Sensitivity of the Atlantic Meridional Overturning Circulation to the melting from northern glaciers in climate change experiments

A weakening of the Atlantic Meridional Overturning Circulation (AMOC) in the next century is simulated by most state-of-the-art coupled models but none of them accounted for land-ice melting. Here we evaluate the impact of this melting on future climate projection using the IPSL-CM4 coupled ocean-atmosphere model. For this purpose we use two different versions of the model, one with a crude land-ice melting parameterization, and the other without. The analysis compares results of experiments where atmospheric CO₂ increases by 1%/yr, performed with the two versions of this model. The AMOC is reduced by 47% when the melting of land-ice is considered, and represents an extreme melting scenario. This reduction is of 21% without this melting. It is shown that this difference in AMOC impacts the northern hemisphere mostly through the sea-ice cover feedback.