Here is a discussion of the "motivation" of global warming deniers.
I think the reasons given for why the deniers are old retired guys is correct. The comment about how the definition of "liberal" and "conservative" is no longer meaningful is also correct. I think it is odd but absolutely correct that now people who do not support authoritarian government are vilified as "conservative." It appears to me that liberals now support totalitarian government.

http://www.numberwatch.co.uk/2009%20February.htm#insult