Subtropical marine cloud brightening suppresses the El Niño-Southern Oscillation

However, their effects on the El Niño–Southern Oscillation (ENSO), a critical mode of climate variability, are poorly understood. Here we use ensembles of climate model simulations to show that deploying MCB in the subtropical eastern Pacific dramatically reduces ENSO amplitude by approximately 61%, while SAI has a negligible impact.

MCB increases cloud albedo, which cools the subtropical eastern Pacific and triggers a loss of moist static energy. This cooling promotes atmospheric subsidence, dries the tropical Pacific, and intensifies the trade winds. The ultimate effect is a dramatic reduction in all air‐sea feedback processes operating during ENSO, which we demonstrate using a mixed‐layer heat budget.