It is not always the case, but I think a lot of "denialism" derives from a weakness of ideological conviction. Many feel that the threat of climate change would justify political stances that they would otherwise disagree with, and they therefore deny climate change in order to maintain their political outlook. If they were to concede that there was anthropogenic climate change, they feel that their case would be irreparably damaged. This would at least explain why so many "denialists" are slanted to the right, as they are typically averse to the governmental intervention that is often justified under the "green banner".
I too underwent difficulty in this regard. Ultimately, rather than denying climate change or giving way to the political proposals of a certain crowd, my belief strengthened in a smaller state as both a morally desirable policy and a practically preferable solution to the problems of climate change. A lot of people don't take this route.