Abstract
Previous results indicate that the global hydrological cycle is more
sensitive to Solar Radiation Modification (SRM) than is the surface
temperature. Thus, it is expected that restoring temperature with SRM
would decrease evaporation and precipitation. However, here we show that
a more complete radiative antidote to CO2 can be obtained by spectrally
tuning the SRM intervention, reducing insolation at some wavelengths
more than others. By concentrating solar dimming at near-infrared
wavelengths, where H2O has strong absorption bands, the direct effect of
CO2 on the tropospheric energy budget can be offset, which minimizes
perturbations to the hydrological cycle. Idealized cloud-resolving
simulations of radiative-convective equilibrium confirm that
spectrally-tuned SRM can simultaneously maintain surface temperature and
precipitation at their unperturbed values even as large quantities of
CO2 are added to the atmosphere. These results illuminate the connection
between the spectral properties of SRM interventions and their potential
impacts on precipitation.