 If we had definitive proof that CO2 was causing serious problems and we could prove it, don't you think they would write that down on a piece of paper somewhere so people could read it? I think so. They don't have definitive proof, period, in science. I'm a student of the philosophy and history of science, and I know that the scientific method has not been applied in such a way as to prove that carbon dioxide is causing the Earth to warm.