Space sunshades and climate change

Abstract

The accelerated rate of increase in atmospheric CO2 concentrations in recent years and the inability of humankind to move away from carbon-based energy system have led to the revival of the idea of counteracting global warming through geoengineering schemes. Two categories of geoengineering proposals have been suggested: solar radiation management (SRM) and carbon dioxide removal (CDR) methods. SRM schemes would attempt to reduce the amount of solar radiation absorbed by our planet. Placing reflectors or mirrors in space, injecting aerosols into the stratosphere, and enhancing the albedo of marine clouds are some of the proposed SRM methods. In this section, the various space-based SRM methods which are likely to reduce the incoming solar radiation uniformly across the globe are discussed. In the past decade, the effects of these space sunshades on the climate system have been simulated using climate models by reducing the amount of incoming solar radiation by appropriate amounts (reduced solar constant). Key modeling results on the extent of global and regional climate change mitigation, unintended side effects, and unmitigated effects are briefly discussed.