U.S. Supreme Court to hear Boulder climate case Monday

The U.S. Supreme Court will hear oral argument for Boulder County and the City of Boulder's lawsuit against ExxonMobil and Suncor Energy on Monday, Oct. 5, the first case of the fall 2026 Supreme Court term. Arguments are scheduled to begin at 10 a.m. (8 a.m. Mountain Time).

Boulder County and the City will be represented in the argument by Kevin Russell of Russell & Woofter LLC. Russell will deliver his argument and take questions from the Justices.

Visit the U.S. Supreme Court website to listen to a livestream of the oral arguments.

The counsel team and clients will not be available for media interviews in advance of the argument.

About the Case

The City of Boulder and Boulder County seeks to hold the oil companies responsible for what they allege are harms to Boulder resulting from the companies knowingly contributing to the harmful alteration of the climate while concealing the dangers of their products and misleading the public.

Boulder County and the City of Boulder originally sued Suncor entities and ExxonMobil in April 2018. Since 2018, the lawsuit has won at every stage and survived repeated attempts by the companies to move or dismiss it.

The United States Supreme Court will be reviewing last year's Colorado Supreme Court ruling that allowed the case to proceed. In its May 2025 ruling, the Colorado Supreme Court concluded that "federal law did not preempt Boulder's claims and that those claims could therefore proceed under state law." The companies claim that federal law shields them from all accountability for harms from altering the climate, and that no state law can apply even where they cause harm in Colorado. The Supreme Court is considering the companies' bid for immunity.

The lawsuit seeks to ensure fossil fuel companies pay their fair share for climate-driven harms affecting local communities. The ultimate question in the case is whether these companies should pay their fair share of the rising costs of climate impacts on Colorado, or whether Boulder taxpayers must bear these costs alone.

The lawsuit is not about regulating emissions or stopping fossil fuel production. Colorado is already experiencing trends associated with climate change such as extreme heat, wildfires, drought, and poor air quality, all of which create significant public costs.

The plaintiffs are represented by Richard Herz, Michelle Harrison, and Alison Borochoff-Porte of EarthRights International; Kevin Hannon and Yohania Santana of Singleton Schreiber, LLP; the Law Office of Marco B. Simons; and Kevin K. Russell of Russell & Woofter LLC.

For more information on the case, visit the Boulder County website.