The head of the Environmental Protection Agency on Tuesday questioned whether global warming is harmful to humans and suggested warm climate could be beneficial.

"We know that humans have most flourished during times of, what? Warming trends. So I think there's assumptions made that because the climate is warming, that that necessarily is a bad thing," Administrator Scott Pruitt told KSNV News 3 Las Vegas, disputing whether climate change is an "existential threat."

"Do we really know what the ideal surface temperature should be in the year 2100 in the year 2018?" he continued. "I mean, that's somewhat fairly arrogant, for us to think that we know exactly what it should be in 2100."

Pruitt has been skeptical previously about whether human activity is the primary cause of global warming. Last summer, he raised the idea of funding a debate over whether humans are the main contributors to rising temperatures.

But he seemed to acknowledge that humans contribute to climate change on Tuesday.

"No one disputes the climate changes, is changing, and we see that is a constant. We obviously contribute to it," Pruitt said. "We live in the climate, right. So our activity contributes to the climate changing, to a certain degree."

Pruitt's comments contradict the general scientific consensus that humans are the main contributors to the planet's rising temperatures due to the greenhouse effect.

"There are very important questions around the climate issue that folks really don't get to," Pruitt said. "And that's one of the reasons 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."

He added that as head of the EPA he has to balance the issue of what the science says with what "authority" the agency has to implement related regulations.