Donald Trump has rescinded a pivotal 2009 scientific determination that concluded greenhouse gases endanger public health — a ruling that has served as the legal foundation for nearly all federal efforts to curb planet-warming emissions.
The so-called “endangerment finding,” introduced during the first year of Barack Obama’s administration, determined that six key greenhouse gases, including carbon dioxide and methane, pose a threat to human health and welfare. The finding became central to regulatory actions under the Clean Air Act, particularly in limiting emissions from vehicles, power plants, oil and gas operations, landfills, and aircraft.
Announcing the move in the Oval Office, Trump described the 2009 ruling as “a disastrous Obama-era policy that severely damaged the American auto industry and massively drove up prices for American consumers.”
“This radical rule became the legal foundation for the Green New Scam, one of the greatest scams in history,” the Republican president said, referencing Democratic climate initiatives.
White House: “Largest Deregulation in American History”
The White House characterized the decision as the “largest deregulation in American history,” arguing it would reduce regulatory burdens and lower consumer costs. Officials claim overturning the finding could save more than $1 trillion in compliance expenses.
Press Secretary Karoline Leavitt said reversing the rule would cut automakers’ costs by approximately $2,400 per vehicle, potentially lowering car prices and reducing energy and transportation expenses nationwide.
Administration officials argue that removing the legal basis for strict emissions standards will strengthen domestic manufacturing and restore competitiveness in the auto industry.
Environmental Groups Prepare Legal Challenge
Environmental advocates and legal experts view the move as the most significant climate rollback yet attempted. Several groups have indicated they will challenge the decision in court, arguing that it undermines established scientific consensus and longstanding Clean Air Act interpretations.
Former EPA and Department of Justice attorney Meghan Greenfield described the endangerment finding as the “lynchpin” of US greenhouse gas regulation.
“It really runs the gamut,” she noted, referring to rules governing vehicles, power plants, oil and gas operations, methane emissions, and aviation — all of which rely on the original finding.
Former President Obama, who rarely comments on sitting administrations, warned that repealing the finding would increase public vulnerability.
“Without it, 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,” he wrote on X.
Economic and Industry Implications
Some environmental analysts dispute the administration’s cost-saving projections. Peter Zalzal of the Environmental Defense Fund argued that weaker efficiency standards could increase long-term fuel costs by an estimated $1.4 trillion and lead to serious health consequences, including tens of thousands of premature deaths and millions of additional asthma cases.
There is also uncertainty within the US auto sector. Michael Gerrard, a climate law expert at Columbia University, noted that while the rollback cements prior relaxations of fuel economy standards, it may create challenges for American automakers competing in markets where stricter emissions rules remain in place.
“It really does put US automakers in a bind,” he said, suggesting global consumers may be less inclined to purchase less fuel-efficient vehicles.
A Defining Climate Policy Moment
The reversal represents one of the most consequential environmental decisions of Trump’s second term. By targeting the foundational scientific ruling behind federal climate regulation, the administration is reshaping the legal landscape of US climate policy — a move that is likely to trigger prolonged legal battles and deepen political divisions over how the country addresses climate change.
