Trump’s bid to scrap EPA climate finding may hit CA car emissions, experts warn
AI-generated summary reviewed by our newsroom.
- Trump's EPA proposal targets 2009 climate finding that underpins emissions rules.
- Experts warn repeal could disrupt California's authority over vehicle emissions.
- California officials and 23 attorneys general argue rollback defies climate science.
California officials this week lined up in opposition to the Trump administration’s proposal to rescind the 2009 Endangerment Finding, led by Gov. Gavin Newsom, who called the plan a “moral abdication” in a letter to EPA Administrator Lee Zeldin while accusing the agency of betraying its mission to protect Americans.
“By siding with polluters over science, EPA is telling wildfire victims to ignore the flames, flood victims to ignore the rising water, and parents of asthmatic children to ignore the dirty air that chokes their respiratory systems and takes their breath away,” Newsom wrote on Monday as the public comment period ended.
In an email to The Sacramento Bee, the EPA said the agency “welcomes all public comments on the proposal through September 22, 2025,” and that it “looks forward to reviewing a diverse array of perspectives on this issue.”
The Trump administration’s latest attempt to roll back environmental protections targets what is widely considered the legal foundation for regulating carbon dioxide, methane and other greenhouse gases. Experts warn that undoing it could weaken national climate policy, with ripple effects felt in California.
The 2009 Endangerment Finding, issued by the U.S. Environmental Protection Agency under the Obama administration, determined that six greenhouse gases such as carbon dioxide and methane “endanger both the public health and the public welfare of current and future generations” under the Clean Air Act.
In July, EPA Administrator Lee Zeldin called the Endangerment Finding and the emissions standards that followed “the real threat to Americans’ livelihoods,” blaming them on costly federal regulations.
“In our work so far, many stakeholders have told me that the Obama and Biden EPAs twisted the law, ignored precedent and warped science to achieve their preferred ends and stick American families with hundreds of billions of dollars in hidden taxes every single year,” Zeldin said.
“If finalized, rescinding the Endangerment Finding and resulting regulations would end $1 trillion or more in hidden taxes on American businesses and families.”
The goal, according to the EPA, is “reinstating consumer choice and giving Americans the ability to purchase a safe and affordable car for their family,” while lowering the cost of living on goods delivered by trucks.
California’s stricter auto emissions
For California, the consequences of the repeal are complicated. Experts agree that the state’s broad authority to regulate pollution from power plants, refineries and other stationary sources under its own climate laws would remain intact, even if the Endangerment Finding were rescinded.
Where the impact is less clear is on vehicle standards, which have been central to California’s climate policy, because under the Clean Air Act, California can apply for a waiver to set stricter vehicle emissions rules than the federal government.
“There are two possibilities. One is, if the federal government is no longer regulating greenhouse gasses, there might be some argument that California no longer even needs a waiver outside of the Clean Air Act,” Dan Farber, professor of law at the University of California, Berkeley, said.
The other possibility, Farber added, is that if California still needs a waiver, the legal rules for obtaining one would remain unchanged.
“I don’t really see that California is harmed anyway in terms of regulating vehicles,” Farber continued.
Albert Lin, co-director of the California Environmental Law and Policy Center at the UC Davis, agreed that California will still be able to regulate stationary sources like power plants and refineries, while noting the situation is more uncertain for vehicles.
If EPA claims it has no authority to regulate greenhouse gases from cars, that could weaken the federal rules that normally block states from setting their own standards. In that case, California might be able to step in. But Lin cautioned that the final word would rest with the courts.
AGs: Rescinding climate finding would be unlawful
Lin also pointed to a comment letter filed on Monday from a coalition of 23 attorneys general, led by California Attorney General Bob Bonta, which argued that rescinding the Endangerment Finding would be unlawful and ignore established scientific evidence on climate change. The comment letter argues that the proposal undermines climate protections, which are critical as climate change harms “every region of our country, and especially California,” through extreme summer heat and the resulting increase in heat-related illness and deaths.
“We could expect to see the kind of climate change impact we’ve already seen in California and in the Sacramento region, intensifying some of those effects that are already familiar to many residents,” said Frances Moore, an associate professor of environmental science and policy at the University of California, Davis, pointing to the destruction of property and lives, as well as the “serious health implications of wildfire smoke” from wildfires, as examples.
“Sacramento is really vulnerable to flooding…that’s the other major immediate climate impact in addition to just extreme temperatures.”
Meanwhile, Newsom denounced President Donald Trump on Wednesday at a climate event while speaking to the New York Times a day after the president dismissed climate change as “the greatest con-job ever perpetrated on the world.” Newsom called Trump’s remarks an “abomination,” an “embarrassment,” and a “fraud.”
“And I say that as a guy that lives in one of the most crisis-prone states in America ... a state that’s seen lifestyles, places, traditions completely destroyed because of the reality of climate change,” Newsom said.
This story was originally published September 25, 2025 at 2:00 AM with the headline "Trump’s bid to scrap EPA climate finding may hit CA car emissions, experts warn."
