[Mike Darancette]

Climate change denial is now “something of a litmus test for Republican politicians to prove their conservative bona fides,” says Riley Dunlap, a sociologist at Oklahoma State University.

Skepticism is a litmus test for the aptitude of critical thinking. Who in their right mind believes that CO2 levels can be reduced to 1850 levels or that the totality mankind's GHG output can be eliminated by 2050?

[Cincinatus' Wife]

And...

“A hypothesis can be refuted (proven wrong, or falsified), but it never can be proven to be true. (It is impossible to perform enough experiments to be certain that the answer will always be the same, and that the same explanation will hold true every time.) However, if a hypothesis is tested again and again and is never falsified, it may become elevated to the level of a theory.”

http://www.bio.miami.edu/dana/dox/scientific_method.html