Climate Change Litigation: Three Cases Filed against the Same Company

American Electric Power Co. .. Connecticut established that the Clean Air Act's comprehensive regulatory scheme for greenhouse gas emissions displaces federal common law public nuisance claims against major emitters, but the case explicitly left open whether state common law nuisance claims survive the same preemption analysis.

State common law claims do not automatically share the same fate as federal common law claims in the AEP preemption analysis, because federal statutory law typically displaces federal common law when Congress provides a regulatory alternative, but federal statutory law preempts state law only under the narrower and more demanding Supremacy Clause analysis. The circuit courts have split on whether the Clean Air Act field preempts state common law climate nuisance claims, with the Second Circuit in City of New York v. Chevron Corp. .olding that state common law claims are displaced but other circuits taking different approaches in cases still working through the appellate system.

The preemption defense's availability depends significantly on whether the plaintiff brings the claim under federal common law, state common law, or a state statutory theory, because the preemption analysis differs for each. A plaintiff who carefully pleads state law public nuisance under a state statute rather than federal common law presents a harder preemption challenge for the defendant, while a plaintiff who pleads federal common law theories provides the defendant with AEP's clear preemption precedent as a defense. An attorney who handles environmental law compliance and climate change litigation matters can evaluate which preemption arguments apply to the specific claims and whether the case presents grounds for early dismissal.

The forum in which climate change litigation proceeds is among the most consequential variables in the outcome because state and federal courts apply different law, different preemption standards, different personal jurisdiction rules, and different discovery regimes that each significantly affect the plaintiff's ability to prove the case and the defendant's ability to defeat it.

Plaintiffs filing climate nuisance suits strategically choose state courts in jurisdictions with favorable public nuisance law, because state court cases apply state common law that is not displaced by AEP's federal common law preemption holding and that is not subject to federal Supremacy Clause preemption in the same way. State court cases also allow plaintiffs to use state court discovery rules to reach internal company communications about climate science that plaintiffs allege show decades of knowing concealment of climate risks.

The Supreme Court's 2021 decision in BP P.L.C. .. Mayor and City Council of Baltimore addressed the scope of appellate review available when cases are removed to and then remanded from federal court, holding that courts of appeals have jurisdiction to review the complete removal decision when any federal officer removal ground was asserted. This procedural ruling has affected the forum battle by giving defendants more pathways for appellate review of remand orders and slowing the pace at which remanded cases return to state court. An attorney who handles environmental liability and climate change litigation defense matters can evaluate the removal strategy and the jurisdictional arguments most likely to succeed in the specific circuit.

The Montana Supreme Court's 2024 decision in Held v. Montana upheld a ruling that a state law allowing fossil fuel project permits without climate review violated Montana's constitutional right to a clean and healthful environment, creating one of the first judicial holdings worldwide that a government's failure to account for climate change in permitting violates a constitutional right. The decision is significant not because Montana's specific constitutional provision transfers directly to other states but because the litigation theory it validates is being pursued in multiple other state court systems, expanding the constitutional track of climate change litigation alongside the common law nuisance and securities fraud tracks that are further developed.

Corporate defense in climate change litigation requires a strategy that addresses the causation challenges in government nuisance suits, the scienter elements in securities fraud claims, the materiality disputes in greenwashing cases, and the procedural arguments available to challenge the forum and standing in each category simultaneously.

In government nuisance suits, the most powerful defenses are the preemption argument under AEP and its progeny, the causation challenge to the attribution science methodology, the standing challenge to the government plaintiff's ability to demonstrate particularized harm traceable to the specific defendants' emissions, and the political question doctrine, which some courts have held bars courts from adjudicating what is essentially a policy dispute that the political branches must resolve. None of these defenses guarantees dismissal in all circuits, but they each create opportunities for early case resolution through motions practice before discovery into internal climate science communications begins.

Climate litigation risk management requires companies to audit their public climate commitments, sustainability marketing, and climate-related disclosures for internal consistency, because inconsistencies between what the company says in marketing materials and what it discloses in regulatory filings are among the most productive sources of evidence for plaintiffs in both securities and greenwashing claims. An attorney who handles environmental and climate change and climate litigation risk management matters can conduct a privileged audit of the company's climate-related communications and develop a disclosure consistency framework that reduces the evidentiary surface area available to plaintiffs across all three litigation tracks.

Climate change litigation encompasses three primary legal tracks that operate simultaneously against the same corporate defendants. The first is government suits by states and municipalities seeking money damages for climate adaptation costs under public nuisance, fraudulent concealment, and related state common law theories. The second is securities fraud class actions alleging that companies made materially misleading statements about climate risk in SEC filings, seeking stock price recovery under Rule 10b-5. The third is consumer fraud and greenwashing claims alleging that net-zero commitments and sustainability marketing were materially misleading under state UDAP statutes and FTC Green Guides standards. Each track involves different legal standards, different parties, different standing requirements, and different remedies.

The Supreme Court's 2011 decision in American Electric Power Co. .. Connecticut held that the Clean Air Act's comprehensive regulation of greenhouse gas emissions displaces federal common law public nuisance claims against major emitters, eliminating federal common law nuisance as a theory in climate suits. The decision did not resolve whether state common law nuisance claims against the same defendants are also preempted, leaving that question to the lower courts. Plaintiffs responded by refiling cases in state court asserting only state common law theories, creating the forum battle that now dominates the procedural posture of government climate suits. The preemption analysis for state common law claims is less settled than for federal common law claims, and different circuits have reached different conclusions.

Greenwashing claims allege that a company's environmental marketing statements were materially misleading to consumers, including claims that products are carbon neutral, net-zero, sustainable, or eco-friendly when those claims are not adequately substantiated. The FTC Green Guides at 16 C.F.R. Part 260 provide standards for environmental marketing claims, specifying that carbon offset claims must be substantiated, that environmental certifications must be clearly disclosed, and that general environmental benefit claims are deceptive unless supported by specific substantiated environmental improvements. Companies that made net-zero commitments in marketing without a credible disclosed pathway to achieve them face state UDAP claims that the commitments were deceptive regardless of intent, because materiality and likely consumer deception are objective standards applied to the reasonable consumer.

Director and officer liability for climate disclosure failures arises through two parallel theories. Securities fraud class actions allege that directors and officers who certified the company's SEC filings made materially misleading statements about climate risk, with individual liability attaching when the officer signed or certified the allegedly misleading disclosure with scienter. Separately, the Caremark duty of oversight requires boards to implement a system for monitoring material risks including climate-related risks, and directors who failed to establish board-level oversight of climate risk management face derivative suit liability for that failure. An attorney who handles D&O and professional liability and climate litigation defense matters can evaluate whether the board's current climate oversight structure satisfies both standards.

Standing in federal climate litigation requires a plaintiff to demonstrate injury in fact that is concrete, particularized, and actual or imminent; causation that traces the injury to the defendant's conduct rather than to global aggregate emissions generally; and redressability showing that a favorable court decision would remedy the specific harm. The causation element is particularly challenging in climate cases because climate change results from global aggregate emissions from thousands of sources over decades, making it difficult to demonstrate that any single defendant's emissions caused the specific local harm the plaintiff suffered. The Ninth Circuit's 2021 decision in Juliana v. United States held that youth plaintiffs challenging the government's fossil fuel policies lacked standing to obtain the broad systemic relief they sought because courts could not redress that injury through individual litigation.

The most effective risk management steps target the inconsistencies between climate-related marketing and regulatory disclosures that plaintiffs use most productively as evidence. Companies should audit net-zero commitments for disclosed transition plans that substantiate the commitment, ensure carbon offset claims satisfy FTC Green Guides substantiation standards, verify that SEC climate disclosures fully reflect material climate-related risks disclosed elsewhere in the company's communications, and document board oversight of climate risk through committee charters and board minutes. The goal is internal consistency across the three evidentiary records that plaintiffs in nuisance, securities fraud, and greenwashing cases all examine: internal documents about what the company knew, public disclosures about what the company said, and marketing about what the company promised. An attorney who handles environmental compliance and litigation and climate litigation risk management matters can conduct a privileged audit and develop a consistency framework across all three records.