The two-year exercise completed in August covered 6,032 kilometres of coastline. It suggests that 40 per cent of India’s 7,500 kilometre-long coastline has been eroded to a greater or lesser extent over different periods since 1968.
“An average of the erosion data from satellites gives us an idea of the changes over the entire period from 1968,’’ explains S. Srinivasulu, professor at the Institute of Ocean Management (IOM). He adds that the mapping provides valuable inputs for the country’s efforts to cope with possible sea level rise and devise strategies to adapt to climate change.
The IOM partnered in the mapping exercise with the National Centre for Sustainable Coastal Management (NCSCM), Anna University, Chennai, which has already been engaged in coastal bio-zonal mapping, sand dune and sediment mapping, and the mapping of ecologically sensitive coastal areas.
Srinivasulu tells SciDev.Net that the coastline vulnerability assessment would help draw up plans, over the next two — three years, to cope with the possible submergence of such major coastal cities as Chennai, Mumbai and Kolkata, as well as smaller ones.
“In some cases we would not do anything, in other cases retreat would be considered, while a third option is to use existing sand dunes along with the planting of trees,” Srinivasulu says. “The hard option is to artificially bolster the coastlines —10 per cent of the coastline has already been shored up in this manner.”
However, the best method, Srinivasulu emphasises, is to “reduce CO2 emissions to prevent rise in sea surface temperatures which would, in turn, prevent ice melt, and consequent rise in sea levels.”
NCSCM director, Ramesh Ramachandran, tells SciDev.Net that the maps would be an additional tool in the hands of the Indian government to decide whether to grant or deny approvals for infrastructure projects in eroded areas.
“The eroded areas could be taken up for conservation while restricting development projects,’’ says Ramachandran.
According to Ramachandran, the macro-level mapping is a step towards high resolution mapping on a 1:4000 scale.
The ministry of environment and forests estimates sea levels to rise by 89—879 millimetres between 1990 and 2100, resulting in saline ingress into coastal groundwater, endangered wetlands and inundated coastal communities.
This article has been produced by SciDev.Net's South Asia desk.