The island city of Mumbai, along with western India, increasingly faces threats from climate change including rising sea levels and a significant increase in mean temperatures predicted over the next 75 years, or by the end of the century.
The city has witnessed increased rainfall, excessive flooding with frequency of extreme weather events like heat waves, partly due to rising temperatures and more precipitation, plus the urban ‘heat island effect’ where urban centres become considerably warmer than their rural surroundings due to human activities, experts said.
On August 5, 2020, south Mumbai experienced heavy floods with 225 mm rainfall in just 10 hours, the highest single day downpour for the month since 1974.
The BrihanMumbai Municipal Corporation (BMC) received flak for the unprecedented waterlogging in areas like Churchgate, Nariman Point, Marine Drive, with fingers pointed at the Mumbai Coastal Road Project and the Colaba-SEEPZ fully underground Mumbai Metro line.
These are believed to have choked the drainage lines of the 140-year-old British-era drainage systems that serve Mumbai, which are now overburdened due to unplanned development and reduced green spaces.
Scientists at ASAR Social Impact Advisors grimly said that the projections for Maharashtra and western India point to an increase of temperatures by 1 degree C to 2 degrees C in the coming years with more ‘rainy days’, and pose significant challenges to agriculture, urban infrastructure and natural ecosystems.
Maharashtra has witnessed many noteworthy climate anomalies in recent years triggered by the impact of climate change, as a few examples denote.
In monsoon 2021, the state recorded an estimated 10,000 landslides, as per a quick assessment of the Advanced Centre for Water Resources Development and Management, Pune, commissioned by the UNICEF, Maharashtra office and the state Disaster Management Authority.
The landslides, big and small, were reported in the coastal regions of Mumbai, Raigad, Ratnagiri, Sindhudurg, Satara and Pune owing to incessant rainfall, rapid soil erosion as some areas received 100 mm rainfall within five hours over a fortnight. The study noted that the landslides in these areas have been increasing exponentially since 2011.
The state has recorded 600-900 percent excess rainfall in several districts leading to severe floods in Raigad, Ratnagiri, Sindhudurg, Pune, Satara and Kolhapur.
In 2021, Ratnagiri broke a 40-year-old record getting 1,781 mm downpour in three weeks starting July 1, surpassing the month’s average of 973 mm, while Mahabaleshwar hill station was lashed by 1,075 mm rain on July 22-23, Mumbai and its suburbs witnessed floods due to heavy rain, six-seven times the normal daily average. These are part of a broader trend of the changing monsoon patterns in the country.
On July 19, 2023 Raigad’s tiny village Irshalwadi on a hillslope was wiped off the face of the earth after a major hillslide following torrential rain of 400 mm in barely 24 hours.
This caused the entire semi-barren hilltop to crash onto the village, burying nearly half of the village’s 25 homes. Similar tragedies in Raigad have claimed more than 300 lives in the past 17 years, including Taliye and Jui villages, owing to reduced greenery, tree-cover and consequently soil degradation as the key triggers.
At the other extreme, the rain-fed agriculture dependent Marathwada and Vidarbha regions were plagued by drought-like conditions owing to significant variations in rainfall patterns.
ASAR experts say that upto 85 percent of the state’s farmers depend on rainfall, but one-third of the state falls under the semi-arid climatic zone where drought hits around once in a decade.
However, the situation has worsened in the past few years owing to plummeting groundwater levels, acute water shortages and severe crop losses in both the Kharif and Rabi seasons, hitting agriculture, domestic food needs, livestock and the livelihood of thousands of poor and marginal farmers.
Nevertheless, the region still relies heavily on water from dams which is either expensive or inaccessible to many tillers, leading to over exploitation of other sources like groundwater that create fresh complications.
In June 2020, the devastating Cyclone Nisarga with wind speeds touching 120 kmph, lashed coastal Maharashtra with landfall at Raigad, but Mumbai escaped its fury by a whisker.
Cyclone Nisarga wreaked havoc and reinforced the urgent need for climate adaptation and resilience in urban and environmental planning for coastal megacities exposed to rising sea levels, high population with vulnerability to floods and ecological degradation.
The Intergovernmental Panel of Climate Change (IPCC) has noted that by 2070, port cities like Mumbai could be risks in terms of population and assets exposed to coastal flooding due to rapid warming of the Arabian Sea, making it more conducive to cyclone formation and potentially resulting in an increase in the number of cyclones here.
While the Mumbai Climate Action Plan (MCAP) has been initiated to make the city ‘climate-resilient’, experts and critics point out gaps in MCAP and the BMC’s budget, and the need for more comprehensive and effective measures to address the multifaceted challenges posed by climate change.
(Quaid Najmi can be contacted at: q.najmi@ians.in)
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