On May 17, 2021, in Mayor and City Council of Baltimore v. BP P.L.C., et al., the U.S. Supreme Court held that the Fourth Circuit erred in its review of a remand order involving Baltimore's suit against oil and gas companies for their alleged knowing contribution to climate change-related harms. The defendants removed the suit to federal court on eight different theories of removal, including federal officer removal. The district court granted Baltimore's motion for remand, and the Fourth Circuit affirmed. The Supreme Court disagreed in a ruling that may help keep climate change suits out of state courts.

Appellate courts are generally barred by 28 U.S.C. § 1447(d) from reviewing district courts' remand orders. However, federal officer removal (and civil rights removal) is excepted under § 1447(d). Prior to the Supreme Court's ruling, there was a circuit split regarding whether § 1447(d) allows appellate courts to consider the entire remand on review or just the portion of the remand on federal officer removal. In a 7-1 opinion authored by Justice Neil Gorsuch, the Supreme Court resolved this circuit split by holding that the ordinary meaning of § 1447(d) allows appellate review of the lower court's entire remand order when a defendant relies on federal officer or civil rights removal as one ground for that removal. Justice Alito did not participate and Justice Sotomayor was the lone dissent.

In its ruling, the Court did not address the question of whether climate change tort suits belong in state or federal court despite the fact that the Court was urged to address this issue. Other Circuit courts have addressed whether federal law governs these cases in the context of both removal and preemption. For example, the Ninth Circuit in City of Oakland v. BP PLC held that climate change nuisance suits do not arise under federal law and cannot be removed to federal court on federal-question grounds (the Supreme Court has been petitioned to overturn the Ninth Circuit's decision, and a decision on that petition is expected soon). In a recent case that did not present removal issues, however, the Second Circuit held that these suits address a "uniquely international problem of national concern" and thus are governed by federal common law (which the Second Circuit then found displaced by the Clean Air Act). Now that Baltimore's case is remanded, the Fourth Circuit has a second chance to decide the removal issue for itself, although the Supreme Court will likely be the final decision maker on this issue. Nonetheless, the Supreme Court's May 17 decision represents a procedural win for corporate defendants, as it provides a potential avenue for keeping climate change suits out of state courts.