lab_art_RSAColdHoldingsLimitedMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">RSA Cold Holdings Limited</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_RSAColdHoldingsLimitedMember" xlink:href="art-20260806.xsd#art_RSAColdHoldingsLimitedMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_RSAColdHoldingsLimitedMember" xlink:to="lab_art_RSAColdHoldingsLimitedMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventsAbstract_label_en-US" xlink:label="lab_us-gaap_SubsequentEventsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Events [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventsAbstract" xlink:to="lab_us-gaap_SubsequentEventsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_019e1743-ab7d-7400-a449-02d349d01e41_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAbstract" xlink:to="lab_us-gaap_SegmentReportingAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_DominguezHillsCA1Member_019e1743-a9d5-7413-9966-398f3b9d49e5_terseLabel_en-US" xlink:label="lab_art_DominguezHillsCA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dominguez Hills, CA</link:label>
    <link:label id="lab_art_DominguezHillsCA1Member_label_en-US" xlink:label="lab_art_DominguezHillsCA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dominguez Hills, CA 1 [Member]</link:label>
    <link:label id="lab_art_DominguezHillsCA1Member_documentation_en-US" xlink:label="lab_art_DominguezHillsCA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Dominguez Hills, CA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_DominguezHillsCA1Member" xlink:href="art-20260806.xsd#art_DominguezHillsCA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_DominguezHillsCA1Member" xlink:to="lab_art_DominguezHillsCA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CostOfRevenue_019e1743-a9d5-715e-be43-0856e198548d_terseLabel_en-US" xlink:label="lab_us-gaap_CostOfRevenue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cost of operations</link:label>
    <link:label id="lab_us-gaap_CostOfRevenue_019e1743-a9d5-7173-a3ab-d85df995066a_verboseLabel_en-US" xlink:label="lab_us-gaap_CostOfRevenue" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total segment expenses</link:label>
    <link:label id="lab_us-gaap_CostOfRevenue_label_en-US" xlink:label="lab_us-gaap_CostOfRevenue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cost of Revenue</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfRevenue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostOfRevenue" xlink:to="lab_us-gaap_CostOfRevenue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NonoperatingIncomeExpenseAbstract_019e1743-a9d5-77fd-adeb-e4f184369d1d_terseLabel_en-US" xlink:label="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other (expense) income:</link:label>
    <link:label id="lab_us-gaap_NonoperatingIncomeExpenseAbstract_label_en-US" xlink:label="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nonoperating Income (Expense) [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:to="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_art_WesternConferenceofTeamstersPensionFundMember_019e1743-aa65-7db0-9b56-c4d892c60aec_terseLabel_en-US" xlink:label="lab_art_WesternConferenceofTeamstersPensionFundMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Western Conference of Teamsters Pension Fund</link:label>
    <link:label id="lab_art_WesternConferenceofTeamstersPensionFundMember_label_en-US" xlink:label="lab_art_WesternConferenceofTeamstersPensionFundMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Western Conference of Teamsters Pension Fund [Member]</link:label>
    <link:label id="lab_art_WesternConferenceofTeamstersPensionFundMember_documentation_en-US" xlink:label="lab_art_WesternConferenceofTeamstersPensionFundMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Western Conference of Teamsters Pension Fund [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_WesternConferenceofTeamstersPensionFundMember" xlink:href="art-20260806.xsd#art_WesternConferenceofTeamstersPensionFundMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_WesternConferenceofTeamstersPensionFundMember" xlink:to="lab_art_WesternConferenceofTeamstersPensionFundMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LulaGA1Member_019e1743-a9d5-7755-8bfa-8159f389c0cc_terseLabel_en-US" xlink:label="lab_art_LulaGA1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lula, GA</link:label>
    <link:label id="lab_art_LulaGA1Member_label_en-US" xlink:label="lab_art_LulaGA1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lula, GA 1 [Member]</link:label>
    <link:label id="lab_art_LulaGA1Member_documentation_en-US" xlink:label="lab_art_LulaGA1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lula, GA 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LulaGA1Member" xlink:href="art-20260806.xsd#art_LulaGA1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LulaGA1Member" xlink:to="lab_art_LulaGA1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding_019e1743-aaf8-78e8-bcea-885cc788c1ac_terseLabel_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate grant date fair value of awards</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding_label_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Grant Date Fair Value, Outstanding</link:label>
    <link:label id="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding_documentation_en-US" xlink:label="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Grant Date Fair Value, Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding" xlink:href="art-20260806.xsd#art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding" xlink:to="lab_art_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateGrantDateFairValueOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember_019e1743-a9d5-7710-927a-0520728f68b4_terseLabel_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior Unsecured Revolving Credit Facility</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember_label_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facility [Member]</link:label>
    <link:label id="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember_documentation_en-US" xlink:label="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2022/2020 Senior Unsecured Revolving Credit Facility</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember" xlink:href="art-20260806.xsd#art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember" xlink:to="lab_art_A20222020SeniorUnsecuredRevolvingCreditFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_019e1743-aaf8-7cfe-a0dd-d72a36035a3b_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common shares, par value (in USD per share)</link:label>
    <link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_label_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Par or Stated Value Per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UseOfEstimates_019e1743-aa65-73b6-91db-feb2b1c996b7_terseLabel_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Use of Estimates</link:label>
    <link:label id="lab_us-gaap_UseOfEstimates_label_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UseOfEstimates" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UseOfEstimates"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UseOfEstimates" xlink:to="lab_us-gaap_UseOfEstimates" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss_019e1743-a922-7f54-8063-e463f3523c89_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in gross carrying amount due to foreign exchange rate</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Foreign Currency Translation Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock_019e1743-ab7d-7b28-8fbb-5a7ddd10a88e_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Assets and Liabilities Measured at Fair Value</link:label>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_IndustryCAMember_019e1743-a921-735d-83b3-256c5de17fec_terseLabel_en-US" xlink:label="lab_art_IndustryCAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Industry, CA</link:label>
    <link:label id="lab_art_IndustryCAMember_label_en-US" xlink:label="lab_art_IndustryCAMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Industry, CA [Member]</link:label>
    <link:label id="lab_art_IndustryCAMember_documentation_en-US" xlink:label="lab_art_IndustryCAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Industry, CA</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_IndustryCAMember" xlink:href="art-20260806.xsd#art_IndustryCAMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_IndustryCAMember" xlink:to="lab_art_IndustryCAMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CurrencyAxis_019e1743-a921-7e90-a2be-fbcc7f4b0b5c_terseLabel_en-US" xlink:label="lab_srt_CurrencyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Currency [Axis]</link:label>
    <link:label id="lab_srt_CurrencyAxis_label_en-US" xlink:label="lab_srt_CurrencyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Currency [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CurrencyAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CurrencyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CurrencyAxis" xlink:to="lab_srt_CurrencyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_019e1743-a9d5-7498-ac72-d4081538de25_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearFive_019e1743-ab7d-7ef4-9396-ecbe1d52f706_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">2030</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Five</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearFive_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDueYearFive" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDueYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDueYearFive" xlink:to="lab_art_LeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock_019e1743-aaf8-7608-9d02-1143d8f16e75_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Net Periodic Benefit Cost</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Costs of Retirement Plans [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_art_A501KentileNJ1Member_019e1743-a9d5-743a-a290-be489876fdb5_terseLabel_en-US" xlink:label="lab_art_A501KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">501 Kentile, NJ</link:label>
    <link:label id="lab_art_A501KentileNJ1Member_label_en-US" xlink:label="lab_art_A501KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">501 Kentile, NJ 1 [Member]</link:label>
    <link:label id="lab_art_A501KentileNJ1Member_documentation_en-US" xlink:label="lab_art_A501KentileNJ1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">501 Kentile, NJ 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_A501KentileNJ1Member" xlink:href="art-20260806.xsd#art_A501KentileNJ1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_A501KentileNJ1Member" xlink:to="lab_art_A501KentileNJ1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LurganMember_019e1743-aa65-7043-ae01-aaa41977f4a0_terseLabel_en-US" xlink:label="lab_art_LurganMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lurgan</link:label>
    <link:label id="lab_art_LurganMember_label_en-US" xlink:label="lab_art_LurganMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lurgan [Member]</link:label>
    <link:label id="lab_art_LurganMember_documentation_en-US" xlink:label="lab_art_LurganMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lurgan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LurganMember" xlink:href="art-20260806.xsd#art_LurganMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LurganMember" xlink:to="lab_art_LurganMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LulaGA2Member_019e1743-ab7d-7f6f-9ec6-9757f5baad38_terseLabel_en-US" xlink:label="lab_art_LulaGA2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lula, GA</link:label>
    <link:label id="lab_art_LulaGA2Member_label_en-US" xlink:label="lab_art_LulaGA2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lula, GA 2 [Member]</link:label>
    <link:label id="lab_art_LulaGA2Member_documentation_en-US" xlink:label="lab_art_LulaGA2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lula, GA 2</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LulaGA2Member" xlink:href="art-20260806.xsd#art_LulaGA2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LulaGA2Member" xlink:to="lab_art_LulaGA2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableRateAxis_019e1743-aaf8-7458-8c29-2ed64a85c07a_terseLabel_en-US" xlink:label="lab_us-gaap_VariableRateAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable Rate [Axis]</link:label>
    <link:label id="lab_us-gaap_VariableRateAxis_label_en-US" xlink:label="lab_us-gaap_VariableRateAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Rate [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableRateAxis" xlink:to="lab_us-gaap_VariableRateAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ConsolidationItemsAxis_019e1743-aa65-7c2e-865b-3c608bde8ee7_terseLabel_en-US" xlink:label="lab_srt_ConsolidationItemsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidation Items [Axis]</link:label>
    <link:label id="lab_srt_ConsolidationItemsAxis_label_en-US" xlink:label="lab_srt_ConsolidationItemsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation Items [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidationItemsAxis" xlink:to="lab_srt_ConsolidationItemsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LessorOperatingLeaseOptionToExtend_019e1743-a9d5-7d63-8e3e-f8251ed215fc_terseLabel_en-US" xlink:label="lab_us-gaap_LessorOperatingLeaseOptionToExtend" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease, option to extend</link:label>
    <link:label id="lab_us-gaap_LessorOperatingLeaseOptionToExtend_label_en-US" xlink:label="lab_us-gaap_LessorOperatingLeaseOptionToExtend" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lessor, Operating Lease, Option to Extend</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseOptionToExtend" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorOperatingLeaseOptionToExtend"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LessorOperatingLeaseOptionToExtend" xlink:to="lab_us-gaap_LessorOperatingLeaseOptionToExtend" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BabcockWIMember_019e1743-ab7d-72d3-8839-b440a8c11727_terseLabel_en-US" xlink:label="lab_art_BabcockWIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Babcock, WI</link:label>
    <link:label id="lab_art_BabcockWIMember_label_en-US" xlink:label="lab_art_BabcockWIMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Babcock, WI [Member]</link:label>
    <link:label id="lab_art_BabcockWIMember_documentation_en-US" xlink:label="lab_art_BabcockWIMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Babcock, WI</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BabcockWIMember" xlink:href="art-20260806.xsd#art_BabcockWIMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BabcockWIMember" xlink:to="lab_art_BabcockWIMember" xlink:type="arc" order="1"/>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther_019e1743-ab7d-766e-b674-621426276d19_terseLabel_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquisition, cyber incident, and other, net</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther_019e1743-ab7d-76ec-9d52-a76f45fb6fc5_negatedTerseLabel_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Acquisition, cyber incident, and other, net</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther_label_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition Related Expenses, Litigations Expense And Other</link:label>
    <link:label id="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther_documentation_en-US" xlink:label="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business Combination, Acquisition Related Expenses, Litigations Expense And Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:href="art-20260806.xsd#art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:to="lab_art_BusinessCombinationAcquisitionRelatedExpensesLitigationsExpenseAndOther" xlink:type="arc" order="1"/>
    <link:label id="lab_art_AtlantaGACorporate1Member_019e1743-a922-710d-8eea-958f6a8133f3_terseLabel_en-US" xlink:label="lab_art_AtlantaGACorporate1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Atlanta, GA - Corporate</link:label>
    <link:label id="lab_art_AtlantaGACorporate1Member_label_en-US" xlink:label="lab_art_AtlantaGACorporate1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Atlanta, GA - Corporate 1 [Member]</link:label>
    <link:label id="lab_art_AtlantaGACorporate1Member_documentation_en-US" xlink:label="lab_art_AtlantaGACorporate1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Atlanta, GA - Corporate 1</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_AtlantaGACorporate1Member" xlink:href="art-20260806.xsd#art_AtlantaGACorporate1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_AtlantaGACorporate1Member" xlink:to="lab_art_AtlantaGACorporate1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearTwo_019e1743-aa65-7408-916c-2ab33a4b13db_totalLabel_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">2027</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearTwo_label_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Two</link:label>
    <link:label id="lab_art_LeaseLiabilityPaymentsDueYearTwo_documentation_en-US" xlink:label="lab_art_LeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lease, Liability, Payments, Due Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_LeaseLiabilityPaymentsDueYearTwo" xlink:href="art-20260806.xsd#art_LeaseLiabilityPaymentsDueYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_LeaseLiabilityPaymentsDueYearTwo" xlink:to="lab_art_LeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_art_PensionPlanTerminationCharges_019e1743-aa65-7f20-8e10-fc7a80121091_terseLabel_en-US" xlink:label="lab_art_PensionPlanTerminationCharges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension plan termination charges</link:label>
    <link:label id="lab_art_PensionPlanTerminationCharges_label_en-US" xlink:label="lab_art_PensionPlanTerminationCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pension Plan Termination Charges</link:label>
    <link:label id="lab_art_PensionPlanTerminationCharges_documentation_en-US" xlink:label="lab_art_PensionPlanTerminationCharges" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Pension Plan Termination Charges</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_art_PensionPlanTerminationCharges" xlink:href="art-20260806.xsd#art_PensionPlanTerminationCharges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_art_PensionPlanTerminationCharges" xlink:to="lab_art_PensionPlanTerminationCharges" xlink:type="arc" order="1"/>
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