The climate impacts of sulfate aerosols

Sulfate aerosols (SO4) from anthropogenic emissions of sulfur dioxide (SO2) generally have a cooling effect. However, if SO2 emissions fall over time, accounting for sulfate aerosols will increase the predicted warming from greenhouse gases. This paper integrates the four marker emission scenarios for CO2 and SO4 from the Special Report on Emissions Scenarios (SRES), the UIUC general circulation model (GCM), and a country-specific impact model (GIM) to calculate the impacts of sulfate aerosols. By 2100, lower SO2 emissions slightly increase warming in the temperate and polar regions causing small damages in the former and small benefits in the latter. If SO2 emissions are also lower in tropical regions, temperatures will rise causing small damages there as well. However, if SO2 emissions rise in tropical regions, temperatures will fall leading to small benefits.