He isn't the only Republican presidential candidate to express skepticism toward the science of climate change. Former Sen. Rick Santorum (Pa.) has said "there's no such thing as global warming," and Rep. Michele Bachmann (Minn.) said in 2009 that human activity barely affects the amount of CO2 in the atmosphere.
Former House Speaker Newt Gingrich (R-Ga.) has caught flack for appearing in a commercial with then-House Speaker Nancy Pelosi (D-Calif.) talking about the need to address climate change. But he's also labeled President Obama's energy policies as "anti-American," and talked about the need for more oil-and-gas exploration.
Former Massachusetts Gov. Mitt Romney (R) and former Ambassador to China Jon Huntsman (R) have been two of the few Republicans to openly embrace the science behind climate change.
"I believe the world is getting warmer, and I believe that humans have contributed to that," Romney said earlier this month in New Hampshire. "It's important for us to reduce our emissions of pollutants and greenhouse gases that may be significant contributors."
"This is an issue that ought to be answered by the scientific community; I’m not a meteorologist. All I know is 90 percent of the scientists say climate change is occurring," Huntsman told Time magazine last month. Like Pawlenty, Huntsman has rejected his past support for a cap-and-trade regime.
"I denounced it for a number of reasons, one of which is the science is bad, and it's in great dispute," Pawlenty explained Tuesday. "There is climate change — there's always been climate change — but until recently, people were worried as much about global cooling."