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# Colorado Climate Case Opens Supreme Court Term Monday
- URL: https://www.theamericanquorum.com/state-news-colorado-2026-09-30-b/
- Published: 2026-09-30T17:57:15.000Z
- Updated: 2026-09-30T17:57:15.000Z
- Description: The Supreme Court will hear Boulder’s climate lawsuit against ExxonMobil and Suncor on Oct. 5, testing whether federal law blocks Colorado tort claims and whether the justices have jurisdiction at this stage.
- Author: News Desk
- Tags: Policy, Colorado

The U.S. Supreme Court will open its new term Monday, Oct. 5, with a Colorado dispute that could decide whether Boulder’s climate-damages lawsuit against ExxonMobil and Suncor may proceed under state law. The [court docket](https://www.supremecourt.gov/docket/docketfiles/html/public/25-170.html?ref=theamericanquorum.com) identifies two questions: whether federal law precludes state-law claims over harms attributed to global greenhouse-gas emissions, and whether the justices have statutory and constitutional jurisdiction to hear the case at this stage.

Boulder County and the City of Boulder filed the lawsuit in 2018\. They allege that the companies’ production, promotion and sale of fossil fuels contributed to local climate-related damage and that the companies misled the public about the risks. The communities seek monetary relief under Colorado claims including nuisance, trespass, unjust enrichment and civil conspiracy; they are not asking the court to set emissions limits.

## How the case reached Washington

The [Colorado Supreme Court ruled in 2025](https://www.coloradojudicial.gov/system/files/opinions-2025-05/24SA206%5F0.pdf?ref=theamericanquorum.com) that the claims were not displaced by federal law and could continue in state court. Its decision was narrow: the state justices did not decide whether Boulder would prove its allegations or how damages should be calculated. They upheld the rejection of the companies’ federal-preemption defense at the motion-to-dismiss stage.

ExxonMobil and Suncor argue that claims tied to interstate and international emissions necessarily arise under federal law and cannot be governed by one state’s tort rules. Boulder responds that its lawsuit seeks compensation for local injury caused in part by allegedly deceptive commercial conduct and fits within established Colorado law. The parties’ competing positions and merits briefs are collected on the [Supreme Court’s public docket](https://www.supremecourt.gov/docket/docketfiles/html/public/25-170.html?ref=theamericanquorum.com).

The justices added a threshold complication when they granted review: whether the Supreme Court has jurisdiction over an interlocutory state-court decision that allows litigation to continue but does not finally resolve the case. If the court finds jurisdiction lacking, it could dismiss the federal appeal without deciding the preemption question.

## What Colorado should watch

The argument is scheduled for Oct. 5, according to the [county’s case notice](https://bouldercounty.gov/news/u-s-supreme-court-to-hear-boulder-climate-case-monday/?ref=theamericanquorum.com). Justice Samuel Alito will not participate, a court official told the parties this week; [The Associated Press reported](https://apnews.com/article/74c9d15bbed62075406985c10ba8ce06?ref=theamericanquorum.com) the recusal after questions about oil-company stock holdings. Eight justices therefore are expected to hear the case, creating the possibility of a 4-4 split that would leave the Colorado judgment in place without a national precedent.

A ruling for Boulder would not establish corporate liability. It would return the dispute to the trial process, where jurisdictional facts, causation, defenses and damages remain contested. A ruling for the companies on preemption could end this case and affect climate suits filed by other state and local governments; [Reuters reports](https://www.reuters.com/legal/government/facing-climate-lawsuits-big-oil-again-turns-us-supreme-court-2026-09-30/?ref=theamericanquorum.com) that nearly 60 similar cases are pending nationally.

For Colorado, the immediate significance is procedural but substantial: after eight years of litigation, the Supreme Court will decide whether state courts may even apply Colorado law to the alleged local harms. A decision is expected by the end of the court’s term, though the justices announce no fixed timetable.