The Atlantic Meridional Overturning Circulation (AMOC) is an active component of the Earth’s climate system¹ and its response to global warming is of critical importance to society. Climate models have shown an AMOC slowdown under anthropogenic warming since the industrial revolution^2,3,4, but this slowdown has been difficult to detect in the short observational record^5,6,7,8,9,10 because of substantial interdecadal climate variability. This has led to the indirect detection of the slowdown from longer-term fingerprints^11,12,13,14 such as the subpolar North Atlantic ‘warming hole’¹¹. However, these fingerprints, which exhibit some uncertainties¹⁵, are all local indicators of AMOC slowdown around the subpolar North Atlantic. Here we show observational and modelling evidence of a remote indicator of AMOC slowdown outside the North Atlantic. Under global warming, the weakening AMOC reduces the salinity divergence and then leads to a ‘salinity pile-up’ remotely in the South Atlantic. This evidence is consistent with the AMOC slowdown under anthropogenic warming and, furthermore, suggests that this weakening has likely occurred all the way into the South Atlantic.

大西洋子午线翻转循环（AMOC）是地球气候系统¹的活跃组成部分，其对全球变暖的反应对社会至关重要。自工业革命^2,3,4以来，气候模型已显示出人为变暖导致AMOC减慢，但由于年代际间存在较大的变率，很难在短期的观测记录^{5,6,7,8,9,10中}检测到这种减缓。。这导致间接检测到^较慢的指纹^{11、12、13、14}（如亚极北大西洋的“暖洞” ^11）的减速。但是，这些指纹显示出一些不确定性¹⁵是北极副极周围AMOC放缓的所有本地指标。在这里，我们显示了北大西洋以外AMOC减速的远程指标的观测和建模证据。在全球变暖的情况下，减弱的AMOC减少了盐分差异，然后导致南大西洋偏远的“盐分堆积”。这一证据与人为变暖引起的AMOC减慢是一致的，此外，这表明这种减弱可能一直发生到南大西洋。