Deltas of the Ganga, Krishna, Godavari, Cauvery and Mahanadi on the east coast may also be threatened along with irrigated land and adjoining settlements, according to a Government report.
"It is estimated that sea level rise by 3.5 to 34.6 inches between 1990 and 2100 would result in saline coastal groundwater, endangering wetlands and inundating valuable land and coastal communities. The most vulnerable stretches along the western Indian coast are Khambat and Kutch in Gujarat, Mumbai and parts of the Konkan coast and south Kerala," says the report submitted to the UN.
The report -- India's Second National Communication to the United Nations Framework Convention on Climate Change-- was prepared by multi-disciplinary teams and other stakeholders comprising more than 220 scientists belonging to over 120 institutions.
"The loss of these important economic and cultural regions could have a considerable impact in some states," it says.
The experts who prepared the report visited some vulnerable areas, including the 2004 tsunami-hit Nagapattinam in Tamil Nadu, backwaters surrounding Kochi in Kerala and Paradip in Odisha, in order to make a detailed impact study of the rise in sea level.
The study, using digital elevation model data (90m resolution), digital image processing and GIS software, showed that estimated inundation areas are 4.2 sq km and 42.5 sq km in case where the sea level rise is 1.0 m and 2.0 m respectively in the region surrounding Nagapattinam.
"But for the same sea level conditions, 169 sq km and 599 sq km will be inundated in the coastal region surrounding Kochi," says the report.