A new paper published by Ditlevsen and Ditlevsen in Nature Communications finds early warning signals of a critical transition of the Atlantic Meridional Overturning Circulation (AMOC), a large system of ocean currents that carry warm water from the tropics northwards into the North Atlantic. Their analysis suggests that the AMOC could collapse around the middle of the century, or potentially any time from 2025 onwards, under continued greenhouse gas emissions. The implications of a shutdown of the AMOC would be severe impacts on the climate of the North Atlantic region and around the world. The paper outlines that this kind of abrupt climate change was last experienced during Dansgaard-Oeschger events in the last glacial period caused by the collapse and restoration of the AMOC. It led to mean Northern Hemisphere temperature fluctuations of 10–15 degrees Celsius within a decade, much greater than present changes of 1.5 degrees in a century. The strength of the AMOC has only been monitored continuously since 2004, and these observations have shown the AMOC to be weakening, but longer records are needed to assess the magnitude of this change. Recent IPCC assessments suggest that a full collapse of the AMOC is unlikely within the 21st century. For more information on this study, please see the article:

Ditlevsen, P., Ditlevsen, S. Warning of a forthcoming collapse of the Atlantic meridional overturning circulation. Nat Commun 14, 4254 (2023). https://doi.org/10.1038/s41467-023-39810-w

The above text was adapted from the official press release. 


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