Strong Remote Control of Future Equatorial Warming by Off-Equatorial Forcing
The tropical climate response to greenhouse gas forcing is spatially non-uniform. While most models simulate enhanced warming on the equator, the physical mechanisms responsible for it remain debated. Here, we developed a new theory to explain this tropical warming pattern using a hierarchy of idealized climate model experiments. We found that off-equatorial radiative forcing is responsible for most of the equatorial warming due to a coupled feedback that involves the Hadley circulation, oceanic subtropical cells, and clouds.
Our mechanism highlights the role that off-equatorial forcing can play for equatorial warming. For instance, we expect that a future reduction of aerosols in subtropical and mid-latitude Asia would lead to pronounced warming near the equator.
We demonstrated the large role that off-equatorial radiative forcing can play in controlling equatorial warming patterns via a coupled feedback involving both circulation and cloud changes.