• Peer-Reviewed
Geophysical Research Letters · 2020

Designing a Radiative Antidote to CO₂

Jacob T. Seeley, Nicholas J. Lutsko, and David W. Keith

Solar radiation modification (SRM) reduces the CO₂-induced change to the mean global hydrological cycle disproportionately more than it reduces the CO₂-induced increase in mean surface temperature. Thus, if SRM were used to offset all CO₂-induced mean warming, global-mean precipitation would be less than in an unperturbed climate. Here, we show that the mismatch between the mean hydrological effects of CO₂ and SRM may partly be alleviated 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 mean hydrological cycle. Idealized cloud-resolving simulations of radiative-convective equilibrium confirm that spectrally tuned SRM can simultaneously maintain mean surface temperature and precipitation at their unperturbed values even as large quantities of CO₂ are added to the atmosphere.

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