A coast-benefit analysis
Old maps of Mumbai are collectors’ items because of how the shape of the city has changed, as it was claimed, colonised, reclaimed and built up over about 250 years. A clump of seven marshy islands has turned into one of the world’s most densely populated megalopolises, the city and suburbs alone home to an estimated 12.4 million people.
Today’s maps could soon be collectors’ items too. The sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC) estimates that large parts of the city could vanish under the sea by 2100, as levels rise. In 30 years, about 70% of south Mumbai could be underwater, the city’s municipal commissioner Iqbal Chahal said last August, while announcing that the city was beginning work on a Mumbai Climate Action Plan.
This is a megalopolis that juts into the sea, is built in large parts on reclaimed land, and has a coastline under constant attack from construction (it has some of the world’s most highly priced real-estate) and from infrastructure projects such as the coastal road, which the IPCC report terms “maladaptive”.
Now, as storms intensify on the western coast and cyclones begin to form in the Arabian Sea, this will have a cascading effect.
“Mumbai is in a unique location, where huge moisture surges generated from the very warm western Indian Ocean enter the landmass, and move towards central India, causing extreme rainfall along the way,” says climate scientist Subimal Ghosh, convener of the interdisciplinary programme in climate studies at the Indian Institute of Technology (IIT) - Bombay, and one of the lead authors of the IPCC report. “It acts as sort of a gateway for these events too.”
In terms of mitigation, the municipal corporation last month launched the Mumbai Climate Action Plan, a 30-year strategy aimed at readying the city for coming crises.
It identifies priority areas such as air pollution, urban greening, water resource management and sustainable mobility. The plan includes building flood resistant infrastructure, and improving the century-old stormwater drains that flood even in a normal monsoon.
“The plan ticks all the boxes, but it’s not clear how it is all going to be carried out on the ground,” says Anjal Prakash, research director at the Bharti Institute of Public Policy of the Indian School of Business, Hyderabad, and one of the lead authors of the recent IPCC report.
Without some extraordinarily new approach, the Mumbai Climate Action Plan risks ending up like the ambitious Brimstowad (Brihanmumbai Stormwater Disposal System), a project that dates back to 1985, got a boost after the deluge of 2005, but remains mired in litigation and delays nearly 40 years on.