Mitigation isn't a big technological challenge per se. The big showstopper is the fear of the unknown unknowns; the remote possibility that despite our careful

Mitigation isn't a big technological challenge per se. The big showstopper is the fear of the unknown unknowns; the remote possibility that despite our careful science and engineering, the cure ends up being worse than the disease. Because we only have one shot, and no "undo" button, large scale geoengineering will be put off for as long as possible.