Breaking Environmental Lawsuits: Supreme Court, EPA, Youth Cases

Climate change lawsuits are moving through American and international courts in unprecedented numbers, and the next twelve to eighteen months will decide much of what climate law looks like for a generation. The U.S. Supreme Court has agreed to hear a case that could shut down state-court climate suits against oil companies. The EPA has repealed the scientific finding that anchored federal climate regulation, and coalitions of states, youth plaintiffs, and public health groups have sued to reverse it. The Justice Department is suing states to block their climate laws. Meanwhile, more than 3,000 climate-related cases have been filed across 55 countries as of mid-2025.¹ Below is what is actually being litigated, where each case stands, and what turns on the outcome.

The Supreme Court Case That Could End Local Climate Suits

The single most consequential climate case on the docket is Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County. On February 23, 2026, the Supreme Court agreed to decide whether federal law blocks state-law tort claims seeking damages for injuries caused by greenhouse gas emissions. The Court also ordered the parties to address whether it has jurisdiction at all, since the Colorado Supreme Court’s ruling may have been interlocutory rather than final.²³

The case began in 2018, when Boulder County and the City of Boulder sued Suncor Energy and ExxonMobil in Colorado state court, alleging nuisance, trespass, unjust enrichment, civil conspiracy, and statutory violations connected to climate change. In May 2025, the Colorado Supreme Court ruled that the Clean Air Act does not preempt those state-law claims. The fossil fuel companies appealed, and the Trump administration filed an amicus brief supporting them.⁴

At least 29 similar lawsuits have been filed by states, cities, counties, and tribal governments against fossil fuel companies across the country.⁵ A ruling that federal law preempts state-law climate tort claims could effectively end the entire category. Oral argument is expected during the October 2026 term, with a decision likely by mid-2027. Amicus filings have poured in from state attorneys general, members of Congress, the American Petroleum Institute, the U.S. Chamber of Commerce, former foreign affairs officials, and legal scholars.⁶

The Fight Over the EPA Endangerment Finding

In February 2026, the EPA finalized the rescission of the 2009 “endangerment finding,” the scientific determination that greenhouse gas emissions from motor vehicles threaten public health and welfare. That finding, established after the Supreme Court’s 2007 ruling in Massachusetts v. EPA, has served as the legal foundation for federal vehicle emission standards and much of the EPA’s climate authority under the Clean Air Act. EPA Administrator Lee Zeldin argued the agency lacked statutory authority to regulate greenhouse gases from vehicles, and President Trump called the repeal “the single largest deregulatory action in American history.”⁷⁸

The repeal triggered an immediate wave of lawsuits, all filed in the D.C. Circuit. On February 18, 2026, a coalition of health and environmental groups including the American Lung Association, NRDC, Sierra Club, Center for Biological Diversity, and Union of Concerned Scientists sued the EPA, represented by the Clean Air Task Force and Earthjustice.⁹ The same day, 18 young people aged one to 22, represented by Our Children’s Trust and Public Justice, filed a separate petition — Venner v. EPA — arguing the repeal violates their Fifth Amendment rights to life and liberty and their First Amendment right to freely practice their religion.¹⁰ In May 2026, the youth petitioners asked the court to pause the repeal while the case proceeds.¹¹

In March 2026, California Attorney General Rob Bonta, Governor Gavin Newsom, and the California Air Resources Board co-led a 25-state coalition, joined by 10 cities and counties, in filing their own D.C. Circuit petition. The coalition argues the EPA ignored established science, violated the Clean Air Act and the Administrative Procedure Act, and relied on a “DOE Climate Working Group” made up of climate change contrarians who never produced a final report.¹²¹³

There is an unresolved tension in the repeal. The fossil fuel industry has argued for years that the Clean Air Act and the endangerment finding preempt state-law climate lawsuits. Removing the federal regulatory framework could weaken that argument and potentially expose polluters to more common-law liability at the state level.¹⁴

The Federal Government Suing States to Stop Climate Suits

Beyond deregulation, the Trump administration has opened a legal front to stop states from suing oil companies. The Department of Justice filed suits against New York and Vermont to invalidate their “climate Superfund” laws, which impose financial liability on major emitters for climate adaptation and disaster costs. DOJ filed complaints in May 2025 and moved for summary judgment against Vermont’s law in September 2025, arguing the laws usurp federal authority, punish businesses for “ill-defined harms,” and threaten to “throttle energy production.”¹⁵ The laws, enacted in 2024, target companies responsible for more than one billion tons of greenhouse gas emissions between 2000 and 2024.¹⁶

DOJ also filed preemptive suits against Hawaii and Michigan, trying to stop those states from pursuing climate liability litigation before they had even filed. Both federal suits were dismissed. The Hawaii case was thrown out on April 15, 2026, with the court finding that the government’s claims rested on “abstract, theoretical concerns” and a “speculative theory of harm.”¹⁷ Both states then proceeded with their own suits against the industry.¹⁸ The DOJ campaign has been driven by a presidential executive order titled “Protecting American Energy from State Overreach.”

State and Local Lawsuits Against Oil Companies

State and local governments continue to file and advance climate lawsuits against major oil companies. More than 30 such cases are active or have been filed nationwide against companies including ExxonMobil, Chevron, Shell, BP, ConocoPhillips, and the American Petroleum Institute.¹⁹ Most center on allegations that the industry knew about the dangers of fossil fuel combustion for decades and deliberately misled the public. Plaintiffs have brought claims for public nuisance, consumer fraud, products liability, failure to warn, racketeering, and antitrust violations.²⁰

Recent results are mixed. In Colorado and Hawaii, state supreme courts have allowed climate cases to proceed. Cases in Boulder, Honolulu, and Massachusetts had been cleared for trial before the Supreme Court took up Suncor.⁵ In Maryland, the state Supreme Court dismissed climate lawsuits by Baltimore, Annapolis, and Anne Arundel County in March 2026, ruling that claims about greenhouse gas communications occurring beyond state borders fell outside state-court reach.¹⁹ A North Carolina court dismissed Town of Carrboro v. Duke Energy Corp. in February 2026, finding the claims involved nonjusticiable political questions.³

Michigan’s Antitrust Theory

Michigan took a different approach in January 2026, when Attorney General Dana Nessel filed an antitrust suit against BP, ExxonMobil, Chevron, Shell, and the American Petroleum Institute in federal court. Rather than alleging climate deception, the suit accuses the defendants of operating as a “cartel” that conspired to suppress renewable energy competition, eliminate consumer choice, and raise energy prices. Specific allegations include shutting down internal electric vehicle research, using patent litigation to block competitors, and orchestrating disinformation campaigns about climate science.²¹ The defendants have filed motions to dismiss.²²

Tribal Climate Suits in Washington

In Washington state, the Shoalwater Bay Indian Tribe and the Makah Indian Tribe are pursuing climate deception claims against ExxonMobil, Shell, and other oil companies. On April 29, 2026, King County Superior Court Judge James Rogers denied the industry’s motions to dismiss, holding that federal law does not preempt the tribes’ state-law claims because it “does not speak to deceptive marketing.”²³ The tribes bring claims under the Washington Public Nuisance Statute and the Washington Product Liability Act, seeking damages for sea level rise and flooding costs. The court also refused to pause the case while Suncor is pending, finding a stay would “greatly prejudice” the tribes.²⁴

Youth Climate Lawsuits

Young plaintiffs have been at the forefront of climate litigation for more than a decade, with results ranging from precedent-setting wins to procedural defeat.

Juliana v. United States

The most prominent youth climate case, Juliana v. United States, ended in March 2025 when the Supreme Court declined to hear the plaintiffs’ final appeal. Filed in 2015 by 21 young people and Our Children’s Trust, the suit argued that the federal government’s fossil fuel energy system violated constitutional rights to life, liberty, and property. The case survived early challenges and nearly went to trial, but the Ninth Circuit ruled in 2020 that the plaintiffs lacked Article III standing. Further attempts to amend the complaint and challenge the Ninth Circuit’s authority failed, and the case was ordered dismissed.²⁵²⁶ Our Children’s Trust has said the framework the case established has inspired over 60 youth-led climate lawsuits worldwide.

Held v. Montana

Where Juliana failed, Held v. Montana succeeded at the state level. The first youth-led constitutional climate lawsuit to reach trial produced a June 2023 district court ruling that Montana violated its constitution’s guarantee of a “clean and healthful environment” by excluding greenhouse gas emissions from environmental reviews of fossil fuel projects. On December 18, 2024, the Montana Supreme Court affirmed, holding that a “stable climate system” is protected under the state constitution and that the challenged statute failed strict scrutiny.²⁷ The state did not challenge the district court’s factual findings on climate science. In September 2025, the trial court awarded the plaintiffs over $2.85 million in attorney fees and costs.²⁸

The victory has already drawn legislative pushback. Montana’s 2025 legislature passed new laws restricting state agency authority to regulate greenhouse gases or consider climate impacts when issuing fossil fuel permits. In January 2026, the same youth plaintiffs refiled to enforce the original ruling and challenge those new laws. That case, sometimes called Held v. Montana II, is pending.²⁹

Navahine F. v. Hawaii DOT

In Hawaii, youth plaintiffs secured a court-approved settlement in Navahine F. v. Hawaiʻi Department of Transportation on June 20, 2024. The agreement requires the Hawaii DOT to achieve zero emissions across all ground, interisland sea, and interisland air transportation by 2045. Specific commitments include completing pedestrian, bicycle, and transit networks within five years, dedicating at least $40 million to expand the public electric vehicle charging network by 2030, creating a climate mitigation unit within the department, and reforming budgeting to prioritize greenhouse gas and vehicle miles traveled reductions.³⁰ The agreement also mandates a volunteer youth council to advise the department. The court retains jurisdiction until 2045.³¹

The Anti-ESG and Corporate Disclosure Front

A parallel campaign is using litigation to attack environmental, social, and governance investing practices and to challenge state climate disclosure rules. In February 2026, Vanguard agreed to pay $29.5 million to settle an antitrust suit filed by Republican-led states, led by Texas, which alleged that Vanguard, BlackRock, and State Street colluded through industry climate groups to restrict coal production and inflate energy prices.³² As part of the deal, Vanguard agreed to “passivity commitments” for five years: it will not use its shareholdings to direct the business strategies of portfolio companies, will not push shareholder proposals related to environmental or social issues, and must withdraw from groups advocating specific emissions targets.³³ The case continues against BlackRock and State Street, both of which have called the suit “baseless and without merit.”

A Texas federal court also awarded $4.6 million in attorney’s fees in Spence v. American Airlines, after ruling the airline breached its fiduciary duty under ERISA by allowing ESG objectives to influence retirement plan management.³

California’s climate disclosure laws are also being litigated. SB 253, which requires corporations with at least $1 billion in revenue to report their supply-chain carbon emissions, remains in effect with a first-year reporting deadline of August 10, 2026.³⁴ Its companion SB 261, which would require businesses with over $500 million in revenue to disclose climate-related financial risks, was enjoined by the Ninth Circuit in November 2025.¹⁴ ExxonMobil separately challenged both laws in an October 2025 federal lawsuit.³⁵

International Climate Rulings

Climate litigation has been moving fast outside the United States too. In July 2025, the International Court of Justice issued an advisory opinion confirming that the 1.5°C temperature target is legally binding under the Paris Agreement and that customary international law requires states to take preventive measures on climate change. The ICJ found that failure to act, including through fossil fuel production or inadequate regulation of private actors, can constitute an internationally wrongful act.³⁶

Other international courts have reached similar conclusions. In April 2024, the European Court of Human Rights ruled in Verein KlimaSeniorinnen Schweiz v. Switzerland that the Swiss government breached human rights obligations through insufficient climate action, a ruling binding on all signatory states.³⁷ The Inter-American Court of Human Rights issued its own advisory opinion in July 2025, becoming the first international court to require states to tackle climate disinformation. The International Tribunal for the Law of the Sea ruled in May 2024 that states must reduce greenhouse gas emissions to protect the marine environment. In May 2026, the UN General Assembly voted 141 to 8 in favor of a resolution urging countries to limit warming to 1.5°C by tripling renewable energy capacity and accelerating the phase-out of fossil fuels.

What the Numbers Show

As of mid-2025, more than 3,000 climate-related cases had been filed across 55 national jurisdictions and 24 international courts and tribunals.³⁸ The count grew from 884 cases in 2017 to 1,550 in 2020 to 2,180 in 2022.¹ At least 226 new cases were filed in 2024, with the United States accounting for 164 of them.³⁹

Over 80% of 2024 filings were classified as “strategic,” brought not to resolve narrow disputes but to shape law and policy. About 20% targeted corporations or their officers and directors, and cases against corporate defendants appear to have higher success rates than those against governments. At the same time, roughly a quarter of new 2024 filings were classified as “not aligned with climate goals,” reflecting the rise of anti-climate litigation aimed at deregulating environmental protections or attacking ESG standards. Courts are increasingly using attribution science to connect specific extreme weather events to greenhouse gas emissions, and litigation has expanded to reach greenwashing, carbon offsets, and the emissions from energy-intensive data centers.³⁹

The overall picture is one of tension. Courts around the world are recognizing that climate inaction carries legal consequences, even as the U.S. federal government works to dismantle the regulatory architecture that has underpinned domestic climate policy for nearly two decades. How the Supreme Court rules in Suncor v. Boulder, and whether the D.C. Circuit restores the endangerment finding, will do more than any other decisions to determine whether American courts remain a viable venue for climate accountability.

1
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2
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3
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22
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32
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