by Sarah Childress

Watch Climate of Doubt , FRONTLINE’s exploration of the massive shift in public opinion on climate change.

Last week, the U.N.’s Intergovernmental Panel on Climate Change went further than it ever has in blaming humans for the role in climate change in its fifth report, warning that the warming is happening faster, and will only get worse.

“Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions,” said Thomas Stocker, a Working Group co-chair. “As a result of our past, present and expected future emissions of [carbon dioxide], we are committed to climate change, and effects will persist for many centuries even if emissions of CO2 stop.”

But has the new report changed the mind of any of the leading climate change skeptics? FRONTLINE asked several for their thoughts. Here’s what two of them told us:

“The global warming establishment is in denial,” said Myron Ebell, director of Freedom Action and the Center for Energy and Environment at the Competitive Enterprise Institute. “The IPCC summary is merely further evidence of this denial of reality. They are living in cloud-cuckoo land or, perhaps more accurately (to switch to a more modern satirist), they are remarkably similar to the projectors in Gulliver’s third voyage.”

He added: “Nothing the IPCC can claim at this point can change the debate, which is over: global warming may become a problem at some point in the next fifty or a hundred years (although the chances are slim), but global warming is not a crisis.”

Christoper Monckton at the Science and Public Policy Institute slammed the IPCC, saying “Set against real-world observations and problems, the IPCC process has become a costly, self-indulgent, self-centered, self-serving, selfish organized-crime racket.”

He added: “However many lies the IPCC and the mad governments who back it tell, the truth remains unaltered and unalterable. Man’s influence on the climate is puny and will remain puny. … The science is in; the truth is out; Al Gore is through; Green stocks are down; the game is up; the panic is off; and the scare is over.”

In Climate of Doubt, FRONTLINE explored how a small cadre of skeptics, including Ebell and Monckton, began working to challenge the science behind climate change. The film reveals how climate skeptics mobilized, built their argument, and undermined public acceptance of a global scientific consensus.

It started in 1998, when the then-chief executive of ExxonMobil, Lee Raymond, decided to take on not only the business, but the science on climate change. Exxon began funding groups to explore his theory, including the Global Climate Science Team, which drew up a national plan to challenge global warming science.

“Victory will be achieved when … average citizens ‘understand’ (recognize) uncertainties in climate science; recognition of uncertainties becomes part of the “conventional wisdom,” the team wrote.

They’ve had some success. Most Americans — more than six in 10 — do not think global warming is an imminent threat, according to a poll conducted earlier this year.

In the film, FRONTLINE correspondent John Hockenberry asks Ebell about the potential consequences of their work.

JOHN HOCKENBERRY: What if you’re wrong? MYRON EBELL: What if anybody is wrong in this debate? JOHN HOCKENBERRY: What if you’re wrong? MYRON EBELL: Then I’ll have to say I’m sorry, and I wish we could speed up our efforts to reverse the policies that we have supported here at CEI.

Watch the full film online right here.