Harvard’s David Keith explains why it’s time to move forward with outdoor experiments and broader research programs.
Harvard professor David Keith
Harvard professor David Keith has done as much as any single researcher to push the touchy topic of geoengineering toward the scientific mainstream (see “A Cheap and Easy Plan to Stop Global Warming”).
He was among the first to seriously assess potential ways of altering the climate to ease global warming, and he has undertaken some of the most detailed research on a promising approach known as stratospheric injection. He also wrote a book on the subject, A Case for Climate Engineering, and co-manages a Bill Gates–backed energy and climate fund that has supported research in this area. This year, Keith helped launch Harvard’s Solar Geoengineering Research Program, and announced plans with a colleague to carry out what would be among the earliest outdoor experiments in the field (see “The Growing Case for Geoengineering”).
The basic idea behind stratospheric injection is that spraying particles high above the Earth could help reflect more heat back into space, offsetting rising temperatures. It would mimic a natural phenomenon that occurs when large volcanic eruptions blast sulfur dioxide into the atmosphere, which nudges down global temperatures in the months that follow.
For the proposed experiment, Keith and fellow Harvard professor Frank Keutsch plan to launch high-altitude balloons that would spray small amounts of materials such as sulfur dioxide, alumina, or calcium carbonate into the stratosphere. They would then employ sensors to measure the reflectivity of the particles, the degree to which they disperse, and how they interact with other compounds. Initial test flights could occur as early as next year.
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