Figure 1. Proposed methods for modifying Earth’s radiation budget, including SRM methods and cirrus cloud thinning.
Stratospheric aerosol injection (SAI): a strategy for increasing the number of small reflective aerosols in the stratosphere to increase the reflection of incoming sunlight.
Marine cloud brightening (MCB): a strategy for adding aerosol to the lower atmosphere over ocean regions to increase the reflectivity of low-lying marine clouds.
Cirrus cloud thinning (CCT): a strategy for modifying the properties of high altitude ice clouds to increase the transmission of outgoing terrestrial radiation to space.
Surface albedo enhancement: increasing the reflectivity of surfaces through, for example, white roofs or land-cover changes.
Space-based methods: proposed methods have primarily considered large “mirrors” in space to reflect sunlight.