This study concentrates on the impact of sea level rise on coastal infrastructure, ecosystem and land in the state of Tamil Nadu, India.
Sea level rise, due to climate change, 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. 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. This study examines the potential impacts of sea level rise on coastal infrastructure, ecosystem and land in Tamil Nadu.
Using GIS technology and information available from the government and some private entities, the study estimates the replacement cost of infrastructure, present value of ecosystems and market value of land in Tamil Nadu that will be at risk from a 1-metre rise in sea levels. The following types of major infrastructure along the coast were identified: ports, power plants, nuclear facilities, major roads and highways. For each of these, investment costs were obtained, directly from public agencies, through Right to Information (RTI) requests or from published data in the public domain. The data was processed using ArcGIS software as both raster and vector data types.
The study identifies the area at risk from a 1m SLR is estimated 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 SLR, because of the very high storm surges that already affect them. For the remaining eight 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 SLR.
Findings from the study also indicate that the total replacement value of infrastructure – ports, power plants and roads – impacted by sea level rise is estimated to be between Rs. 47,418 and Rs. 53,554 crores (2010). 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 of SLR alone.
Considering the implications of extensive infrastructure development in coastal areas in light of these findings, similar studies may well be conducted for states such as Andhra Pradesh, Orissa and West Bengal – that are subject to even more severe cyclones from the Bay of Bengal than Tamil Nadu – as well as Maharashtra and Gujarat, which have much higher levels of investment along the coast.