The Probability of an AMOC Collapse Onset in the Twenty-First Century

The Atlantic Ocean circulation, in particular its zonally averaged north-south volume transport indicated by the Atlantic Meridional Overturning Circulation (AMOC), is sensitive to surface buoyancy anomalies. It may undergo a transition to a climate-disrupting state within a century under continuing greenhouse gas emissions. The potential climate and societal impacts are expected to be large, and therefore reliable estimates of the probability of the onset of such a collapse before the year 2100 are crucial for policymakers. This article addresses whether current Earth system models are fit for purpose to capture present-day AMOC stability and presents the current status of estimates of collapse onset probabilities.