Deep convection that feeds the AMOC may occur in Arctic Sea under a warming climate

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

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  1. A more recent study analyzed a high-resolution ocean reanalysis product (GLORYS12) to suggest that deep water formation decreased in the Nordic Sea during 1993-2020. This decrease was countered by an increase in deep water formation near the Arctic Mid-Ocean Ridge (north of Svalbard). Thus, the transport of dense overflow waters to the AMOC’s lower limb remained unchanged.

    Marius Årthun et al., Atlantification drives recent strengthening of the Arctic overturning circulation. Sci. Adv. 11, eadu1794 (2025). https://www.science.org/doi/10.1126/sciadv.adu1794

    Here is another paper on the topic:

    Bretones, A., K. H. Nisancioglu, M. F. Jensen, A. Brakstad, and S. Yang, 2022: Transient Increase in Arctic Deep-Water Formation and Ocean Circulation under Sea Ice Retreat. J. Climate, 35, 109–124. https://doi.org/10.1175/JCLI-D-21-0152.1

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