Mitt Romney's shifting views on climate change

The longer he runs for president, the more doubts Republican front-runner Mitt Romney seems to have about the science behind global climate change.

Speaking at a closed-door fundraiser Thursday in Pittsburgh, Romney's position on the causes of global warming continued the rightward shift that has been underway for several months. "My view is that we don't know what's causing climate change on this planet. And the idea of spending trillions and trillions of dollars to try to reduce CO2 emissions is not the right course for us," he told donors at the Consol Energy Center.

As recently as his 2010 book, No Apology, Romney wrote, "I believe that climate change is occurring. ... I also believe that human activity is a contributing factor. I am uncertain how much of the warming, however, is attributable to man and how much is attributable to factors out of our control."

In June of this year, Reuters reported that Romney said that the United States should "reduce our emissions of pollutants and greenhouse gases that may be significant contributors." Then in August, Texas Gov. Rick Perry, who openly questions the science of climate change factors, entered the GOP primary race, and Romney appeared to dial down his own certainty of the science, saying, "I think the earth is getting warmer. ... I think humans contribute to that. I don't know by how much. It could be a little. It could be a lot."

While Romney's expressed skepticism about climate change plays well with conservatives, Democrats are bound to use it against him with the moderate and independent voters who hold sway in a general election. His remarks at the Pittsburgh fundraiser were captured on video, which ended up in the hands of the liberal Center for American Progress. The center distributed the video to news outlets today.

Romney spokesman Ryan Williams said Friday, "Governor Romney has been consistent in his statements on global warming."

At the fundraiser, Romney was asked by a member of the audience to explain his position on man-made global warming and asked further whether he would reject a cap-and-trade bill to limit carbon emissions linked to climate change.

Romney replied, "Man-made global warming and cap and trade and so forth - I actually had in Massachusetts a consortium of states that came together with a cap and trade program. It was called the Regional Greenhouse Gas Initiative. And all the governors, Governor Pataki and so forth, signed it. I refused to sign. I do not believe in a cap and trade program."

By the way, they do not call it America warming, they call it global warming. So the idea of America spending massive amounts, trillions of dollars to somehow stop global warming is not a great idea. It loses jobs for Americans and ultimately it won't be successful, because industries that are energy intensive will just get up and go somewhere else. So it doesn't make any sense at all. My view is that we don't know what's causing climate change on this planet. And the idea of spending trillions and trillions of dollars to try to reduce CO2 emissions is not the right course for us. My view with regards to energy policy is pretty straightforward. I want us to become energy secure and independent of the oil cartels. And that means let's aggressively develop our oil, our gas, our coal, our nuclear power."

Sarah Boxer contributed to this story.