A new study shows that geoengineering should work. Just not exactly how we imagined:

Geoengineering could indeed cool the atmosphere, ecologist Ken Caldeira of the Carnegie Institution in Stanford, California, and colleagues conclude in their new analysis. The team examined the impact of 11 possible projects over the next century using computer simulations and assuming trends in greenhouse-gas emissions will continue unchecked.

The good news is such measures would be effective even if undertaken decades from now, the researchers report online this week in the Proceedings of the National Academy of Sciences. The bad news is that in all cases studied, reducing solar radiation would also shift global rainfall patterns, potentially drenching some areas and parching formerly productive agricultural land. Worse, the simulations predict that if the atmospheric fiddling suddenly stopped, the warming would accelerate dramatically — possibly to 20 times the current rate — because CO2 would still be accumulating.