Climate change litigation refers to lawsuits that use legal theories ranging from traditional tort law to constitutional rights and securities regulation to force governments and corporations to answer for their contributions to global warming. More than 3,000 such cases have been filed worldwide as of mid-2025, with the majority originating in the United States. The field is moving fast: the U.S. Supreme Court is currently weighing whether federal law blocks state climate tort suits, and a ruling either way will reshape dozens of pending cases.
What follows is a plain look at the main types of climate suits being brought, who is bringing them, what they are asking for, and where they stand.
Suits Against Fossil Fuel Companies
The most visible wave of climate litigation comes from cities, counties, and states suing major oil and gas producers for damages tied to rising seas, worsened storms, and extreme heat. More than two dozen of these cases are moving through U.S. courts. They rest on overlapping tort theories.
Public nuisance is the workhorse claim. Plaintiffs argue that producing and selling fossil fuels at industrial scale interferes with shared resources, breathable air, stable coastlines, functioning stormwater systems, in ways that harm whole communities. The relief sought includes compensation for infrastructure already damaged and court orders funding future adaptation like seawalls and drainage upgrades.
Private nuisance and trespass claims often accompany these suits where property owners can point to flooding, saltwater intrusion, or erosion on specific land. Negligence theories argue the companies failed to take reasonable steps to prevent foreseeable harm from their products.
A sharper claim is failure to warn. Plaintiffs allege that major energy companies conducted internal research in the 1970s and 1980s confirming that burning fossil fuels would warm the planet and cause serious harm, then buried the findings and funded campaigns casting doubt on climate science. The argument runs that communities, had they known sooner, could have built and planned differently to protect themselves. Concealment made that impossible.
Across all these theories, causation remains the hardest piece. A plaintiff harmed by a hurricane has to connect that specific event to a specific company’s emissions, which is difficult when greenhouse gases mix globally. Defendants argue, consistently, that no single company’s output can be meaningfully linked to any particular storm or local impact.
How Attribution Science Changed the Causation Problem
The emergence of attribution science over the past decade has started to answer the causation question in ways courts can work with.
Event attribution uses climate models to estimate how much human-caused warming raised the probability or intensity of a specific weather event. A landmark study of the 2003 European heatwave found that climate change had at least doubled the likelihood of that event, and more likely increased it sixfold. That kind of probabilistic finding fits the ordinary tort standard that harm was “more likely than not” caused by the defendant’s conduct.
Source attribution then traces global emissions back to individual contributors. Researchers estimate each company’s proportional share of cumulative greenhouse gas emissions and extrapolate a proportional responsibility for documented climate impacts. This mirrors the statistical and proportional reasoning courts have long accepted in toxic tort and public health cases.
Defendants still contest the models and point to confounding factors like land-use change and population growth. But courts are increasingly willing to let juries weigh attribution evidence rather than dismiss cases at the threshold, and European courts have already relied on attribution research in evaluating government obligations under the Paris Agreement.
Procedural Barriers That Decide Most Cases
Many climate suits never reach a verdict because defendants raise procedural objections that can end a case before it starts. These barriers matter as much as the substantive theories.
Standing
Federal courts require plaintiffs to meet the three-part standing test from Lujan v. Defenders of Wildlife: a concrete and actual injury, a causal connection between that injury and the defendant’s conduct, and a likelihood that a court ruling will actually fix the problem.1Cornell Law Institute. Lujan v Defenders of Wildlife 504 US 555 Each element creates friction. Injuries from gradual warming can look abstract. Tracing harm to one defendant is hard when thousands of sources contribute. And courts sometimes question whether ordering one company or government to cut emissions would meaningfully address a worldwide problem. Plaintiffs who can point to specific, documented harm, a flooded neighborhood, a damaged water system, measurable coastal erosion, generally do better than those alleging generalized environmental degradation.
Preemption and the Pending Supreme Court Case
Whether federal law blocks climate tort claims is now the single most consequential question in the field. In 2011, the Supreme Court ruled in American Electric Power v. Connecticut that the Clean Air Act and the EPA’s authority under it displaced any federal common law right to seek emissions reductions from power plants.2Justia Law. American Electric Power Co v Connecticut 564 US 410 That decision closed off federal nuisance claims but left open whether state-law tort claims survive.
The current wave of lawsuits has been filed under state law specifically to avoid that problem. Fossil fuel defendants respond by removing cases to federal court and arguing that state tort claims involving interstate and international emissions are inherently federal and therefore blocked. Plaintiffs fight to send cases back to state court, where their claims are more likely to proceed on the merits.
The Supreme Court granted review of that exact issue in Suncor Energy v. Board of County Commissioners of Boulder County in February 2026. Merits briefing runs through the summer, with the petitioners’ brief due in May and respondents’ brief due in July.3Supreme Court of the United States. Suncor Energy v Board of County Commissioners No 25-170 A ruling that federal law preempts state climate tort claims would effectively end most pending municipal lawsuits. A ruling for the plaintiffs would clear the way for dozens of cases to proceed to discovery and trial.
The Political Question Doctrine
Early climate suits were dismissed on the theory that regulating greenhouse gases was a political question for Congress and the executive, not the courts. A federal district court called the claims “patently political” and “transcendently legislative” in 2005. That reasoning has largely faded. The Second Circuit reversed that dismissal, and when the Supreme Court took up AEP v. Connecticut, no justice argued the political question doctrine barred review. Courts now address climate claims on substantive grounds rather than refusing to hear them.
Suits Against Governments
A separate track of litigation targets government inaction. These cases argue that officials violate constitutional or public trust duties when they approve fossil fuel projects, fail to regulate emissions, or ignore climate risks in planning.
The Public Trust Doctrine
The public trust doctrine is a common law principle holding that governments must manage certain natural resources, traditionally navigable waters, tidelands, and submerged lands, for the public rather than let them be degraded for private gain. Climate plaintiffs have tried to expand the doctrine to cover the atmosphere, arguing governments hold the climate system in trust for present and future generations.
Courts have been skeptical. The Supreme Court noted in PPL Montana that the public trust doctrine is fundamentally state law, which has limited its reach in federal cases. The federal district court in Juliana v. United States sidestepped the atmosphere question, finding it unnecessary to resolve because plaintiffs had alleged trust violations connected to the territorial sea. No court has definitively accepted the atmosphere theory.
State Constitutional Environmental Rights
Some state constitutions offer stronger ground. Pennsylvania, Montana, and New York have “Green Amendments” in their bills of rights, provisions explicitly guaranteeing a right to a clean and healthy environment. Several other states have environmental protections located elsewhere in their constitutions, where placement outside the bill of rights limits enforceability.
Montana’s provision produced the most significant plaintiff victory to date. In Held v. State of Montana, sixteen young plaintiffs challenged state energy policies that promoted fossil fuel extraction in violation of their constitutional right to a clean and healthful environment. The trial court ruled entirely in their favor in August 2023, and the Montana Supreme Court upheld the decision in December 2024. The state has yet to bring its policies into compliance, and in December 2025 the plaintiffs filed a follow-up petition asking the Montana Supreme Court to enforce the original ruling.
Juliana and the Federal Constitutional Claim
Juliana v. United States was the highest-profile attempt to establish a federal constitutional right to a stable climate. Twenty-one young plaintiffs argued the federal government violated their due process rights by knowingly fostering a fossil fuel-dependent energy system. The district court allowed the case to proceed, with the judge writing that “the right to a climate system capable of sustaining human life is fundamental to a free and ordered society.”4United States Courts. Juliana v United States No 18-36082 The Ninth Circuit reversed in 2020, finding the case presented a political question beyond what courts could remedy, and the Supreme Court ultimately denied review, ending the case.5U.S. Department of Justice. Justice Department Statement on Juliana Case The case failed to establish a federal constitutional climate right but generated judicial language that helped inspire the state-level cases, particularly Held, that have since succeeded.
Greenwashing and Consumer Protection Suits
A growing category of climate litigation targets what companies say about their environmental performance rather than what they emit. These cases allege that businesses make false or misleading sustainability claims to attract eco-conscious consumers, a practice commonly called greenwashing.
The legal foundation is straightforward. The Federal Trade Commission Act empowers the FTC to prevent unfair or deceptive acts in commerce and seek monetary redress for consumers harmed by them.6Federal Trade Commission. Federal Trade Commission Act State consumer protection statutes give parallel authority and often allow private plaintiffs to sue directly. The FTC’s Green Guides offer guidance on what environmental marketing claims require substantiation, though they carry no independent force of law.
Cases focus on vague branding, “carbon neutral,” “net zero by 2040,” “eco-friendly,” used without evidence to back it up. Courts and regulators ask whether a reasonable consumer would be misled. Unlike tort claims, greenwashing suits don’t require proof of atmospheric damage or physical harm. The question is simply whether the marketing was honest, which makes the bar to bring a case meaningfully lower.
Enforcement has picked up. In a joint action, the FTC, SEC, CFTC, and DOJ pursued CQC Impact Investors for submitting false data to carbon credit registries, resulting in a $1 million fine and invalidation of all fraudulent offsets. A class action against Oatly alleging overstated sustainability claims settled for $9.5 million in 2024. The National Advertising Division directed JBS USA to stop advertising a “net-zero by 2040” goal it had no concrete plan to achieve. The penalties remain modest, but the direction is clear.
Securities Suits and Climate Risk Disclosures
Publicly traded companies face a separate set of obligations under federal securities law. The Securities Exchange Act of 1934 requires corporations to disclose information investors would find relevant, and the SEC enforces those requirements against companies that disseminate fraudulent or incomplete information.7Cornell Law Institute. Securities Exchange Act of 1934 Climate change creates two kinds of material risk a company may need to disclose: physical risks (damage to facilities from flooding, wildfire, or extreme heat) and transition risks (financial losses from shifting regulations, carbon pricing, or declining demand for fossil fuels).
Shareholders sue when they believe a company hid or downplayed these risks, inflating its stock price. When the true exposure surfaces, through a climate disaster, a new regulation stranding assets, or a delayed reckoning, investors suffer losses they argue they should have been warned about. Litigation over stranded assets, particularly fossil fuel reserves that may never be economically extractable, falls squarely into this category.
The regulatory landscape here is in flux. The SEC finalized rules in 2024 that would have required standardized climate risk disclosures, including greenhouse gas emissions reporting. But in March 2025, the Commission voted to stop defending those rules in court and withdrew its legal arguments.8U.S. Securities and Exchange Commission. SEC Votes to End Defense of Climate Disclosure Rules The rules had already been stayed pending litigation. As of 2026, there is no federal mandate for standardized climate risk disclosure, leaving investors to rely on general materiality principles and private litigation to hold companies accountable for omissions. California’s own climate disclosure law, which requires large companies doing business in the state to report emissions, may partially fill the void, but it faces its own legal challenges.
Human Rights Climate Cases Abroad
Outside the United States, climate litigation increasingly draws on human rights law, and some of those rulings are rippling back into domestic legal debates. The core argument is that government failure to address climate change violates fundamental rights to life, health, and private life.
The most significant decision came in April 2024, when the European Court of Human Rights ruled in KlimaSeniorinnen v. Switzerland that Switzerland had violated the European Convention on Human Rights. The Grand Chamber found that Article 8, the right to respect for private and family life, encompasses a right to effective government protection from the serious effects of climate change on life, health, and well-being. Switzerland lost because it had failed to quantify national emissions limits through a carbon budget or equivalent mechanism, leaving gaps in its regulatory framework. The court also found that Swiss courts had violated the plaintiffs’ right to a fair trial by refusing to examine the merits of their case or the underlying scientific evidence.
Litigants in these cases frequently invoke the Paris Agreement to establish a benchmark for adequate government action. While the Agreement itself is not directly enforceable in most domestic courts, it informs the standard of care. Courts ask whether a government’s emissions targets and policies are consistent with the Agreement’s goal of limiting warming to well below 2°C, and if they fall short, that shortfall becomes evidence of a rights violation. Remedies in these cases typically involve orders requiring governments to strengthen targets or implement specific adaptation measures rather than pay damages. The KlimaSeniorinnen ruling is now a reference point for similar challenges in dozens of countries subject to the European Convention, and its reasoning is being cited in proceedings before the International Court of Justice.
Insurance as a Quiet Pressure Point
As climate litigation grows, a quieter battle is playing out in the insurance market. Companies facing climate suits look to their liability policies for coverage, and insurers are pushing back.
Standard commercial general liability policies contain “pollution exclusions” originally designed for traditional environmental contamination like chemical spills and factory runoff. Whether those exclusions also cover greenhouse gas emissions is unsettled. Jurisdictions that read policy language broadly tend to classify any “irritant or contaminant” as a pollutant, which could sweep in carbon dioxide. Jurisdictions that focus on the reasonable expectations of the insured tend to limit the exclusion to traditional pollutants, leaving room for climate-related coverage.
Directors and officers face their own exposure. Climate-related claims against corporate leadership, for failing to disclose risks, making misleading sustainability commitments, or ignoring foreseeable threats to the business, increasingly trigger D&O insurance. Insurers have responded by developing model climate exclusion clauses to limit their liability. If those exclusions become standard, corporate officers may find themselves personally exposed to climate-related suits with no insurance backstop. The insurance market is becoming an indirect enforcement mechanism for climate accountability, even where regulation and litigation leave gaps.