Over the past several years, solar geoengineering, also known as solar radiation management (SRM), has been presented to the public as a possible last-ditch response option in the event of a “climate emergency” (Blackstock et al., 2009; Long et al., 2011).

Many technical and scientific uncertainties remain, but the available evidence suggests that methods such as stratospheric aerosol injection (SAI), which theoretically would reflect a small but significant amount of incoming shortwave radiation sufficient to restore global mean temperatures to approximately preindustrial values, would act relatively quickly, possibly within months (Royal Society, 2009).

The fast-acting nature of such measures would seem to make them especially suitable for urgent situations requiring quick action. In the climate context, such scenarios are commonly referred to as “climate emergencies.”