Is Aerosol Geoengineering Ethically Preferable to Other Climate Change Strategies?

As a strategy for responding to climate change, aerosol geoengineering (AG) carries various risks, thus raising ethical concerns regarding its potential deployment. I examine three ethical arguments that AG ought not to be deployed, given that it (1) risks harming persons, (2) would harm persons, and (3) would be more harmful to persons than some other available strategy. I show that these arguments are not successful. Instead, I defend a fourth argument: in scenarios in which all available climate change strategies would result in net harm, we ought to adopt the strategy that would result in the least net harm. Barring substantial cuts in greenhouse gas emissions, we can reasonably expect future scenarios in which all available strategies would result in net harm. In such cases, there is good reason to suspect that AG would result in less net harm than emissions mitigation, adaptation, or other geoengineering strategies.