Climate change lawsuits have reached record numbers, with 3,099 climate-related cases filed across 55 countries and 24 international or regional judicial bodies by mid-2025, according to a joint report from the United Nations Environment Programme and the Sabin Center for Climate Change Law.1UNEP. Global Climate Litigation Report: 2025 Status Review At least 226 new cases were filed in 2024 alone, and more than 80 percent were classified as “strategic,” meaning plaintiffs sought to change behavior or public debate rather than recover individual damages.2Earth.org. Climate Litigation No Longer a Niche Concern as Impacts Become Increasingly Visible The most active fronts are state suits against oil companies, youth constitutional challenges, international advisory opinions, and an aggressive federal and industry counter-push.
State and Local Suits Against Oil Companies
The largest wave of U.S. climate litigation involves state and local governments suing major oil and gas companies for damages tied to climate change. These cases sit in state courts and rely on consumer protection, public nuisance, and fraud theories. Plaintiffs allege that ExxonMobil, Chevron, Shell, BP, ConocoPhillips, and their trade groups knew for decades that burning fossil fuels would warm the planet and ran coordinated campaigns to obscure that science.
California Attorney General Rob Bonta filed one of the highest-profile suits in September 2023 and amended the complaint in June 2024, accusing five oil majors and the American Petroleum Institute of “decades-long” deception and greenwashing, and seeking disgorgement of profits under state consumer protection laws.3State of California Department of Justice. Attorney General Bonta Files Amended Complaint in Lawsuit Against Five Largest Oil and Gas Companies In October 2024, a San Francisco Superior Court judge denied the companies’ motion to dismiss, ruling the court had jurisdiction because the claims arose from the defendants’ “extensive contacts with California.”4ESG Dive. Big Oil Loses Bid to Dismiss California Greenwashing Suits
Hawaii became the tenth state to sue. In January 2025, the U.S. Supreme Court declined to hear an appeal from oil companies trying to block Honolulu’s climate lawsuit, letting the case proceed in state court.5Reuters. U.S. Supreme Court Rejects Bid by Oil Companies to Toss Honolulu’s Climate Suit Courts have also rejected motions to dismiss climate suits in Vermont, Minnesota, Connecticut, and the District of Columbia.6Center for Climate Integrity. 2025: The Year in Big Oil Accountability Not every case survives. Officials in Puerto Rico and Charleston, South Carolina, dropped their suits in 2025, and a North Carolina court dismissed a climate suit against Duke Energy in February 2026, ruling it raised a nonjusticiable political question.7Sabin Center for Climate Change Law. Climate Litigation Updates — March 23, 2026
The Supreme Court Case That Could End Them
The single most consequential pending climate case in the United States is Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County. The U.S. Supreme Court agreed to hear it on February 23, 2026.8Stateline. Supreme Court Takes Up Climate Case Testing Local Lawsuits Against Oil Companies The question is whether federal law, particularly the Clean Air Act, preempts state-law claims for damages caused by interstate and international greenhouse gas emissions. ExxonMobil and Suncor argue the case should be dismissed because they operated under national regulations. Boulder contends the suit involves state consumer protection and fraud laws that belong in state court.9PBS. Supreme Court Agrees to Hear Arguments From Oil and Gas Companies Trying to Block Climate Change Lawsuits
The case originated from a 2018 suit by Boulder County and the City of Boulder. The Colorado Supreme Court ruled that federal law did not foreclose the claims and returned it to the trial court. Petitioners filed their merits brief in May 2026, with the respondents’ brief due in July 2026.10SCOTUSblog. Suncor Energy Inc. v. County Commissioners of Boulder County The Trump administration has intervened in support of the oil companies. If the Court rules that federal law preempts these claims, it could effectively block the dozens of similar suits filed by state and local governments nationwide.
New Damages Theories: Wrongful Death and Insurance Costs
Two 2025 filings pushed climate litigation into new territory. In May 2025, Misti Leon filed what is believed to be the first wrongful death lawsuit against fossil fuel companies over climate change. Her mother, Juliana Leon, died at age 65 from hyperthermia during the June 2021 Pacific Northwest heat dome, with an internal body temperature of 110 degrees Fahrenheit.11The New York Times. Oil Companies Wrongful Death Lawsuit Heat Dome The King County Superior Court suit names ExxonMobil, BP, Chevron, Shell, ConocoPhillips, and Phillips 66 and alleges product liability and public nuisance.12InsideClimate News. The Estate of a Woman Who Died in the 2021 Pacific Northwest Heat Dome Sues Big Oil for Wrongful Death A federal court sent the case back to state court in October 2025 after rejecting the companies’ removal attempt, and a Washington trial court denied a defense motion to stay proceedings in April 2026.13Sabin Center for Climate Change Law. Leon v. Exxon Mobil Corp.
In late November 2025, two Washington state homeowners filed a federal class action, Kennedy v. Exxon Mobil Corp., alleging that fossil fuel companies’ climate deception directly caused a spike in home insurance costs. The complaint cites a 51 percent increase in Washington state home insurance rates over six years and brings claims under the federal RICO statute alongside state fraud and consumer protection laws.14InsideClimate News. Washington Homeowners Sue Oil Companies Over Insurance Rates Defendants include ExxonMobil, BP, Chevron, ConocoPhillips, Shell, and the American Petroleum Institute.15Center for Climate Integrity. Kennedy v. Exxon Mobil Corp.
The Federal Government Is Suing States
The federal government under President Trump has taken an unusually aggressive posture against state-level climate suits. On April 30, 2025, the Department of Justice filed preemptive lawsuits against Hawaii and Michigan to block those states from suing fossil fuel companies over climate damages. A day later, it filed suits challenging “climate superfund” laws in New York and Vermont.16CNN. Trump Climate Lawsuits Hawaii Michigan New York Vermont The legal basis rests on Clean Air Act preemption, the Commerce Clause, and the argument that climate change is an inherently federal and international issue outside state authority.17U.S. Department of Justice. Justice Department Files Complaints Against Hawaii, Michigan, New York, and Vermont
The actions were taken under Executive Order 14260, “Protecting American Energy from State Overreach.” Hawaii’s attorney general called the lawsuit “a direct attack on Hawaiʻi’s rights as a sovereign state,” while Michigan’s attorney general described the federal suit as “frivolous.”16CNN. Trump Climate Lawsuits Hawaii Michigan New York Vermont Michael Gerrard, director of the Sabin Center for Climate Change Law at Columbia, called the preemptive filings “highly unusual” and “an aggressive move in support of the fossil fuel industry.”
Climate Superfund Laws Under Attack
New York and Vermont have enacted first-of-their-kind statutes that take a legislative approach to recovering costs from fossil fuel companies. New York’s Climate Change Superfund Act, scheduled to take effect in 2026, requires companies that emitted one billion tons or more of greenhouse gases between 2000 and 2018 to pay fees proportional to their contribution, totaling an estimated $75 billion over 25 years.18Floodlight News. New York to Bill Fossil Fuel Industry Billions for Climate Damage Revenue is earmarked for coastal restoration, stormwater infrastructure, energy-efficient buildings, and community health programs.
A coalition of 22 Republican state attorneys general, led by West Virginia, filed suit to block the New York law in West Virginia v. James, arguing it imposes retroactive penalties for lawful out-of-state conduct and is preempted by the Clean Air Act.19ESG Today. 22-State Coalition Sues to Block New York Law Charging Oil Companies $75 Billion The U.S. Chamber of Commerce brought a parallel challenge that was consolidated with the state case in the Northern District of New York, and cross-motions for summary judgment are pending.20Sabin Center for Climate Change Law. West Virginia v. James Vermont’s Climate Superfund Cost Recovery Program faces a nearly identical challenge from the American Petroleum Institute and the U.S. Chamber of Commerce in Chamber of Commerce v. Moore, with 24 states intervening in support of the plaintiffs.21Sabin Center for Climate Change Law. Chamber of Commerce of the United States of America v. Moore Vermont’s law uses a strict-liability framework for companies responsible for more than one billion metric tons of emissions between 1995 and 2024 and is not scheduled to take effect until 2028. California, Maryland, Massachusetts, New Jersey, and Oregon have introduced similar proposals.
Youth Climate Cases
Lawsuits brought by young people asserting a constitutional right to a stable climate have produced some of the field’s most dramatic moments.
Held v. Montana
On December 18, 2024, the Montana Supreme Court affirmed 6–1 that Montana’s constitutional guarantee of a “clean and healthful environment” includes a “stable climate system.” The case was brought by 16 young Montanans who challenged a state law barring environmental reviews from considering greenhouse gas emissions.22Daily Montanan. Montana Supreme Court Affirms Decision in Held, Historic Youth Climate Case The court ruled the restriction unconstitutional under strict scrutiny.23Justia. Held v. State, 2024 MT 312 Chief Justice Mike McGrath wrote for the majority, relying on the intent of delegates to Montana’s 1972 constitutional convention. Justice Jim Rice dissented, warning that the court was “legislating from the bench.” The decision is seen as a potential template for cases in Hawaii, Massachusetts, Illinois, and Pennsylvania, all of which have strong environmental provisions in their constitutions.
Juliana v. United States
The federal counterpart, Juliana v. United States, ended in 2025 after a decade of litigation. Filed in 2015 in the District of Oregon by 21 young plaintiffs, the case argued federal energy policies violated their constitutional rights. The Ninth Circuit twice ordered dismissal for lack of standing, and the Supreme Court denied certiorari on March 24, 2025.24U.S. Department of Justice. Justice Department Statement on Juliana Case Fifteen of the original plaintiffs filed a petition with the Inter-American Commission on Human Rights in September 2025, alleging that U.S. energy policies violate rights under the American Declaration of the Rights and Duties of Man.25Jones Day. American Youth Climate Litigants Take the International Stage as U.S. Litigation Continues
Sagoonick v. Alaska
Eight young Alaskans, ages 11 to 22, filed suit in May 2024 challenging the state-mandated Alaska LNG Project, a roughly $39 billion pipeline they allege would triple Alaska’s greenhouse gas emissions for decades.26Reuters. Youth Climate Change Lawsuit Targets Alaska LNG Project A trial judge dismissed the case in March 2025, ruling the policy was beyond judicial review. The Alaska Supreme Court heard oral arguments on March 4, 2026, and a decision is pending.27Our Children’s Trust. Alaska
International Rulings Expanding State Duties
Three landmark international rulings in 2024 and 2025 significantly expanded the legal framework for climate accountability.
On April 9, 2024, the Grand Chamber of the European Court of Human Rights ruled for the first time that a government’s failure to take sufficient climate action violates the European Convention on Human Rights. In Verein KlimaSeniorinnen Schweiz and Others v. Switzerland, the court found that Article 8’s right to respect for private and family life includes a right to effective state protection from serious adverse effects of climate change. Switzerland had failed to quantify its national emissions budget in line with the 1.5°C Paris Agreement goal and had missed its 2020 emission reduction targets.28Cambridge University Press. Climate Protection Obligations Under the European Convention on Human Rights: The KlimaSeniorinnen Judgment Two companion cases were declared inadmissible on procedural grounds.
On July 3, 2025, the Inter-American Court of Human Rights issued Advisory Opinion OC-32/25 on the “Climate Emergency and Human Rights,” ruling that all 34 Organization of American States member countries, including the United States and Canada, must protect the climate system as part of their human rights obligations. The court recognized the right to a healthy climate and declared that preventing harm to the climate system is a “global legal obligation.”29Human Rights Watch. Inter-American Court Says Countries Must Prevent Climate Harms30CEJIL. The IACtHR Sets a Historic Precedent
On July 23, 2025, the International Court of Justice issued an advisory opinion on Obligations of States in respect of Climate Change, requested by the U.N. General Assembly. The opinion established that states have a duty of “stringent” due diligence under both treaty and customary international law, requiring them to take all reasonably available measures to mitigate climate change, including regulating the production, consumption, and subsidization of fossil fuels.31Cambridge University Press. The 2025 International Court of Justice Advisory Opinion on Obligations of States in Respect of Climate Change The court identified the 1.5°C threshold as the “legally pivotal” temperature goal and ruled that climate mitigation obligations are erga omnes, meaning any state may invoke responsibility for breaches.32ICJ. Advisory Opinion: Obligations of States in Respect of Climate Change
The Counter-Litigation
A parallel wave of lawsuits runs in the opposite direction. Sixty cases filed in 2024 were classified as explicitly “not aligned with climate goals,” challenging government authority to pursue climate policy, corporate sustainability commitments, or both.2Earth.org. Climate Litigation No Longer a Niche Concern as Impacts Become Increasingly Visible
In February 2026, Vanguard Group settled an antitrust lawsuit filed by 13 Republican state attorneys general, paying $29.5 million without admitting wrongdoing. The states, led by Texas Attorney General Ken Paxton, had accused Vanguard, BlackRock, and State Street of conspiring through climate-focused industry groups to artificially constrict coal production. Vanguard agreed to “passivity commitments” prohibiting it from directing portfolio companies’ business strategies on carbon emissions, nominating directors, making shareholder proposals, or threatening to sell holdings to force corporate action. The firm also agreed to withdraw from the U.N.-backed Principles for Responsible Investment.33Reuters. Vanguard Says It Settles Litigation Filed by Texas Attorney General, Other States34ESG Dive. Vanguard Settles Antitrust Coal Case With Texas, Red States BlackRock and State Street remain defendants; State Street has called the lawsuit “baseless and without merit.”
Industry groups and Republican attorneys general have also lobbied for federal legislation that would create a “liability shield” for fossil fuel companies, modeled on 2005 gun manufacturer protection laws, to grant immunity from climate-related lawsuits.6Center for Climate Integrity. 2025: The Year in Big Oil Accountability House Republicans have proposed legislation to bar the District of Columbia from using consumer protection laws against oil and gas companies for environmental claims.
What Comes Next
None of the major climate tort suits against fossil fuel companies have reached settlement or gone to trial. The Supreme Court’s forthcoming decision in the Boulder case is the likely turning point. A ruling for the oil companies would shut down state-court climate suits on preemption grounds; a ruling for Boulder would clear the way for years of merits litigation across the country, with the wrongful death and insurance-cost theories waiting in line behind the older public nuisance and consumer protection cases.