Sea Level Rise

Sea Level Rise (SLR) is a critical environmental issue gaining attention due to its potential impact on coastal cities and ecosystems. The recent report titled 'Sea Level Rise Scenarios and Inundation Maps for Selected Indian Coastal Cities' by the Centre for Study of Science, Technology, and Policy (CSTEP) highlights the alarming rate of sea-level rise in India.

Key Observations from the Report

• Maximum Sea Level Rise (1991–2020):
• Mumbai saw the highest increase in sea level (4.44 cm), followed by Haldia (2.72 cm), Visakhapatnam (2.38 cm), and other coastal cities.
• Submergence by 2040:
• More than 10% of land in Mumbai, Yanam, and Thoothukudi is projected to be submerged.
• 5%–10% of land in Panaji and Chennai and 1%–5% in Kochi, Mangaluru, Visakhapatnam, and others will also face submersion due to rising sea levels.

Factors Contributing to Sea Level Rise

• Ocean Thermal Expansion:
• Oceans absorb over 90% of the heat trapped by greenhouse gases, causing water expansion as temperatures rise.
• Ice Melting:
• The melting of glaciers, ice caps, and ice sheets in Greenland and Antarctica further contributes to the rise in sea levels.

Impacts of Sea Level Rise

• Increased Coastal Erosion:
• Rising sea levels lead to more frequent and extreme coastal flooding and storm surges, accelerating coastal erosion.
• Around 32% of India's coastline has experienced erosion between 1990 and 2018 (NCCR report).
• Coastal Inundation and Flooding:
• Low-lying coastal regions are at higher risk of flooding and inundation due to increased sea levels, impacting both urban and rural areas.
• Freshwater Salinization:
• Saltwater intrusion threatens freshwater sources, including aquifers and river deltas, affecting drinking water supplies and agriculture.
• Coastal Community Displacement:
• Low-lying communities, particularly in South Asia, are at risk. Approximately 3.6 million people have been displaced in the region over the past decade (Internal Displacement Monitoring Centre).
• Coastal Habitat Loss:
• Critical ecosystems like mangroves, salt marshes, and coral reefs face severe threats. The Gulf of Mannar's coral reefs are already at risk.
• Infrastructure Vulnerability:
• Urban infrastructure such as roads, bridges, and buildings face higher risk from rising waters and floods, necessitating costly repairs and upgrades.

Steps Taken by the Government of India

• Protection and Control of Coastal Erosion (2020):
• The Central Water Commission has issued guidelines for designing coastal protection measures based on varying erosion rates across India's coastline.
• Coastal Vulnerability Index (CVI):
• The Indian National Centre for Ocean Information Services (INCOIS) developed a CVI to assess coastal vulnerability based on seven key parameters, including sea-level change rate, coastal geomorphology, and tidal range.
• National Disaster Response Fund (NDRF):
• Under the 15th Finance Commission, ₹1000 crore is allocated for the resettlement of people displaced due to coastal erosion.
• Coastal Regulation Zone Notification, 2019:
• Issued by the Ministry of Environment, Forest and Climate Change, this regulation aims to conserve coastal stretches while ensuring the livelihood security of coastal communities, including fisherfolk.
• Mangrove Initiative for Shoreline Habitats and Tangible Incomes (MISHTI):
• Launched to develop 540 sq. km of mangrove forests across 11 states and 2 union territories to protect shorelines and generate income for coastal communities.
• Shelterbelt Plantations:
• Rows of trees planted along the coastline act as natural buffers to reduce sea erosion, as seen in the coastal district of Ramanathapura

Adaptation strategies

Adaptation strategies for sea-level rise are crucial in mitigating the risks and ensuring the resilience of coastal regions. Below are some key strategies:

1. Build Flood Barriers to Protect Infrastructure

• Ecosystem-Based Coastal Protection:
• Utilizing natural defenses, such as oyster beds, coral reefs, and mangrove forests, helps absorb wave energy, reducing coastal erosion and acting as natural breakwaters.
• Example: Oyster beds can act as natural buffers, minimizing the impact of waves and storm surges.
• Man-Made Structures:
• Seawalls, levees, and dikes constructed from concrete or masonry provide a robust barrier against rising seas and storm surges.
• Example: Seawalls along cities like Mumbai, which have long coastlines, can prevent flooding and protect infrastructure.

2. Sea-Level Rise and Storm Surge Modelling

• Modelling and Predictive Tools:
• Conducting sea-level rise and storm surge modeling is essential for identifying vulnerable areas and informing the strategic placement of critical infrastructure like roads, power plants, and hospitals.
• Data-driven decision-making can significantly reduce the risks to coastal populations and economies.

3. Floating Cities

• Flood-Proof Urban Development:
• Cities built on floating platforms are emerging as innovative solutions to address urban flooding due to sea-level rise. This concept is being pioneered in countries like Maldives and South Korea.
• These cities are designed to rise and fall with the tides, ensuring continuous habitation without flooding risks.

4. Integrated Coastal Zone Management (ICZM)

• Sustainable Coastal Development:
• ICZM promotes the sustainable development of coastal zones by integrating environmental, social, and economic factors to protect coastal ecosystems while ensuring the security of coastal communities.
• It focuses on balancing development with the conservation of sensitive habitats like mangroves, wetlands, and coral reefs.

5. Push for a Climate Action Plan

• Comprehensive Climate Policies:
• Cities and states should develop climate action plans addressing sea-level rise, coastal erosion, and extreme weather events linked to climate change. These plans should include mitigation (reducing emissions) and adaptation strategies tailored to local conditions.
• Example: Cities like Mumbai, Chennai, and Kolkata could benefit from localized climate action plans that incorporate adaptive infrastructure, disaster preparedness, and community resilience-building.

Adopting these strategies can help protect lives, livelihoods, and infrastructure from the detrimental effects of rising sea level