Empirical methods to reduce uncertainty about solar geoengineering

It’s possible that the deliberate alteration in the Earth’s radiative balance—solar geoengineering—can offer a significant reduction in climate risks when compared to a world with the same emissions trajectory but without geoengineering. Current estimates of the ability of large-scale geoengineering to reduce risks (its efficacy) or the extent to which it introduces new risks (its risks) are almost entirely based on numerical experiments with large-scale models. While it will never be possible
to fully determine the efficacy and risks, the combination of models and experiments—both laboratory
and outdoors—offers the best pathway to reduce uncertainties.