Ocean currents in the North Atlantic. Warmer colors indicate higher temperatures. NASA
A vast system of Atlantic currents that delivers warmth to northern Europe is at risk of collapse, according to a growing body of research. The latest study to warn of its demise finds there is at least a 10 percent chance that a collapse may already be “locked in.”
The Atlantic Meridional Overturning Circulation, or AMOC, ferries warm water from the tropics to northern Europe. As the water cools, it becomes more dense and drops to the ocean depths, where it flows south, back toward the tropics. But as oceans warm, those waters are not so cool, or so dense, as they once were, causing the system of ocean circulation to slow down. At the same time, the melting of the Greenland ice sheet is introducing large amounts of fresh water, which is less dense than salty water, further slowing circulation.
By one estimate, if the AMOC were to collapse, its flow slowing to a near halt, temperatures in northern Europe would drop by 9 to 27 degrees F (5 to 15 degrees C).
The new modeling study found that even in a scenario where global emissions peaked in 2025 and the melting of the Greenland ice sheet raises sea levels by just 2 inches this century, there is a 10 percent chance that the AMOC will eventually collapse. In scenarios where the Greenland ice sheet unleashes more meltwater, the probability of collapse rises to 23 percent, according to the study, which has not yet undergone peer review.
Coauthor Tim Lenton, of the University of Exeter, told New Scientist, “What the model is saying to me is, ‘Let’s do everything in our power to get to net-zero as quickly as possible to try to keep this probability down at the 10 percent level.’”
ALSO ON YALE E360
Why Fears Are Growing Over the Fate of a Key Atlantic Current
