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News Archive

February 23, 2026

U.S. Supreme Court decides to hear climate case against ExxonMobil and Suncor Entities

Court will consider companies’ bid for immunity from damages claims after Colorado localities’ win in state supreme court

Key points:

  • The United States Supreme Court has decided to review a Colorado Supreme Court decision allowing Boulder County and the City of Boulder's lawsuit against ExxonMobil and two Suncor entities to proceed.
  • The communities filed this lawsuit years ago, alleging that the oil companies’ actions have greatly contributed to an altered climate that harms the communities.
  • The rising costs of dealing with the climate crisis led these communities to take legal action so that the costs do not fall on taxpayers alone.
  • This legal fight has been going on since 2018.
  • Boulder County has argued that the case belongs in local court.
  • To receive this information in another language, contact Emily Sandoval by phone 303-413-7095 or email esandoval@bouldercounty.gov

Boulder, CO — The United States Supreme Court today decided to review last year’s Colorado Supreme Court ruling that allowed the City of Boulder and Boulder County’s climate accountability case to proceed—granting Exxon Mobil and Suncor entities’ petition to hear the case.

The City of Boulder and Boulder County’s case seeks to hold the oil companies responsible for knowingly contributing to climate change while concealing the dangers of their products. In its May ruling last year, the Colorado Supreme Court concluded that “federal law did not preempt Boulder’s claims and that those claims could therefore proceed under state law.” In their petition to the U.S. Supreme Court, the companies claimed that federal law shields them from state-level accountability for in-state harms. The Supreme Court will now consider the companies’ bid for immunity.

The grant comes as the realities of climate alteration continue to mount for Colorado. Colorado is one of the fastest-warming states and continues to experience injuries associated with rising temperatures. The City of Boulder and Boulder County face significant and rising costs to address the impacts of climate change—costs that would otherwise fall on local taxpayers. Their lawsuit aims to ensure that the corporations that caused the harm pay their fair share, rather than shifting the burden to Colorado communities.

Boulder County, San Miguel County, and the City of Boulder originally sued Suncor entities and Exxon in April 2018. San Miguel County’s case, which was separated from the City of Boulder and Boulder County case, is now proceeding in Denver district court and was placed on hold pending the companies’ petition.

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

Statements

  • “The oil companies have tried every avenue to delay our climate accountability case or move it to an out of state court system,” said Boulder County Commissioner Ashley Stolzmann. “As everyone continues to face rising costs that put budgets under pressure, we must hold oil companies accountable for the significant harm they’ve caused our communities. We move forward with renewed energy and purpose for the next step toward justice.”
  • “Local communities are living with the mounting costs of climate change. The Supreme Court should affirm Colorado's right to hold these companies accountable for the harm they have caused in Colorado,” said City of Boulder Mayor Aaron Brockett.
  • “Our case is, fundamentally, about fairness. Boulder is already experiencing the effects of a rapidly warming climate, and the financial burden of adaptation should not fall solely on local taxpayers. We are hopeful that the Supreme Court will not hamstring our right under Colorado law to seek the resources needed to build a safer, more resilient future,” said City of Boulder Climate Initiatives Director Jonathan Koehn.
  • “This case is about remedying harm to local Coloradans. Exxon’s argument that state law cannot provide damages for in-state harms has no basis in the Constitution. The Supreme Court has rejected similar arguments, and should reject this one,” said Richard Herz, Chief Litigation Attorney of EarthRights International.
  • “This lawsuit is based on a fundamental legal principle: you have to pay your fair share for the harm that you cause. Nothing in federal law stops Colorado courts from applying that principle to the fossil fuel industry’s deception about climate change and their knowing alteration of our climate, as the Colorado Supreme Court has found,” said attorney Marco Simons, Law Office of Marco B. Simons.
  • “The Colorado Supreme Court properly ruled that Colorado law is fully capable and appropriate to address climate harms occurring in Colorado. After over seven years, Boulder County and the City of Boulder should be permitted to have their day in court,” said Kevin Hannon, Partner, Singleton Schreiber, LLP.

Aerial photo of the town of Lyons in Boulder County, Colorado.

The town of Lyons in Boulder County, Colorado.

Collage of all three Boulder County Commissioners