AMOC ocean circulation faces collapse risk from rapid warming

New research suggests that the risk of a collapse in the Atlantic Meridional Overturning Circulation (AMOC) depends not only on the total increase in global temperatures, but also on the speed of that warming. The AMOC acts as a massive conveyor belt, transporting warm, salty water from the tropics to the North Atlantic and returning cold, deep water southward, which regulates European climate and influences global rainfall and sea levels.

Scientists led by René van Westen, Reyk Börner, and Henk Dijkstra argue that rapid climate forcing could destabilize the system even if temperature increases remain below previously estimated critical thresholds, such as the four-degree mark. Because the ocean possesses significant thermal inertia, its deep layers require decades or centuries to respond to atmospheric changes. Consequently, the rate at which the climate system reaches certain temperatures may determine whether the ocean can adapt or if the circulation hits a point of no return.