UN warns rising seas are already putting communities at risk

The United Nations has warned that sea-level rise is no longer a distant environmental threat, but a growing global crisis that is already reshaping coastlines, displacing communities and putting economies, infrastructure and even some countries at risk.

UN Deputy Secretary-General Amina Mohammed launched the UN Secretary-General’s report, Challenges Related to Sea-Level Rise and Ways and Approaches to Address Them, during the 55th Pacific Islands Forum Leaders Meeting in Palau. The report turns the latest scientific evidence into a call for urgent international action, highlighting the growing risks faced by coastal and island communities.

According to the report, sea levels are rising faster than at any point in recorded history, driven mainly by ocean warming and melting glaciers.

Nearly 770 million people – about one in 10 people worldwide – already live in coastal areas less than five metres above the high-tide line, leaving them increasingly exposed to flooding and other risks.

In 2024 alone, global sea levels rose by almost 6mm, the highest annual increase on record, the report said. At least half a metre of further sea-level rise is now considered unavoidable, even under the most optimistic climate scenarios. A rise of two metres by the end of the century is considered less likely, but could have devastating consequences.

Displacement

The report warned that as many as 1.2 billion people could be displaced by 2050 without urgent action. Relocations are already taking place in countries including Fiji, Vanuatu and the Solomon Islands. Pacific island states have experienced sea-level rises of more than twice the global average, with levels increasing by more than 15cm in some areas over the past three decades.

Meanwhile, nearly 500 million people live in low-lying river deltas, with millions of people in major South Asian cities facing the risk of permanent flooding.

The economic cost is already significant. Damage to coastal infrastructure is estimated at more than US$1.8 trillion, while annual global losses could reach between US$1.2 trillion and US$4 trillion without adequate adaptation measures.

Tourism-dependent regions are particularly vulnerable. In the Caribbean, where ocean tourism accounts for more than half of exports, rising seas could result in the loss of almost 40% of beaches and up to 20% of tourism revenue by 2050.

But the impact goes beyond money.

More than money

Rising seas threaten cultural heritage, food and water security, housing and basic human rights. Communities are increasingly being separated from ancestral lands and cultural traditions, while vulnerable World Heritage sites could eventually be lost to the sea.

The UN report also highlights a major gap in climate finance. Developing countries are estimated to need between US$310 billion and US$365 billion a year for adaptation, yet only about US$26 billion was available in adaptation finance in 2023.

The UN is calling for action on two fronts: cutting greenhouse gas emissions as quickly as possible while helping communities adapt to sea-level rise that is already happening.

Governments are being urged to build sea-level resilience into national planning, strengthen early-warning systems, protect food and water supplies, safeguard jobs and infrastructure, and expand social protection.

The report also raises growing legal concerns, including questions around statehood and maritime boundaries. It argues that countries most affected by climate change should not face additional legal or territorial losses because of a crisis they did not create.