A foundational climate regulation is under threat

The Environmental Protection Agency announced this week that it’s starting the process of undoing 31 environmental regulations, including a ruling that’s foundational to US climate policy. But undoing any regulation is a cumbersome process, and with the climate rule in particular, the EPA may end up painting itself into a corner.

The big target here is the 2009 endangerment finding, in which the EPA concluded that greenhouse gases threaten public health and welfare, therefore the agency must limit them. The finding is the foundation for regulations that ensued, like requiring power plants and vehicles to cut their emissions of gases that are heating up the planet. Without the endangerment finding, these regulations could be rescinded.

The rollbacks are yet another manifestation of the Trump administration’s longstanding antipathy toward all things related to climate change. “By overhauling massive rules on the endangerment finding, the social cost of carbon and similar issues, we are driving a dagger through the heart of climate-change religion and ushering in America’s Golden Age,” EPA administrator Lee Zeldin wrote in the Wall Street Journal.

But it will take more than press releases and editorials to get rid of greenhouse gas rules. The endangerment finding stems from a 2007 Supreme Court ruling in Massachusetts v. EPA that says greenhouse gases are covered under the Clean Air Act and the EPA has to figure out whether these gases could endanger public health or welfare.

Based on science alone, the endangerment finding is on solid ground. The evidence is overwhelming that rising temperatures are worsening problems like heat stress and facilitating the spread of diseases carried by insects, which poses a threat to public health. And on welfare, the text of the Clean Air Act specifically says it includes “effects on soils, water, crops, vegetation, manmade materials, animals, wildlife, weather, visibility, and climate.”

So to undo the endangerment finding, the EPA would have to establish a factual record that climate change isn’t happening due to burning fossil fuels, and that even if it is, it doesn’t hurt anything.

Trump administration officials have hinted that they are indeed making the case that efforts to limit climate change are worse than its harms and that warming might benefit humanity on balance.

“This is truly ridiculous,” said David Bookbinder, director of law and policy at the Environmental Integrity Project and one of the attorneys who litigated Massachusetts v. EPA. “I could go into the DC Circuit and argue against this in pig latin and win it.”

It’s likely that states led by Democrats, particularly California, as well as environmental groups, will sue to stop the EPA’s efforts to repeal the endangerment finding, but a lot has to happen before it even gets to that point. The EPA has to make another factual determination, write a proposed rule, provide a justification, and invite public comments, all before they issue a final rule.

“Nothing they’ve done so far on the endangerment finding counts as a final agency action that can be challenged in court, so there’s really nothing to sue on yet,” said Shaun Goho, legal director for the Clean Air Task Force.

The Trump administration may also face an unexpected complication in its efforts, thanks to a Supreme Court decision that many conservatives cheered. In the 2024 Loper Bright Enterprises v. Raimondo decision, the Court overturned “Chevron deference,” a legal doctrine that lets federal agencies figure out the particulars of implementing complicated laws like the Clean Air Act when the wording is vague.

The Loper Bright decision gave courts much more authority to second-guess an agency’s decision by claiming that the agency’s action is not consistent with a federal statute. But Bookbinder argued that this actually works against the Trump administration’s climate rollbacks. Since the EPA can’t easily make its own determinations anymore about whether climate change is a threat, it has to stick to the letter of the law, and the law unambiguously says that “climate” is included in the obligation to protect welfare under the Clean Air Act.

“Now we’re in a better position legally with the end of Chevron,” Bookbinder said. The other hurdle for the EPA is that with so many layoffs and job cuts across the agency, it will be much harder to find the staffing power to put together all the paperwork and argue the legal case for reversing the endangerment finding.

The litigation around the endangerment finding may wend its way back to the Supreme Court, where Republicans have a 6-3 majority, but historically courts have backed it and the case may not be the layup that the Trump administration may be anticipating.

“The endangerment finding has been implemented by multiple administrations and both parties,” Goho said. “It’s been upheld in the courts repeatedly. The science and then the law are really clear. It would be very misguided for the EPA to try to move forward with repealing it.”