EXCLUSIVE: Anna University Study Reveals Rising Sea Levels Pose A Threat To India
Sea level rise (SLR) is primarily driven by the melting of glaciers and the thermal expansion of seawater.
Published : September 10, 2025 at 7:19 PM IST
By S Ravichandran
Chennai: Sea level rise (SLR) represents one of the most serious concerns stemming from climate change, primarily driven by the melting of glaciers and the thermal expansion of seawater as global temperatures increase.
A recent study published in Theoretical and Applied Climatology projects substantial SLR along India's 7,500 km coastline. This was conducted by a team of researchers led by Prof A Ramachandran, Emeritus Professor at the Centre for Climate Change and Disaster Management (CCCDM), Anna University.
The research examines historical trends and future projections under the IPCC's ARB Shared Socioeconomic Pathways (SSPs). It highlights escalating risks to coastal ecosystems, infrastructure, and communities, emphasising the need for region-specific strategies.
The analysis draws on data from the Permanent Service for Mean Sea Level (PSMSL). NOAA satellite altimetry (1992-2023), and Indian Meteorological Department (IMD) cyclone records (1991-2023).
Key insights include:
- Historical Trends: PSMSL data reveal significant spatial and temporal variability. with rates ranging from -0.17 mm/year to 3.82 mm/year, showing higher acceleration in the Bay of Bengal compared to the Arabian Sea (using 1900 levels as baseline).
- Monitored Locations on the West Coast (6 PSMSL sites across 5 states): Kandla and Okha (Gujarat), Mumbai (Maharashtra), Mormugao (Goa), Karwar (Karnataka), Cochin (Kerala).
- Monitored Locations on the East Coast (8 PSMSL sites across 4 states): Tuticorin. Nagapattinam, and Chennai (Tamil Nadu): Visakhapatnam (Andhra Pradesh): Paradip (Odisha); Gangra, Haldia, and Diamond Harbour (West Bengal).
- Future Projections: Utilising SimCLIM with an ensemble of 39 CMIP6 General Circulation Models (bias-corrected against PSMSL data), SLR could reach 25 cm under low-emission scenarios or up to 110 cm under high-emission scenarios by 2100.
- High-Risk Regions: Visakhapatnam, Sundarbans, and Nagapattinam are most vulnerable due to low-lying topography (close to zero mean sea level) and river confluences, which amplify flooding and erosion.
- Cyclone and Storm Surge Impacts: The Bay of Bengal faces high uncertainties in rainfall and cyclone predictions. Between 1992 and 2023, 62 cyclones (87%) made landfall on the East Coast (Bay of Bengal), compared to 9 (13%) on the West Coast (Arabian Sea). Storm surges compound SLR effects, necessitating enhanced resilience.
- Adaptation Recommendations: Integrate local knowledge to foster community ownership and commitment, improve project sustainability, and generate economic co-benefits. Strategies should combine engineering solutions, nature-based approaches (e.g., mangrove restoration), and stakeholder engagement.
"This research underscores the imperative for tailored adaptation frameworks to safeguard India's coastal populations," stated Prof A Ramachandran, adding, "By merging scientific projections. With indigenous insights, we can mitigate risks to vital ecosystems and livelihoods amid accelerating climate impacts."
The study stresses that the East Coast is disproportionately affected, with threats to biodiversity hotspots like the Sundarbans and agricultural areas in Odisha and Tamil Nadu. Advocates for robust early warning systems, inclusive policy development, and long-term resilience planning.
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