Solar geoengineering refers to the idea of deliberately increasing Earth’s albedo to temporarily cool the planet while we cut emissions and remove greenhouse gases from the atmosphere. There are many ways this could be achieved, the most studied is stratospheric sulfate injection, which mimics what happens during a volcanic eruption. The increase in Earth’s albedo is not the only effect of stratospheric sulfate injection, yet many studies just reduce the solar constant (or ‘turn down the sun’) to simulate solar geoengineering. As part of the Geoengineering Model Intercomparison Project (GeoMIP), the G6sulfur and G6solar simulations reduce the warming from the high-tier emission scenario to the medium-tier emission scenario by adding a stratospheric sulfate aerosol layer (G6sulfur) or a uniform reduction in the solar constant (G6solar). By analysing the differences between these two simulations, we can isolate the climate impacts of stratospheric aerosol injection that arise independently from the increase in Earth’s albedo.

• https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JD033952