Climate-driven change in the North Atlantic and Arctic oceans can greatly reduce the circulation of the North Sea

Abstract We demonstrate for the first time a direct oceanic link between climate-driven change in the North Atlantic and Arctic Oceans and the circulation of the northwest European shelf seas. Downscaled scenarios show a shutdown of the exchange between the Atlantic and the North Sea and a substantial decrease in the circulation of the North Sea in the second half of the 21st century. The northern North Sea inflow decreases from 1.2-1.3 Sv (1 Sv = 106 m3/s) to 0.0-0.6 Sv with Atlantic water largely bypassing the North Sea. This is traced to changes in oceanic haline stratification and gyre structure and to a newly identified circulation-salinity feedback. The scenario presented here is of a novel potential future state for the North Sea, with wide-ranging environmental management and societal impacts. Specifically, the sea would become more estuarine and susceptible to anthropogenic influence with an enhanced risk of coastal eutrophication.