Arctic and Antarctic sea-ice extent are both projected to dramatically decline over the coming century. The effects of Arctic sea-ice loss are not limited to the northern high latitudes, and reach deep into the tropics. Yet little is known about the effects of future Antarctic sea-ice loss outside of the southern high latitudes. Here, using a fully coupled climate model, we investigate the tropical response to Antarctic sea-ice loss and compare it with the response to Arctic sea-ice loss. We show that Antarctic sea-ice loss, similar to Arctic sea-ice loss, causes enhanced warming in the eastern equatorial Pacific and an equatorward intensification of the Intertropical Convergence Zone. We demonstrate that Antarctic sea-ice loss causes a mini global warming signal comparable to the one caused by Arctic sea-ice loss, and reminiscent of the response to greenhouse gases. We also show that ocean dynamics are key to capturing the tropical response to sea-ice loss. In short, we find that future Antarctic sea-ice loss will exert a profound influence on the tropics. Combined Arctic and Antarctic sea-ice losses will account for 20–30% of the projected tropical warming and precipitation changes under the high-emissions scenario Representative Concentration Pathway 8.5.

预计北极和南极海冰面积将在未来世纪急剧下降。北极海冰流失的影响不仅限于北部高纬度地区，而且还深入热带地区。关于南部高纬度地区未来南极海冰损失的影响知之甚少。在这里，使用完全耦合的气候模型，我们研究了热带对南极海冰损失的响应，并将其与对北极海冰损失的响应进行了比较。我们表明，与北极海冰流失相似，南极海冰流失会导致赤道东太平洋的变暖加剧以及热带辐合带的赤道加剧。我们证明，南极海冰损失引起的全球变暖迷你信号可与北极海冰损失造成的信号相比，让人想起对温室气体的反应 我们还表明，海洋动力学是捕获热带对海冰损失的反应的关键。简而言之，我们发现未来南极海冰的流失将对热带地区产生深远的影响。在高排放情景“代表性浓度路径8.5”下，北极和南极海冰的总损失将占预计的热带变暖和降水变化的20％至30％。