Impacts of three types of solar geoengineering on the Atlantic Meridional Overturning Circulation

Abstract. Climate models simulate lower rates of North Atlantic heat transport under greenhouse gas climates than at present due to a reduction in the strength Meridional Overturning Circulation (AMOC). Solar geoengineering whereby surface temperatures are cooled by incoming shortwave radiation may be expected ameliorate this effect. We investigate using six Earth system running scenarios from GeoMIP (Geoengineering Model Intercomparison Project) cases (i) solar constant, mimicking dimming sun; (ii) sulfate aerosol injection into equatorial stratosphere; and (iii) brightening ocean regions, enhancing tropospheric cloud amounts. find that despite across-model differences, AMOC decreases attributable reduced air–ocean temperature differences September Arctic sea ice extent, with no significant impact changing winds or precipitation ? evaporation. Reversing freshening overturning regions caused decreased summer helps promote AMOC. When comparing types after normalizing them for top-of-atmosphere radiative forcing, we is more effective either marine stratospheric injection.