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.