Rising Sea Levels Threaten India’s Eroding Coastline

Source: Indian Express
GS III: Environment, Climate Change and Disaster Management

Why in the News?

On 24 September, the UN General Assembly adopted its first-ever declaration on rising sea levels, recognising sea-level rise as a major threat to vulnerable populations and island nations.

News in Brief

• The UN declaration urges countries to incorporate sea-level-rise projections into coastal infrastructure planning, which is particularly relevant for India due to its long coastline, islands and coastal erosion.
• The global rate of sea-level rise more than doubled from 2.1 mm/year (1993–2002) to 4.7 mm/year (2015–2024), while global sea level rose by about 6 mm in 2024.
• Global sea level could rise by around 38 cm by 2100 under a low-emissions pathway and up to about 77 cm under higher emissions.
• Around one-third of India’s mainland coastline is eroding, and an estimated 45 million Indians could be at risk from sea-level rise by 2050.

What is Sea-Level Rise?

Sea-level rise refers to the long-term increase in the average level of the world’s oceans.

Major causes

• Thermal expansion- seawater expands as ocean temperatures rise.
• Melting glaciers- warming causes glaciers to lose mass.
• Greenland and Antarctic ice-sheets loss- melting of land-based ice adds water to the oceans.
• Changes in terrestrial water storage- groundwater extraction and other human activities can transfer water to the oceans.

Sea-level rise can increase coastal flooding, erosion, saltwater intrusion, displacement and damage to infrastructure.

UN Declaration on Rising Sea Levels

• The UN declaration focuses particularly on vulnerable island nations such as Tuvalu, Kiribati, Maldives.
• It recognizes that sea-level rise can threaten not only territory and livelihoods but also the continuity of states and their maritime rights.

Key Provisions

• The declaration supports a “presumption in favour of continued statehood” for countries affected by sea-level rise.
• This means that loss or submergence of territory would not automatically mean the disappearance of the affected state.
• The declaration also calls for:
  • Respect for the human rights of people affected by sea-level rise.
  • Greater international cooperation for affected populations.
  • Integration of sea-level-rise projections into coastal infrastructure planning.
  • Greater attention to vulnerable island and coastal communities.

Can a Country Retain its Statehood if its Territory is lost?

• Under the 1933 Montevideo Convention, statehood traditionally involves four elements:
  • Permanent population
  • Defined territory
  • Government
  • Capacity to enter into relations with other states
• Sea-level rise creates a new legal question: Can a state continue to exist if its territory becomes submerged or uninhabitable?
• The UN declaration supports the continued statehood of such vulnerable countries.
• It also supports maintaining their sovereignty, rights and UN membership, while protecting their maritime boundaries.

Climate Mobility

• The problem is already visible in island nations.
• For example, by December 2025, more than one-third of Tuvalu’s population had applied for climate visas to migrate to Australia under a bilateral arrangement.

Relevance of the Declaration for India

• India supported the declaration and emphasized;
  • Stable maritime zones
  • Continuity of statehood
  • Equity
  • Common but Differentiated Responsibilities and Respective Capabilities (CBDR-RC)
• India has a significant stake because of its extensive coastline and offshore islands.
• According to the 2023-24 remeasurement;
  • India has 1,298 offshore islands and islets.
  • Its coastline is about 11,098 km long.
  • Lakshadweep and the Andaman & Nicobar Islands extend
  • India’s maritime presence deep into the Arabian Sea and Bay of Bengal.
• Therefore, maintaining stable maritime boundaries is important for India’s territorial sovereignty, maritime security and blue economy.

India’s Coastal Erosion

• The National Centre for Coastal Research (NCCR) assessed India’s mainland shoreline between 1990 and 2016.
• Findings
  • About one-third of India’s coastline was eroding.
  • Around 234 sq km was lost to erosion.
  • Around 231 sq km was gained elsewhere through accretion.
  • Nearly 400 km of coastline was retreating by more than 5 metres per year.
  • Another 225 km was retreating by around 3–5 metres per year.
  • West Bengal had more than 170 km in the fastest erosion category.
• Thus, although erosion and accretion may appear broadly balanced at the national level, erosion is highly concentrated in vulnerable stretches.

Coastal Regulation Zone and Sea-Level Rise

• The Coastal Regulation Zone (CRZ) framework regulates development along India’s coast.
• In densely populated rural areas, the no-build zone can extend 50 metres from the relevant high-tide line after approval of the state’s Coastal Zone Management Plan.
• In other areas, the corresponding distance can be 200 metres.
• These distances are measured from the High Tide Line (HTL).

Problem

• The HTL is based on the present coastal position.
• If a coastline is retreating rapidly, today’s setback distance may not provide adequate protection in the future.
• Example:
  • If the coast retreats by 5 metres every year:
  • A 50-metre setback could effectively be consumed in about 10 years.
  • A 200-metre setback could be consumed in about 40 years.
• This shows why coastal planning needs to account for future erosion and projected sea-level rise, rather than relying only on present-day shoreline positions.

Hazard Line

• The Survey of India has mapped a hazard line that incorporates sea-level rise, shoreline changes and coastal hazards.
• The hazard line has been shared with coastal States.
• It can support disaster management planning, land-use planning and coastal infrastructure planning.
• However, there is a need to integrate this hazard-based approach more directly into coastal development regulations.

Where Does India Fall Short?

Sundarbans

The Sundarbans illustrate the consequences of coastal erosion and displacement.

• Ghoramara Island
  • According to the India Water Portal, Ghoramara Island shrank from around 7.2 sq km in 1972 to around 2.6 sq km in 2022.
  • People who had earlier moved to Ghoramara from Lohachara Island, which disappeared in the early 2000s, faced displacement again.
  • The experience highlights problems such as:
    • Repeated displacement
    • Loss of land
    • Insecure tenure
    • Loss of livelihoods
    • Lack of adequate rehabilitation

Lack of a Comprehensive Legal Framework

• India does not have a clear legal category specifically dealing with people who gradually loss land because of coastal erosion and rising sea levels.
• Relocation therefore tends to be handled on a case-by-case basis.
• An estimated 45 million Indians could be at risk from sea-level rise by 2050, highlighting the need for a comprehensive legal framework to address climate-induced displacement and related risks.
• International example
  • Fiji incorporated relocation into its Climate Change Act, 2021, including a trust fund mechanism to support relocation.

Key Challenges for India

Environmental 

• Rising sea levels can accelerate shoreline retreat and loss of coastal land.
• Increasing sea levels raise the long-term vulnerability of low-lying coastal areas.
• Higher sea levels increase the risk of flooding during cyclones, storms and high tides.
• Seawater intrusion can contaminate groundwater and reduce agricultural productivity.
• Coastal ecosystems may shrink, reducing natural protection against floods and erosion.

Socio-economic

• Coastal communities may be forced to relocate from increasingly vulnerable areas.
• Erosion and flooding can damage houses, farmland, fisheries and other sources of income.
• Salinity and habitat loss can reduce agricultural output and affect fishery resources.
• Relocated families may face difficulties in securing land ownership and long-term housing.

Governance

• Coastal infrastructure may not sufficiently account for future sea-level rise and erosion.
• Overlapping responsibilities can make coordinated coastal planning difficult.
• India lacks a comprehensive framework specifically addressing slow-onset climate-induced displacement.
• Providing land, housing and livelihood support to displaced communities remains difficult.

Strategic

• Sea-level rise can create concerns regarding the stability of maritime zones and coastal sovereignty.
• Islands such as Lakshadweep and the Andaman and Nicobar Islands face greater exposure to coastal hazards.
• Ports, roads and other critical infrastructure are vulnerable to erosion, flooding and storm surges.
• Damage to coastal ecosystems and infrastructure can affect India’s blue economy, maritime activities and coastal security.

The UN Declaration calls for scaled-up, timely and predictable climate finance.

• • The UN Environment Programme estimates developing countries adaptation needs at more than $320 billion annually by 2035, compared with much lower international public adaptation finance.
  • India has also argued internationally for greater and more accessible climate finance.

Way Forward and Conclusion

India should adopt a climate-resilient approach to coastal management by using sea-level projections in planning, strengthening coastal monitoring, protecting mangroves and wetlands, and creating a framework for climate-induced displacement.

Sea-level rise threatens livelihoods, infrastructure and coastal communities. Scientific planning, ecosystem protection and adequate climate finance can help India build resilient and sustainable coastal regions.

UPSC Prelims and Mains Practice Question

Consider the following statements regarding sea-level rise and India’s coastline:

1. Thermal expansion of seawater is one of the major contributors to global sea-level rise.
2. Coastal erosion and sea-level rise can increase the displacement risk of coastal communities.
3. India’s coastal management can rely exclusively on the present High Tide Line because future shoreline changes do not affect coastal setback requirements.

Which of the statements given above is/are correct?

A) 1 and 2 only

B) 2 and 3 only

C) 1 and 3 only

D) 1,2 and 3

Mains Practice Question

Q) Rising sea levels pose not only an environmental challenge but also a threat to coastal livelihoods, infrastructure and territorial sovereignty. Discuss the implications of sea-level rise for India and suggest measures for building climate-resilient coasts. ( 250 words)

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