变暖世界中冰盖淡水排放的竞争气候反馈。

Competing climate feedbacks of ice sheet freshwater discharge in a warming world.

作者信息

Li Dawei, DeConto Robert M, Pollard David, Hu Yongyun

机构信息

Key Laboratory of Polar Ecosystem and Climate Change, Ministry of Education, and School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200030, China.

Shanghai Frontiers Science Center of Polar Science, Shanghai Jiao Tong University, Shanghai, 200030, China.

出版信息

Nat Commun. 2024 Jun 18;15(1):5178. doi: 10.1038/s41467-024-49604-3.

DOI:10.1038/s41467-024-49604-3

PMID:38890359

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11189430/

Abstract

Freshwater discharge from ice sheets induces surface atmospheric cooling and subsurface ocean warming, which are associated with negative and positive feedbacks respectively. However, uncertainties persist regarding these feedbacks' relative strength and combined effect. Here we assess associated feedbacks in a coupled ice sheet-climate model, and show that for the Antarctic Ice Sheet the positive feedback dominates in moderate future warming scenarios and in the early stage of ice sheet retreat, but is overwhelmed by the negative feedback in intensive warming scenarios when the West Antarctic Ice Sheet undergoes catastrophic collapse. The Atlantic Meridional Overturning Circulation is affected by freshwater discharge from both the Greenland and the Antarctic ice sheets and, as an interhemispheric teleconnection bridge, exacerbates the opposing ice sheet's retreat via the Bipolar Seesaw. These results highlight the crucial role of ice sheet-climate interactions via freshwater flux in future ice sheet retreat and associated sea-level rise.

摘要

冰盖的淡水排放会导致地表大气冷却和海洋次表层变暖，这分别与负反馈和正反馈相关。然而，这些反馈的相对强度和综合效应仍存在不确定性。在此，我们在一个冰盖 - 气候耦合模型中评估相关反馈，并表明对于南极冰盖而言，在未来适度变暖情景以及冰盖退缩的早期阶段，正反馈占主导地位，但在南极西部冰盖发生灾难性崩塌的强烈变暖情景中，负反馈会占据主导。大西洋经向翻转环流受到格陵兰和南极冰盖淡水排放的影响，并且作为一个半球间遥相关桥梁，通过两极跷跷板效应加剧了相对冰盖的退缩。这些结果凸显了通过淡水通量进行的冰盖 - 气候相互作用在未来冰盖退缩及相关海平面上升中的关键作用。