Sea level could rise 10 times faster by 2100; Mumbai at risk, says study
Sources cited in the report have estimated that approximately 28 million people across Mumbai, Kolkata, Surat, Chennai, Kochi and Vishakhapatnam are at risk with the global mean sea level projected to rise 10 times faster by 2100, if global greenhouse gas emissions are not curtailed.
According to the United Nations’ Intergovernmental Panel on Climate Change (IPCC), a global climate science body, Mumbai is one of six Indian cities at critical risk from sea level rise, which could lead to infrastructural damage, severe flooding, economic losses and a surge in extreme weather events. IPCC’s Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), released on Wednesday, examines how a drastic rise in sea surface temperatures may affect marine life and the threats posed by rising water levels to islands and coastal regions by the end of the century.
Sources cited in the report have estimated that approximately 28 million people across Mumbai, Kolkata, Surat, Chennai, Kochi and Vishakhapatnam are at risk with the global mean sea level projected to rise 10 times faster by 2100, if global greenhouse gas emissions are not curtailed. Islands like Andaman, Nicobar and Lakshadweep may not be habitable in a few years, which would mean relocating thousands. The SROCC, which was approved by 195 governments, directly associates rising greenhouse gas emissions to changes in the ocean environment.
“Mumbai’s infrastructure and drainage capacity has to be climate resilient to take into account the impacts of changing weather patterns. This can be done based on early choices made by the government to combine environment planning with the city’s development plans,” said Anjal Prakash, coordinating lead author, SROCC and associate professor at TERI School of Advanced Studies.
A 2018 study by Jawaharlal Nehru University (JNU) found low-lying areas like Haji Ali, Worli and stretches between Nariman Point and Marine Drive could be completely submerged by 2100 due to the rise in sea level. The coastal belt from Gorai to Mira Bhayander would be worst-affected.
Prakash said that globally, sea level is currently rising twice as fast – 3.6 mm per year and accelerating – as it did in the entire 20th century. “It would reach around 30-60cm by 2100 even if greenhouse gas emissions are sharply reduced and global warming is limited to below 2 degrees Celsius. In the event of high greenhouse gas emissions, it would rise to 60-110 cm,” he said.
For coastal cities like Mumbai, this would mean high salinity ingress. “This will not only pollute freshwater bodies, but lead to huge economic losses as it will directly impact the domestic water sector and then food production,” said Prakash. Extreme weather events like cyclones in the Arabian Sea may also increase in frequency. This year has already seen two cyclones (Vayu and Hikka).
“The increase in extreme weather events witnessed this monsoon in Mumbai is already an indicator of this changing climate scenario, and new technology needs to be adopted much faster to understand and respond to this,” said Prakash.