Rapid and extensive warming following cessation of solar radiation management

Abstract

Solar radiation management (SRM) has been proposed as a means to alleviate the climate impacts of ongoing anthropogenic greenhouse gas (GHG) emissions. However, its efficacy depends on its indefinite maintenance, without interruption from a variety of possible sources, such as technological failure or global cooperation breakdown. Here, we consider the scenario in which SRM—via stratospheric aerosol injection—is terminated abruptly following an implementation period during which anthropogenic GHG emissions have continued. We show that upon cessation of SRM, an abrupt, spatially broad, and sustained warming over land occurs that is well outside 20th century climate variability bounds. Global mean precipitation also increases rapidly following cessation, however spatial patterns are less coherent than temperature, with almost half of land areas experiencing drying trends. We further show that the rate of warming—of critical importance for ecological and human systems—is principally controlled by background GHG levels. Thus, a risk of abrupt and dangerous warming is inherent to the large-scale implementation of SRM, and can be diminished only through concurrent strong reductions in anthropogenic GHG emissions.