Most of the United States’ major climate regulations are underpinned by one important document: It’s called the endangerment finding, and it concludes that greenhouse gas emissions are a threat to human health and welfare.

The Trump administration is trying to eliminate it.

Environmental Protection Agency Administrator Lee Zeldin announced on July 29, 2025, that the EPA would soon publish a rule to rescind the endangerment finding and allow 45 days for public comment.

A draft released by the EPA of the proposal argues that the agency didn’t have the authority to issue the endangerment finding in 2009 or regulations based on it. The draft also argues that U.S. vehicle emissions are not significant in terms of global emissions of greenhouse gases and that the costs to consumers outweigh the benefits.

These are dubious factual and legal propositions that will require deeper analysis once the proposal is officially published in the Federal Register.

Revoking the endangerment finding isn’t a simple task. If the rule is finalized, it will also trigger an onslaught of lawsuits. And revoking the finding could have unintended consequences for the very industries President Donald Trump is trying to help.

As a law professor, I have tracked federal climate regulations and the lawsuits and court rulings that have followed them over the past 25 years. To understand the challenges, let’s look at the endangerment finding’s origins and Zeldin’s options.

Origin and limits of the endangerment finding

In 2007, the U.S. Supreme Court ruled in Massachusetts v. EPA that six greenhouse gases are pollutants under the Clean Air Act and that the EPA has a duty under the same law to determine whether they pose a danger to public health or welfare.

The court also ruled that once the EPA made an endangerment finding, the agency would have a mandatory duty under the Clean Air Act to regulate all sources that contribute to the danger.

The court emphasized that the endangerment finding was a scientific determination and rejected a laundry list of policy arguments made by the George W. Bush administration for why the government preferred to use nonregulatory approaches to reduce emissions. The court said the only question was whether sufficient scientific evidence exists to determine whether greenhouse gases are harmful.

The endangerment finding was the EPA’s response.

The finding was challenged and upheld in 2012 by the U.S. Court of Appeals for the D.C. Circuit. In that case, Coalition for Responsible Regulation v. EPA, the court found that the “body of scientific evidence marshaled by the EPA in support of the endangerment finding is substantial.” The Supreme Court declined to review the decision. The endangerment finding was updated and confirmed by the EPA in 2015 and 2016.

Challenging the endangerment finding

The scientific basis for the endangerment finding is stronger today than it was in 2009.

The Intergovernmental Panel on Climate Change’s latest assessment report, involving hundreds of scientists and thousands of studies from around the world, concluded that the scientific evidence for warming of the climate system is “unequivocal” and that greenhouse gases from human activities are causing it.

According to the National Climate Assessment released in 2023, the effects of human-caused climate change are already “far-reaching and worsening across every region of the United States.”

During Trump’s first term, then-EPA Administrator Scott Pruitt considered repealing the endangerment finding but ultimately decided against it. In fact, he relied on it in proposing the Affordable Clean Energy Rule to replace President Barack Obama’s Clean Power Plan for regulating emissions for coal-fired power plants.

Zeldin’s cost argument

Zeldin had previewed some of his arguments for rescinding the endangerment finding in a news release on March 12.

His first argument then was that the 2009 endangerment finding did not consider costs. However, that argument was rejected by the District of Columbia Circuit Court in Coalition for Responsible Regulation v. EPA in 2012. Cost becomes relevant once the EPA considers new regulations – after the endangerment finding.

Moreover, in a unanimous 2001 decision, the Supreme Court in Whitman v. American Trucking Associations held that the EPA cannot consider cost in setting air quality standards.

What happens if the EPA revokes the endangerment finding?

Even if Zeldin is able to revoke the endangerment finding, that does not automatically repeal all the rules that rely on it. Each of those rules must go through separate rulemaking processes that will also take months. The agency will also face lawsuits.

Zeldin could simply refuse to enforce the rules on the books.

However, a blanket policy abdicating any enforcement responsibility could be challenged in lawsuits as arbitrary and capricious. Further, the regulated industries would be taking a chance if they delay complying with regulations, only to find the endangerment finding and climate laws still in place.

A repeal could backfire

Repealing the endangerment finding could also backfire on the fossil fuel industry.

States and cities have filed dozens of lawsuits against the major oil companies. The industry’s strongest argument has been that these cases are preempted by federal law. In AEP v. Connecticut in 2011, the Supreme Court ruled that the Clean Air Act “displaced” federal common law, barring state claims for remedies related to damages from climate change.

However, if the endangerment finding is repealed, then there is arguably no basis for federal preemption, and these state lawsuits would have legal grounds. Prominent industry lawyers have warned the EPA about this and urged it to focus instead on changing individual regulations. The industry is concerned enough that it may try to get Congress to grant it immunity from climate lawsuits.

To the extent that Zeldin is counting on the conservative Supreme Court to back him up, he may be disappointed.

In 2024, the court overturned the Chevron doctrine, which required courts to defer to agencies’ reasonable interpretations when laws were ambiguous. That means Zeldin’s reinterpretation of the statute is not entitled to deference. Nor can he count on the court overturning its Massachusetts v. EPA ruling to free him to disregard science for policy reasons.

This article, originally published March 19, 2025, has been updated with the EPA’s announcement to rescind the endangerment finding.

Patrick Parenteau, Professor of Law Emeritus, Vermont Law & Graduate School

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Imagine that you own a small, 20-acre farm in California’s Central Valley. You and your family have cultivated this land for decades, but drought, increasing costs and decreasing water availability are making each year more difficult.

Now imagine that a solar-electricity developer approaches you and presents three options:

• You can lease the developer 10 acres of otherwise productive cropland, on which the developer will build an array of solar panels and sell electricity to the local power company.
• You can select 1 or 2 acres of your land on which to build and operate your own solar array, using some electricity for your farm and selling the rest to the utility.
• Or you can keep going as you have been, hoping your farm can somehow survive.

Thousands of farmers across the country, including in the Central Valley, are choosing one of the first two options. A 2022 survey by the U.S. Department of Agriculture found that roughly 117,000 U.S. farm operations have some type of solar device. Our own work has identified over 6,500 solar arrays currently located on U.S. farmland.

Our study of nearly 1,000 solar arrays built on 10,000 acres of the Central Valley over the past two decades found that solar power and farming are complementing each other in farmers’ business operations. As a result, farmers are making and saving more money while using less water – helping them keep their land and livelihood.

A hotter, drier and more built-up future

Perhaps nowhere in the U.S. is farmland more valuable or more productive than California’s Central Valley. The region grows a vast array of crops, including nearly all of the nation’s production of almonds, olives and sweet rice. Using less than 1% of all farmland in the country, the Central Valley supplies a quarter of the nation’s food, including 40% of its fruits, nuts and other fresh foods.

The food, fuel and fiber that these farms produce are a bedrock of the nation’s economy, food system and way of life.

But decades of intense cultivation, urban development and climate change are squeezing farmers. Water is limited, and getting more so: A state law passed in 2014 requires farmers to further reduce their water usage by the mid-2040s.

The trade-offs of installing solar on agricultural land

When the solar arrays we studied were installed, California state solar energy policy and incentives gave farm landowners new ways to diversify their income by either leasing their land for solar arrays or building their own.

There was an obvious trade-off: Turning land used for crops to land used for solar usually means losing agricultural production. We estimated that over the 25-year life of the solar arrays, this land would have produced enough food to feed 86,000 people a year, assuming they eat 2,000 calories a day.

There was an obvious benefit, too, of clean energy: These arrays produced enough renewable electricity to power 470,000 U.S. households every year.

But the result we were hoping to identify and measure was the economic effect of shifting that land from agricultural farming to solar farming. We found that farmers who installed solar were dramatically better off than those who did not.

They were better off in two ways, the first being financially. All the farmers, whether they owned their own arrays or leased their land to others, saved money on seeds, fertilizer and other costs associated with growing and harvesting crops. They also earned money from leasing the land, offsetting farm energy bills, and selling their excess electricity.

Farmers who owned their own arrays had to pay for the panels, equipment and installation, and maintenance. But even after covering those costs, their savings and earnings added up to US$50,000 per acre of profits every year, 25 times the amount they would have earned by planting that acre.

Farmers who leased their land made much less money but still avoided costs for irrigation water and operations on that part of their farm, gaining $1,100 per acre per year – with no up-front costs.

The farmers also conserved water, which in turn supported compliance with the state’s Sustainable Groundwater Management Act water use reduction requirements. Most of the solar arrays were installed on land that had previously been irrigated. We calculated that turning off irrigation on this land saved enough water every year to supply about 27 million people with drinking water or irrigate 7,500 acres of orchards. Following solar array installation, some farmers also fallowed surrounding land, perhaps enabled by the new stable income stream, which further reduced water use.

Changes to food and energy production

Farmers in the Central Valley and elsewhere are now cultivating both food and energy. This shift can offer long-term security for farmland owners, particularly for those who install and run their own arrays.

Recent estimates suggest that converting between 1.1% and 2.4% of the country’s farmland to solar arrays would, along with other clean energy sources, generate enough electricity to eliminate the nation’s need for fossil fuel power plants.

Though many crops are part of a global market that can adjust to changes in supply, losing this farmland could affect the availability of some crops. Fortunately, farmers and landowners are finding new ways to protect farmland and food security while supporting clean energy.

One such approach is agrivoltaics, where farmers install solar designed for grazing livestock or growing crops beneath the panels. Solar can also be sited on less productive farmland or on farmland that is used for biofuels rather than food production.

Even in these areas, arrays can be designed and managed to benefit local agriculture and natural ecosystems. With thoughtful design, siting and management, solar can give back to the land and the ecosystems it touches.

Farms are much more than the land they occupy and the goods they produce. Farms are run by people with families, whose well-being depends on essential and variable resources such as water, fertilizer, fuel, electricity and crop sales. Farmers often borrow money during the planting season in hopes of making enough at harvest time to pay off the debt and keep a little profit.

Installing solar on their land can give farmers a diversified income, help them save water, and reduce the risk of bad years. That can make solar an asset to farming, not a threat to the food supply.

Jacob Stid, Ph.D. student in Hydrogeology, Michigan State University; Annick Anctil, Associate Professor of Civil and Environmental Engineering, Michigan State University, and Anthony Kendall, Professor of Earth and Environmental Sciences, Michigan State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.