Seasonally modulated stratospheric aerosol geoengineering alters the climate outcomes

Previous research has shown that multiple injection latitudes can be used to maintain not only global mean temperature, but also interhemispheric and equator-to-pole temperature gradients. However, the regional climate response depends not only on where the SO2 is injected, but also on when.

We show here that even with these same objectives and same choices of latitudes, injecting in only one season instead of continuously throughout the year results in significant differences in regional climate, for instance in the magnitude of precipitation changes over India. The differential outcomes highlight the potential for underlying trade-offs, with different choices regarding deployment leading to a different distribution of benefits or harms.