Mayor & City Council of Baltimore v. BP p.l.c.

On June 3, 2025, the Mayor & City Council of Baltimore, the <a href="https://climatecasechart.com/case/city-of-annapolis-v-bp-plc/">City of Annapolis</a>, and <a href="https://climatecasechart.com/case/anne-arundel-county-v-bp-plc/">Anne Arundel County</a> (the municipalities) filed their opening brief in the Maryland Supreme Court in their appeals of trial court decisions dismissing their climate change cases against fossil fuel industry defendants. The municipalities initially appealed to the Appellate Court; the defendants then filed a petition for writ of certiorari in the Maryland Supreme Court; and the Supreme Court issued a writ of certiorari on April 24, 2025, limited to seven questions, the first of which asked whether the U.S. Constitution and federal law preempted “state law claims seeking redress for injuries allegedly caused by the effects of out-of-state and international greenhouse gas emissions on global climate.” The other six questions related to whether Maryland law precluded nuisance, failure-to-warn, and trespass claims in the context of products produced, promoted, sold, and used around the world and whether the municipalities stated claims for public and private nuisance, strict liability and negligent failure to warn, and trespass. The municipalities argued that their claims were not preempted by federal common law or the Clean Air Act, or barred by any constitutional provision. They disputed the trial courts’ characterization of their claims as operating as “de facto regulation” of greenhouse gas emissions. They also contended that their claims were actionable under Maryland law.