Just a few years ago, climate change was widely considered an "inconvenient truth" — something that would likely be expensive and difficult to fix, but an issue that nearly all politicians felt compelled to reckon with. In the 2008 election, Republicans and Democrats alike talked about global warming as one of the most pressing problems our nation faced. But in 2012, climate change has all but evaporated as a political issue. The new Frontline documentary, Climate of Doubt, investigates the organizations that challenged the science, and all but took climate change off the table of political discourse.

Though 98 percent of climate scientists agree that climate change is real, and mostly human-caused, groups like the Heartland Institute and the Americans for Prosperity have not only called these claims into doubt, but continually framed politicians and scientists who believe in climate change as alarmists or conspirators who manipulate data. They say the science "isn't settled," and that the consensus on global warming is not a scientific consensus, but a political one. 

By challenging the consensus, these groups have made climate change seem like one of many theories. Politicians like Mitt Romney and Newt Gingrinch, who just a few years ago reached across the aisle to join Democrats in saying that climate change was a serious issue that needed attention, have now taken to saying that the science on climate change is inconclusive. Even President Obama has been quiet on the issue. The skeptics are more than happy to take credit for this change — they see it as American freedom and democracy triumphing over a liberal conspiracy.

Coral Davenport, energy and environment correspondent for the National Journal, and Bill McKibben, environmentalist and author, discuss the campaign that has cast a shadow of doubt across what was considered the truth just five years ago, and the potentially devastating consequences if inaction persists.