As head of the Environmental Protection Agency, Scott Pruitt has repeatedly questioned the scientific consensus that rising levels of carbon dioxide from human-fueled activity are warming the planet.

He’s now taking a different tack: Even if climate change is occurring, as the vast majority of scientists say it is, a warmer atmosphere might not be so awful for humans, according to Pruitt.

“We know humans have most flourished during times of what, warming trends,” Pruitt said Tuesday during an interview on KSNV, an NBC affiliate in Las Vegas. “So I think there’s assumptions made that because the climate is warming, that that necessarily is a bad thing. Do we really know what the ideal surface temperature should be in the year 2100, in the year 2018? That’s fairly arrogant for us to think that we know exactly what it should be in 2100.”

Pruitt continued: “There are very important questions around the climate issue that folks really don’t get to. And that’s one of the reasons why I’ve talked about having an honest, open, transparent debate about what do we know, what don’t we know, so the American people can be informed and they can make decisions on their own with respect to these issues.”

Not long after taking office last February, Pruitt seemed to reject the established science of climate change in a nationally televised interview — a move that outraged scientists, environmental advocates and his predecessors at the EPA.

“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,” Pruitt said on CNBC’s “Squawk Box” in March. “We need to continue the debate and continue the review and the analysis.”

At the time, his comments represented a startling statement for an official so high in the U.S. government. They put him at odds not only with leaders around the world, but also with the EPA’s own official scientific findings. President Trump has famously called the idea of human-driven climate change a hoax. Other Cabinet members, including Energy Secretary Rick Perry, have questioned the scientific basis for combating global warming.

He now seems to have embraced an argument long held by other climate-science skeptics: that a warmer atmosphere may in fact be better for humanity.

“The climate is changing. That’s not the debate. The debate is how do we know what the ideal surface temperature is in 2100? . . . I think the American people deserve an open honest transparent discussion about those things,” Pruitt said in an interview with Reuters last month. He added, “This agency for the last several years has been more focused on what might be happening in 2100, as opposed to what is happening today.”

And during a hearing on Capitol Hill later in January, Pruitt said, “There are questions that we know the answer to; there are questions we don’t know the answer to. For example, what is the ideal surface temperature in the year 2100? [It’s] something that many folks have different perspective on.”

The theme echoes one advanced by Kathleen Hartnett White, Trump’s pick to lead the White House’s Council on Environmental Quality, who once touted carbon dioxide as “the gas of life on this planet.” The White House withdrew her nomination on Saturday after even Republican senators raised questions about her expertise.

Pruitt also has been the main administration official pushing for a governmentwide effort to debate the science of climate change. He first raised the possibility of such a “red team-blue team” exercise in an interview in June.

“What the American people deserve, I think, is a true, legitimate, peer-reviewed, objective, transparent discussion about CO2,” Pruitt told Breitbart’s Joel Pollack.

During his most recent congressional testimony, Pruitt came back to the same idea.

“That red team-blue team exercise is an exercise to provide an opportunity to the American people to consume information from scientists that have different perspectives on key issues,” Pruitt told Sen. Jeff Merkley (D-Ore.), “and frankly could be used to build consensus in this body.”

It’s unclear why Pruitt thinks warmer temperatures may be better for people. The last 11,700 years, before the end of the last ice age, constitute a relatively stable period of climate for human civilization. Many of the cities built during those millennia dot the coasts of Earth’s continents and were situated there assuming relatively stable sea levels.

And while rising temperatures may indeed boost agricultural yield in some regions, they are projected to cause debilitating drought elsewhere.

Although the not-so-bad argument may be new for Pruitt, some conservative and fossil-fuel industry groups have used it for almost three decades. In 1991, for example, the Western Fuels Association funded “The Greening of Planet Earth,” a 30-minute video arguing that more CO2 in the air helps farmers.

In 2001, the Cato Institute echoed the video’s message. “The video was right,” Patrick J. Michaels, a senior fellow at the libertarian think tank, wrote. “The greens were wrong.”