Since we’ve only made moderate progress in cutting greenhouse gas emissions, climate science has turned to seriously investigating options that have typically been in the “far-fetched” category. That includes something called “solar radiation management”—increasing the reflectivity of the atmosphere to, in essence, shade the planet. That could provide a bit of human-caused cooling to temporarily offset some human-caused warming.
Eliminating greenhouse gas emissions is the only long-term solution, but solar radiation management could buy us time to get our act together.
Such a planet-wide intervention certainly makes many uneasy, and we’ve long known that it would come with some side-effects. For example, while greenhouse warming generally causes an increase in global precipitation, cooling the planet in this way would cause an even stronger precipitation decrease that more than cancels that out. And while most ideas revolve around injecting tiny aerosol particles into the upper atmosphere, the spatial pattern of cooling can depend on where those injections are done.