Hydrological Consequences of Solar Geoengineering

As atmospheric carbon dioxide concentrations rise and climate change becomes more destructive, geoengineering has become a subject of serious consideration. By reflecting a fraction of incoming sunlight, solar geoengineering could cool the planet quickly, but with uncertain effects on regional climatology, particularly hydrological patterns. Here, we review recent work on projected hydrologic outcomes of solar geoengineering, in the context of a robust literature on hydrological responses to climate change. While most approaches to solar geoengineering are expected to weaken the global hydrologic cycle, regional effects will vary based on implementation method and strategy. The literature on the hydrologic outcomes and impacts of geoengineering demonstrates that its implications for human welfare will depend on assumptions about underlying social conditions and objectives of intervention as well as the social lens through which projected effects are interpreted.We conclude with suggestions to reduce decision-relevant uncertainties in this novel field of Earth science inquiry.

Automated summary

As carbon dioxide concentrations continue to increase and climate change becomes more severe, geoengineering has become an important topic of discussion. Solar geoengineering, which involves reflecting a portion of incoming sunlight, has the potential to quickly cool the planet, but its effects on regional climate patterns, particularly hydrological patterns, are uncertain. This review examines recent studies on the projected hydrologic outcomes of solar geoengineering, taking into account existing literature on hydrological responses to climate change. While most solar geoengineering approaches are expected to weaken the global hydrologic cycle, the specific regional effects will vary depending on the method and strategy of implementation. The findings highlight the importance of considering social conditions and objectives when interpreting the implications of geoengineering on human welfare. Suggestions are made for reducing uncertainties in decision-making in this emerging field of Earth science inquiry.