Signal US Supreme Court to Hear Boulder Climate Liability Case as Term's First Argument

Summary

The U.S. Supreme Court will hear oral argument on Monday, October 5, 2026 at 10 a.m. in Boulder County and the City of Boulder's climate lawsuit against ExxonMobil and Suncor Energy, the first case of the fall 2026 term. The justices will consider two questions: whether the Court has statutory and Article III standing to hear the case, and whether federal law preempts state-law tort claims over harms from interstate and international greenhouse-gas emissions. Boulder first sued the companies in April 2018, alleging they deceived the public about their products' role in climate change. In May 2025, Colorado's Supreme Court ruled 5-2 in Boulder's favor, rejecting the companies' federal preemption argument. The U.S. Department of Justice argued in a September 17, 2026 brief that Boulder cannot set global energy policy from Colorado. The case is seen as a pivotal test of whether local climate-liability suits can proceed under state law.