Texas Tech atmospheric scientist Katharine Hayhoe is an evangelical Christian who travels widely talking to conservative audiences and wrote a book with her husband, a pastor and former climate change denier, explaining climate change to skeptics.

A physicist by training, John Cook is an evangelical Christian who runs the website skepticalscience.com, which seeks to debunk climate change deniers’ arguments. Barry Bickmore is a Mormon, a professor of geochemistry at Brigham Young University and the blogger behind Anti-Climate Change Extremism in Utah, where he recently rebuked Sen. Orrin G. Hatch (R-Utah) for his climate views and posted editorials mentioning his Republican affiliation.

Emanuel waded into the fray early last year. He wrote a letter to the Wall Street Journal criticizing a friend and colleague for dismissing the evidence of climate change and clinging “to the agenda of denial.” Then Emanuel added his name to the Climate Science Rapid Response Team, a website run by scientists to provide accurate information from top researchers in climate-related fields.

“I’ve always rebelled against the thinking that ideology can trump fact,” said Emanuel, 55. “The people who call themselves conservative these days aren’t conservative by my definition. I think they’re quite radical.”