Key infra in 6 coastal cities may submerge by ’50
NEW DELHI: A new analysis on the impact of sea level rise on coastal Indian cities has revealed that some critical properties and road networks in Mumbai, Kochi, Mangalore, Chennai, Vishakhapatnam, and Thiruvananthapuram will be submerged by 2050.
The analysis by RMSI, a global risk management firm, has found that Haji Ali dargah, Jawahar Lal Nehru Port Trust, Western Express Highway, Bandra-worli Sea-link,and Queen’s Necklace on Marine drive, all in Mumbai, are at risk of submergence.
RMSI considered findings from the Intergovernmental Panel on Climate Change’s sixth assessment report ‘Climate Change 2021: The Physical Science Basis’ released in August last year; various publications based on the IPCC report, the latest climate change data, and its own models to find out possible impact on the Indian coastline.
Six coastal cities of India, Mumbai, Chennai, Kochi, Vizag, Mangalore, and Thiruvananthapuram were considered for this analysis. RMSI’S experts created a high-resolution Digital Terrain
Model (topography) for the coastline of the identified cities. They then used a coastal flood model to map the cities’ inundation levels based on various sealevel rise forecasts.
IPCC has projected that the sea level around India will rise significantly by 2050. ‘Assessment of climate change over the
Indian region’ a report of the Ministry of Earth Sciences (MOES) also said that sealevel rise in the North Indian Ocean (NIO) occurred at a rate of 1.06–1.75 mm per year during 1874–2004 and has accelerated to 3.3 mm per year in the last two-and-a-half decades (1993–2017), which is comparable to the current rate of global mean sea-level rise.
The moderate emissions (RCP 4.5) scenario of IPCC projects that steric sea level (variation in the ocean volume due to density changes) of the north Indian Ocean will rise by approximately 300 mm (a foot) relative to the average values from 1986 to 2005, the MOES report said. The corresponding projection for the global mean rise is approximately 180 mm.
“How much water will go inland is a function of what kind of continental shelf we have. The impact of sea level rise will be different in different parts. No client asked us to do these modelling studies. Because the IPCC report suggested Indian coastal cities could be in danger, we felt we should quantify these findings. We intend to reach out to affected state governments and we will definitely share the findings with the World Bank and National Disaster Management Authority,” said Pushpendra Johari, senior VP , Sustainability, RMSI Pvt Ltd.
Johari added that with early knowledge of how coastal cities are going to be impacted, some interventions can be made, including land reclamation; increasing the height of roads and strengthening buildings against corrosion or relocating them.
“We considered RCP 4.5 which is an intermediate scenario. Sea level is expected to rose at least 2050 and then stabilise,” he said.