Former secretary of state John F. Kerry responded in disbelief when a Republican congressman challenged his credentials on climate change, prompting the veteran politician to ask, “This is really happening here?”

Kerry, who helped broker the 2015 Paris climate accord that President Trump pulled out of, returned to Capitol Hill on Tuesday to serve as a witness for a House Oversight Committee hearing on the need for leadership to combat climate change.

Rep. Thomas Massie (R-Ky.), who has two engineering degrees from the Massachusetts Institute of Technology, began his line of questioning attempting to undermine Kerry’s authority on the issue by asking him about his “science degree” from Yale.

Kerry explained it was actually a bachelor of arts in political science.

“How do you get a bachelor of arts in a science?” Massie asked.

“Well, it’s liberal arts education . . .” Kerry replied.

“So, it’s not really science,” Massie said. “I think it’s somewhat appropriate that someone with a pseudoscience degree is here pushing pseudoscience in front of our committee today.”

“Are you serious?” Kerry said. “Is this really serious? This is really happening here?”

It went on like this for several more minutes, with Massie continuing to conflate natural sciences with social sciences.

Kerry, who served in the Senate for 28 years and was the Democrats’ presidential nominee in 2004, sat through four hours of Republicans trying to poke holes in scientific evidence that climate change is real.

Massie, during his bizarre back and forth with Kerry, asked why carbon dioxide was higher on Earth millions of years ago than it is today, to which Kerry responded, “But there weren’t human beings; that was a different world, folks.”

“Did geology stop when we got on the planet?” Massie asked.

An exasperated Kerry replied, “This is just not a serious conversation.”

Other Republicans used the platform to attack the Green New Deal, a sweeping set of policy goals championed by the left to deal with climate change and economic inequality.

When Kerry was asked how the country would pay for such a plan, most commonly associated with Rep. Alexandria Ocasio-Cortez (D-N.Y.), Kerry took a shot.

“Congresswoman Ocasio-Cortez has in fact offered more leadership in one day or one week than President Trump has in his lifetime on this subject,” Kerry said. “And my question is, where is your proposal? Did you have any hearings on it in the last few years? Mostly on Benghazi, if I recall.”