A handful of the world's top public relations companies declared they will not represent clients who say man-made climate change doesn't exist, The Guardian reported.

In what is bound to be a game-changing decision in the global warming debate, ten PR firms said they will not work with anyone who denies climate change or tries to block policies meant to check air pollution by limiting carbon emissions.

"We would not knowingly partner with a client who denies the existence of climate change," the international PR firm Waggener Edstrom told The Guardian.

PR companies Finn Partners, WPP, Text 100, and Weber Shandwick also made the same decision.

"We would not support a campaign that denies the existence and the threat posed by climate change, or efforts to obstruct regulations cutting greenhouse gas emissions and/or renewable energy standards," PR firm Weber Shandwick told the newspaper.

Many PR firms have made a reputation for handling cases dealing with environmental policy. Environmental groups and experts have struggled for years to garner widespread public support for action to protect the environment.

Part of their failings is blamed on PR companies accused of helping the spread of false information- or the disinformation campaign- meant to block solutions to climate change.

"The PR industry is a major component of the influence peddling industry that stretches across Washington and the world, and they are making large sums of money from energy companies and other important players that have businesses connected to fossil fuels and energy policy," Kert Davies, founder of the Climate Investigations Centre which researches disinformation campaigns, told The Guardian.

One American PR company was not so quick to join the trend of refusing clients against climate change. Endelman, the largest independently-owned PR firm in the world, told the newspaper it will accept clients on a case by case basis.

"Expanding the dialogue in a constructive manner and driving productive outcomes to solve energy challenges are the key criteria for evaluating client engagements," the company said.