Summary/Abstract
Proposals for research on geoengineering methods to offset greenhouse-gas driven climate change have attracted controversy, including ocean iron fertilization. High-leverage interventions offer the dual prospect of large benefits and harms. They may reduce climate-change risks faster than any other response. Yet they may also cause environmental harm or worsen policy failures—for example, undermining emissions cuts or triggering international conflict. Research is needed to develop capabilities and assess effectiveness and risks (field research as well as model and laboratory studies), but geo-engineering requires competent, prudent, and legitimate governance. This article proposes specific steps to advance progress on research governance.