The evolution of the North Atlantic Meridional Overturning Circulation since 1980

The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the climate through its transport heat in North Ocean. Decadal changes AMOC, whether internal variability or anthropogenically forced weakening, therefore have wide-ranging impacts. In this Review, we synthesize understanding contemporary decadal bringing together evidence from observations, ocean reanalyses, models and AMOC proxies. Since 1980, there for periods strengthening although magnitudes change (5–25%) are uncertain. subpolar Atlantic, strengthened until mid-1990s then weakened early 2010s, with some thereafter; these probably linked to buoyancy forcing related Oscillation. subtropics, 2001 2005 strong weakening 2014. Such large interannual complicates detection ongoing long-term trends, but does not preclude associated anthropogenic warming. Research priorities include developing robust sustainable solutions monitoring observation–modelling collaborations improve representation processes better ways distinguish variability. has role system. This Review documents since revealing decadal-scale that differ between subtropical regions.