UN General Assembly adopts declaration on sea level rise

News
25 September 2026

The United Nations General Assembly has adopted a landmark declaration on sea-level rise, saying that “its cumulative, severe and irreversible risks demand stronger international cooperation and urgent, coordinated action.” 

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Eroded sandy cliffs with a single tree at the top, fallen trees on the beach, and the ocean in the background under a cloudy sky.

WMO welcomed the declaration, which states that adaptation and mitigation action, “based on the best available science and knowledge,” is essential. It recognizes the essential coordination provided by the UN specialized agencies, including WMO.

The declaration stresses the need to strengthen disaster risk reduction and build resilience through improved data availability, risk assessments, early warning systems, and long-term planning and adaptation.  

“Sea-level rise reaches far beyond the environment. It is a threat multiplier – battering economies, trade, infrastructure, and food systems,” said UN Secretary-General António Guterres.  

“Around 770 million people – nearly one-tenth of humanity – live less than five metres above the high-tide line. For them, every centimetre matters. Without significant adaptation and mitigation, the risks facing coastal cities and communities are projected to increase at least tenfold by 2100,” he said.

Sea-level rise is one of the key climate indicators monitored by the WMO community.  

Ocean warming and melting ice are driving the long-term rise, which has accelerated since satellite measurements began in 1993. At the end of 2025, the global mean sea level was around 11 cm higher than it was in January 1993, according to WMO’s State of the Global Climate 2025 report.  

“We note with appreciation the essential coordination on sea level rise-related data provided by the UN Specialized Agencies, particularly the World Meteorological Organization and the UNESCO Intergovernmental Oceanographic Commission. We call for improved tools for data coherence and uptake to overcome capacity constraints,” said the declaration.

It expresses commitment to strengthening coordinated scientific observation, data collection and exchange and to the Global Ocean Observing System and Global Sea Level Observing System.

WMO welcomed the declaration.  

“Understanding how sea level is changing, and what this means locally, depends on sustained observations — including tide gauges, satellites, ocean heat content, cryosphere and land water changes, and measurements of vertical land movement, alongside the meteorological observations needed to predict storms and coastal flooding,” it said in a statement submitted to the high-level session.

“Yet significant gaps remain, particularly across the oceans, in small island developing States and in other vulnerable coastal regions. These are not simply gaps in scientific knowledge. There are gaps in our collective ability to assess risk, prepare, and make informed decisions.”

Recognizing that sea level rise will exacerbate coastal risks, including storm surges and coastal flooding, the declaration underscores the importance of investment and preparedness to build and maintain resilient societies.  

“We will enhance anticipatory action, multi-hazard early warning systems, climate information systems and integrate all-hazard risk assessments into planning and decision-making frameworks as appropriate,” it says.

The declaration was adopted by acclamation at the high-level segment of the 81st General Assembly on 24 September after a prolonged and intense negotiating process.