Meltwater and ice discharge from a retreating Antarctic Ice Sheet could have important impacts on future global climate. Here, we report on multi-century (present–2250) climate simulations performed using a coupled numerical model integrated under future greenhouse-gas emission scenarios IPCC RCP4.5 and RCP8.5, with meltwater and ice discharge provided by a dynamic-thermodynamic ice sheet model. Accounting for Antarctic discharge raises subsurface ocean temperatures by >1°C at the ice margin relative to simulations ignoring discharge. In contrast, expanded sea ice and 2° to 10°C cooler surface air and surface ocean temperatures in the Southern Ocean delay the increase of projected global mean anthropogenic warming through 2250. In addition, the projected loss of Arctic winter sea ice and weakening of the Atlantic Meridional Overturning Circulation are delayed by several decades. Our results demonstrate a need to accurately account for meltwater input from ice sheets in order to make confident climate predictions.

退缩的南极冰原的融水和冰排放可能对未来的全球气候产生重要影响。在这里，我们报告了使用耦合数值模型进行的多世纪（目前至2250年）气候模拟，该模型是在未来温室气体排放情景IPCC RCP4.5和RCP8.5下集成的，其中动态热力学冰提供了融水和冰排放工作表模型。相对于忽略排放的模拟，考虑到南极排放，冰缘处的地下海洋温度升高了> 1°C。相比之下，南大洋海冰的膨胀以及南大洋的地表温度和地表温度降低了2°至10°C，从而推迟了到2250年预计的全球平均人为变暖的增加。此外，北极冬季海冰的预计损失和大西洋子午线翻转环流的减弱被推迟了几十年。我们的结果表明，有必要准确地解释冰盖中融水的输入量，以便做出可靠的气候预测。