For anyone watching the three presidential debates between Barack Obama and Mitt Romney, two words were surprisingly absent: “climate change.” It’s a strange omission given that 73 percent of Americans shared in a recent poll that dealing with environmental concerns, particularly global warming, was “extremely important” or “very important” to them. Not to mention that just four years ago, in the 2008 election, almost every candidate spoke to the dangers of global warming.

In a Frontline special called “Climate of Doubt,” journalist John Hockenberry (who gave the recent TEDTalk “We are all designers” and interviewed sculptor Tom Shannon for “The painter and the pendulum”) looks at the rise of the climate change skeptics movement, which promotes the idea that manmade climate change is a hoax. Hockenberry interviews several leaders of the movement, including Myron Ebell, Tim Phillips and S. Fred Singer, and explores how the movement has managed to virtually erase the words “climate change” from the political dialogue.

Hockenberry spent the past year doing research for this documentary, and it is both fascinating and chilling. The full report can be seen on Frontline’s website. And tomorrow, Oct. 25 at 2pm (EST), Hockenberry will take part in a live online conversation about it, along with Catherine Upin (who produced the report) and Elizabeth Kolbert (a New Yorker writer who focuses on climate change). They are welcoming any and every question.