U.S. President Donald Trump framed his sweeping rollback of federal climate change policy on Thursday as a political win over the Democratic Party's 'radical' environmental agenda, reprising a message Republicans have used in past elections and could turn to once again ahead of November's crucial midterms.

His announcement at the White House was one of the most significant moves of his second term in office. The president said he was revoking an Obama-era 'endangerment finding' from 2009 which held that pollution harms public health and the environment.

For almost 17 years, the U.S. has used that scientific finding as the legal basis to establish policies to reduce emissions from cars, power plants and other sources of planet-warming gases.

'This radical rule became the legal foundation for the Green New Scam,' Trump said, using a term popular with Republicans for describing Democratic environmental and climate policies.

The move marks the culmination of a decade-long push by Trump to tear up policies that Democrats and many climate experts say are needed to rein in emissions. And it is one of the most far-reaching reversals of American climate policy yet.

Trump, who has called climate change a 'hoax' and a 'con job,' dismissed the science underpinning the Obama-era rule in remarks that at times took on the air of a victory lap over his Democratic opponents.

It was yet another sign that, for the president, this issue is as much a political one as it is scientific.

He focused on the economic impacts of reversing the endangerment finding, arguing that boosting fossil fuels instead of clean energy would lead to lower energy costs for American consumers.

Trump also singled out the U.S. auto industry as a major beneficiary of the change. He announced that ending the endangerment finding would eliminate an electric vehicle 'mandate' put in place by his predecessor, former President Joe Biden.

The rollback sparked fury among Democrats and environmental groups who said it would wreck the U.S.'s ability to combat climate change. 'We'll be less safe, less healthy, and less able to fight climate change - all so the fossil fuel industry can make even more money,' former President Barack Obama wrote on social media.

Whether the strategy of climate rollbacks can help Republicans pick up votes in the November midterm elections remains to be seen.

In the U.S., 63% of Americans say they are worried about global warming, a potential warning sign for Republicans who embrace Trump's climate record in November.

At the White House, Trump dismissed questions about whether he was concerned his decision would be unpopular with the public, declaring that the era of stringent climate regulations was 'dead, gone, over.'