U.S. Supreme Court Hears Boulder Climate Case

Today, the U.S. Supreme Court heard oral arguments in the City of Boulder and Boulder County’s lawsuit against ExxonMobil and Suncor Energy. The lawsuit seeks to hold the oil companies responsible under state law for harms to Boulder resulting from the companies knowingly contributing to climate change while concealing the dangers of their products. The plaintiffs argued that the case should be allowed to move forward, and that the Court should reject Exxon's argument that the company is immune from Boulder's lawsuit.

A recording of the arguments will be available online.

Following the hearing, City of Boulder City Manager, Nuria Rivera-Vandermyde issued the following statement:

Hello, my name is Nuria Rivera-Vandermyde, and I am honored to serve as the City Manager for the City of Boulder.

Today marks a milestone in a years-long effort by our community.

Today, we asked the Supreme Court to reject Exxon and Suncor’s argument that they are immune from suit for the harms they have caused to Boulder. Boulder, like other cities and counties across the country, is confronting realities associated with climate change every day, from wildfires and floods to drought, extreme heat, and growing pressures on our water and infrastructure.

Communities like ours are paying for climate impacts. Local governments don't have any choice —we have to respond. We repair roads after floods, prepare for wildfire, manage extreme heat, and protect public health. Those are real costs borne by our residents that are being exacerbated due to the alteration of the climate.

The legal question before the court is whether taxpayers must bear these costs alone or must the defendants also pay their fair share for the harms they have caused.

Today, we are asking the court to allow our case to continue. We believe communities should be able to seek a fair share of the costs associated with the impacts they are experiencing.

That is why today's arguments matter. We believe the Supreme Court should not create a special shield that prevents communities from seeking a fair contribution.

The people and institutions closest to these impacts should have a meaningful opportunity to present their evidence; that the oil companies knowingly contributed to climate alteration while concealing the dangers of their products.

In Boulder, we are fortunate to have approached this work together. The City and County have different responsibilities, different resources and different roles, but we share a community, a climate and a responsibility to the people who live there.

We know that whatever comes next, the challenges facing our community will not wait.

We will continue preparing our neighborhoods for wildfire.

We will continue protecting our water resources.

We will continue investing in resilience and working to reduce the risks and costs our community faces as our climate changes.

And we will continue to believe in a simple principle: the people who are experiencing these impacts should have an opportunity to seek a fair share of the costs.

This case is about Boulder, but it is also about communities everywhere standing up for themselves and the people they serve.

We are grateful for the opportunity to be heard today, and we are ready for whatever comes next.

Thank you.

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.

Boulder County and the City were represented in the Supreme Court argument by Kevin Russell of Russell & Woofter LLC. The plaintiffs are also represented by Richard Herz, Michelle Harrison, and Alison Borochoff-Porte of EarthRights International; Kevin Hannon and Yohania Santana of Singleton Schreiber, LLP; and the Law Office of Marco B. Simons.

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