Ryan N. Gajarawala
As the Gordon McKay Professor of Applied Physics at the Harvard School of Engineering and Applied Sciences, David Keith is best known for his work on the science, technology, and public policy of solar geoengineering.
Year after year, the threat of an impending climate catastrophe looms larger in the public consciousness. David W. Keith, an applied physics professor, is working on a solution.
David W. Keith’s office is tucked inside a glass skywalk between the Mallinckrodt and Hoffman labs, nestled within a maze of cramped hallways that belie the massive scale of his research. Year after year, the threat of an impending climate catastrophe looms larger in the public consciousness, and Keith, an applied physics professor, is working on a solution.
Keith is a co-director of Harvard’s Solar Geoengineering Research Program, a cross-disciplinary collaboration examining approaches to and policy surrounding solar geoengineering. He leads a group that researches solar geoengineering, a technique that aims to reflect some of the sun’s energy to mitigate global temperature increases. In 2019, Keith, in collaboration with Chemistry Professor Frank N. Keutsch, may become one of the first to execute a controlled experiment in geoengineering.
The experiment is called the Stratospheric Controlled Perturbation Experiment. It would test a version of geoengineering called Stratospheric Aerosol Injection, which involves spraying sulfate aerosols into the stratosphere to reflect a small percentage of incoming sunlight. It’s what media outlets have in recent months been calling “dimming the sun.”
SAI is only one of many proposed techniques under the heading of solar geoengineering. Other proposals have included sending mirrors to space, painting mountaintops white, and brightening the clouds over the ocean to make them more reflective. “The idea is actually really old,” Keith says. “In some sense there is not very much innovative here — the idea emerged about the same time as modern understanding of climate.” A number of researchers and advocates of geoengineering suggest that SAI would be one of the most efficient and cost-effective methods for geoengineering.