On Thursday, President Donald Trump declared that the Environmental Protection Agency (EPA) is revoking a critical certification that has been in effect for almost 20 years, aimed at reducing heat-trapping pollution from vehicles, refineries, and factories.

This significant reversal of the so-called endangered finding could drastically alter U.S. policies designed to combat climate change.

The 2009 EPA study indicated that global warming, driven by greenhouse gases like carbon dioxide and methane, threatens the health and welfare of both present and future generations.

“We are officially ending the so-called endangered study, a catastrophic Obama-era policy,” President Trump stated during a press conference. “There was no factual or legal basis for this decision. Fossil fuels, in fact, have saved millions of lives and lifted billions out of poverty globally.”

Prominent environmental organizations are challenging the government’s revocation of the endangered status designation and are gearing up for legal action.

The findings substantiated the EPA’s capabilities in regulating greenhouse gas emissions from vehicles and power plants while mandating companies to report their emissions, advocating for climate change action consistent with the Clean Air Act.

The Supreme Court’s 2007 ruling affirmed the EPA’s authority to regulate greenhouse gases, highlighting the severe and well-recognized harms linked to climate change, and led to the 2009 endangered finding.

According to the White House and EPA, this reversal marks “the largest deregulatory action in U.S. history.”

This initiative is one of the Trump administration’s most significant efforts to unwind climate action, coinciding with the U.S. retreat from the 2015 Paris Agreement and its expected withdrawal from the United Nations Framework Convention on Climate Change.

President Trump has previously labeled climate change a “swindle” and cut nearly $8 billion in funding for renewable energy projects in October, though a court later found some cancelations illegal. Recently, the Department of Energy announced a $175 million investment to extend the lifespan of six coal-fired power plants, highlighting continued support for coal.

According to the European Union’s Copernicus Climate Change Agency, last year was the third warmest on record, and the past 11 years have been the hottest ever documented.

President Trump and EPA Administrator Lee Zeldin also announced the elimination of all greenhouse gas emissions standards for vehicles.

“We are reversing the unreasonable hazard findings and abolishing unnecessary emissions standards imposed on vehicle models and engines from 2012 to 2027 and beyond,” President Trump affirmed.

The EPA intends to continue regulating pollutants from tailpipe emissions that affect air quality, including carbon monoxide, lead, and ozone.

Former President Obama emphasized that failing to maintain these standards could make Americans “less safe, less healthy, and hinder efforts against climate change,” benefitting only the fossil fuel industry.

The U.S. Climate Alliance, headed by California Governor Gavin Newsom and Wisconsin Governor Tony Evers, criticized the repeal for being “illegal, dismissive of fundamental science, and disconnecting from reality.”

Multiple organizations, including the American Lung Association and the American Public Health Association, have pledged to sue in response to this unlawful repeal.

“As an organization dedicated to public health, we reject this unwarranted repeal,” they declared in a statement.

Manish Bapna, president of the Natural Resources Defense Council, remarked that the repeal is “a windfall for the fossil fuel sector” and that they are prepared for a legal fight.

“We will oppose this action because it lacks scientific support, is economically detrimental, and is illegal. We’ll see the government in court,” he stated.

This legal struggle could extend for years, as the government attempts to justify the repeals in the face of robust scientific evidence regarding climate change’s dangers.

Michael Gerrard, founder of Columbia University’s Sabin Center on Climate Change Law, noted that the future of this repeal could hinge on the Supreme Court, which may need to overturn 16 years of established precedent.

“The 2007 ruling was a 5-4 decision; all five justices in the majority are no longer in office. Of the dissenting justices, three are still serving,” Gerrard explained. “Typically, courts require a comprehensive explanation and supporting documentation when an agency makes such significant changes.”

Megan Greenfield, a partner at Jenner & Block who oversaw EPA rulemaking during the Biden administration, stated that the current administration may face challenges in court due to existing legal precedents and compelling scientific evidence highlighting climate change’s effects. She emphasized that the administration must demonstrate adherence to proper procedures when issuing regulations.

“Regulatory processes usually require around three years, but this rule was finalized in about a year,” she mentioned. “Only after rigorous compliance can more complex legal issues be addressed.”

As of 4 p.m. ET Thursday, the EPA had yet to publish the final text of the rule and did not respond to inquiries regarding its expected release.

The agency contended that a draft proposal released in August overstated the risks of heat waves, predicted accelerated global warming, and underestimated the advantages of increased carbon emissions, like enhanced plant growth. Most independent scientific organizations have dismissed these claims.

“EPA’s 2009 Endangered Findings stem from extensive research,” stated the American Geophysical Union on Thursday. “To override such a landmark scientific and legal determination is a denial of conclusive science, an ignorance of current struggles, and a direct threat to our collective future.”

The administration has also signaled plans to revisit other regulations reliant on endangered findings, including methane regulations, a potent greenhouse gas.

Interior Secretary Doug Burgum proclaimed on FOX Business that the findings’ reversal would breathe new life into the coal industry.

“CO₂” [carbon dioxide] “was never a pollutant; this whole situation is an opportunity to rejuvenate clean, beautiful American coal,” he stated.