If you are living in your dream sea-facing villa or planning to purchase one, here’s a warning. In 25 years, property less than 500m from the sea may get frequently flooded by the rising sea. City scientists say that by 2050, climate change and local factors could make 102.2km or 76% of the coast of Chennai, Tiruvallur and Chengalpet prone to hazards such as cyclones, coastal erosion and sea level rise.Of that, 77km with structures, roads, industries, lagoons, creeks, swamps and beaches face very high climate risk.
Climate risk includes a projected sea level rise of 19.2cm in three districts by 2050, which may lead to inundation of 6,120 hectares. This is applicable if CO2 emissions remain near the current levels till mid-century and decline thereafter.
Rising seas mean cyclonic storms travel further inland and more frequent flooding caused by high tides. This can worsen coastal erosion, affect groundwater resources and inundate wetlands that act as protective barriers. These projections are in a draft report titled ‘Climate risk assessment and adaptation plan of Tamil Nadu — coastal ecosystem’ by Centre for Climate Change and Disaster Management (CCCDM), Anna University.
“Tiruvarur, Nagapattinam and Chengalpet have extensive coastlines with high vulnerability due to salinity levels and low elevation areas. Districts such as Kanyakumari,Chennai and Cuddalore have more than 60% of their coastlines exposed to climate change, influenced by factors such as land use and infrastructure,” the report said.
For Tamil Nadu, projected sea level rise for 2050 indicates an average increase of 19.71cm with Tiruvarur, Nagapattinam and Thanjavur districts being the most affected, the report added. Between 1916 and 2015, there has been a relative sea level rise of 0.18feet in 100 years along Chennai coast. Global sea level rise along with other local factors such as local subsidence due to anthropogenic activities such as groundwater and hydrocarbon extraction will influence regional sea levels.
Risk to the coast was identified based on shoreline changes, sea level rise and proximity to cyclone track; vulnerability factors such as coastal plains and groundwater salinity; and exposure factors such as land use and road networks. Of the 43,868 hectares in Chennai, 28,330 hectares or 64% is built-up land.
“A combination of soft and hard measures are required to reduce coastal risks. The soft measures are primarily nature-based solutions such as mangrove restoration and conservation, shelterbelt plantation, integrated coastal zone management, artificial beach nourishment. Hard measures include coast protection structures such as breakwater, revetment, vertical walls. Early warning systems and livelihood support schemes are also essential,” said Kurian Joseph, director, CCCDM.
