Rising Sea Level Threat to India’s Eroding Coastline

On 24 September 2026, the UN General Assembly adopted its first-ever declaration on sea-level rise, recognising it as an existential threat to vulnerable populations.

Rising Sea Levels: Key Trends

• Global sea-level rise accelerated from about 2.1 mm/year during 1993–2002 to 4.7 mm/year during 2015–2024.
• In 2024, sea level increased by around 6 mm, the largest annual rise on record.
• Even under low-emission scenarios, global sea levels could rise by about 38 cm by 2100; continued high emissions could push this to around 77 cm.
• Sea levels are expected to continue rising for centuries even after achieving net-zero emissions.

Statehood of Sinking Island Nations

• The declaration establishes a presumption in favour of continued statehood even if a country loses physical territory to rising seas.
• Vulnerable island nations such as Tuvalu, Kiribati and Maldives can retain sovereignty, international rights and assets.
• Countries are also encouraged to maintain their existing maritime boundaries even if coastlines retreat.
• The declaration stresses protection of the rights and dignity of climate-displaced populations.

Why It Matters for India

• India has a coastline of about 11,098 km and more than 1,200 offshore islands and islets after recent remeasurement.
• The Lakshadweep and Andaman & Nicobar Islands extend India’s maritime jurisdiction deep into the Arabian Sea and Bay of Bengal.
• Stable maritime boundaries are therefore important for protecting India’s EEZ, marine resources and strategic interests.

India’s Coastal Erosion Challenge

• About one-third of India’s coastline has experienced erosion in recent decades.
• Around 234 sq km of coastal land has been lost, although sediment deposition has created land elsewhere.
• Nearly 400 km of coastline is retreating by more than 5 metres annually, while another 225 km is retreating by 3–5 metres.
• West Bengal is among the most severely affected States, with more than 170 km of coastline experiencing rapid retreat.

Limitations of India’s Coastal Regulation

• The Coastal Regulation Zone (CRZ) Notification, 2019 prescribes no-development zones based largely on the present High Tide Line.
• Such static setback lines may become inadequate as the coastline progressively retreats.
• The UN declaration strengthens the case for incorporating projected sea-level rise and local erosion rates into coastal planning.

Where India Falls Short

• In the Sundarbans, islands such as Ghoramara have lost substantial land, while some settlements have disappeared entirely.
• Climate-displaced families often face repeated relocation, insecure land tenure and livelihood loss.
• India currently lacks a comprehensive legal framework specifically addressing people displaced gradually by coastal erosion and sea-level rise.
• Studies estimate that around 45 million Indians could be exposed to sea-level-rise risks by 2050.

What India Should Do

• Replace static coastal setbacks with hazard-based zoning linked to projected sea-level rise and local erosion rates.
• Prioritise protection and relocation planning for stretches identified by the National Centre for Coastal Research (NCCR) as rapidly eroding.
• Develop a legal framework for climate-induced displacement, ensuring land rights, housing and livelihood support.
• Strengthen mangroves, dunes and other nature-based coastal defences.
• Push for greater international adaptation and loss-and-damage finance for developing countries.

Rising seas are no longer only an environmental issue for India; they affect coastal livelihoods, infrastructure, internal displacement, maritime boundaries and national security, requiring long-term climate-resilient coastal planning.