Historic Climate Opinion and Its Potential Impact on U.S. Litigation

Not for the faint hearted” by Neil Moralee (CC BY-NC-ND 2.0)

On May 21, 2024, the International Tribunal for the Law of the Sea (ITLOS) issued a historic advisory opinion which held that State parties to the United Nations Convention on the Law of the Sea (UNCLOS) have concrete legal obligations to undertake efforts to mitigate climate change in order to prevent, reduce, and control pollution of the marine environment and to protect and preserve the marine environment.

The opinion was issued in response to a request submitted by the Commission of Small Island States on Climate Change and International Law (COSIS) in 2022. It is the first opinion by an international court or tribunal to articulate the obligations of states to address climate change. While it may be the first opinion of its kind, it is almost certainly not the last. Additional advisory opinion requests are pending before the Inter-American Court of Human Rights and the International Court of Justice.

For a detailed summary and analysis of the opinion, you can read my thoughts here as well as commentary and analysis by others. There are a few points in the opinion that may be of particular interest to TLBlog readers. First, the Tribunal found that mere compliance with obligations under the Paris Agreement was not sufficient for State parties to meet their obligations under UNCLOS. Second, it held that all State parties have an obligation to undertake climate mitigation efforts, including through the reduction of greenhouse gas emissions. It also held that the obligation to ensure that activities within a State’s jurisdiction or control does not cause damage to another State and its environment specifically applies to marine pollution from greenhouse gas emissions. Finally, it held that States must ensure that non-State actors within their jurisdiction or control comply with measures enacted to protect and preserve the marine environment.

As Zachary Clopton has observed, climate change litigation is “exploding.” Cases are being filed in courts around the world, with trends demonstrating an increasing number of cases being filed against the “Carbon Majors,” including state-owned entities and transnational corporations.

It is unclear how the opinion will impact transnational litigation domestically as the United States is not a State party to UNCLOS. While being deeply involved in the negotiating process in the 1970s and early 80s, the United States has not signed or ratified the Convention. The Convention was transmitted to the Senate for advice and consent by President Bill Clinton, and its ratification has been supported by the W. Bush, Obama, and Biden administrations, but it has not made past the Senate Committee on Foreign Relations.

Even though the United States is not a party to the Convention, U.S. policy is thought to be generally in line with many UNCLOS provisions, some of which have been considered by members of the U.S. government to be reflective of customary international law. Concerns remain, however, with the Convention’s provisions on deep-seabed mining and how resources are to be distributed by the International Seabed Authority as well as the Convention’s compulsory dispute resolution mechanism, which could expose the United States to binding arbitration procedures should it ratify the Convention. While the advisory opinion is not legally binding, it is an authoritative statement of law with “legal effect” that will greatly influence how UNCLOS State parties’ obligations are interpreted. Given the language in the opinion on how a State’s international responsibility would be engaged if it fails to “take all necessary measures to prevent, reduce and control marine pollution from anthropogenic [greenhouse gas] emissions, including measures to reduce such emissions,” it seems unlikely the Senate will be eager to take up consideration of UNCLOS. This is especially true given the bipartisan consensus that the United States should not expose itself to liability for carbon emissions.

This is not to say the advisory opinion is unlikely to have any effect on transnational litigation in U.S. courts. A petition for a writ of certiorari is currently pending before the United States Supreme Court in Sunoco LP v. City and County of Honolulu, Hawaii. The defendants include several multinational corporations, including British-owned BP p.l.c. The plaintiffs in the case allege that the corporate defendants “knew about the dangers of using their fossil fuel products, failed to warn consumers about those known dangers, and engaged in a sophisticated disinformation campaign to increase fossil fuel consumption, all of which exacerbated the impacts of climate change in Honolulu.” The case is not designed to hold these companies directly responsible for their emissions or to require the companies to stop selling and producing fossil fuels. Rather, the plaintiffs seek damages for the defendants’ misrepresentation of the science of climate change and “deceptive promotion of dangerous products.” The case has been brought under state law claims of public nuisance, private nuisance, strict-liability failure to warn, negligent failure to warn, and trespass. Significantly, as it relates to the UNCLOS advisory opinion, the plaintiffs allege that the defendants’ conduct led to sea level rise, ocean warming, ocean acidification, and the destruction of coral reefs, leading to damage of plaintiffs’ property, decreased revenue from tourism, and public health impacts.

It is possible that the Supreme Court could take up this case as a vehicle to further limit personal jurisdiction over non-resident defendants. However, should cert be denied (as it was the first time around) and should the case make its way back up to the Hawai‘i Supreme Court, there might be occasion to connect the case to the ITLOS opinion. The Hawai‘i Supreme Court is generally progressive, particularly when it comes to issues related to climate change, and has a tradition of justices embracing international law or referencing other landmark climate decisions from non-U.S. jurisdictions in their opinions. Cases with similar theories of liability have so far been dismissed or removed to federal court. However, at least one judge asked the parties to present a “tutorial” on the available science on global warming and sea level rise before ultimately dismissing the case. While this is purely speculative, justices on the Hawai‘i Supreme Court could look to the ITLOS opinion as a model of how to engage with and set out obligations related to the “best available science” and how to articulate standards of conduct in light of the “high risks of serious and irreversible harm to the marine environment by climate change impacts and ocean acidification.”