UN Adopts First Declaration on Sea-Level Rise and Continuity of Island Statehood

The United Nations General Assembly adopted its first Political Declaration regarding sea level rise through a high-level meeting held in New York on September 24, 2026. The declaration touches on the legal, environmental, economic and humanitarian implications of the problem of rising water levels, giving special consideration to small island developing states (SIDS) and low-lying countries. The declaration promotes the continuation of statehood and sovereignty in spite of the rise in sea level and recognizes the permanent nature of the maritime zones under the UNCLOS.

Continuity of Statehood for Island Nations

One of the key issues in the declaration is the legal status of states whose territory will be threatened by the rise in sea level.

The declaration recognizes a presumption of continuity of statehood and sovereignty in light of sea-level rise and UN membership. It will help address the problems of vulnerable island states where some of their territory might disappear underwater or become uninhabitable.

The problem is especially important for Small Island Developing States, including countries of the Pacific region.

The declaration continues international efforts in the field of continuity of statehood and reflects legal trends, such as the advisory opinion of the International Court of Justice in July 2025 on climate change obligations.

Maritime Zones and UNCLOS

Furthermore, the declaration deals with the stability of maritime zones in light of rising sea levels.

It clarifies that the stability of maritime zones in accordance with UNCLOS does not depend on the physical changes caused by rising sea levels. It thus increases legal certainty regarding the maritime rights and entitlements of the concerned states.

Maritime zones are important because they determine the rights and jurisdiction of coastal states over areas of the sea and its resources.

The stance adopted in the declaration is in line with contemporary international legal developments. The International Court of Justice has made it clear that states do not need to revise their charts or geographical coordinates just because of physical changes due to climate-related rising sea levels, while maritime zones need to be respected.

The Relevance of Sea-Level Rise to Island States

Sea-level rise poses many dangers to small and low-lying nations and coastal communities, including,

• Land loss and erosion
• Coastal flooding
• Infrastructure damage
• Salinization of fresh water resources
• Dangers to agricultural and livelihood interests
• Population displacement
• Cultural endangerment
• Maritime claims ambiguity

In this regard, the UN General Assembly’s high-level meeting stressed the need to view the sea-level rise problem as an issue of development, humanitarian, economic and security concern, apart from environmental concerns. According to the UN General Assembly President, about 900 million people inhabit low-lying coastal areas, while over 1 billion people may be vulnerable to coastal threats by 2050.

Adaptation, Early Warning Systems, and Climate Finance

The statement urges greater international collaboration on adapting to higher sea levels.

Main elements are,

• Multi-hazard early warning systems
• Climate risk assessment in development planning
• Coastal defense
• Resilient infrastructure
• Nature-based adaptation solutions
• Scientific and technological cooperation
• Improved access to climate finance
• Helping developing nations, especially SIDS and LDCs

Nature-based solutions like mangrove preservation and restoration, kelp forests, and seagrass habitats may help in building coastal resilience.

The statement connects adaptation with people, livelihoods, infrastructure, culture, and heritage protection.

Role of Small Island Developing States

Small Island Developing States have been highly influential in ensuring that the legal implications of sea-level rise become an international issue.

Previous actions include the 2021 Pacific Islands Forum Declaration for Preserving Maritime Zones and the 2023 Pacific Islands Forum Declaration for Continuity of Statehood and Protection of Persons in Light of Climate Change-Associated Sea-Level Rise.

Furthermore, the Alliance of Small Island States (AOSIS) has proposed declarations relating to the matter of sea-level rise, maritime zones, and statehood.

These are among the events that led to the international discourse preceding the 2026 UN Political Declaration.

Sea Level Rise and International Law

The declaration of 2026 is relevant to the relationship between climate change and international law.

There are three legal concerns that stand out,

• Statehood continuity in the face of climate change territorial alterations.
• Stability of existing maritime zones under the UNCLOS.
• Protection of those people, rights, culture, and identity impacted by sea level rise.

This declaration offers a common political framework in relation to these concerns, as well as calls for adaptation and resilience.