Newt Gingrich.Photo: @mjb1.  Newt Gingrich

Presidential candidate, former speaker of the U.S. House

Before: He cozied up with Nancy Pelosi in 2008 to issue a joint call for climate action in an ad for Al Gore’s group Alliance for Climate Protection.

After: “It’s an act of egotism for humans to think we’re a primary source of climate change,” he told Grist in June 2010. And in April 2011, he said, “I would not adopt massively expensive plans over a theory.”

Read more about Gingrich and climate.