J37.1 Building Confidence and Reducing Risks with Strategic Geoengineering

Wednesday, 10 January 2018: 8:30 AM
Room 16AB (ACC) (Austin, Texas)
Jadwiga H. Richter, NCAR, Boulder, CO; and S. Tilmes, B. Kravitz, D. MacMartin, M. Mills, and I. R. Simpson

Solar radiation management (SRM) is a proposed method of geoengineering that aims to reduce incoming sunlight to cool the Earth, counteracting some of the effects of global warming. However, previous studies using solar dimming experiments and injections of sulfate aerosol precursors into the tropical stratosphere have found considerable side effects of SRM. Side effects of SRM primary include overcooling of the tropics, undercooling of the polar regions, and shifts in precipitation patterns. Recently, a feedback mechanism has been successfully implemented in the Community Earth System Model, version 1 with the Whole Atmosphere Community Climate Model as its atmospheric component CESM1(WACCM), which optimizes sulfur dioxide (SO2) injections into the stratosphere that reduces some of these risks and side effects of SRM. The feedback algorithm adjusts the SO2 injection strategy yearly to keep the global mean temperature, the pole-to-pole temperature gradient, and the equator-to-pole temperature gradient at 2020 levels. Here we present the results of a large ensemble of century long simulations with such a strategic geoengineering approach using CESM1(WACCM). We demonstrate that when such a strategy is implemented, common risks of geoengineering are significantly reduced. Regional changes to temperature and precipitation patterns are discussed.
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