Background: Why a UN Declaration Now?
Sea-level rise has long been identified as one of the gravest consequences of climate change. However, it was only recently that the United Nations adopted its first dedicated declaration on sea-level rise, recognising the existential threat it poses — particularly to small island developing states (SIDS) and low-lying coastal nations. This landmark step came in response to mounting scientific evidence and urgent calls from vulnerable member states.
What Causes Sea-Level Rise?
Sea levels are rising due to two primary mechanisms:
- Thermal expansion: As ocean water warms due to increasing global temperatures, it expands in volume. This accounts for roughly half of the observed sea-level rise.
- Melting of glaciers and ice sheets: The melting of mountain glaciers and the Greenland and Antarctic ice sheets adds vast quantities of freshwater to the oceans. The West Antarctic Ice Sheet alone, if fully melted, could raise global sea levels by over 3 metres.
According to the IPCC Sixth Assessment Report (AR6), global mean sea levels rose by approximately 20 cm between 1901 and 2018. Under a high-emission scenario, sea levels could rise by 0.6 to 1 metre by 2100, with the possibility of exceeding 2 metres in the worst-case scenarios.
Impacts on Coastal Regions
The consequences of rising seas are profound and wide-ranging:
- Coastal flooding and erosion: Storm surges, which were once considered rare events, are becoming far more frequent. Cities like Mumbai, Kolkata, and Chennai in India face significant risks.
- Salinisation of freshwater: Saltwater intrusion contaminates coastal aquifers and agricultural land, threatening food and water security.
- Displacement and climate migration: The UNHCR estimates that hundreds of millions of people in low-lying areas could be displaced by 2100. Nations like Bangladesh, the Maldives, Kiribati, and Tuvalu face an existential threat.
- Biodiversity loss: Coastal ecosystems such as mangroves, coral reefs, and wetlands are severely impacted, disrupting fisheries and natural protective barriers.
- Economic losses: The World Bank estimates that without adaptation, sea-level rise could cost $1 trillion annually in damages to coastal infrastructure by 2050.
Particularly Vulnerable Regions
Certain geographies are disproportionately at risk:
- Pacific Island Nations (Kiribati, Tuvalu, Marshall Islands): At risk of complete submergence. Some have already begun purchasing land in other countries for future relocation.
- Bangladesh: With 10% of its land area less than 1 metre above sea level, it is among the most vulnerable nations in the world.
- India's Coastal Zones: The Sundarbans delta, parts of Kerala's backwaters, and major port cities are highly exposed. India's coastline spans ~7,516 km with over 170 million people residing in coastal districts.
- Southeast Asia: Vietnam's Mekong Delta and Indonesia's capital Jakarta (which is sinking due to groundwater extraction) face compounded risks.
- Small Island Developing States (SIDS): Recognised by the UN as a special category requiring dedicated support under climate negotiations.
Key Points of the UN Declaration
The UN declaration represents a significant diplomatic achievement and includes several critical provisions:
- Recognition of sea-level rise as a global security and humanitarian issue, not merely an environmental one.
- Reaffirmation that greenhouse gas emission reductions are the most effective long-term solution.
- Call for enhanced climate finance to help developing nations adapt, including through the Loss and Damage Fund established at COP28.
- Recognition of the legal personhood and statehood of threatened island nations, even if their territories become submerged — a groundbreaking legal concept.
- Increased investment in early warning systems, coastal defences, and managed retreat strategies.
India's Position and Response
India has been an active participant in international climate negotiations and has consistently advocated for:
- The principle of Common But Differentiated Responsibilities (CBDR), holding developed nations accountable for historical emissions.
- Adequate and timely climate finance transfers to developing nations.
- Technology transfer and capacity building for adaptation.
Domestically, India is implementing the National Action Plan on Climate Change (NAPCC) with the National Water Mission and National Mission for Sustainable Habitat as relevant sub-missions addressing coastal vulnerability.
Way Forward
Addressing sea-level rise demands a dual strategy:
- Mitigation: Accelerating the global transition to clean energy to limit temperature rise to 1.5°C above pre-industrial levels as per the Paris Agreement.
- Adaptation: Building seawalls, restoring mangroves (which act as natural buffers), developing climate-resilient infrastructure, and planning for managed coastal retreat.
The UN declaration signals a critical shift — from treating sea-level rise as a future problem to recognising it as a present-day emergency demanding immediate, coordinated global action.
Key Terms to Remember
- Thermal Expansion: Rise in sea level due to warming of ocean water.
- SIDS: Small Island Developing States — most vulnerable to sea-level rise.
- Loss and Damage Fund: Established at COP28 for climate-vulnerable nations.
- IPCC AR6: The latest IPCC report projecting future sea-level scenarios.
- Managed Retreat: Planned relocation of populations away from high-risk coastal zones.