The winds of change are stirring at the Environmental Protection Agency.

Newly confirmed administrator Scott Pruitt expressed skepticism of the scientifically accepted fact that carbon dioxide is a primary contributor to climate change. This view conflicts with the stated position of the agency he leads, which started regulating emissions after a 2007 Supreme Court decision classified the gas as a pollutant. His comments hint at a marked shift in EPA policy, and a possible return of power to the states that had been consolidated at the federal level under the Obama administration.

"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," Mr. Pruitt told CNBC's "Squawk Box."

He admitted to continued need for data collection and analysis, adding, "but we don't know that yet.... We need to continue the debate and continue the review and the analysis."

Researchers largely agree about the degree of impact, as reflected by NASA and the National Oceanic and Atmospheric Administration's January statement declaring 2016 the hottest year on record, for the third year in a row.

“The planet's average surface temperature has risen about 2.0 degrees Fahrenheit (1.1 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere,” the agencies wrote in a press release.

Meanwhile, 2017 got off to a hot start as well, with February temperatures breaking record highs in more than 11,000 locations across the country, compared with about 400 lows. The national monthly average contiguous temperature reached 7 degrees F., above average, but still two-tenths of a degree behind the record-holding 1954, according to NOAA's National Centers for Environmental Information.

“I don’t recall ever seeing a February like this,” Princeton University climate scientist Gabriel Vecchi told CBS. “We expect this to happen with more and more frequency over time.”

The EPA’s own website says that while natural causes such as changes in the brightness of the sun do affect the climate, “Research indicates that natural causes do not explain most observed warming, especially warming since the mid-20th century. Rather, it is extremely likely that human activities have been the dominant cause of that warming.”

How Pruitt will reconcile his views with those of his agency remains to be seen. The Supreme Court ruled in 2007 that greenhouse gases can be regulated under the Clean Air Act, a definition the EPA took advantage of two years later, classifying CO2 and five other gases as pollutants based on the idea that climate change can negatively impact health. This move let the agency set new vehicles emissions standards in 2010 and 2011.

Where Democrats see health and environmental protection, Pruitt, who has sued the EPA more than a dozen times as Oklahoma's attorney general, sees government overreach. The EPA was founded at the behest of former President Richard Nixon under a model of “cooperative federalism,” in which federal research and standards pave the way for states to implement and enforce their own policies, but many Republicans believe that process has broken down.

“The Clean Air Act stipulates that the states are supposed to be first among equals,” William Yeatman, a senior fellow at the conservative Competitive Enterprise Institute previously told The Christian Science Monitor. “Demonstrably, that’s the way it has not worked over the last eight years. What we’ve seen is this shift from cooperative federalism to coercive federalism.”

Many observers now expect Pruitt, who told CNBC Congress should revisit the Supreme Court’s carbon dioxide decision, to respond by devolving some of the federal power consolidated during the Obama administration to the states.

“He is deeply committed to federalism in a proper sense of this word,” David Rivkin, a constitutional lawyer who represented Pruitt and Oklahoma on their lawsuit against the EPA's power sector emissions rule, in a January interview with the Monitor. “It’s something that very much animates his thinking. I think what a lot of people don't understand is a lot of the lawsuits he brought are driven entirely by his constitutional views.”

But Democrats argue that a patchwork network of state-run environmental programs can’t live up to the task of protecting the country as a whole.

"In my state," Sen. Tom Carper (D) of Delaware told the Monitor, "the air pollution includes mercury, ozone and any number of toxic substances that are put up not in Delaware but in other states and it’s simply blown to our part of the country."

Should Pruitt succeed in getting the regulation ball into the states' courts, the country will still be bound by the Paris Agreement, under which the United States is responsible for reducing its greenhouse gas emissions between 26 and 28 percent below 2005 levels in the next eight years.

Pruitt has called the agreement “a bad deal,” arguing that it should have been put to a vote in the Senate. Instead it was the State Department that negotiated the accord, and it's the State Department that would have the power to withdraw, not the EPA.

Secretary of State Rex Tillerson’s position on climate change is vague. He admitted during his confirmation hearing that greenhouse gases are having an effect on the environment, but said that “our ability to predict that effect is very limited.”

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Nevertheless, unlike Pruitt he spoke out strongly in favor of the Paris Agreement. “It’s important that the US maintain its seat at the table,” Tillerson told the Senate Committee on Foreign Relations, Scientific American reports. The threat of global warming is real and “requires a global response.”

“No one country is going to solve this on its own,” he added.