“I DON’T want to be called a denier,” CNBC anchor Joe Kernen said to Environmental Protection Agency Administrator Scott Pruitt on Thursday morning. “I know you don’t want to be called that, either.”

But what else can one call Mr. Pruitt, after he said this to Mr. Kernan: “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. But we don’t know that yet. . . . We need to continue the debate and continue the review and the analysis.”

That is not “skepticism,” a term that implies reasonable doubt in the face of inadequate information. That is denial of a scientific consensus built on ample evidence that gets stronger every year, and it is denial of Mr. Pruitt’s essential responsibilities as the nation’s chief environmental watchdog.

If Mr. Pruitt had merely said that it is hard to establish humanity’s effects on the climate with precision, no one could accuse him of being wrong. Scientists cannot say exactly how much warming will occur after a given amount of carbon dioxide is pumped into the atmosphere — and probably will not be able to until after the warming has occurred. But that is not evidence of no or small effect. Scientists have calculated a range of possible values for the planet’s “sensitivity” to carbon dioxide released by human activity — and it is not a comfortable one. The numbers suggest that, even if experts are far too pessimistic in their estimates, the risks of continuing to rapidly change the atmosphere’s chemistry are worryingly high and demand that every country on Earth act before doing so becomes much more expensive or impossible.

Yet Mr. Pruitt did not stick to mere misdirection about climate sensitivity. He argued, wrongly, that there is insufficient evidence to conclude that carbon dioxide is even “a primary contributor” to the climate change scientists have already measured — even though they have painstakingly ruled out alternative culprits.

In fact, the notion that greenhouse-gas emissions play a leading role in global warming is not questionable. There is still plenty of room for more research about the future manner and severity of the impact but not for denial that there is a significant impact that humans should attempt to limit.

Accepting the expert consensus is a matter of reason vs. unreason. On the side of reason are scientists armed with decades of data and the insights of basic physics, which counsel that adding heat-trapping gases to the atmosphere will trap more heat. Human fingerprints are increasingly visible in the data. Here, per CNBC’s own account of the Pruitt interview, is the joint conclusion of NASA and the National Oceanic and Atmospheric Administration: “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.”

It is little wonder the Trump administration is reportedly preparing to sharply cut NOAA’s budget. Ignoring data may seem easier if you collect less of it.