The anti-climate effort has been largely underwritten by conservative billionaires, often working through secretive funding networks. They have displaced corporations as the prime supporters of 91 think tanks, advocacy groups and industry associations which have worked to block action on climate change. Such financial support has hardened conservative opposition to climate policy, ultimately dooming any chances of action from Congress to cut greenhouse gas emissions that are warming the planet, the study found.

“I call it the climate-change counter movement,” said the author of the study, Drexel University sociologist Robert Brulle. “It is not just a couple of rogue individuals doing this. This is a large-scale political effort.”

Brulle's study, published on Friday in the journal Climatic Change, offers the most definitive exposure to date of the political and financial forces blocking American action on climate change. Still, there are big gaps.