On February 23, 2026, the U.S. Supreme Court agreed to hear arguments in a climate‑change lawsuit brought by Boulder County and the city of Boulder against Exxon Mobil and Suncor Energy entities.
The energy companies had asked the Colorado courts to dismiss the case, arguing that federal environmental law and the federal government’s foreign‑affairs role should take precedence over the plaintiffs’ state law claims.
The Colorado Supreme Court held in May 2025 that federal law did not preempt Boulder’s state-law tort claims and allowed the litigation to proceed in Colorado state court. Exxon Mobil and Suncor then asked the U.S. Supreme Court to decide whether federal law bars or displaces these types of state law climate‑change lawsuits. The Trump administration also requested that the high court take up the case when it filed a brief supporting the oil companies’ position.
The Supreme Court agreed and will hear arguments sometime next fall.
Why It Matters
Dozens of lawsuits have been filed in recent years alleging that companies that contribute large amounts of greenhouse gas emissions can be held accountable for their role in climate change. Cities and states often file these cases under state law, in part because they view state forums as more favorable than federal courts for these claims.
In similar litigation, federal district and appellate courts have split on the issue. Some have rejected removal arguments, holding that the state‑law framing of these climate tort claims keeps them in state court, while others have held that federal law does preempt state law given the current complex web of federal and international environmental laws on greenhouse gas emissions.
A Lot at Stake
Advocates of a strong climate policy fear that the EPA’s recent repeal of its 2009 Endangerment Finding is just the first domino in a broader rollback of environmental restrictions imposed on energy producers, auto manufacturers, and other industries. Perhaps paradoxically, the EPA’s repeal may harm the government’s case, as a rollback of federal regulations suggests that federal laws may not completely preempt state regulations on greenhouse gas emissions.
However, the Supreme Court’s decision to review Boulder’s case, in a term when the federal government is also reassessing its climate obligations, has led some observers to think the Court may be receptive to the energy companies’ arguments, even though it denied cert in a similar Hawaii‑based climate lawsuit last year.
Ruling on the companies’ bid to shut down Boulder’s lawsuit is not straightforward. The case presents several layers of issues, starting with whether the Supreme Court has statutory and Article III jurisdiction to hear this case at all (given that it comes from a state court and is at an interlocutory stage).
If the Court reaches the merits, it will have to decide whether federal law preempts or otherwise displaces state law claims seeking damages for greenhouse‑gas‑related harms. A broad ruling that federal law occupies the field (known as “complete preemption”) could sharply limit state‑law remedies for climate‑related injuries. The justices may also consider how EPA’s new position on its authority to regulate greenhouse gases affects the balance between federal and state law in cases like Boulder’s. If they conclude that the federal scheme cuts off state‑law claims, Boulder’s suit would likely be dismissed in state court.
If the Court resolves Boulder’s case with a broader opinion about the role of state law, its decision will have outsized consequences for the many similar climate‑damage suits now pending in courts across the country. Plaintiffs in well over a dozen pending suits against alleged polluters will be holding their breath in the meantime.
Related Resources
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- Synthetic Food Dyes Targeted by U.S. Health Officials (FindLaw’s Law and Daily Life)
