The Republican presidential nominee, Donald Trump, says climate change is a "scam." He plans to roll back Environmental Protection Agency regulations on fossil fuels and pull the US out of the international Paris agreement on emissions reductions. The 2016 Republican party platform mentions climate change only to dismiss it.
So it's become really easy to forget that the Republican Party wasn't always compelled to reject scientific evidence on climate change.
In 2008, the Republican presidential candidate actually campaigned on a promise to fight global climate change. The party platform that year said:
The same human economic activity that has brought freedom and opportunity to billions has also increased the amount of carbon in the atmosphere. While the scope and long-term consequences of this are the subject of ongoing scientific research, common sense dictates that the United States should take measured and reasonable steps today to reduce any impact on the environment. Those steps, if consistent with our global competitiveness will also be good for our national security, our energy independence, and our economy.
In addition to John McCain, Republicans like Mitt Romney, Newt Gingrich, Rudy Giuliani, Mike Huckabee, and even Sarah Palin agreed that taking action to mitigate climate change was a conservative thing to do. When business leaders published a letter in 2009 explicitly calling for climate legislation, guess who signed it.
So what happened? How did it become politically risky for Republicans to talk about the challenges climate change will pose to global health and security? How did they go from listening to experts to accusing them of conspiracies? And how can they now paint themselves (and the whole country) out of this corner?
Watch the video above to see how the climate debate in the US devolved into fully polarized gridlock.