The Trump administration is about to tear down a load-bearing ruling that considers climate change as a threat to Americans’ health.
Today, the Environmental Protection Agency is announcing that it will publish its final rule to dismantle the endangerment finding for greenhouse gases — the legal foundation of the EPA’s major US climate regulations. But when it comes to climate regulation, a final rule is not the final word, and the move means frustrating uncertainty for industry, for the environment, and for ordinary people.
This is the culmination of a long campaign for President Donald Trump and his allies to undo climate change regulations. The endangerment finding — which an EPA spokesperson described to Vox in an email as “one of the most damaging decisions in modern history” — was name-checked as a target in Project 2025. Last year, EPA Administrator Lee Zeldin wrote that repealing these rules would drive “a dagger through the heart of climate-change religion.”
The tale of the endangerment finding is its own saga. In 2007, the US Supreme Court ruled that the EPA has the authority to regulate greenhouse gases under the Clean Air Act if they harm public health. In 2009, the EPA under President Barack Obama found that, indeed, gases that heat up the planet endanger people’s lives. The fossil fuel industry and Republican-led states have challenged the decision over the years, but federal courts have continued to uphold it.
The most important consequence of this finding is that it justifies tougher pollution limits on cars and trucks. Car companies can then stay within those caps by increasing fuel efficiency or electrifying their fleets. The transportation sector is the largest source of greenhouse gas emissions in the US, the bulk of which come from road vehicles. Without the endangerment finding, these specific regulations on greenhouse gas emissions from cars go away.
Once this domino falls, other climate change regulations like those governing pollution from power plants are likely to fall next.
But of course, nothing the government does is simple.
Here are three possible ways this all could play out — though one thing we know for certain is that there will be lawsuits.
Outcome 1: The endangerment finding repeal is blocked
Environmental groups argue that the Trump administration’s justification for the repeal is weak on the science and on the law. And here they have an advantage.
The core of the endangerment finding is that convincing research shows that the heat-trapping gases resulting from burning fuels like gasoline and diesel are warming up the planet. That then leads to consequences like more extreme heat that can worsen ground-level ozone pollution, greater concentrations of allergens like pollen, and more severe weather events.
This was well established in 2009, and in the years since, the connection between climate change and health has only grown stronger. The EPA has a mandate to protect Americans’ health, and if you look at the evidence, regulating greenhouse gases is clearly part of that mandate.
The Trump administration is likely to argue that the evidence for this is too muddled to make that case, but as Dan Becker, director of the Safe Climate Transport Campaign at the Center for Biological Diversity, argues, “This is flat-Earth science.”
“They’re essentially taking robust science that has only become more clear since the endangerment finding was issued and they’re saying that it’s, as Trump puts it, a hoax,” Becker added.
The endangerment finding has withstood numerous legal challenges over the years in federal courts. “The endangerment finding and EPA authority is well established at this point as a legal matter,” said Michael Burger, executive director of the Sabin Center for Climate Change Law at Columbia Law School.
The challenge to the repeal of the endangerment finding may end up back at the Supreme Court. Could the high court buck its own precedent? As the overturning of Roe v. Wade in 2023 showed, it’s within the realm of possibility. And as the West Virginia v. EPA decision in 2022 demonstrated, the court is happy to handcuff the EPA’s efforts to address climate change.
However, the current 6-3 Republican majority on the court hasn’t yet hinted that they think the original 2007 decision confirming the EPA’s authority to regulate greenhouse gas emissions was bad law.
Andres Restrepo, a senior attorney at the Sierra Club, said that in cases dealing with specific laws like this, the Supreme Court does tend to let prior decisions stand. “I think that ultimately the government before the Supreme Court will be hard-pressed to make a winning case,” Restrepo said.
If the Trump administration loses and the endangerment finding survives, they will be bound by law to come up with regulations for greenhouse gas emissions. But “[the Trump administration] will probably try to get around it and issue the weakest standards possible,” Restrepo said. “In those cases, we’ll be ready to challenge them.”
Outcome 2: The endangerment finding repeal stands
If the courts side with the Trump administration, the government won’t be in the business of regulating greenhouse gases anymore. That doesn’t necessarily mean that big polluters will be home free, though. Federal climate regulations stood in place of other avenues of litigation from communities against fossil fuel, power, and auto companies. With the endangerment finding gone, businesses could face a new wave of legal action from small parties.
“If the Trump administration indeed goes ahead and removes this endangerment finding, I think that will eliminate that liability shield for major companies,” Restrepo said. “I think that they’re actually going to be exposing industry to significant litigation risk by doing this and I think a lot of people in industry are nervous about that.”
However, even if Trump ultimately succeeds in revoking the endangerment finding, it may not stay buried for long.
Outcome 3: This frustrating game of ping-pong continues
In two short years, there will be another presidential election. And the pendulum on climate change could swing back. A Democrat could take the White House and undo Trump’s work to undo the rule. “It would be the first order of business for a future administration to overturn this,” Restrepo said.
The root of the problem that has led to this regulatory back-and-forth is that Congress has never been able to pass a new law to directly regulate greenhouse gas emissions, as it was able to in the 1970s with conventional air pollutants. As a result, every Democratic attempt to regulate climate change has been forced to rely on a law that was never designed to regulate climate change. Without a dedicated law, efforts to limit greenhouse gases will remain vulnerable to political whims.
Getting the ball rolling to reinstate the endangerment finding is its own process. The next administration would have to go through another notice and comment period to reinstate the endangerment finding that would also be subject to judicial review.
This long-running, tedious ping-pong match is robbing Americans of meaningful action against a genuine threat to their health while making their lives more expensive.
Because the two parties can’t agree on the endangerment finding, climate regulations keep getting tied up in court and reversed by new administrations, never getting a real chance to cut emissions. The US has made progress to rein in climate change: its greenhouse gas emissions have declined over the past 20 years. But that was mainly due to the market-driven decline of coal power and gains in efficiency.
If limits on climate pollution from cars and power plants actually took effect during all of these years of squabbling over the regulation, the dropoff would have likely been much faster.
In the meantime, many of the sources of carbon dioxide also emit pollutants that have immediate detrimental effects on health. During Trump’s first term, his EPA found that weakening greenhouse gas regulations would lead to hundreds more premature deaths and tens of thousands more asthma attacks each year.
And all of this capriciousness is damaging to the industries that the Trump administration is trying to boost.
Greenhouse gas-emitting sectors like the auto industry and power generation generally would prefer weaker pollution rules than strong ones, but having the goalposts move every few years is even worse for them. Car companies are already designing cars for the 2030s, but right now it’s not clear what regulations they’ll face, creating uncertainty and raising costs for the auto industry. US carmakers also want to sell their cars in other countries, many of which have their own climate regulations and mandates for electric vehicles. If they pump the brakes in their drive toward greater efficiency and electrification, they become less competitive.
Similarly, power companies have to design plants that require billions of dollars in upfront investment that will be paid back over decades. Constantly changing the rules makes it harder for them to make a business case — and can end up increasing power bills for all of us.
The EPA says that the endangerment finding repeal is part of a strategy to save money for Americans, since stricter pollution standards can raise the price of vehicles and electricity production. But tougher emissions limits on cars improve their efficiency, so drivers would spend less on fuel. Gasoline is already the single-biggest energy expense for most US households.
The Trump administration has also been trying to resuscitate the US coal industry, but coal-fired power plants have been shutting down across the country because they were more expensive than competitors like natural gas and renewable power.
All these stops, starts, and reversals are frustrating for everyone, but particularly for the effort to limit climate change. “Of course, none of this is desirable,” Burger said. “You would want this to be a steady state of reducing greenhouse gas emissions consistent with what science demands in order to avert scenarios of high impact, but this is where we are.”
Durable action on climate change will likely demand dedicated legislation, but Congress is unlikely to pass any such measure anytime soon. Until then, advocates for action on climate change will have to use the imperfect tools they have to build the world they want.
