Exploring the geoengineering of climate using stratospheric sulfate aerosols: The role of particle size

A prediction of aerosol size requires a much more complex representation and assumptions about the delivery mechanism beyond the scope of this study, so we explore the response when particle size is prescribed. More aerosol is required to counteract greenhouse warming if aerosol particles are as large as those seen during volcanic eruptions (compared to the smaller aerosols found in quiescent conditions) because the larger particles are less effective at scattering incoming energy, and trap some outgoing energy.

About 1.5 Tg S/yr are found to balance a doubling of CO₂ if the particles are small, while perhaps double that may be needed if the particles reach the size seen following eruptions.