The day before Thanksgiving 2025, a Connecticut Superior Court judge rejected every one of ExxonMobil's motions to strike the state's consumer fraud lawsuit. The court concluded that the lawsuit was not precluded or preempted by federal law and sufficiently alleges unfair and deceptive acts or practices under the Connecticut Unfair Trade Practices Act.
Connecticut is one of four New England states—alongside Massachusetts, Rhode Island and Maine—where climate lawsuits filed by state attorneys general are now advancing past the procedural stages that consumed the better part of a decade. The jurisdictional battles that allowed fossil fuel companies to delay these cases in federal court have largely been resolved.
What's left is the substance: what companies knew, when they knew it and what they said to consumers while they knew it.
- New England climate cases have cleared early hurdles and are moving into discovery, shifting risk from theory to real cost and operational exposure.
- U.S. climate litigation now totals 1,986 cases, with state consumer fraud claims driving the next wave, especially in Massachusetts, Connecticut and Rhode Island.
- Venue fights are largely over. State courts are winning, while federal rollbacks may reopen claims defendants thought were closed.
- Firms that prepare now gain speed, credibility and pricing leverage as 2026 rulings reshape demand.
Climate Litigation Statistics: How Fast the Field Is Growing
Climate litigation has grown from a legal curiosity into a global industry. A cumulative 3,099 climate-related cases were filed across 55 national jurisdictions and 24 international or regional courts and tribunals, as of June 2025, according to the UN Environment Programme. This compares to just 884 cases in 2017. That's more than a 250% increase in under a decade.
The United States remains the most active jurisdiction with 1,986 cases filed to date. And while the overall global rate of new filings has moderated as litigation matures, the character of U.S. cases is shifting in a direction that carries specific implications for New England.
Cases are no longer mostly challenges to federal regulations or early-stage nuisance suits. They are consumer protection and fraud actions in state courts, with motions to dismiss largely behind them, moving toward discovery and trial.
Around 20% of climate cases filed in 2024 targeted companies or their directors and officers. The legal exposure is no longer theoretical. It is increasingly a financial risk to corporations.
Climate Lawsuits by State: Massachusetts, Rhode Island, Connecticut and Maine
Massachusetts is the jurisdiction every climate litigator in the country is watching. The AG's lawsuit against ExxonMobil, filed in 2019, is now deep into pre-trial discovery and is widely regarded as the case most likely to go to trial first among the dozens of similar actions pending across the country. If the Massachusetts suit wins a ruling that fossil fuel companies can be held liable for climate damages, it would prompt a flood of cases as other attorneys general seek money for their states.
Rhode Island has the longest-running case. Filed in 2018, it was the first state climate lawsuit in the nation. In April 2025, a state superior court rejected Chevron's procedural challenge and found the state had a good-faith basis for its allegations, keeping the case moving toward discovery. The Rhode Island legislature is also considering a climate superfund bill that would charge fossil fuel companies based on their share of greenhouse gas emissions between 1990 and 2024..
In Connecticut, a November 2025 state court ruling rejected Exxon's argument that federal common law prevents the state from pursuing civil penalties and disgorgement of profits for more than five decades of allegedly unlawful conduct. Meanwhile, Maine's case against fossil fuel companies was remanded to state court in 2025 after federal defendants failed to establish grounds for removal.
Basil Seggos, partner and senior policy director at Boston-based Foley Hoag and former commissioner of the New York State Department of Environmental Conservation, has been direct about the trajectory: "The next 12 months are going to be extraordinarily important for the nation's long-term protection of the environment and commitment to renewable energy."
State Court vs. Federal Court: Why Climate Plaintiffs Are Winning on Venue
The venue choices in these cases are deliberate. Plaintiffs are in state court because state court is where their strongest claims live, and because a decade of federal appellate rulings has validated that choice. Seven federal appeals courts and more than a dozen federal district courts have unanimously ruled against the fossil fuel industry's arguments to remove climate accountability cases to federal courts, and the U.S. Supreme Court has declined to hear appeals of those rulings.
The legal theory behind the state court strategy is also well-developed. The early wave of public nuisance claims that failed in federal court after the Supreme Court's 2011 decision in American Electric Power v. Connecticut gave way to claims sounding in consumer protection, unfair trade practices, and fraud, theories that do not ask courts to regulate emissions but rather to hold companies accountable for what they said to consumers. That distinction has survived every attempt to collapse it.
It is about to become even more consequential. The Trump administration's February 2026 repeal of the EPA's 2009 endangerment finding—the scientific determination that greenhouse gases pose a public health threat—has unsettled the legal landscape in ways that cut against fossil fuel defendants.
University of Pennsylvania law professor Sarah Light noted the implication directly: “If the Clean Air Act no longer applies to greenhouse gas emissions, then there’s no comprehensive statutory scheme in which Congress intended to displace nuisance claims, so they would likely be able to proceed in court.” What was once a closed door in federal court may be opening again while the state court track continues to advance on a parallel and increasingly fast-moving schedule.
Which Law Firm Practice Areas Face the Most Climate Litigation Exposure
The growth in climate litigation is not concentrated in a single practice area, and for New England firms, understanding where demand is expanding matters for both hiring and positioning.
Environmental and energy litigation is the most obvious beneficiary, and large firms with established climate practices are capturing significant work. AmLaw firms with dedicated climate practices are competing aggressively for the largest mandates on both sides.
Mid-size New England firms face a different calculus. They cannot match the resources of national practices on sprawling multiparty litigation. But they hold significant advantages in local court relationships, regional regulatory familiarity, and the ability to serve the municipal clients that are filing their own climate actions or responding to infrastructure disputes.
Insurance law is also absorbing growing complexity. New lawsuits focused on financial harm are increasingly asking courts to define how climate damages should be valued and repaired. Coverage disputes, climate risk modeling, and policyholder litigation against carriers who have withdrawn from coastal markets are emerging as a distinct sub-specialty.
A Preview of Climate Litigation to Come
Corporate governance and ESG compliance practices are under different but equally significant pressure. Companies doing business across New England face climate risk disclosure obligations, internal governance requirements, and litigation exposure for greenwashing claims.
A proposed class action filed in Massachusetts federal court in late 2025 alleged that a clean energy company misrepresented how its electricity rates were calculated and misled environmentally conscious consumers about the source of energy it supplied. That case is a preview of the kind of consumer protection litigation that is not limited to fossil fuel majors.
The creation of dedicated climate litigation teams reflects the recognition that climate cases require a specific combination of tort, administrative, and regulatory expertise that general environmental lawyers do not always possess. Regional firms that have not yet made that investment are increasingly at a disadvantage when competing for climate-intensive clients, particularly in insurance, municipal law and the energy sector.
How Law Firms Should Prepare for Climate Litigation in 2026 and Beyond
The Supreme Court's decision to hear Exxon v. Boulder—the Colorado climate deception case—will be the most consequential climate liability ruling in over a decade, and its implications will extend to every pending case in New England and beyond. If the Court rules that state climate lawsuits are preempted by federal law, it would be a major win for oil companies and could prevent many other pending cases from moving forward in state courts. But the repeal of the endangerment finding complicates that calculus, potentially undermining the very preemption argument fossil fuel companies have been pressing for years.
At the same time, the fossil fuel industry is pursuing a parallel legislative strategy. The American Petroleum Institute announced that blocking state climate lawsuits is a top 2026 priority, and legislation has been proposed in Congress that would grant fossil fuel companies immunity from climate accountability suits modeled on a 2005 law protecting gun manufacturers. Whether that effort succeeds will determine whether state-court litigation remains viable or whether clients face an entirely new strategic landscape.
For firms advising clients in the industries at highest risk, the guidance partners should be delivering now is not to wait. The cases in discovery in Massachusetts, Connecticut, and Rhode Island will define what discovery looks like in a climate trial. Understanding what categories of internal documents are likely to be demanded, what expert frameworks courts will accept for climate attribution, and what remedies are realistically on the table is the kind of preparation that cannot start the day after a trial date is set.
Climate litigation in New England has graduated from the docket into the discovery room. The firms that grasp that shift and staff and position themselves accordingly will define what legal leadership in this space looks like for the decade ahead.
