A group of small island nations threatened by frequent storms and rising seas is for the first time appearing before an international court to seek its help, hoping for a decision that excessive greenhouse gases are pollutants that violate international law.
If the group’s request is successful, the court’s opinion could lead to wide-ranging claims for damages.
Hearings in the case opened on Monday at the request of nine Pacific and Caribbean island nations that have joined. The sessions at the International Tribunal for the Law of the Sea in Hamburg, Germany, are expected to last for two weeks and have drawn wide attention.
Representatives of more than 50 countries, including large emitters of greenhouse gases including China, India and European Union members, have asked to participate via oral or written interventions.
Arguments will revolve around the 1982 United Nations Convention on the Law of the Sea, the legal framework that covers uses of the oceans and their resources, including the obligation to protect the marine environment. The convention has been ratified by 168 nations, though not by the United States.
But the convention, negotiated in the 1970s, does not mention emissions of greenhouse gases and their effects on the warming and acidification of the oceans, and on sea-level rise.
For the tribunal, this will be a test case: The Oceans Court, as it is also called, has ruled on issues like fisheries, rights of passage, and seabed mining and pollution, but it has never heard a case on greenhouse gases and their impact on climate change and the oceans.
Addressing the tribunal on Monday, Gaston Alfonso Browne, the prime minister of Antigua and Barbuda, noted that “in the past weeks we have witnessed the highest ocean temperatures on record.”
He asked for the judges to clarify existing laws and obligations to help stem further disaster, warning that “the world is teetering dangerously on the precipice of a climate catastrophe.’’
Leaders of the island nations argue that they did not create the problems and account for only 1 percent of carbon emissions but bear catastrophic effects from climate change. Some atolls have disappeared underwater, coasts are eroding, and land has become uninhabitable as fresh water for drinking and planting crops has turned saline. They believe broader disaster looms.
Kausea Natano, the prime minister of Tuvalu, said the island nations had been issuing warnings and pleading for attention since 1990 but had not seen the necessary action.
Tuvalu, which is made up of nine islands in the Pacific, “will become mostly uninhabitable, if not inundated, in the next few decades,” he said. “More than 10,000 people will be forced to leave.”
Naima Te Maile Fifita, a lawyer from Tuvalu, said she spoke as a mother and on behalf of island youth as she asked the judges for a “robust response.”
She said that young islanders, including law students and activists, had been pushing their elders to turn to the courts. “It is fitting that young people have been at the forefront,” she said. “It is we who will inherit the decisions made before us.”
The island nations are not suing for damages but are seeking a so-called advisory opinion on what legal obligations countries have to prevent damaging the oceans. The key question is whether the judges, as they interpret the law on protection, will take into account the scientific consensus on the impact of greenhouse gases on the climate and the marine environment.
Experts say the answer could affect claims for damages in international and national courts.
If the judges conclude that the causes of ocean warming can be defined as marine pollution, it “would open the way to bringing successful proceedings for claims here or in other international courts,” Alan Boyle, an emeritus professor of international law at the University of Edinburgh, has said.
Experts say the tribunal’s opinion could also affect national jurisdictions, where activists are increasingly taking on governments and energy companies for climate damage and have achieved some successes.
The problems of the island states vary: Volcanic islands in the Caribbean have suffered infrastructure damage from a growing number of hurricanes. Low-lying atolls, mainly in the Pacific, have lost landmass from erosion and flooding, and fresh water for crops and drinking because of salinity. Some residents have had to leave.
David Freestone, a co-author of a 2021 World Bank report on the legal dimensions of sea-level rise, said the tribunal could also clarify other questions stemming from the impacts of changes in the oceans.
Countries are asking how their territorial waters are affected when land disappears. Low-lying islands may shrink or expand. And, Mr. Freestone said, they are asking about their vast exclusive economic zones and vital fishing rights. “After much debate, the jury is still out,” he said. “An authoritative modern tribunal of Law of the Sea specialists could clarify such ambiguities.”
The islands petitioning the Hamburg tribunal have also asked the International Court of Justice to weigh in on governments’ legal obligations “in respect of climate change” and what the consequences might be if they failed to meet them.
That request was made by the United Nations General Assembly in March.
Lawyers believe that the judges in Hamburg will respond first, perhaps within a few months, and that their opinion will carry special weight because of their expertise as members of the Law of the Sea tribunal.