I heard someone make a good point about why geoengineering is an inevitable response that we need to put significant resources toward to prevent the effects of climate change.
Granting that the Earth's climate changes on its own, we need to make preparations to prevent mass starvation and crop failures in the event (which we have evidence to believe is already happening) that the Earth is warming (for whatever reason). Geoengineering makes a lot of Green types pretty mad, but it seems inevitable to me to prevent huge famines.