evidence: The head of the Environmental Protection Agency administrator said Thursday he does not believe that carbon dioxide is a primary contributor to global warming – a stance at odds with leading climate scientists. Scott Pruitt made the comment to CNBC’s Joe Kernen when he was asked if he believes that carbon dioxide "is the primary control knob for climate." "I think that 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 global warming that we see," he said on CNBC’s "Squawk Box."