I wouldn’t go as far to say T-paw and others are lying. I think it’s either ignorant disbelief or stubborn self-assuredness.
Ignorant Disbelief is kind of a base stage, where they don’t understand the science of climate change, or simply aren’t aware of any of it, but can’t believe that us little humans can have an effect on the big ol’ climate of the entire planet. They don’t know/aren’t aware of how many people there really are, how carefully balanced climate and ecosystems really are, and thus can’t fathom the magnitude of effect resulting from us.
Stubborn Self-Assuredness builds upon that, but is far worse a view. It’s not that they can’t understand the science, it’s that they can’t admit that they’re wrong. They can’t admit that their view is wrong, and/or they can’t admit that what industrialized civilization has been/is doing is wrong and having a detrimental effect on planet earth. It doesn’t matter why they don’t accept it (“God’s Plan”, religious fate, nefarious NWO conspiracy, environmentalist plot to take over the world, etc etc), it’s ultimately a psychological barrier, not a logical one, preventing them from coming to terms with reality. Thus they gain information about the issue not based on objective data and reliable sources, but based upon how well it conforms with their preconceived notions. They will listen to their neighbor or internet chat rooms and see them as right but discount the world of Nobel laureates and scientific experts as wrong.

Ignorant Denial is a lot easier to deal with. These deniers are the good kind, if one can go so far as to say that, because all it takes to change their minds is the simple presentation of evidence and a good talking-to to refute their beliefs. I’ve done this with some members of my family, and while they used to be deniers, they weren’t lying; they just didn’t know any better.
The stubborn kind are really hard to get through to, if at all. To overcome their views, evidence won’t work; they first have to learn how to “be wrong” and change their minds. And while I wouldn’t say that they are lying either, blind irrational conviction is at least as bad, if not worse.

Pawlenty, and especially Bachmann/Palin, seem to be of the Stubborn Self-Assured group. While you may argue that as politicians, they are catering to their base, the numerous examples of both not being able to publicly admit they are wrong and instead trying to create pretzel-logic way in which they were originally right has me leaning to SSA.