Energy Secretary Rick Perry told CNBC on Monday he does not believe carbon dioxide emissions from human activity are the main driver of climate change, joining the EPA administrator in casting doubt on the conclusion of some of the government’s top scientists.

Asked whether CO2 emissions are primarily responsible for climate change, Perry told CNBC’s “Squawk Box”: “No, most likely the primary control knob is the ocean waters and this environment that we live in.”

“The fact is this shouldn’t be a debate about, ‘Is the climate changing, is man having an effect on it?’ Yeah, we are. The question should be just how much, and what are the policy changes that we need to make to effect that?” he said.

In March, Environmental Protection Agency Administrator Scott Pruitttold “Squawk Box” he does not believe carbon dioxide is a primary contributor to global warming.

Those statements contradict the public stance of the Environmental Protection Agency, at least until recently.