We explore the representation of the Atlantic Meridional Overturning Circulation (AMOC) in 27 models from the CMIP6 multi‐model ensemble. Comparison with RAPID and SAMBA observations suggests that the ensemble mean represents the AMOC strength and vertical profile reasonably well. Linear trends over the entire historical period (1850‐2014) are generally neutral, but many models exhibit an AMOC peak around the 1980's. Ensemble‐mean AMOC decline in future (SSP) scenarios is stronger in CMIP6 than CMIP5 models. In fact, AMOC decline in CMIP6 is surprisingly insensitive to the scenario at least up to 2060. We find an emergent relationship among a majority of models between AMOC strength and 21^st century AMOC decline. Constraining this relationship with RAPID observations suggests that the AMOC might decline between 6 and 8 Sv (34‐45%) by 2100. A smaller group of models projects much less AMOC weakening of only up to 30%.

中文翻译：

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CMIP6模型预测21世纪大西洋经线翻转环流的显着下降

我们从CMIP6多模型合奏中探索了27个模型中大西洋子午向翻转循环（AMOC）的表示形式。与RAPID和SAMBA观测值的比较表明，总体均值相当好地表示AMOC强度和垂直剖面。整个历史时期（1850-2014年）的线性趋势通常是中性的，但是许多模型在1980年代前后都出现AMOC峰值。在CMIP6中，将来的整体平均AMOC下降（SSP）情景要比CMIP5模型更强。实际上，至少在2060年之前，CMIP6中AMOC的下降对这种情况并不敏感。我们发现AMOC强度与^21st之间的大多数模型之间都出现了紧急关系。世纪AMOC下降。将这种关系与RAPID观测值加以约束表明，到2100年AMOC可能会下降6至8 Sv（34-45％）。一小组较小的模型预测AMOC的减弱最多只有30％。