David Keith has worked near the interface of climate science, energy technology, and public policy for twenty five years. He took first prize in Canada's national physics prize exam, won MIT's prize for excellence in experimental physics, and was one of TIME magazine's Heroes of the Environment. Best known for work on solar geoengineering, David’s analytical work has ranged from the climatic impacts of large-scale wind power to an early critique of the prospects for hydrogen fuel. David has built a high-accuracy infrared spectrometer for NASA's ER-2 and developed new methods for reservoir engineering to increase the safety of stored CO2. David is Professor of Applied Physics in the John A. Paulson School of Engineering and Applied Sciences and Professor of Public Policy in the Harvard Kennedy School. He spends about a third of his time in Calgary, where he helps lead Carbon Engineering a company developing technology to capture of CO2 from ambient air. In his spare time David climbs rock, ice, and plastic, and goes on occasional multi-week wilderness trips.