Sea level rise – Impact on major infrastructure, ecosystems and land along the Tamil Nadu coast – A report by IFMR and IIT Madras

The Tamil Nadu coastline is about 1,076 km, with thirteen coastal districts, and it forms a fairly large contiguous and narrow coastal strip dotted with fragile ecological features and rampant development activities. There are major, existing and proposed, economic and infrastructure developments, including ports, power plants, highways and even airports, which are being planned very close to the shoreline along India’s coast.

Sea level rise will affect the coastline in India in a variety of ways, including inundation, flood and storm damage associated with severe cyclones and surges, erosion, saltwater intrusion, and wetland loss.

This report aims to highlight the financial implications of sea level rise on existing and proposed infrastructure along the Tamil Nadu coast and to provide thereby an “early warning” of the implications of indiscriminate development close to the shoreline. The study does not evaluate the impact on human populations along the coast from sea level rise, which is likely to cause devastation, as recent experience from cyclones and the tsunami indicate.

The study employs Geographic Information Systems and information available in the public domain. The analysis in this report provides preliminary estimates of the replacement value of major infrastructure, the present value of ecosystem services associated with damage to wetlands and the market value of land at risk from 1m of sea level rise by 2050.

Some of the specific points it makes are –

• Since the area at risk from sea level rise is much larger than the area that is actually inundated, the area at risk for a 1m rise in mean sea level is also identified on the basis of district-level analyses of the likely impacts from storm surges. 
• For five coastal districts, Nagapattinam, Thiruvarur, Thanjavur, Pudukottai, and Ramanathapuram, the area along the coast that is below 10m above current mean sea level is estimated to be at risk from a 1 metre sea level rise, because of the very high storm surges that already affect them.
• For the remaining height coastal districts, the coastal area that lies below 5m elevation relative to current mean sea level is estimated to be at risk from a 1 metre sea level rise. A 1m rise in average sea level would permanently inundate about 1091 square kilometres along the Tamil Nadu coast, but the total area at risk would be nearly six times as much.
• The study estimates the total replacement value of infrastructure (ports, power plants and major roads) impacted by sea level rise to be between Rs. 47,418 and Rs. 53,554 crores (in 2010 terms).
• The present value of wetlands (estimated in terms of foregone ecosystem services through 2050) impacted by sea level rise is estimated to be between Rs. 3,583 and Rs. 14,608 crores.
• By far the largest impact will be on the land at risk, whose market value is estimated to be between Rs. 3,17,661 and Rs. 61,15,471 crores. In comparison, Tamil Nadu’s annual Gross Domestic Product is estimated to be around Rs. 2,50,000 crores, indicating that very significant value is at risk along the coast due to climate change impacts from sea level rise alone.

The report recommends a comprehensive vulnerability assessment of the entire coast, the integration of climate change considerations into all coastal infrastructure development, special efforts to protect wetlands, and the careful assessment of coastal protection measures and implementation of these where they may be useful.

Image Courtesy:

The Hindu

Download the report here -