Global temperature and carbon cycle changes after AMOC collapse

There is increasing interest in understanding how the collapse of the Atlantic Meridional Overturning Circulation (AMOC) impacts global climate, yet its effects on the carbon cycle remain underexplored. While previous studies have focused on these impacts under preindustrial conditions, our research takes a novel approach by examining equilibrium states under different CO2 levels, offering a perspective not previously addressed.

Using the intermediate-complexity Earth system model CLIMBER-X, we conducted a series of hosing experiments to simulate AMOC collapse under various CO2 equilibrium conditions. Our analysis focuses on the carbon cycle and global climate changes resulting from AMOC collapse, while also exploring the roles of ocean dynamics and carbon cycle during this process.

Our findings highlight that under a warming climate, a potential AMOC collapse could result in significant oceanic carbon release to the atmosphere, amplifying global warming. Although it would take hundreds to thousands of years for the AMOC to reach equilibrium after collapse and fully produce these effects, the rate of this process can vary depending on the CO2 levels of the equilibrium. Furthermore, certain scenarios may even trigger additional warming before the AMOC collapse is fully realized.