The largest, most-consistent money fueling the climate denial movement are a number of well-funded conservative foundations built with so-called "dark money," or concealed donations, according to an analysis released Friday afternoon.

The study, by Drexel University environmental sociologist Robert Brulle, is the first academic effort to probe the organizational underpinnings and funding behind the climate denial movement.

It found that the amount of money flowing through third-party, pass-through foundations like DonorsTrust and Donors Capital, whose funding cannot be traced, has risen dramatically over the past five years.

In all, 140 foundations funneled $558 million to almost 100 climate denial organizations from 2003 to 2010.

Meanwhile the traceable cash flow from more traditional sources, such as Koch Industries and ExxonMobil, has disappeared.

The study was published Friday in the journal Climatic Change.

"The climate change countermovement has had a real political and ecological impact on the failure of the world to act on global warming," Brulle said in a statement. "Like a play on Broadway, the countermovement has stars in the spotlight – often prominent contrarian scientists or conservative politicians – but behind the stars is an organizational structure of directors, script writers and producers."

"If you want to understand what's driving this movement, you have to look at what's going on behind the scenes."

Consistent funders

To uncover that, Brulle developed a list of 118 influential climate denial organizations in the United States. He then coded data on philanthropic funding for each organization, combining information from the Foundation Center, a database of global philanthropy, with financial data submitted by organizations to the Internal Revenue Service.

According to Brulle, the largest and most consistent funders where a number of conservative foundations promoting "ultra-free-market ideas" in many realms, among them the Searle Freedom Trust, the John Williams Pope Foundation, the Howard Charitable Foundation and the Sarah Scaife Foundation.

Another key finding: From 2003 to 2007, Koch Affiliated Foundations and the ExxonMobil Foundation were "heavily involved" in funding climate change denial efforts. But Exxon hasn't made a publically traceable contribution since 2008, and Koch's efforts dramatically declined, Brulle said.

Coinciding with a decline in traceable funding, Brulle found a dramatic rise in the cash flowing to denial organizations from DonorsTrust, a donor-directed foundation whose funders cannot be traced. This one foundation, the assessment found, now accounts for 25 percent of all traceable foundation funding used by organizations promoting the systematic denial of climate change.

Jeffrey Zysik, chief financial officer for DonorsTrust, said in an email that neither DonorsTrust nor Donors Capital Fund "take positions with respect to any issue advocated by its grantees."

"As with all donor-advised fund programs, grant recommendations are received from account holders," he said. "DonorsTrust and Donors Capital Fund ensure that recommended grantees are IRS-approved public charities and also require that the grantee charities do not rely on significant amounts of revenue from government sources. DonorsTrust and Donors Capital Fund do not otherwise drive the selection of grantees, nor conduct in-depth analyses of projects or grantees unless an account holder specifically requests that service."

Matter of democracy

In the end, Brulle concluded public records identify only a fraction of the hundreds of millions of dollars supporting climate denial efforts. Some 75 percent of the income of those organizations, he said, comes via unidentifiable sources.

And for Brulle, that's a matter of democracy. "Without a free flow of accurate information, democratic politics and government accountability become impossible," he said. "Money amplifies certain voices above others and, in effect, gives them a megaphone in the public square."

Powerful funders, he added, are supporting the campaign to deny scientific findings about global warming and raise doubts about the "roots and remedies" of a threat on which the science is clear.

"At the very least, American voters deserve to know who is behind these efforts."

Editor's Note (12/24/13): This story has been updated to reflect a late comment from DonorsTrust.

This article originally appeared on The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.