Fast recovery of North Atlantic sea level in response to atmospheric carbon dioxide removal

Abstract

Sea level rise due to anthropogenic warming threatens coastal environments and human societies, but its regional reversibility under successful climate mitigation efforts remains unclear. Here, we investigate sea level fluctuations in the Subpolar North Atlantic using idealized atmospheric carbon dioxide ramp-up and -down experiments. During the ramp-up period, the Subpolar North Atlantic experiences a faster sea level rise than the global mean, followed by a more rapid sea level decline over several dacades with decreasing carbon dioxide. These rapid sea level fluctuations are mainly driven by the response of the Atlantic Meridional Overturning Circulation to carbon dioxide forcing. The enhanced meridional salinity transport triggered by the rapid recovery of the Atlantic Meridional Overturning Circulation plays a crucial role in the regional sea level decline. Our study highlights the potential for pronounced sea level changes in the Subpolar North Atlantic and surrounding coastal areas under climate mitigation scenarios. The Atlantic Meridional Overturning Circulation’s response to carbon dioxide forcing is crucial for rapid sea level fluctuations in the Subpolar North Atlantic, indicating potential for fast changes under climate mitigation scenarios, according to results from carbon dioxide ramp-up and -down experiments to investigate sea level variation.