In the weeks after the election of Donald Trump, friends and journalists called Deborah Sivas with roughly the same question: How bad could things get?

Sivas is a professor of environmental law at Stanford University, and she has decades of experience working as a litigator for environmental-rights groups. She knows how hostile new presidents can overturn green protections and she knows how lawsuits from friendly states and nonprofits can shore up those rules.

So when reporters asked about the fate of signature Obama-era issues—the Clean Power Plan, the Paris Agreement, the Dakota Access pipeline—she replied that they should focus on an issue with less name recognition. It seemed likely, she said, that the Trump administration and its allies in the car industry would attack California’s ability to regulate greenhouse-gas pollution from car tailpipes.

This may sound niche. But if Trump revoked the special federal waiver that gives California this power, it could hinder the ability of the United States to address climate change for decades to come, she said.

It now appears that her instincts were correct. On Saturday, The New York Times reported that Scott Pruitt, the new administrator of the U.S. Environmental Protection Agency, was exploring how to withdraw this waiver from California. The announcement could come later this week, when the Trump administration begins to roll back nationwide regulations on pollution from car tailpipes.

“We hear a lot about Paris and the Clean Power Plan, but this [waiver] is a big part of it too,” Sivas told me. “These were the years—2017 and going forward—when the curve was supposed to bend a lot on car emissions.”

The probable withdrawal has so far avoided attracting significant activist attention, perhaps because the idea of the waiver is difficult to explain or because at first glance it appears to be a local issue affecting only Californians.

But if Scott Pruitt and the Trump administration succeed in revoking the waiver, it could spell catastrophe for California’s climate policy, which is one of the most aggressive and technologically important in the developed world.

It could also worsen the health of the roughly 130 million Americans who depend directly on the Golden State’s more stringent environmental standards.

(Mike Blake / Reuters)

The California waiver program is unique: There appears to be nothing like it throughout the rest of U.S. federal law.

When Congress amended the Clean Air Act in 1970, it empowered the EPA to set new national standards on air pollution from cars and factories. It was the federal government’s most aggressive attempt ever to address the dangers of smog and toxic air pollution.

But this was old hat for California, which had already been dealing with smog for two decades.

Officials in Los Angeles spent the late 1940s and early 1950s clamping down on air pollution from factories, only to find the city’s smog getting worse and worse. In 1954, Arie Jan Haagen-Smit, a Dutch chemist working at the California Institute of Technology, identified that smog was tied to the gases that came out of car tailpipes. Six years later, the state established laws to restrict air pollution from car tailpipes.

“California was the first state—the first, really, governmental entity—to enact tailpipe standards,” says Ann Carlson, a professor of environmental law at the University of California Los Angeles who has written extensively about the waiver.

When Congress began drafting the 1970 Clean Air Act, the state fought to maintain its ongoing regulatory scheme. It argued that its program should be left alone, since it was successful, and that its air problems were naturally worse than other states’.

“[California argued] that there is this geographically unfortunate set of factors that traps smog into the Los Angeles basin,” says Carlson. “That has turned out to be completely true.”

California succeeded—and dramatically so. California is written into the Clean Air Act by name: At any time, it can ask the EPA administrator for a waiver to restrict tailpipe pollution more stringently than the federal government. If its proposed rules are “at least as protective of public health and welfare” as the EPA’s, then the administrator must grant the waiver.

This power is reserved alone for California, and it only covers pollution from cars. No other state can ask for a waiver. (In all of federal law, this might be the only time that a specific state is given special authority under such a major statute.)

Under the same provision, any other state can choose to adopt California’s more stringent standards. Fifteen states currently opt for the tougher rules, including Georgia, Pennsylvania, North Carolina, and the entire New York metro area. This means that California’s rules actually cover 135 million people, more than 40 percent of the U.S. population.

And since any car dealership in a state bordering a waiver state can sell California-compliant cars, the vast majority of Americans live at least partly under the Golden State rules.

December 31, 2007, was a smoggy day in Los Angeles.
(Lucy Nicholson / Reuters)

“So [California] has been receiving waivers from the federal government for 45 years, and from every administration the waivers have been granted—with one exception,” says Carlson.

That was 10 years ago, when the Bush administration issued the first-ever denial of a California waiver request. California had sought to restrict not only the “traditional” toxic air pollutants—like ozone and particulate matter—but also greenhouse gases, the non-poisonous pollutants that accumulate in the atmosphere and cause climate change.

The Bush administration said no, and California sued. But the case was never decided. Barack Obama became president, and, in May 2009, he announced new national standards on greenhouse gas emissions from cars while simultaneously announcing a bailout for the U.S. auto industry.

He also granted California its waiver as part of the same deal. As a concession, California harmonized its greenhouse-gas rules with the federal government.

In the years since, California has enacted some of the most aggressive climate policies in the rich world. The state aims to cut its greenhouse-gas emissions 40 percent by 2030: a feat that, if successful, would set a model for how to mitigate climate change for the rest of the country and the planet. It has promoted electric cars and dotted the state with wind and solar plants.

But its powerful Air Resources Board can only issue rules about cars thanks to the waiver. If it loses its special authorization, California’s regulations are moot and automatically overridden by the federal government.

This especially matters now because the car companies are trying to get the greenhouse-gas standards rewritten at the national level. In a letter to Pruitt sent last month, 17 major automobile manufacturers wrote that nixing the rules would be “the single most important decision the E.P.A. has made in recent history.”

The rules were also slated to get much more stringent in the years to come: essentially, after a slow, decade-long buildup, the amount of greenhouse-gas emissions from cars was supposed to start falling quickly in 2017. Pruitt seems poised to cancel those rules, which makes California’s independent regulatory power all the more important.

“The car companies said, ‘Well, let us ramp up slowly, and then the curve will bend up.’ We’re now at the point where the curve is bending up. They’ve brokered a deal where they got the benefits of the early, slow ramp-up, and now when they really have to dig in and do it, they say, we really need relief from this,” Sivas told me.

The car companies say that American consumers aren’t interested in buying the cars that would let them meet the regulations and that they don’t have the technological capability to make larger, more popular cars—like crossovers and SUVs—as efficient as the government demands.

Environmental groups say this is a bizarre complaint: The rules only require that types of cars get more efficient every year, and they grant automakers exceptions if consumers opt for larger cars.

“When a manufacturer sells more trucks and SUVs, its regulatory target is lowered,” said Dave Cooke, an analyst at the Union of Concerned Scientists, in a blog post last year. “It’s the automakers that requested this flexibility, so it’s particularly galling for them to suggest this somehow creates difficulty for them.”

All this haggling is important because, since last year, the transportation sector has contributed more to U.S. greenhouse-gas emissions than power plants. If California has any hope of tackling this issue at the state level, it must secure its waiver.

Scott Pruitt, the new administrator of the EPA, meets with members of the Oklahoma Farm Bureau in December 2016. (Nick Oxford / Reuters)

Could the Trump administration succeed in revoking California’s special status? It depends on their first move.

If Pruitt tries to withdraw a waiver from California, he may quickly run into legal trouble: The Clean Air Act provides no mechanism for the EPA to ever revoke a waiver. He would more or less be identifying a new power in an old law specifically to attack a state’s sovereignty, experts said.

California would also likely prevail if Pruitt tries to revoke its special authority to regulate toxic air pollutants. The EPA has granted California its waiver for conventional pollutants for four decades, across all parties and presidents. To deny it now would seem capricious in the extreme.

The big question is whether Pruitt can withhold the waiver for greenhouse gases only. This is a more open question. Though the EPA argued that California should get a waiver for greenhouse-gas emissions throughout the Obama administration, there is no caselaw that assures them this right.  

During Pruitt’s confirmation hearing in January, Senator Kamala Harris of California asked if he would follow other EPA administrators in granting the waiver. He declined to make any promises about it—either on the conventional-pollutant or greenhouse-gas front. “Administrators in the past have not granted the waiver and have granted the waiver,” he told Harris. “That is a review process that will be conducted.”

“I thought that Pruitt’s testimony was sufficiently broad that it’s conceivable that EPA could just start denying its waiver authority for broader conventional pollutants,” Carlson told me.

If he did so, it would tee up a legal fight between the Trump administration and the state of California that would have deep and long-lasting consequences for the planet, no matter its outcome. “The state of California is gearing up for fighting all this stuff. They’re almost giddy to do it. They’re like, let’s go. Bring it on,” said Sivas.

She feared that this fight in the courts would accompany a political fight in Congress, as the administration would seek to amend the Clean Air Act to remove California’s waiver power before they lost the lawsuit.

And—almost in preparation for that battle—she asked Americans to take a step back and examine why regulating greenhouse gases from cars is important.

“It feels like this very technical thing about, ‘blah blah, waivers, blah blah blah,’ but it’s a very important part of the climate policy,” Sivas told me. “People aren’t going to stop driving, really. And transportation’s 40 percent of carbon emissions. The only way to get [those emissions] down is to get [fuel] mileage up. If the feds are going to take their foot off the gas—and to fight the states who are doing it—it could be a huge setback,” said Sivas.

Car fuel-efficiency regulation happens for years that can seem far off. If the EPA revokes any power from California, it will be the power to make new car-emissions rules for the model years 2022 to 2025. During the next four years, the state will also probably want to set new standards for the 2025 to 2030 period.

That’s why environmental groups see this fight as so important: If California doesn’t get its waiver, it will harm fuel efficiency as far as two decades from now. And that will only intensify climate change. The carbon emissions from all those cars will stay in the air for centuries to come, long after most Trump-era policies are forgotten.