The Economist just recently published an article on geoengineering. If you read between the lines it's actually very scary stuff.
Some academics, notably Chomsky, openly talk about the extinction of our species as a plausible outcome of global warming. I asked him about geoengineering. He just said, 'it seems hazardous.'
http://www.economist.com/news/special-report/21678963-man-ma...