NEW YORK — More than 450 scientists — including members of the Union of Concerned Scientists — are calling on PR and advertising firms to stop working with fossil fuel companies, the latest move in an ongoing campaign by activists to see agencies cut ties with the world’s biggest polluters.

“As scientists who study, and seek to communicate, the realities of the climate emergency on both the planet and people, we are constantly faced with the challenge of overcoming advertising and PR efforts by fossil fuel companies that seek to obfuscate or downplay our data, and the risk of the climate emergency. In fact, these campaigns represent one of the biggest barriers to the government action science shows is necessary to mitigate the ongoing climate emergency, and avert total disaster,” the scientists wrote in a letter being distributed today to PR and advertising firms.

“A scientifically sound approach for PR and advertising agencies considering what clients to continue working with leads to only one conclusion: end all relationships with companies that plan to expand their production of oil and gas. Stop all work that weakens legislative efforts to reduce carbon pollution,” it said.

The letter’s signatories include scientists Jason Box (Geological Survey of Denmark and Greenland), Astrid Caldas (Union of Concerned Scientists), Peter Gleick (Pacific Institute) and Ayana Elizabeth Johnson (Urban Ocean Lab).

“For decades, the fossil fuel industry has misled the public with greenwashing campaigns and sabotaged climate action, even as the climate crisis worsens,” Caldas said. “It’s clear we need to sharply cut carbon pollution as soon as possible—by at least 50% this decade and reaching net-zero preferably well before but no later than 2050—to avoid the most dangerous climate change impacts. But the PR and advertising companies that abet the spread of climate disinformation are standing in the way. We’re calling on them to use their skills and resources to align with the science instead, and promote bold, ambitious, equitable climate action beginning with the Build Back Better Act.”

The effort was coordinated in partnership with the Union of Concerned Scientists and Clean Creatives, an ad and PR industry advocacy organization which, in November, launched a high-profile celebrity and influencer campaign calling on Edelman to drop fossil fuel clients, most notably ExxonMobil.

The action also comes less than two weeks after Edelman unveiled a series of actions it pledged to take in response to those calls, which include walking away from companies that do not meet a series of criteria on climate action. Edelman has identified 20 emissions-intensive clients for follow-up discussions after a 60-day review of its portfolio.

Edelman, however, stopped short of dropping fossil fuel companies across-the-board, saying its work pushing clients toward achieving net zero goals is more productive than walking away.

“Scientists have been sounding the climate alarm for decades, but they’ve been drowned out by billions of dollars of PR and advertising from the fossil fuel industry,” said Jamie Henn, the director of Fossil Free Media, home of the Clean Creatives campaign. “Now, scientists are saying enough is enough. The pollution of our airwaves is inextricably tied to the pollution of our atmosphere. The only way to clean up both is to stop this propaganda at the source: the PR and ad agencies that continue to work on behalf of fossil fuels. It’s time for creatives to come clean.”