States and Municipalities Advance Climate Change Cases as Trump Administration Attempts to Block Them
Even though the Trump administration is moving to block state- and local-level climate liability efforts, many states and municipalities are continuing to pursue lawsuits to hold fossil fuel companies responsible for harms related to climate change. The State of Hawaii filed a lawsuit against the fossil fuel industry for climate deception, while the City of Charleston in South Carolina submitted a briefing to a pending case. Both alleged that the fossil-fuel industry had engaged in a decades long campaign of misinformation about the risks of fossil-fuel consumption and climate changes. Both developments come as the Trump administration escalates its opposition to such suits, issuing on April 8 an executive order (EO), Protecting American Energy From State Overreach, targeting and filing lawsuits making constitutional challenges to state-led climate litigation and legislative actions–including a preemptive action against Hawaii just days before the state’s filing.
Hawaii Files Suit Against Oil Companies–Despite DOJ’s Preemptive Legal Threat
On May 1, 2025, Hawaii Attorney General, Anne Lopez, filed suit in Hawaii state court against 20 major oil companies and the American Petroleum Institute. The state claims that the defendants knew, as early in the 1960s, fossil fuel combustion posed “catastrophic climate risks” but concealed these risks from the public. They also actively misled consumers by marketing their products to the public as safe, necessary, or environmentally friendly. The state also argues that the companies’ alleged failure to warn and affirmative misrepresentations delayed the transition to a lower-carbon economy.
Hawaii asserts eight causes of action under state law, including negligence, public and private nuisance, trespass, failure to warn, and violations of Hawaii’s Unfair or Deceptive Acts or Practices (UDAP) statute. The complaint seeks compensatory and punitive damages, natural resource damages, and civil penalties and treble damages under the UDAP statute, as well as equitable relief to fund climate adaptation, mitigation and resilience efforts.
Notably, the state’s lawsuit was filed the day after the U.S. Department of Justice (DOJ) filed lawsuits against Hawaii and Michigan, seeking to preemptively enjoin the states from pursuing precisely this kind of tort-based climate litigation. The DOJ’s complaints heavily rely on President Trump’s April 8 EO, which directs the Attorney General to challenge state and local efforts deemed to burden domestic energy production, including, expressly, climate change litigation. The DOJ’s complaints rely heavily on President Trump’s April 8 EO, which directs the Attorney General to challenge state and local efforts deemed to burden domestic energy production–including, expressly, climate change litigation.
Against this backdrop, Hawaii’s lawsuit emerges as a test case in the growing legal battle over whether states can pursue tort claims for climate-related damages and whether the federal government can lawfully block them.
Charleston Rejects Executive Order’s Relevance in Ongoing Litigation
On April 17, in the City of Charleston’s pending climate deception lawsuit against more than two dozen fossil fuel companies, a South Carolina state court requested briefing on whether the April 8 EO has any implications on the litigation. Charleston’s 2020 lawsuit alleges the same thing as Hawaii’s new case: that the defendants misled public about climate risks associated with fossil-fuel use, resulting harms such as sea level rise, tidal floods and infrastructure damage. The City of Charleston cited the EO’s stated purpose – to challenge state and local action that “burden
identification, development, siteing, production, use, or energy resources domestically” – as well as its prospective nature in arguing that its lawsuit does not impose such burdens. The case focuses on past deceptive behavior. “
he focus of this lawsuit,” the City wrote, “is Defendants’ deceptive conduct that has caused the City’s climate change injuries.”[]Charleston further argued that the EO should not be given any deference:[T]The City submits that any deference to this Executive Order, especially given its forward-looking intent, threatens the core import of judicial review. This Executive Order or the Executive branch does not have the constitutional authority to tell this Court or the judicial systems how to rule on pending cases. The defendants cited the DOJ’s recent lawsuits against Hawaii, Michigan and other states to block similar climate tort claims as further evidence that the federal government opposes non-federal attempts to impose liability on global emissions. The defendants concluded by requesting a hearing on their pending motions to dismiss.
Climate Attribution Science Continues to Develop
As climate liability lawsuits advance, advocates hope that ongoing developments in the evolving field of climate attribution science will help address one of the most challenging, and yet-untested legal hurdles to recovery: causation. A paper published last month in the scientific journal Nature outlines a peer reviewed “end-to end” attribution framework which aims to link emissions from individual fossil-fuel producers to quantifiable and localized climate-related damage. The paper estimates that emissions traceable back to major oil and natural gas companies caused trillions of dollar in global heat-related losses between 1991 and 2021. The authors argue that their methodology supports the legal standard for “but for” causation and could be used to assess liability for both cumulative and event-specific climate harms, such as heatwaves and extreme weather events.
Plaintiffs in cases like those filed by Hawaii and Charleston may seek to utilize this paper and others in a rapidly growing body of attribution science to support proof of causation. It is not yet clear whether the judges will find these emerging methodologies reliable enough to satisfy the standards of admissibility for expert evidence. And, even if so, it remains to be seen whether and to what extent courts will find them sufficient to establish causation under applicable state tort doctrines against the weight of any rebuttal evidence that may be developed.
Looking Ahead: Courts Will Decide the Balance of Power
These legal battles are unfolding in courts across the country, with several constitutional questions now squarely at issue. As these cases move into expert discovery and liability phases, the reliability and admissibility of emerging climate attribution science will likely take center stage. This will raise novel questions under Rule 702 and analogous state-law evidentiary standards. As these cases move into expert discovery and liability phases, the reliability and admissibility of emerging climate attribution science will likely take center stage–raising novel questions under Rule 702 and analogous state-law evidentiary standards.
Pillsbury will continue to monitor these developments closely and stands ready to assist clients in navigating the expanding legal, regulatory, and reputational risks posed by the evolving climate litigation landscape.
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