Climate change study: ‘3 million living within a km from Mumbai’s coast at risk from floods’
Almost three million people living within a kilometre from the city’s coastline (high-tide line) are under “severe” threat from flooding, storm surges and rise in sea level, according to an analysis released on Thursday.
The high-tide line is the corresponding point on land where the tide reaches maximum height.
New research from private group McKinsey & Company Inc. identified risks of multiple hazards with increasing intensity due to climate change from now till 2050 for Mumbai’s coast. The analysis builds on a global report titled ‘Climate risk and response: Physical hazards and socioeconomic impacts’ released by McKinsey & Company at the World Economic Forum in January 2020.
Mumbai-specific details were released during the Climate Crisis Conclave hosted by not-for-profit group Mumbai First and the Maharashtra government on Thursday.
According to the analysis, Mumbai could witness a 25% increase in flash-flood intensity events by 2050, with average flood depth rising from 0.46m to 0.82m by 2050. Flooded area (for every 0.05m across the city) would rise from the current 46% to 60%, which would lead to cost escalation for infrastructure damage (capital stock damage) from the current 580 million USD to 920 million USD by 2050.
The analysis also raised an alarm about extreme weather events and storm surges accelerating by 1.5 times rise with 100 km/hour wind speed being the new normal.
“If we thought the 2005 deluge had a certain risk associated with it, our assessment found that the next event, if it happens, the risk would be much higher (50% to 100% worse),” said Shirish Sankhe, senior partner, McKinsey’s Mumbai office. “The aim is not to create another alarmist report, but to see how we can come up with solutions.”
The analysis used risk modelling or assessment (not a forecast) for multiple aspects of climate change-related events including the assessment of flash floods over 40 years, heat waves, and extreme-weather events. The average sea level increase for Mumbai over the next 30 years is predicted to be over 0.5m.
“We need to factor in climate risk in our decision making architecture. For example, if storm surge and sea level increases by one metre, then we may need coastal walls to withstand the impact. Mumbai has the money and many of these things can be done better for the financial capital than other cities. If there is understanding emerging, then intent will emerge,” said Sankhe.
Civic chief Praveen Pardeshi said Mumbai needed to build on climate-resilient infrastructure through a circular economy and also spoke about mitigation measures such as eco concrete and Miyawaki plantations that BMC was undertaking. “We are really not that well prepared because we don’t factor in climate risk quantitatively into the design of our infrastructure, which we should be doing even more. There is a huge conflict in Mumbai between greenery and new infrastructure. We need to think globally and act locally,” he said.
RA Rajeev, metropolitan commissioner, MMRDA, said enhancing public transport network would directly work towards greenhouse gas reduction. “By 2025-26, all 300-km of Mumbai’s Metro lines will be constructed. Fuel consumption (mostly private vehicles) will reduce 30%, and overall air pollution will go down by 60%,” he said.
Meanwhile, in August last year, the state environment department set up a task force with Mumbai First, comprising local and international experts, to study climate-change impacts, action against flooding and unplanned reclamation for Mumbai. Thursday’s conference was undertaken under this programme. “About 40% of Mumbai could be under water by 2050 under rising sea levels. Forward-looking policy measures and investment are required to enable Mumbai to confront the challenges of climate change. Our goal should be to ensure Mumbai regains its title of Urbs primus in India — India’s premier city,” said Narinder Nayar, chairman, Mumbai First.
“Independent groups and the state representatives are now saying what they needed to 20 years ago. However, there is still no coordination on strategies for being climate resilient neither any consensus among top bureaucrats on how development and coastal safety can be balanced,” said Debi Goenka, trustee, Conservation Action Trust.