PNNL

Abstract

Sulfur-rich volcanic eruptions happen sporadically. If Stratospheric Aerosol Injection (SAI) were to be deployed, it is likely thatexplosive volcanic eruptions would happen during such a deployment. Here we use an ensemble of Earth System Modelsimulations to show how changing the injection strategy post-eruption could be used to reduce the climate risks of a largevolcanic eruption; the risks are also modifi ed even without any change to the strategy. For a medium-size eruption (10 Tg-SO ) comparable to the SAI injection rate, the volcanic-induced cooling would be reduced if it occurs under SAI, especially ifartifi cial sulfur dioxide injections were immediately suspended. Alternatively, suspending injection only in the eruption hemisphere and continuing injection in the opposite would reduce shifts in precipitation in the tropical belt and thus mitigate eruption-induced drought. Finally, we show that for eruptions much larger than the SAI deployment, changes in SAI strategy would have minimal effect.