David Keith

Gordon McKay Professor of Applied Physics, Harvard John A. Paulson School of Engineering and
Applied Sciences; Professor of Public Policy, Harvard Kennedy School, Harvard University

Solar geoengineering research aims to reduce the impacts of global climate change. One possibility is to put aerosols into the stratosphere to alter Earth’s energy budget. This emerging technology entails risks and uncertainties, along with serious challenges to global governance. The greatest threat, perhaps, is that it will be used as a technical fix and encourage people to avoid the emissions cuts that are fundamental to curbing long-term climate risks. David Keith describes the simple physics underlying the climate’s response to stratospheric aerosols, the risks and the trade-offs among solar geoengineering, carbon removal and emissions reductions.