Not too long ago, belief in climate science wasn’t a political issue. Honestly! As recently as the 2008 U.S. presidential election, both the Democratic and Republican candidates professed belief in the threat of global warming, and each advanced policies designed to curb U.S. carbon emissions. Senator John McCain had even co-sponsored one of the first congressional bills to create a carbon cap-and-trade system. And it wasn’t just McCain; Mitt Romney, runner-up for the GOP nomination last time around, supported a regional cap-and-trade program while he was governor of Massachusetts. There was still a wide gap between Democrats and Republicans on the severity of the climate-change threat and on how ambitious carbon-cutting policy should be, but at least there was a general agreement that global warming was a real thing.

Not anymore. With the exception of Jon Huntsman — who barely registers in polls — you can’t find a Republican presidential candidate who unequivocally believes in climate science, let alone one who wants to do anything about it. Instead of McCain — who has walked back his own climate-policy realism since the 2008 elections — we have Texas Governor Rick Perry, who told voters in New Hampshire over the weekend that “I don’t believe manmade global warming is settled in science enough.” And many Republicans agree with him: the percentage of self-identified Republicans or conservatives answering yes to the question of whether the effects of global warming were already being felt fell to 30% or less in 2010, down from 50% in 2007-08. Meanwhile, liberals and Democrats remained around 70% or more.(See pictures of the effects of global warming.)

That’s deeply troubling. It’s one thing when people disagree on the effectiveness of different approaches to fix a problem; it’s worse when they refuse even to believe that a problem exists — despite an overwhelming scientific consensus that says it does. One of America’s major political parties has, in effect, adopted denial as policy. How did we get here?

via Why Climate-Change Denial Is So Powerful – TIME.