Sea surface temperature (SST) has been increasing since industrialization with rising greenhouse gases. However, a warming hole exists in the North Atlantic where SST has cooled by 0.4 K/century during 1900–2017. It has been argued that this cooling is due to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), and subpolar North Atlantic SST has thus been utilized to estimate AMOC variability. We assess the robustness of subpolar North Atlantic SST as a proxy for AMOC strength under historical forcing, abrupt quadrupling of CO₂, and a medium future emissions pathway, finding that AMOC's fingerprint on SST depends upon forcing scenarios. AMOC is important in warming hole development during significant warming periods, although SST may introduce uncertainties for AMOC reconstruction in stabilized regimes due to diverse forcing mechanisms and decadal variability. Our results caution against using SST alone as a proxy for AMOC variability—both on paleoclimatic and contemporary time scales.

中文翻译：

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大西洋经向翻转环流指纹对海面温度的非平稳性


自工业化以来，随着温室气体排放的增加，海面温度（SST）一直在上升。然而，北大西洋存在一个变暖洞，1900年至2017年海表温度每世纪降温0.4 K。有人认为，这种降温是由于大西洋经向翻转环流 (AMOC) 减慢造成的，因此利用北大西洋副极地海温来估计 AMOC 的变化。我们评估了北大西洋副极地海表温度作为 AMOC 在历史强迫、CO ₂突然翻两番和中期未来排放路径下的强度代理的稳健性，发现 AMOC 对海表温度的影响取决于强迫情景。尽管由于不同的强迫机制和年代际变化，海表温度可能会给稳定状态下 AMOC 的重建带来不确定性，但 AMOC 在显着变暖时期对暖洞的形成很重要。我们的结果警告不要单独使用海表温度作为 AMOC 变化的代理——无论是在古气候还是当代时间尺度上。