A new letter signed by 42 climate scientists warns that the Atlantic Meridional Overturning Circulation (AMOC) pattern may collapse much sooner than expected, with devastating consequences for the global climate.

The risk of AMOC collapsing is much higher than previously estimated by the IPCC, according to these scientists. The latest IPCC report from 2021 estimates with medium confidence that the AMOC “will not collapse abruptly before 2100, but if it were to occur, it would very likely cause abrupt shifts in regional weather patterns, and large impacts on ecosystems and human activities.” Recent research, on the other hand, suggests collapse might occur within the next few years or decades, although there is still much debate about data and models, and whether stopgap emergency measures like solar radiation management should be deployed right away.

Adaptation to a climate catastrophe of this magnitude may not be possible. As noted in the letter:

The impacts particularly on Nordic Countries would likely be catastrophic, including major cooling in the region while surrounding regions warm. This would be an enlargement and deepening of the ‘cold blob’ that already has developed over the subpolar Atlantic Ocean and likely lead to unprecedented extreme weather. While the impacts on weather patterns, ecosystems and human activities warrant further study, they would potentially threaten the viability of agriculture in northwestern Europe. Many further impacts are likely to be felt globally, including a shift in tropical rainfall belts, reduced oceanic carbon dioxide uptake (and thus faster atmospheric increase) as well as major additional sea-level rise particularly along the American Atlantic coast, and an upheaval of marine ecosystems and fisheries. Recognizing that adaptation to such a severe climate catastrophe is not a viable option, we urge the Council of Nordic Ministers to (a) initiate an assessment of this significant risk to the Nordic countries and (b) take steps to minimize this risk as much as possible. This could involve leveraging the strong international standing of the Nordic countries to increase pressure for greater urgency and priority in the global effort to reduce emissions as quickly as possible, in order to stay close to the 1.5 °C target set by the Paris Agreement.