evidence is murky and biased on BOTH sides.
What we can agree upon is that 6 years ago, most top republicans were blaming mankind for the temp rises - Mitt, Palin, Mccain, and Newt, remember?
it's only when the base decided they didn't like it anymore, that most republicans decided they too were against it.
Here's the bottom line, from a guy who doesn't buy into it:
Most liberals/democrats still blame pollution for air damage and warming trends, most repubs do not. it's that simple.
Therefore, dem politicians keep supporting the theory, and repub politicians do not. They just reflect the views of their average IQ voters, it's that simple, it really is. If the "tea party" supporters believed the theory that man was affecting the air (as repubs used to), so would palin and the other repubs.
Essentially, it just became another issue to divide people, and people were all too happy to choose their side. Seriously, EITHER PARTY scientists could discover cure to cancer tomorrow, and the other party would cry about the damage to healthcare workers in the US, it's how it'll always be. Global warming is another wedge issue that NEITHER side can prove, and both are paying scientists to do just that lol. No credibility from either side at the moment. Give it 20 years.