The debate over climate science has taken a nasty turn.

Vice President Biden painted skeptics of climate change as stupid in a recent interview.

ADVERTISEMENT

“I think it’s close to mindless,” he said of skeptics on the HBO program “Vice.” “I think it’s like, you know, almost like denying gravity now.”

Sen. Jeff Sessions Jefferson (Jeff) Beauregard SessionsTrump's policies on refugees are as simple as ABCs Ocasio-Cortez, Velázquez call for convention to decide Puerto Rico status White House officials voted by show of hands on 2018 family separations: report MORE (R-Ala.) at a March meeting was surprised to see that EPA Administrator Gina McCarthy did not know the details of previous climate change models.

“This is a stunning development, that the head of the Environmental Protection Agency, who should know more than anybody else in the world, who’s proposing hundreds of billions of dollars in costs to prevent this climate and temperature increases, doesn’t know whether their projections have been right or wrong,” Sessions said.

Sen. Jim Inhofe James (Jim) Mountain InhofeChamber of Commerce endorses McSally for reelection Overnight Defense: Top admiral says 'no condition' where US should conduct nuclear test 'at this time' | Intelligence chief says Congress will get some in-person election security briefings Top admiral: 'No condition' where US should conduct nuclear test 'at this time' MORE (R-Okla.), probably the most famous climate skeptic in Congress, brought a snowball to the Senate floor recently. While he didn’t throw it at any of his Democratic antagonists, he used the prop to suggest their demands were misplaced.

“In case we have forgotten, because we keep hearing that 2014 has been the warmest year on record, I ask the chair, do you know what this is,” Inhofe said to Sen. Bill Cassidy (R-La.), who was presiding over the Senate’s debate, as he removed the snowball from a plastic bag. “It’s a snowball. And it’s just from outside here. So it’s very, very cold out. Very unseasonable.”

The fight over climate change has always featured some sharp arrows in Washington, but the debate has taken on a nastier, sometimes personal tone in 2015.

Observers on both sides of the debate agree the civility of arguments have dropped, although each side points to the other as the guilty party, and both warn of drawing a false equivalency.

“I believe that the global warming promoters are the ones on the offensive on this,” said Marc Morano, who publishes a climate skeptic blog. “The skeptics are clearly reacting right now.”

Morano said the increase in nasty rhetoric may be related to pressure building from the Obama administration’s drive to finalize regulations on power plants, which has angered Republicans and industry groups.

The push for a new United Nations climate pact also has people on edge.

“The global warming promoters are so close to what they consider final victory that they’re trying to clear out any remaining roadblocks,” Morano said.

Riley Dunlap, a sociology professor at the University of Oklahoma, said the nasty rhetoric comes in waves and can frequently be tied to major policy decisions, like the EPA rules or the Keystone XL pipeline.

“The opposition to acting on climate change is very upset,” he said. “They don’t want to see any of these things take place ... so they ratchet up the attacks.”