文章标题：Change in future climate due to Antarctic meltwater

文章作者：Ben Bronselaer, Michael Winton, Stephen M. Griffies, William J. Hurlin, Keith B. Rodgers, Olga V. Sergienko, Ronald J. Stouffer & Joellen L. Russell

DOI:https://doi.org/10.1038/s41586-018-0712-z

原文链接：https://www.nature.com/articles/s41586-018-0712-z

内容提要：根据政府间气候变化专门委员会（IPCC）考虑的最高温室气体浓度轨迹（RCP8.5），预计南极冰盖融水将在2100年前造成一米多的海平面上升。然而，广泛使用的CMIP5气候模型不包括来自南极冰盖和冰架的融水影响，由此导致了IPCC气候预测的偏见偏差。本文利用CMIP5模型“GFDL ESM2M”的大型集成模拟，该模型考虑了RCP8.5预计的南极冰盖融水。研究发现，相对于标准的RCP8.5情景，融水使得1.5~2摄氏度的最大全球平均大气升温目标延缓了至少10年。融水增强了南半球的干燥和北半球的湿润，增加了南极海冰的形成（与最近对南极海冰面积增加的观测结果一致），并使南极海岸周围的次表层海洋变暖。此外，融水引起的地下海洋变暖可能通过正反馈机制导致进一步的冰盖和冰架融化。该研究突出了融水效应在未来气候模拟中的重要性。

论文摘要：Meltwater from the Antarctic Ice Sheet is projected to cause up to one metre of sea-level rise by 2100 under the highest greenhouse gas concentration trajectory (RCP8.5) considered by the Intergovernmental Panel on Climate Change (IPCC). However, the effects of meltwater from the ice sheets and ice shelves of Antarctica are not included in the widely used CMIP5 climate models, which introduces bias into IPCC climate projections. Here we assess a large ensemble simulation of the CMIP5 model ‘GFDL ESM2M’ that accounts for RCP8.5-projected Antarctic Ice Sheet meltwater. We find that, relative to the standard RCP8.5 scenario, accounting for meltwater delays the exceedance of the maximum global-mean atmospheric warming targets of 1.5 and 2 degrees Celsius by more than a decade, enhances drying of the Southern Hemisphere and reduces drying of the Northern Hemisphere, increases the formation of Antarctic sea ice (consistent with recent observations of increasing Antarctic sea-ice area) and warms the subsurface ocean around the Antarctic coast. Moreover, the meltwater-induced subsurface ocean warming could lead to further ice-sheet and ice-shelf melting through a positive feedback mechanism, highlighting the importance of including meltwater effects in simulations of future climate.

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