“I really think that people should be suspicious of authority,” he told an interviewer last year. “The more you’re told that you have to believe something, the more you should question it.”

Mr. Ebell leads the Cooler Heads Coalition, a loose-knit group that says it is “focused on dispelling the myths of global warming by exposing flawed economic, scientific, and risk analysis.” He has been one of the nation’s most visible climate contrarians, known for dispensing memorable sound bites on cable news shows and at events like the annual conferences sponsored by the Heartland Institute, a Chicago-based group that rejects the overwhelming scientific consensus on climate change.

Mr. Ebell has said that “a lot of third-, fourth- and fifth-rate scientists have gotten a long ways” by embracing climate change. He frequently mocks climate leaders like Al Gore, and has called the movement the “forces of darkness” because “they want to turn off the lights all over the world.”

No one, it seems, is immune to his criticism. He called Pope Francis’s encyclical on climate change, issued in mid-2015, “scientifically ill informed, economically illiterate, intellectually incoherent and morally obtuse.”

“It is also theologically suspect, and large parts of it are leftist drivel,” he added.

Mr. Ebell cut his teeth in Washington working for Frontiers of Freedom, a research group founded by former Senator Malcolm Wallop, a Wyoming Republican, to advocate for limited government. He also worked for a Republican congressman from Arizona, John Shadegg, on an effort to revamp the Endangered Species Act to make it more respectful of property rights.