Significance We assessed the effects of air pollution and greenhouse gases on public health, climate, and the hydrologic cycle. We combined a global atmospheric chemistry–climate model with air pollution exposure functions, based on an unmatched large number of cohort studies in many countries. We find that fossil-fuel-related emissions account for about 65% of the excess mortality rate attributable to air pollution, and 70% of the climate cooling by anthropogenic aerosols. We conclude that to save millions of lives and restore aerosol-perturbed rainfall patterns, while limiting global warming to 2 °C, a rapid phaseout of fossil-fuel-related emissions and major reductions of other anthropogenic sources are needed.