Terrestrial Vegetation Carbon Responses to an AMOC Collapse in an Earth System Model

Although the Atlantic Meridional Overturning Circulation (AMOC) is considered a critical climate tipping element, its impacts on the terrestrial carbon cycle in Earth system models remain uncertain. Using the Earth system model, CLIMBER-X, we investigate the response of vegetation carbon to idealized AMOC collapse under pre-industrial conditions. We assess the role of carbon-climate feedback by comparing simulations incorporating interactive carbon cycles with experimental results set at atmospheric CO₂ concentrations.

The results indicate that AMOC collapse leads to a large-scale change of vegetation carbon, with significant differences in responses between the Northern and Southern Hemispheres. The simulated global vegetation carbon response depends on whether the carbon-climate interaction is considered in the model, highlighting the importance of interactive carbon cycle processes. Our findings indicate the sensitivity of terrestrial vegetation carbon to AMOC changes and suggest that it is important to account for ocean-terrestrial-carbon coupling in Earth system models when assessing potential AMOC tipping events.