One of the consequences of global warming is sea level rise and the associated concerns about preserving the rights of states to their maritime spaces, the continuity of the state itself and the protection of the people who may be affected and displaced.
According to official sources, sea level along the US coast will rise by an average of 25 to 30 cm over the next 20 years, equal to the total rise of the last 100 years. The Pacific region is experiencing an increase above the global average of 3.4 mm per year, with Kiribati, Tuvalu and the Marshall Islands the most vulnerable island nations.
These and other countries could disappear in the coming decades. In 2014, Kiribati purchased land in Fiji with the apparent intention of relocating its population there if it were flooded. And in 2023, Australia agreed to accept the Tuvalu population at risk of forced relocation (Falepili Union Treaty). Tuvalu is also creating a digital nation to preserve its culture and history and where Tuvaluans can connect with each other.
In our region, the Bahamas is the most threatened country due to the low altitude of its coasts and the high risk of hurricanes and tropical storms. But going into hiding is not the only consequence. Rising seas cause soil salinization, affecting vegetation and water reserves necessary for agriculture and human consumption, which can cause entire areas to become uninhabitable. Argentina is in no danger of being flooded, but with a coastline of 7,750 km (11,235 km if you include Argentina’s Antarctica and the islands in the South Atlantic), it is not immune from danger.
In May 2025, the United Nations International Law Commission, whose mandate is the progressive development and codification of international law, presented the final consolidated report of its Study Group on Sea Level Rise in Relation to International Law, containing the conclusions reached following an in-depth analysis revealing the practice and opinion of States and other relevant elements.
The first conclusion on which an important consensus has emerged among States is that sea rise does not, in principle, change the outer limit of the maritime spaces over which the coastal State exercises sovereign rights or jurisdiction. It is believed that the preservation of maritime spaces created by the state in accordance with international law promotes legal stability and avoids conflicts. Otherwise, third countries would benefit at the expense of the coastal state, e.g. Foreign vessels could fish in a part of Argentina’s current exclusive economic zone that has been converted into the high seas (where fishing freedom prevails) due to sea level rise. This would cause serious damage to Argentina, which has an extensive sea coast.
The second conclusion is that a state does not lose its status (it does not cease to exist) just because its land area is flooded or becomes uninhabitable as a result of sea level rise. Among other things, statehood is crucial for maintaining maritime jurisdictions and is associated with the possibility that situations of de facto statelessness (loss of nationality) may arise. Other alternatives include the transfer of territories, association or unification with other states to which the population has been relocated, or a sui generis system.
The third conclusion is that the current international legal framework is generally applicable to people who need to stay put or move due to the new phenomenon. Sea level rise may affect the enjoyment of human rights protected by international (and regional) conventions, particularly those that relate to already vulnerable people and groups, including the right to life, adequate housing, water and food, and respect for cultural identity. However, existing instruments could be further developed in a more specific, coherent and comprehensive manner in order to effectively protect affected people.
Other conclusions concern the international duty to cooperate and the importance of taking equity into account when addressing the impacts of sea level rise.
The International Court of Justice, the most important legal body of the United Nations, confirmed the findings of the International Law Commission on the effects of sea level rise in its opinion of July 2025.
The Commission’s report and the Court’s opinion are the result of a concerted effort by the most affected States, with the support of many other States and civil society, aimed at raising awareness of sea level rise, and include opinions requested before the International Tribunal for the Law of the Sea in May 2024, the Inter-American Court of Human Rights in July 2025 and the African Court on Human and Peoples’ Rights requested in May 2025. Likewise, since 2023, the Inter-American Judicial Committee of the OAS has been studying the issue from a regional perspective. This demonstrates the hope that the international community continues to place in international law and justice and its potential to contribute to solving problems.
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