LOUISVILLE, COLO. — The U.S. Supreme Court will hear oral arguments in a climate change lawsuit involving Boulder County and the city of Boulder on the first day of its new term. The high court set the case for Monday, Oct. 5, 2026, marking the opening argument of the fall 2026 Supreme Court term.

Eight of the nine justices will participate in the case, as Justice Samuel Alito recused himself one week before arguments due to his ownership of stock in oil companies. The litigation originated in 2018 when the city and county of Boulder filed suit against Suncor Energy and ExxonMobil.

Boulder claimed that Suncor Energy and ExxonMobil violated state law by misleading the public about their role in climate change. The local governments sought unspecified damages to help cover the costs of worsening climate-related disasters. Federal government attorneys contend the lawsuits represent an unconstitutional attempt to regulate greenhouse gas emissions through the courts.

Federal attorneys assert that the Clean Air Act gives the federal government, not individual states, authority over emissions regulation. In a court filing, federal government attorneys stated, "No one state can superimpose its own regulatory preferences on the rest — least of all to address a global problem that exists almost entirely outside its borders and affects the world at large."

The damages cited in the suit include losses from the Marshall Fire on December 30, 2021. Climate change was a contributing factor in the 2021 Marshall Fire. The blaze became the costliest wildfire in Colorado history, with total damage estimated at $2 billion. It burned over 6,600 acres and destroyed more than 1,000 structures.

Tawnya Somauroo's home in Louisville, Colorado, was destroyed in the 2021 Marshall Fire. She described the aftermath of the disaster and the financial burden placed on residents. "We lost our homes and they left us to figure out for ourselves how to make our neighborhoods safe again," Somauroo said.

Somauroo expressed the view that industry participants should share responsibility for the costs associated with climate-related disasters. "At the end of the day, it comes out of our pockets, you know? And it does feel like maybe the oil and gas industry should have a part in this," she said.

Sam Sankar, senior vice president, defended the local governments' approach to seeking compensation. "Boulder County and city aren’t trying to change what’s happening in Texas or New York, they’re trying to get compensation for things happening now in Colorado," Sankar said.

Why It Matters

Boulder County is one of many jurisdictions across the United States pursuing legal action against oil and gas companies to help cover the costs of climate-linked disasters. The outcome of this case could shape how other municipalities pursue similar legal strategies against energy corporations.

The litigation unfolds amid evolving federal regulations. In 2020, the Environmental Protection Agency finalized the Affordable Clean Energy Rule, which replaced the Clean Power Plan and permitted coal-fired power plants to operate with less stringent emissions standards. ExxonMobil has faced multiple legal challenges related to its climate change disclosures, including a 2021 settlement with the New York State Attorney General’s Office over alleged misleading statements about the company’s climate impact and efforts to reduce emissions.

What's New

In 2018, Boulder County and the City of Boulder sued Suncor Energy and ExxonMobil, alleging the companies contributed to climate change and misled the public about the risks of their products. This is the earliest incident involving these operators mentioned in the sources. Boulder County has a long history of environmental advocacy and was among the first jurisdictions in Colorado to adopt a climate action plan in 2007, aimed at reducing greenhouse gas emissions and promoting sustainability.

The U.S. Supreme Court scheduled oral arguments for the case on Monday, Oct. 5, 2026, which is the first case of the fall 2026 Supreme Court term. Suncor Energy has faced criticism for its carbon footprint, with the company emitting a significant volume of CO2 equivalent annually as of 2025, according to data from the International Energy Agency.