Department of Geosciences, University of Arizona, Tucson, AZ, USA.
Geophysical Fluid Dynamics Laboratory, Princeton University Forrestal Campus, Princeton, NJ, USA.
Nature. 2018 Dec;564(7734):53-58. doi: 10.1038/s41586-018-0712-z. Epub 2018 Nov 19.
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.
到 2100 年，在政府间气候变化专门委员会（IPCC）所考虑的温室气体浓度最高轨迹（RCP8.5）下，南极冰盖的融水预计将导致海平面上升多达 1 米。然而，南极冰盖和冰架的融水的影响并未包含在广泛使用的 CMIP5 气候模型中，这给 IPCC 的气候预测带来了偏差。在这里，我们评估了一个大型的 CMIP5 模型“GFDL ESM2M”的集合模拟，该模型考虑了 RCP8.5 预测的南极冰盖融水。我们发现，相对于标准的 RCP8.5 情景，考虑到融水会使全球平均大气升温超过 1.5 和 2 摄氏度的目标超过十年，增强了南半球的干燥，减少了北半球的干燥，增加了南极海冰的形成（与最近观察到的南极海冰面积增加一致）并使南极海岸周围的次表层海洋变暖。此外，融水引起的次表层海洋变暖可能通过正反馈机制导致冰架和冰架进一步融化，突出了在未来气候模拟中包含融水效应的重要性。
