Future strengthening of the Nordic Seas overturning circulation

The overturning circulation in the Nordic Seas involves the transformation of warm Atlantic waters into cold, dense overflows. These overflow waters return to the North Atlantic and form the headwaters to the deep limb of the Atlantic meridional overturning circulation (AMOC). The Nordic Seas are thus a key component of the AMOC. However, little is known about the response of the overturning circulation in the Nordic Seas to future climate change. Here we show using global climate models that, in contrast to the North Atlantic, the simulated density-space overturning circulation in the Nordic Seas increases throughout most of the 21st century as a result of enhanced horizontal circulation and a strengthened zonal density gradient. The increased Nordic Seas overturning is furthermore manifested in the overturning circulation in the eastern subpolar North Atlantic. A strengthened Nordic Seas overturning circulation could therefore be a stabilizing factor in the future AMOC. In contrast to the North Atlantic, the projected overturning circulation in the Nordic Seas increases throughout most of the 21st century in global climate model simulations. The Nordic Seas could therefore be a stabilizing factor in the future AMOC.

Automated summary

Contrary to the North Atlantic, the overturning circulation in the Nordic Seas is projected to increase throughout most of the 21st century, according to global climate models. The increased circulation is attributed to enhanced horizontal circulation and a strengthened zonal density gradient. This could potentially stabilize the future Atlantic meridional overturning circulation (AMOC).