Here is a great article that sums up my opinions on global warming.
I especially like this passage:
I bring up this history not because global warming is an exact parallel to the past “crises” of food and energy that never arrived. In some ways it’s a much tougher problem because it doesn’t lend itself to neat market solutions. There could indeed be unexpected spikes that damage humans and ecosystems. But it’s worth remembering that specialists in the biological or physical sciences can be terribly short-sighted when imagining what problems will beset humans in the future. They can forecast how the physical world will change, but they’re not always accurate even at that, and they’re not not experts in analyzing human responses or in determining the policies that make the most economic and social sense.