A Resilient Atlantic Meridional Overturning Circulation in the Near Future

Statistical methods generally predict a possible tipping of the Atlantic Meridional Overturning Circulation (AMOC) in the near future, suggesting that the climate models overestimate the stability of AMOC. Conversely, observations show a stable AMOC during the past decades, suggesting otherwise. Based on the MITgcm-ECCO2, here we show that the biases in the simulated Arctic sea ice, freshwater content, and the water transport across various straits/passages around the Arctic play a key role in the future stability of AMOC in the climate models. Specifically, most climate models project an increased freshwater export from the Arctic across the Fram Strait in the future. In contrast, our model, with minimal bias for the present day, simulates a decrease in freshwater export across the Fram Strait but an increase across the Lancaster Strait. This shift of location increases AMOC stability as the freshwater coming out of Fram Strait has a direct impact on the surface density over the North Atlantic deepwater formation region.