UN Adopts First-Ever Declaration on Sea Level Rise

The United Nations General Assembly adopted the first declaration ever devoted to sea level rise on Sept. 24, 2026, at a high-level plenary meeting in New York. Member States at the 81st session approved the text by acclamation, with no floor vote needed.

The declaration is the first of its kind to take on the threat rising oceans pose to coastal nations. It calls for stronger international cooperation and lays out how countries should respond when rising seas threaten homes, food systems, infrastructure and, in the most extreme cases, the land itself.

Opening the session, UN Secretary-General António Guterres warned that sea levels rose by almost six millimetres in 2024, the largest annual increase ever recorded. While the rise is measured in millimetres, he said, "its price is measured in millions of shattered lives, uprooted communities, and stolen futures."

What the declaration says

The text is organized around four pillars, according to UN News. The first covers science and data: better ocean observation, shared data between countries and stronger early warning systems for coastal flooding. Governments committed to back the Global Ocean Observing System and the Global Sea Level Observing System.

The second pillar covers finance and resilience. It calls for funding that is more predictable and easier to access, especially for small island developing states and least developed countries, to pay for seawalls, coastline restoration and relocation planning. Guterres told delegates that adaptation finance must triple from current levels.

The third pillar covers livelihoods, culture and heritage. Rising waters threaten fishing, tourism and the cultural identity of coastal communities, and the declaration says the people affected must take part in decisions about their own futures.

The fourth pillar is international law. The declaration affirms a presumption in favour of continued statehood for nations whose territory goes under water, and states that maritime zones set under the UN Convention on the Law of the Sea stand even as coastlines move. It is the first UN political text to say a state can keep existing after its land is gone.

Why the timing matters

The figures behind it are stark. About 770 million people live less than five metres above the high-tide line, according to the World Meteorological Organization. The ocean surface has risen more than 10 centimetres since 1993, averaging 4.7 millimetres a year between 2014 and 2023. UN estimates put the number of people in island and coastal areas facing disaster risk by 2050 at more than one billion.

Without steep emissions cuts the outlook deteriorates quickly. Seas could rise by a full metre by the end of the century, and a half-metre rise alone could force between 150 million and 300 million people from their homes. The World Meteorological Organization estimates seas will rise by at least half a metre by 2100, with the most pessimistic projections reaching two metres.

Some nations are already planning for the worst. Tuvalu, a Pacific island state of about 12,000 people, is becoming the world's first "digital nation," moving state functions online as its physical territory shrinks. Around half of its people live on Fogafale Island, where flooding, shoreline erosion and rising seas threaten the southern lagoon coast.

Guterres said global emissions must peak immediately and fall 60 percent by 2035, and noted that the countries that contributed least to climate change face the greatest danger. Wealthy nations currently provide about 130 billion dollars a year in climate finance to developing countries, which analysts say falls short of what is needed to prevent severe damage.

What it does not do

The declaration is a diplomatic step and is not legally binding. It creates no new funding mechanism and sets no binding emissions targets, which remain under the Paris Agreement. Instead it instructs the UN secretariat to coordinate technical exchanges and report back on finance gaps, leaving fights over replenishing the Green Climate Fund to budget seasons in Washington, Brussels and Beijing.

The Bahamas' prime minister said the agreement could speed up global efforts to address the needs of vulnerable island states, particularly on climate finance and adaptation. The World Meteorological Organization welcomed the declaration in a statement, while cautioning that major observation gaps remain across small island states and vulnerable coastal regions, limiting the ability to assess risk and prepare.

The declaration builds on years of groundwork, including the UN International Law Commission's study of sea level rise and international law from 2019 to 2025. It now goes to national governments to carry out, with the next test being whether promised finance reaches the coastlines already losing ground.