Evidence for a slow down in the major North Atlantic current since 1950

Deep water formation
Major ocean currents

The Atlantic meridional overturning circulation (AMOC)—a system of ocean currents in the North Atlantic—has a major impact on climate, yet its evolution during the industrial era is poorly known owing to a lack of direct current measurements. A recent article provides evidence for a weakening of the AMOC by around 15 per cent since the mid-twentieth century. The weakening can be seen a spatial and seasonal sea-surface temperature ‘fingerprint’—consisting of a pattern of cooling in the subpolar Atlantic Ocean and warming in the Gulf Stream region. The pattern can be explained by a slowdown in the AMOC and reduced northward heat transport, as well as an associated northward shift of the Gulf Stream.  Observed fingerprint of a weakening Atlantic Ocean overturning circulation, L. Caesar, S. Rahmstorf, A. Robinson, G. Feulner & V. Saba, Nature, volume 556, pages191–196 (2018) doi:10.1038/s41586-018-0006-5