Exam Relevance

• UPSC GS-I: Physical Geography | Oceanography | Effects of Climate Change
• UPSC GS-II: International Institutions | International Agreements | Global Cooperation
• UPSC GS-III: Environmental Conservation | Climate Change | Disaster Management
• Prelims: UNGA | UNCLOS | Maritime Zones | Small Island Developing States | Causes of Sea-Level Rise

Why in News?

The United Nations General Assembly (UNGA) adopted its first UN Declaration on Sea-Level Rise on 24 September 2026.

The declaration establishes a shared international position on protecting the statehood, maritime rights and populations of countries affected by rising seas. It also calls for stronger adaptation, scientific cooperation and financial support.

Why is Sea-Level Rise a Growing Concern?

According to the World Meteorological Organization’s State of the Global Climate 2024 report:

• Global mean sea level reached its highest level in the satellite observation record beginning in 1993.
• The average annual rate of rise increased from 2.1 mm during 1993–2002 to 4.7 mm during 2015–2024.
• This means the rate more than doubled between these periods.

Around 770 million people live less than 5 metres above the high-tide line, according to the UN. Rising seas threaten housing, freshwater, agriculture, infrastructure and livelihoods in these areas. This figure describes exposure; it does not mean that all these people will necessarily be displaced.

What Causes Sea-Level Rise?

1. Thermal Expansion

As seawater warms, it expands and occupies more space. This raises sea levels even without additional water entering the oceans.

2. Melting of Land-Based Ice

Melting glaciers and the Greenland and Antarctic ice sheets add water to the oceans.

Thermal expansion and melting land ice are the two main drivers of global mean sea-level rise.

3. Regional and Local Factors

The rise experienced at a particular coastline also depends on ocean circulation and changes in land elevation.

For example, land subsidence, or the sinking of coastal land, can increase local exposure even when the global average rise is smaller. Therefore, global mean sea-level rise and local relative sea-level change are different measurements.

What are the Key Features of the Declaration?

The declaration is organised around four pillars:

It encourages the use of scientific evidence alongside traditional and Indigenous knowledge. It also calls for sea-level projections to inform infrastructure planning and for the restoration of mangroves, coral reefs, coastal wetlands, kelp forests and seagrass meadows.

1. Continuity of Statehood

The declaration affirms a presumption in favour of continued statehood when a country faces sea-level rise.

The loss of a constituent element of an established state would not necessarily end its statehood. It supports the continuity of sovereignty, sovereign rights, responsibilities and UN membership.

This is especially significant for Small Island Developing States (SIDS), whose habitability and territorial integrity face serious risks. It strengthens the position that physical loss of land should not automatically erase a country’s international legal identity.

2. Stability of Maritime Zones

States can maintain maritime zones established in accordance with UNCLOS, despite physical changes caused by sea-level rise, while retaining the ability to update them.

The declaration also encourages technical assistance to help states finalise their baselines. This matters because maritime zones determine important rights over fisheries, seabed resources and other economic activities.

3. Protection of People and Communities

The declaration addresses human rights, participation in decision-making and the preservation of livelihoods and cultural identity.

Its significance extends beyond protecting territory: communities must be able to maintain institutions, social connections and dignity even when relocation becomes necessary.

Why Does Sea-Level Rise Create Questions Under UNCLOS?

The United Nations Convention on the Law of the Sea, 1982, provides the framework for maritime zones.

A baseline is the reference line from which their breadth is measured. The normal baseline generally follows the low-water line along the coast.

These distances are measured from the baseline, not successively from the outer edge of the previous zone.

As coastlines retreat, questions arise about whether baseline changes should affect maritime entitlements. Supporting stable zones can reduce uncertainty over resource access and interstate relations.

Prelims distinction: An EEZ gives a coastal state specified sovereign rights and jurisdiction; it does not grant the same sovereignty exercised over its territorial sea.

Is the Declaration Legally Binding?

The declaration is a political commitment rather than a new treaty. Its adoption does not itself amend UNCLOS or automatically create a comprehensive enforcement mechanism.

However, it has diplomatic and legal significance because it records a common position among states. General Assembly declarations can influence international debate and legal interpretation, even though they do not generally impose binding obligations in the manner of treaties.

Existing obligations under international law remain relevant independently of the declaration.

What is its Significance for India?

1. Coastal Settlements and Infrastructure

India’s coastal cities, ports, transport networks and industrial facilities require planning that accounts for rising seas and coastal flooding.

Sea-level rise can worsen the consequences of storm surges by raising the starting water level from which flooding occurs.

2. Island Territories

Lakshadweep and the Andaman and Nicobar Islands make the declaration relevant to India’s island communities, marine ecosystems and maritime interests.

Stable maritime entitlements are important for long-term resource governance.

3. Livelihood and Water Security

Saltwater intrusion can affect drinking-water sources and agricultural land. Changes to coastal habitats can also place pressure on fishing communities and tourism-based livelihoods.

4. Science-Based Coastal Planning

India already has scientific tools that can support adaptation. INCOIS has prepared Coastal Vulnerability Index maps, incorporating factors such as sea-level rise, coastal elevation, shoreline change and wave conditions.

5. Ecosystem-Based Adaptation

India’s Mangrove Initiative for Shoreline Habitats and Tangible Incomes (MISHTI) is relevant to restoring coastal ecosystems.

Mangroves can support biodiversity and livelihoods while providing natural protection against some coastal hazards.

Analytical point: Coastal erosion has several causes, including sediment changes and human interventions. It should not automatically be attributed entirely to sea-level rise.

What Challenges Remain?

• Implementation: Political commitments need national policies, institutions and sustained funding.
• Finance gaps: Vulnerable countries may struggle to obtain affordable and predictable adaptation finance.
• Limits to adaptation: Protective infrastructure and ecosystem restoration cannot prevent every loss.
• Displacement: Relocation raises difficult questions about housing, livelihoods, nationality, cultural identity and receiving communities.
• Data limitations: Local planning requires reliable information on elevation, land movement, future sea levels and population exposure.
• Institutional continuity: Preserving statehood also requires practical arrangements for governance and public services.
• Climate justice: Countries with limited responsibility for historical emissions may face severe consequences and have fewer resources to respond.

What Should Be the Way Forward?

1. Reduce greenhouse-gas emissions: Adaptation must be accompanied by mitigation to limit the scale of future sea-level rise.
2. Plan for future conditions: Infrastructure decisions should consider projected risks over the full life of a project.
3. Strengthen early warnings: Combine hazard forecasts with clear communication, evacuation planning and accessible shelters.
4. Restore suitable ecosystems: Protect mangroves, wetlands, reefs and seagrass using locally appropriate methods.
5. Improve climate finance: Simplify access and support locally led adaptation.
6. Protect affected communities: Ensure meaningful participation, livelihood support and dignified relocation where required.
7. Strengthen legal cooperation: Translate the declaration’s principles into practical arrangements for maritime rights and institutional continuity.

Mains Practice Question — 250 words

“Sea-level rise is not merely an environmental challenge; it also raises fundamental questions about statehood, maritime rights and climate justice.” Discuss with reference to the UN Declaration on Sea-Level Rise.