Bill Nye the Science Guy loves to go around promoting climate change but seemingly can’t answer basic questions about the theory. When hard-pressed, the result is highly entertaining.

Appearing on Fox News’s Tucker Carlson Tonight on Feb. 27, former stand-up comedian Bill Nye repeatedly failed to answer a specific climate change question from host Tucker Carlson.

Carlson conceded that “most people are open to the idea that the climate is changing” but asked Nye “to what degree is human activity causing it?”

Nye chose to ignore the question and smugly stated that “it’s a settled question. Human activity is causing climate change.”

Carlson pressed him and again asked “to what degree?”

Again, Nye could not give a specific answer to what Carlson asked for and only managed to answer “to a degree that it’s a very serious problem in the next few decades.”

Carlson tried six different times to get Nye to be more specific about the relative impact of human activity on the climate. Seemingly frustrated, Nye claimed that humans are “100 percent” responsible for the change in climate that we may be witnessing.

To Carlson’s last attempt at the question, Nye asserted that “the climate would be like it was in 1750” if not for human actions but offered no scientific evidence to back up his claim. He didn’t offer specifics on how he determined that exact date.

Earlier that day, Nye sat down with Vermont Sen. Bernie Sanders for a “conversation about climate change” on Facebook Live. The former Democratic presidential candidate mentioned that he has colleagues who believe that the earth may be getting warmer but are skeptical of human’s exact involvement. He asked Nye to tell him “why they are wrong.”

Just like with Carlson, Nye simply stated “Well, the science is settled everybody, sorry.” Feeling satisfied with this answer, he moved on to bashing Fox News for “crossing the line” by questioning climate change.

Later in the interview, Sanders asked Nye the same question but again received the same rhetoric that Carlson got but Sanders did not press him on the issue. Nye just stated that “there’s overwhelming proof. Proof isn’t even the word. It’s overwhelming evidence.”

Sanders didn’t press Nye for his idea of locking up climate critics. Carlson had questioned Nye for, in April of 2016, actually suggesting that climate critics could be prosecuted for their beliefs. Nye was disinterested in elaborating on his comments with Carlson.

After Nye refused to give specific and substantial answers to his questions, Carlson argued that Nye was just playing politics. “You’re not a scientist. You’re a popularizer” Carlson said “So much of this you don’t know. You pretend that you know, but you don’t know, and you bully people who ask you questions.”