Atlantic meridional overturning circulation

The Atlantic meridional overturning circulation (AMOC) is a system of ocean currents in the Atlantic Ocean that transports warm, saline water northward near the surface and cold, dense water southward at depth. It is the oceanic engine of the Atlantic Multidecadal Oscillation and a critical regulator of Earth's climate, redistributing heat from the tropics to the subpolar North Atlantic. The AMOC's strength is governed by a delicate balance between wind-driven surface circulation and deep water formation in the Labrador and Nordic Seas, where surface cooling and salinity increases produce water dense enough to sink and drive the overturning. A shutdown or significant weakening of the AMOC — projected by some climate models under sustained greenhouse gas forcing — would have catastrophic consequences for European climate, tropical rainfall patterns, and global sea level.