A pair of Brown University researchers on Tuesday exposed how public relations firms hired by the fossil fuel industry have significantly contributed to misinformation about the worsening climate emergency and impeded action to address it over the past few decades.

The new peer-reviewed paper, published in the journal Climatic Change, comes as Big Oil along with the advertising and PR firms they employ face mounting scrutiny within and beyond Congress—including at a historic U.S. House of Representatives hearing featuring fossil fuel CEOs last month.

Robert J. Brulle and Carter Werthman of the Institute at Brown for Environment and Society wrote that “as major players in the climate political arena,” PR firms such as Cerrell, Edelman, Glover Park, and Ogilvy “have shifted public discourse and the prospects for climate action.”

“The fossil fuel industry’s obstruction of climate action goes beyond misinformation and climate denial,” Brulle told DeSmog. “A major part of the effort to obstruct climate action involves enhancing the positive public reputation for the fossil fuel companies and emphasizing the benefits of continued fossil fuel use.”

“From the severity of climate impacts to policies to address the problem,” he said, “PR firms are a big part of the corporate propaganda machinery that guides the way Americans think about the issue.”

The researchers examined “the extent and nature of involvement” of more than 600 PR firms in climate-related political action by organizations in five sectors: coal, steel, and rail; oil and gas; utilities; renewable energy; and the environmental movement from 1988 to 2020.

“Within each sector, engagement of PR firms is concentrated in a few firms, and the major oil companies and electrical-supply manufactures are the heaviest employers of such firms,” the paper says, noting that the environmental movement engaged the fewest PR firms in the studied period.

“PR firms generally specialize in representing specific sectors, and a few larger PR firms are widely engaged in climate and energy political activity,” the paper continues. “PR firms developed campaigns that frequently relied on third-party groups to engage with the public, criticize opponents, and serve as the face of an advertising campaign.”

“The impact of these campaigns is hard to ascertain. However, these efforts have instantiated cultural concepts such as ‘coal country’ or ‘carbon footprint’ into the taken-for-granted discourse on climate change,” the study adds. Other terms that “originated with” and were “promulgated by” PR firms include “clean coal” and “renewable natural gas.”

Part of what makes this analysis notable is that—despite recent initiatives such as the Clean Creatives campaign—the public relations industry has faced limited scrutiny for its contributions to climate misinformation compared with major polluters and right-wing think tanks.

Brulle told The Washington Post‘s climate-focused newsletter that right-wing think tanks’ opposition to climate action has received far more attention from reporters and lawmakers.

“Everybody knows about the Heartland Institute and the Competitive Enterprise Institute and the Koch brothers. That’s not really news anymore,” Brulle said. “But the other 95% of these companies’ efforts to greenwash their reputations and shift public opinion are being ignored.”

That’s by design. The study points out that “the work of PR firms requires that they ‘remain invisible.’ Accordingly, PR firms and the organizations that engage their services have endeavored to maintain a low profile regarding their role in climate communications efforts.”

Duncan Meisel, director of Clean Creatives, which pressures ad and public relations agencies to drop fossil fuel clients, welcomed the researchers’ efforts to highlight the ties between fossil fuel companies and PR firms.

“Agencies like Edelman, Ogilvy, and WeberShandwick named in this report need to recognize that work for fossil fuel companies is doing significant damage to their reputation and legacy,” Meisel said. “The hard truth is that advertising and public relations agencies are essential to the fossil fuel industry’s propaganda machine, and work for fossil clients has stopped the world from adequately responding to the climate emergency.”

“The best time to stop working for fossil fuel clients was 20 years ago, when we had much more time to stop the climate emergency,” he added. “The second best time is now.”