On most maps, Tuvalu is easy to miss but in international law, it may become impossible to ignore. The Pacific nation is confronting a question that until recently belonged more to legal theory than practical diplomacy. What happens to a country if climate change makes part, or eventually all, of its physical territory uninhabitable?
Tuvalu has decided not to wait for the answer. In 2023 it revised its Constitution to state that Tuvalu will “remain in perpetuity” notwithstanding climate change or other causes resulting in the loss of physical territory. The same constitutional provision fixes the baseline coordinates from which its maritime zones are measured, even if rising seas alter the coastline.
That is an unusually bold constitutional move. The familiar model of statehood assumes a defined territory, a population and a government. International law, however, was not designed with the possible physical disappearance of low-lying island states in mind. Tuvalu is therefore trying to establish legal continuity before geography creates legal uncertainty.
Clearly, a constitution cannot by itself determine how every other country will treat Tuvalu in the future. Recognition, treaties and wider state practice matter too. That is why Tuvalu’s strategy is also diplomatic. It is seeking to turn a national constitutional principle into an internationally accepted one.
It is not acting alone. In 2023, Pacific Islands Forum leaders declared that climate-related sea-level rise should not bring the statehood or sovereignty of their members to an end. A year later, the Australia-Tuvalu Falepili Union entered into force. Among its provisions is Australia’s legally binding recognition that Tuvalu’s statehood and sovereignty will continue despite the effects of sea-level rise.
There is another dimension which is the sea itself. Pacific states have also argued that maritime zones lawfully established under the UN Convention on the Law of the Sea should remain fixed even if coastlines retreat. For Tuvalu, this is hardly abstract. Maritime zones carry economic rights, jurisdiction and resources that are central to the future of the country.
The implications go much further than borders. If territory changes dramatically, what happens to citizenship, passports, diplomatic relations, voting rights, cultural heritage or membership in international organisations? Can a state continue to exist if much of its population lives elsewhere? And can sovereignty be anchored as much in a people, a legal order and international recognition as in dry land?
Tuvalu may be one of the world’s smallest states but it is forcing the international system to confront one of its largest unanswered questions. For centuries, maps have been treated as the fixed background of international politics. Tuvalu is asking us to imagine a future in which the map changes but the state does not.
