Humans have been unintentionally geoengineering the earth for thousands of years. Intintional geoengineering aimed at reversing global climate change is an increasingly talked about idea. However, it's fraught with controversy as well as many many unknowns (unknowables?).
Arthur Max (AP):
They could be physical — unintentionally changing weather patterns and rainfall. Even more difficult, it could be political — spurring conflict among nations unable to agree on how such intervention, or geoengineering, will be controlled.
As Plan A (reducing CO2 emissions through international cooperation) begins to lapse and fail, will once wild ideas like geoengineering seem so crazy and dangerous in the next 100 years?