Impacts of Sunlight Reduction Climate Engineering on Climate Change in the Ocean: a First Look at Geomip Results

Abstract: Many recent studies have examined the impact of climate engineering through sunlight reduction as a means of mitigating surface temperature, precipitation, and sea ice changes from increasing greenhouse gas concentration. Much less attention has been paid to the impact on physical ocean features. This presentation describes the ocean response to CO2 and solar forcing in the GeoMIP model ensemble, outlining common features and areas where the models disagree. In general, models show that solar radiation management is very effective in reversing most of the physical ocean impacts observed with increasing CO2, including changes in temperature, salinity, gyre-scale circulations, meridional overturning circulations, and interior geostrophic flow. These changes can be attributed in large part to the effectiveness of solar geoengineering in reversing changes in wind and restoring surface energy balance. Residual regions where solar radiation management is less effective are the tropical oceans, where a decrease in the equatorial easterlies and in surface buoyancy input from precipitation significantly affects the circulation and seasonal variability.