Warning of a forthcoming collapse of the Atlantic meridional overturning circulation

• Published in: Nature communications 2023-07, Vol.14 (1), p.4254-12, Article 4254
• Main Authors: Ditlevsen, Peter, Ditlevsen, Susanne
• Format: Article
• Language: English
• Subjects: 639/705/531; 704/106/694/2786; Circulation; Climate change; Climate models; Climate system; Emissions; Estimators; Greenhouse gases; Humanities and Social Sciences; Intergovernmental Panel on Climate Change; multidisciplinary; Science; Science (multidisciplinary); Warning systems
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-39810-w

The Atlantic meridional overturning circulation (AMOC) is a major tipping element in the climate system and a future collapse would have severe impacts on the climate in the North Atlantic region. In recent years weakening in circulation has been reported, but assessments by the Intergovernmental Panel on Climate Change (IPCC), based on the Climate Model Intercomparison Project (CMIP) model simulations suggest that a full collapse is unlikely within the 21st century. Tipping to an undesired state in the climate is, however, a growing concern with increasing greenhouse gas concentrations. Predictions based on observations rely on detecting early-warning signals, primarily an increase in variance (loss of resilience) and increased autocorrelation (critical slowing down), which have recently been reported for the AMOC. Here we provide statistical significance and data-driven estimators for the time of tipping. We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions. The Atlantic meridional overturning circulation (AMOC) is a major tipping element in the climate system. Here, data-driven estimators for the time of tipping predict a potential AMOC collapse mid-century under the current emission scenario.