WASHINGTON - The new head of the Environmental Protection Agency says he does not believe carbon dioxide is a primary contributor to global warming.

That puts him at odds with the consensus of virtually all mainstream science.

Former Oklahoma Attorney General Scott Pruitt was appointed to run the EPA by President Donald Trump, who has previously described climate change as a Chinese hoax designed to harm the American economy.

In his confirmation hearings, Pruitt broke from the president and his own past statements, saying he does believe climate change to be real.

But appearing on CNBC's "Squawk Box", he denies that carbon dioxide is a major factor.

"Measuring with precision human activity on the climate is something very challenging to do. And there's tremendous disagreement about the degree of impact. So no, I would not agree that it's a primary contributor to the climate change that we see," Pruitt said.

Mainstream climate scientists say man-made carbon dioxide accounts for 33 times more warming than natural causes.

This is backed up by research from NASA and the EPA itself.

In a statement, the agency reiterates that Pruitt believes human activity does contribute to global warming, but to what extent is up for debate.