The Atlantic Meridional Overturning Circulation (AMOC) is a key ocean circulation system that carries heat, salt, carbon and other biogeochemical elements along its paths, redistributing them between hemispheres and across ocean basins, and thus is a crucial component of the global heat, salt and carbon balances. At present, the subduction of dense water (i.e., deep convection) that feeds the AMOC occurs almost entirely in the subpolar region, in the Labrador, Irminger and Nordic seas. A new study appeared in Nature Climate Change analysed climate model output to show that, in response to warming, the main source regions of the deep convection shift northward to the Arctic basin. The study also suggested that the shrinking winter Arctic sea-ice extent could be the main cause that allow the Arctic basin to emerge as a new deep convection site for the AMOC. An important implication is that due to the northward shift in the deep convection site, the rate of air–sea heat flux and surface carbon uptake may change significantly under a warming climate.
Lique, C., & Thomas, M. D. (2018). Latitudinal shift of the Atlantic Meridional Overturning Circulation source regions under a warming climate. Nature Climate Change, 8, 1013-1020. https://www.nature.com/articles/s41558-018-0316-5