Impact of Solar Geoengineering on Temperature-Attributable Mortality

Temperature-attributable mortality is a major risk of climate change. We analyze the capacity of solar geoengineering (SG) to reduce this risk and compare it to the impact of equivalent cooling from CO2 emissions reductions. We use the Forecast-Oriented Low Ocean Resolution model to simulate climate response to SG. Using empirical estimates of the historical relationship between temperature and mortality from Carleton et al. (2022), we project global and regional temperature-attributable mortality, find that SG reduces it globally, and provide evidence that this impact is larger than for equivalent cooling from emissions reductions. At a regional scale, SG moderates the risk in a majority of regions but not everywhere. Finally, we find that the benefits of reduced temperature-attributable mortality considerably outweigh the direct human mortality risk of sulfate aerosol injection. These findings are robust to a variety of alternative assumptions about socioeconomics, adaptation, and SG implementation.