Whether the Atlantic Meridional Overturning Circulation(AMOC),one of the most vital tipping elements in the Earth’s cli-mate system with far-reaching effects on interhemispheric heat distributions,the carbon cycles,a...Whether the Atlantic Meridional Overturning Circulation(AMOC),one of the most vital tipping elements in the Earth’s cli-mate system with far-reaching effects on interhemispheric heat distributions,the carbon cycles,and a cascade series of hydrocli-matic changes worldwide,is approaching a tipping point has become an increasingly urgent concern[1-4].Climate proxy records arguably suggest that the AMOC is currently at its weakest state over the last millennium,with a marked AMOC weakening trend evident between 1870 and 2020 C.E.[3].A recent physics-based analysis of early warning signals even suggests that an AMOC collapse could occur as early as one year from 2024 C.E.[2].Nevertheless,the IPCC AR6,based on simulations from the Cli-mate Model Intercomparison Project(CMIP),quotes that an AMOC collapse in the 21st century is unlikely(Fig.S1 online)[2].This data-model discrepancy suggests unaccounted-for factors have been influencing AMOC[1].While the AMOC collapse would pose severe cascading impacts on global climate disruption,consider-able uncertainty remains regarding whether and when such an AMOC collapse is coming[2,4,5].One approach to address this challenge lies in a precise comparison of the ongoing AMOC weak-ening with their analogous episodes preserved in paleoclimate records-putting the AMOC weakening into context with a series of presumable AMOC collapse scenarios inferred from Greenland ice core oxygen isotope(d18 O,mainly a proxy of Greenland tem-perature)records[6-8](Fig.S2b online).展开更多
基金supported by the State Key Laboratory of Loess Science(SKLLQGZR2401)the National Natural Science Foundation of China(42372218,42488201,and 423B2204)Guangxi Key Science and Technology Innovation Base on Karst Dynamics(KDL&Guangxi202005)。
文摘Whether the Atlantic Meridional Overturning Circulation(AMOC),one of the most vital tipping elements in the Earth’s cli-mate system with far-reaching effects on interhemispheric heat distributions,the carbon cycles,and a cascade series of hydrocli-matic changes worldwide,is approaching a tipping point has become an increasingly urgent concern[1-4].Climate proxy records arguably suggest that the AMOC is currently at its weakest state over the last millennium,with a marked AMOC weakening trend evident between 1870 and 2020 C.E.[3].A recent physics-based analysis of early warning signals even suggests that an AMOC collapse could occur as early as one year from 2024 C.E.[2].Nevertheless,the IPCC AR6,based on simulations from the Cli-mate Model Intercomparison Project(CMIP),quotes that an AMOC collapse in the 21st century is unlikely(Fig.S1 online)[2].This data-model discrepancy suggests unaccounted-for factors have been influencing AMOC[1].While the AMOC collapse would pose severe cascading impacts on global climate disruption,consider-able uncertainty remains regarding whether and when such an AMOC collapse is coming[2,4,5].One approach to address this challenge lies in a precise comparison of the ongoing AMOC weak-ening with their analogous episodes preserved in paleoclimate records-putting the AMOC weakening into context with a series of presumable AMOC collapse scenarios inferred from Greenland ice core oxygen isotope(d18 O,mainly a proxy of Greenland tem-perature)records[6-8](Fig.S2b online).
