European governments are preparing for a potential collapse of the Atlantic Meridional Overturning Circulation, a vast system of ocean currents that carries warm water from the tropics to the North Atlantic, moderating Europe’s climate. Scientists warn that greenhouse gas emissions are weakening this “heat pump,” with some models suggesting a faster-than-expected slowdown or even a total collapse over decades.

A cooler-than-usual area south of Greenland, dubbed the “cold blob,” has led some researchers to believe the slowdown may have already begun. A severe disruption or collapse of AMOC could trigger harsher winters, drier summers, rising sea levels, and violent storms, disrupting agriculture, infrastructure, and economies across the continent, according to analyses cited by Politico and Romanian media .

Iceland has declared AMOC collapse a national security risk, while the Netherlands is assessing its impact on flood defenses. Finland is studying potential consequences, and the U.K. is investing millions in an early warning system. Nordic ministers have begun discussions on the threat, as governments grapple with how to prepare for a distant but potentially catastrophic event .