Can Solar Geoengineering Be Used as a Weapon?

Solar geoengineering—the idea of using technology to reflect a small fraction of incoming sunlight away from Earth to partially offset climate change—poses many problems, including its potential to discourage emissions cuts, its uncertain distributive consequences, and the possibility that suddenly stopping implementation might result in dangerously rapid warming. And yet available evidence shows that moderate use of solar geoengineering may offer an opportunity to mitigate climate hazards beyond what is possible even if all emissions could be eliminated tomorrow. In our view, the prospect that solar geoengineering could significantly reduce risks for the world's poorest, reducing income inequality, is a strong basis for pursuing research and international governance.

Debate on solar geoengineering, however, is haunted by a concern that such technology might be weaponized. This concern stems from longstanding military interest in weather modification technologies, most notably the U.S. use of cloud-seeding during the Vietnam War, which led to adoption of the 1976 Environmental Modification Convention (ENMOD) restricting hostile use of environmental modification techniques. It also stems from suggestions that governance of nuclear weapons may serve as a useful analog for governance of solar geoengineering....