UN General Assembly’s Declaration on Sea-Level Rise Guarantees Island States’ Statehood and Fixes Their Maritime Zones

The news

United Nations, New York. On September 24, the UN General Assembly approved the Declaration on Sea Level Rise by consensus, The Hindu reports on its Science page. Its most important provision concerns international law: the Declaration affirms that low-lying countries especially threatened by rising seas, such as Fiji, Tuvalu and Vanuatu, will continue to retain their statehood, sovereign rights and UN membership. It also says maritime zones will continue to be defined in line with the UN Convention on the Law of the Sea (UNCLOS), even if rising waters cause coastlines to retreat further inland. In plain terms, a country’s territorial sea and its Exclusive Economic Zone (EEZ) — the belt of sea in which it alone may fish and exploit oil, gas and minerals — are measured from a baseline on its coast; if the coast moves inland, the zones could shrink, and a country whose land disappears entirely could, in theory, lose its claim to be a state. The Declaration closes both doors. It arose from a high-level meeting in 2024, after which member countries negotiated it under a mandate calling for an action-oriented agreement. Spanning four pages, it organises action around four pillars: science and data; adaptation and financing; livelihoods, socio-economic development, data-sharing and early warnings; and the legal consequences of sea-level rise. It asks for responses that protect livelihoods and cultural heritage and involve affected communities. The world’s low-lying island states, organised as the Alliance of Small Island States (AOSIS) in international forums including the COP climate talks, need these assurances because the surrounding seas threaten to swallow most or all of their habitable territory in coming decades. If that happens, the Declaration will ensure that their citizens retain their nationality and economic rights. The current global mean rate of sea-level rise is 4–5 mm a year, the paper notes. The pact also commits UN members to keep engaging on sea-level rise, including a further high-level meeting before the 84th session of the General Assembly ends. A General Assembly declaration is not a treaty: it does not bind states in the way a ratified convention does, but a text adopted by consensus is strong evidence of what states accept as the law. The syllabus link is GS1 (geographical phenomena and their effects), GS2 (international institutions) and GS3 (climate change and disaster management).

Static syllabus linkage

1. UNCLOS measures every maritime zone from a baseline on the coast. The UN Convention on the Law of the Sea was adopted in 1982 and entered into force in 1994; India ratified it in 1995. The normal baseline, under Article 5, is the low-water line along the coast as marked on large-scale charts officially recognised by the coastal state, and Article 7 allows straight baselines where the coast is deeply indented or fringed with islands. From the baseline, the territorial sea extends up to 12 nautical miles, the contiguous zone up to 24 nautical miles and the Exclusive Economic Zone up to 200 nautical miles, while the continental shelf extends at least 200 nautical miles and, where the natural prolongation of land continues, further subject to limits. UNCLOS says nothing explicit about what happens when a baseline moves because the sea rises, which is the gap the Declaration fills.
2. Article 121 separates islands from rocks, which is why shrinking land matters. Under Article 121 of UNCLOS, an island is a naturally formed area of land, surrounded by and above water at high tide, and it generates the same maritime zones as other land territory. But rocks that cannot sustain human habitation or economic life of their own get no EEZ or continental shelf. As seas rise, some small islands could be reduced to rocks or disappear below high tide, and their owners could lose vast ocean areas. For atoll nations, whose sea area is many times their land area, this is an economic threat even before it is an existential one.
3. The Montevideo criteria assume a territory that may one day be underwater. The Montevideo Convention on the Rights and Duties of States, 1933, lists in Article 1 the classic qualifications of a state: a permanent population, a defined territory, a government and the capacity to enter into relations with other states. These criteria are widely treated as reflecting customary international law. International law has long presumed that a state, once established, continues to exist even if it loses effective control for a time, but it has never faced a state whose entire territory is permanently lost. The Declaration strengthens the presumption of continuity so that the loss of territory alone does not end statehood.
4. The ICJ and the ILC have prepared the legal ground. The International Law Commission, the UN body that codifies and develops international law, has been studying ‘sea-level rise in relation to international law’ since 2019, covering the law of the sea, statehood and the protection of affected persons. In July 2025 the International Court of Justice delivered an advisory opinion, requested by the General Assembly on an initiative led by Vanuatu, holding that states have legal obligations under treaties and customary law to protect the climate system, and that breaching them can engage state responsibility. The Pacific Islands Forum declared in 2021 that its members’ maritime zones, once notified under UNCLOS, would not be reduced by sea-level rise. The General Assembly Declaration generalises that regional position to the whole UN membership.

Why UPSC loves this

1. GS1 and GS3 link physical geography to law and disasters. UPSC has asked about the causes and consequences of sea-level rise, the vulnerability of coastal and island regions, and the effect of climate change on India’s coasts. A strong answer now can add the legal dimension, which shows the examiner the candidate understands that climate change redraws political as well as physical maps.
2. Prelims regularly tests UNCLOS zones and definitions. Questions on the width of the territorial sea, contiguous zone and EEZ, and on the difference between the EEZ and the continental shelf, are standard Prelims fare. The island-versus-rock rule in Article 121 and the concept of baselines are the natural next layer, along with AOSIS and the ICJ’s 2025 climate advisory opinion.
3. GS2 asks how India engages with small island states. India’s outreach to the Pacific through the Forum for India–Pacific Islands Cooperation and to the Indian Ocean island states is a recurring theme. Support for the island states’ legal security is a low-cost, high-value way for India to show solidarity with the Global South, and this Declaration is a concrete example to cite.

Analysis

1. Freezing maritime zones rewrites UNCLOS in practice without amending it. UNCLOS was written on the assumption that coasts are stable, and its baselines were understood by many lawyers as ‘ambulatory’, moving with the low-water line. The Declaration effectively fixes them, but it does so through a consensus resolution rather than a formal amendment, which would take years and might never get enough ratifications. That is a pragmatic choice. Its weakness is that a declaration does not bind, so a state that later wishes to challenge a neighbour’s fixed zone could argue that it never accepted the change as law. Consensus adoption, however, makes that argument much harder to sustain.
2. Statehood without territory is a new idea that international law is not fully ready for. A state without land raises practical questions the Declaration does not answer: where its government sits, where its citizens live, who issues passports and under whose law disputes are settled. Arrangements like governments-in-exile or bilateral treaties granting residence to island citizens offer partial models. The Declaration secures the legal shell of statehood and the economic value of the sea, which is what island states most urgently needed. But the lived reality of displaced communities — jobs, land, culture — depends on receiving countries, and the Declaration can only encourage, not compel, their generosity.
3. The Declaration protects rights but does not stop the water. Legal continuity is insurance, not prevention. At 4–5 mm a year, sea-level rise is steady, and it compounds storm surges such as those Hurricane Polo drove onto a Mexican island on September 26, pictured on the same page. The Declaration’s pillars on science, adaptation and financing are where lives are saved, yet they carry no new money in the paper’s account. There is a real danger that states treat the legal guarantee as the achievement and neglect the finance needed for sea walls, relocation and early warnings. Its value will be judged at the next high-level meeting by what has been funded, not what has been declared.
4. India has its own reasons to welcome frozen baselines. India has a long coastline, the low-lying atolls of Lakshadweep, the Andaman and Nicobar Islands, and the sinking Sundarbans delta shared with Bangladesh. Its EEZ is a major economic asset for fisheries and offshore energy. A rule that zones do not shrink as coasts retreat protects India too, and supporting it aligns India with small island states at little cost. The counter-consideration is that fixed baselines could entrench existing maritime boundary claims in contested waters elsewhere, so India will want the rule applied consistently rather than selectively.
5. Consensus was possible because the costs fall on no one immediately. Big maritime powers accepted the text because freezing zones takes nothing from them now, and it avoids the chaos of redrawing boundaries every decade. Harder questions — who pays for relocation, who accepts migrants — were left to future meetings. This is how international law often advances: first the easy principle, then the costly implementation. The test is whether the General Assembly’s follow-up meeting before the 84th session ends turns principle into obligations, or whether the Declaration joins the long list of commitments that were celebrated and forgotten.

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