Reversible Atlantic overturning despite continued Greenland Ice Sheet melt in global climate overshoot scenarios

The Atlantic Meridional Overturning Circulation (AMOC), a key component of the Earth’s climate system, has long been considered vulnerable to irreversible weakening or collapse under global warming and related Greenland Ice Sheet (GrIS) melt, yet its resilience remains uncertain. Here, we use a CO2-emission-driven Earth system model with an interactive GrIS to assess AMOC reversibility under idealised CO2 emission pathways that produce near-linear global warming up to 10 K, stabilisation across 1.5-9 K, and subsequent cooling. We find that although the AMOC attains “collapsed” states by commonly used threshold definitions, these weakened states do not represent dynamical tipping: the overturning weakens quasi-linearly with global temperature increase, yet consistently and promptly recovers under cooling. In contrast, GrIS mass loss accelerates with warming, continues through stabilisations, and is only slowed by cooling, committing the planet to long-term sea-level rise. These results reveal a striking asymmetry in Earth-system resilience: under transient CO2 forcing, the AMOC strength remains dynamically reversible even under continued Greenland meltwater input, whereas the GrIS is locked into persistent decline. Our findings underscore the urgency of rapid emission cuts to limit climate overshoot, AMOC weakening, and irreversible ice-sheet loss.