"Climate change is a major political topic again," ever since President Obama made climate action a priority for this second term, said Taylor. "People are looking for a more centralist view. We're trying to give it to them."
Environmental activists and several scientists said they're not as worried as they might have been just a few years ago.
Cindy Baxter, a longtime climate campaigner, said she thinks climate skeptics "are getting more shrill, but getting less notice," because Americans are more convinced that global warming is real.
"Hurricane Sandy. Droughts. Flooding. Wildfires. People are feeling the effects of climate change. That makes it harder to deny," said Baxter, who is also a co-author of Greenpeace's new report Dealing in Doubt, which chronicles the history of climate skeptic campaigns. Polls say a larger majority of Americans from both parties see recent waves of deadly weather as a sign of climate change.
But Michaels of the Cato Institute said he isn't convinced his messages are falling on deaf ears, especially among IPCC scientists.
"Do I think the IPCC is very sensitive to these critiques?" he said. "Do I think they keep an eye on what me and my apparently few friends are saying? You bet I do."
Correction: An earlier version of this story said Fred Singer is the director of the Heartland Institute's Science and Environmental Policy Project. Singer is founder and director of the Science & Environmental Policy Project and an expert for Heartland.