‘Sea level rise scenarios and inundation maps for selected Indian coastal cities’ titled report was published by a Bengaluru-based think tank, the Centre for Study of Science, Technology and Policy (CSTEP).

An infographic titled 'Do you know?' providing information that as per the IPCC global meaan sea level rose by 0.20 m (0.15-0.25) between 1901 and 2018. It also states that the IPCC has projected a global mean sea level rise of 1.3 to 1.6 meters by 2100 under the high-emission scenario.

Key Observation

Maximum Sea Level Rise (SLR): Maximum SLR over the past three decades (1991–2020) was observed at the Mumbai station (4.44 cm), followed by Haldia (2.72 cm), Visakhapatnam (2.38 cm), etc.
Submergence due to rise in sea levels by 2040: More than 10% of the land in Mumbai, Yanam, and Thoothukudi; 5%–10% in Panaji and Chennai; and 1%–5% in Kochi, Mangaluru, Visakhapatnam, Haldia, Udupi, Paradip, and Puri would be submerged due to rise in sea levels by 2040.

Factors for Sea Level Rise (SLR)

Ocean thermal expansion: Oceans absorb more than 90% of the heat trapped by accumulating greenhouse gases (GHGs), leading to temperatures increase and expansion of water.
Ice melting: The melting of ice from glaciers, ice caps, and ice sheets in Greenland and Antarctica is another cause of SLR.

Impacts of Sea Level Rise

Increased coastal erosion: As the sea level rises, more frequent and extreme coastal floods and storm surges occur, which increase coastal erosion.
- For instance, as per National Centre for Coastal Research (NCCR) report around 32 per cent of India’s coastline underwent sea erosion between 1990 and 2018.
Coastal inundation and flooding: Rising sea levels increase the risk of frequent and severe floods and inundation in low-lying coastal regions and islands.
Freshwater salinization: Freshwater sources, such as subterranean aquifers and river deltas, are susceptible to salinization due to SLR.
Coastal community displacement: Low-lying coastal communities are at risk of land flooding due to SLR.
- For example, as around 3.6 million people have been displaced in South Asia over the past decade. (Internal Displacement Monitoring Centre)
Coastal habitat loss: Sea level rise is especially dangerous for coastal ecosystems, such as mangroves, salt marshes, and coral reefs.
- For example, Coral reefs of the Gulf of Mannar are facing threats.
Infrastructure vulnerability: Higher water levels and more frequent flooding raise the risk of infrastructure disruption and damage, necessitating expensive repairs and modifications.

Steps taken by Government of India

An infographic displaying the tier-wise spatial distribution of Indian coastal cities and towns. It categorizes cities into Tier I (2 cities), represented by red circles (e.g., Mumbai and Chennai), Tier II (6 cities) with yellow squares (e.g., Mangaluru and Visakhapatnam), and towns (7) shown as pink triangles (e.g., Udupi and Paradip). It also marks tide gauge stations with black circles, indicating locations such as Panaji and Kochi. The map includes elevation details, with a color gradient from high to low.

Protection and Control of Coastal Erosion in India: Central Water Commission has published guidelines in 2020 to provide the preliminary design parameters for suitable coastal protection works for different stretches of coastline.
Coastal Vulnerability Index (CVI): Indian National Centre for Ocean Information Services has estimated CVI for the Indian coastline.
- Which is a cumulative impact of seven coastal parameters i.e., shoreline change rate, sea-level change rate, coastal elevation, coastal slope, coastal geomorphology, significant wave height and tidal range.
National Disaster Response Fund (NDRF): Under 15^th Finance Commission, recovery and reconstruction window of NDRF for Rs. 1000 crore is earmarked for resettlement of displaced people affected by erosion.
Coastal Regulation Zone Notification, 2019: Notified by Ministry of Environment, Forest and Climate Change with a view to conserve and protect coastal stretches, marine areas and to ensure livelihood security to the fisher and other local communities.
Mangrove Initiative for Shoreline Habitats and Tangible Incomes (MISHTI):The plan is to comprehensively explore developing 540 sq. km of mangrove forests across 11 states and 2 union territories over the next 5 years, starting from FY 2023-24.
Shelterbelt plantations: Tightly planted rows of trees on the shoreline play a major role in preventing coastal sea erosion. For example-at coastal district of Ramanathapura.

Adaptation strategies for Sea-level rise

Build flood barriers to protect infrastructure:
- Ecosystem-based coastal protection: E.g., Oyster beds along the coast can serve as natural breakwaters.
- Man Made structures: E.g., seawall is a structure made of concrete, masonry or sheet piles.
Conduct sea-level rise and storm surge modelling: Modelling sea-level rise and storm surge dynamics will better inform the placement and protection of critical infrastructure.
Floating Cities: Development of these cities started in Maldives and South Korean which will be flood proof.
Integrated Coastal Zone Management: Aim to promote security of life and livelihood of coastal communities, protect coastal ecosystems and to promote sustainable development.
Push for a Climate Action Plan: Many cities and states do not have plans to address climate change, which is the primary cause of current sea level rise.