It’s that federal spending thing that people deny.
Check it out:

Shawn Donovan, director of the Office of Management and Budget, said on Friday that if you don’t believe in climate change and support federal spending to fight it, you believe the earth is flat.

“The failure to invest in climate solutions and climate preparedness doesn’t get you membership in a fiscal conservatives caucus,” Donovan said at the Center for American Progress in Washington, D.C. “It makes you a member of the Flat Earth Society.”