Scientists offer solutions how city can contain impact of climate change
Kolkata is among eight megacities most vulnerable to disaster-related mortality, noted the recent United Nations (UN) report on climate change.
The city also features among the 20 largest coastal cities with potentially the highest flood losses by 2050, warned the report by the UN Intergovernmental Panel on Climate Change (IPCC). The city in eastern India, along with eight other Asian cities, also run the “additional risk of subsidence due to sea-level rise and flooding”, the research paper added.
Six other megacities in Asia highly exposed to disaster-related deaths are Tokyo, Osaka, Karachi, Manila, Tianjin and Jakarta, according to IPCC.
The 3,676-page final report Working Group II Part of Assessment Report 6 made several references about Kolkata that underline the city’s vulnerability to multiple climatic risks. It also warned about its lack of resilience in combating those risks.
The report warned:
The number of people exposed to 1-in-100-year storm surge events is the highest in Asia. (These include) Guangzhou, Mumbai, Shenzen, Tianjin, Ho Chi Minh City, Kolkata, and Jakarta. It is projected that by 2050, without adaptation, the annual losses incurred in these cities will increase to approximately $32 billion (Rs 2.4 lakh crore).
Cyclones in India are most frequent in West Bengal’s South 24 Parganas district, adjoining Kolkata, a recent report prepared by the Indian Meteorological Department (IMD) pointed out.
Kolkata lost a substantial portion of its green cover due to Cyclone Amphan that struck India’s east coast in May 2020, the UN report said. The estimated cost of the cyclone triggered losses to the tune of $13.5 billion (about Rs 1 lakh crore), it added.
“Significant warming of the Bay of Bengal region caters to the increase of high-intensity cyclones in Bengal coast, which, in turn, are likely to affect Kolkata significantly,” said Roxy Mathew Koll, a weather scientist and former author of IPCC report, to this reporter.
The eastern city is also highly vulnerable to extreme heat waves, according to the IPCC report. “On average, Kolkata will experience heat equivalent to the 2015 record heat waves every year.” In 2015, the heat wave killed 2,500 people in India. Kolkata, along with Delhi and Karachi, have high drought risk, the report said.
The city may not be prepared to handle the crises, the report observed: Evidence from Kolkata demonstrates the limitations of resilience plans to address underlying conditions of vulnerability … under-provision of informal settlements, and spatial segregation of the urban poor.
The drainage and sewage network in the Kolkata Metropolitan Area is sparse and not commensurate with its area of 1,851 square kilometres, a study undertaken earlier by the British Deputy High Commission observed.
“Where the network exists, it is mostly comprised of a century-old drainage and sewage system,” the report had noted. The drainage systems are divided into 25 drainage basins (catchment areas), and the entire metropolitan area is divided into 20 sewer zones (zones for the sewer network), according to the report. “The sewer network in the Kolkata Municipal Corporation covers 55 per cent of the total area.”
The report further reminded that “flooding in Kolkata is an annual feature during the monsoons” and added that “any past incidence of high intensity rainfall synchronised with high tide in River Hooghly has almost always resulted in water-logging in Kolkata”.
The latest IPCC report corroborates data in its August 2021 publication (Working Group I) that also pointed to similar threats. The report had particularly warned about rising sea-level near Sunderbans, which is hardly 100 kilometres from the city.
“A city like Kolkata, which remains located close to the coast, stands extremely threatened,” said Anjal Prakash, an Indian scientist and lead author of the chapter on cities, settlement and key infrastructure in the report.
The city, known for its high malaria and dengue cases, may suffer further as a result of changing climate. “Incidences of malaria, dengue and other vector-borne diseases will increase,” said Chandni Singh, an Indian scientist who was a lead author on the Asia chapter as well as contributed on cities.
Solutions at hand
Kolkata can still combat the ill-effects of climate change if it seeks appropriate solution measures, scientists said.
“Green and blue infrastructure needs to be conserved in Kolkata. While green infrastructure (urban greenery) will help the city in withstanding climate risks like warming and impacts linked to that, blue infrastructure, which refers to protecting and enriching waterbodies, lake systems, wetlands and rivers across the city, is also important in terms of climate resilience,” said Prakash.
Preserving wetlands, River Hoogly and water bodies is a key to the city's survival,” said Aditi Mukherji, the coordinating lead author for the water chapter. “Kolkata is a natural sponge city but unfortunately, the sponge is getting increasingly encroached upon.”
The city and state administration should include climate change adaptation issues in all the major development activities of the city, said Sanjay Vashist, director of Climate Action Network South Asia.
“The architecture planning of the buildings in the city also needs a strong relook as the city has turned into a heat island,” said another expert. Kolkata’s average temperature has increased most at global benchmark in the last six decades till 2018, they cited another recent IPCC report.
Mayor Firhad Hakim admitted that the city is already under severe climate risk and informed that the civic body is planning to put in place a detailed plan quickly to combat the trend. “This time, my priority is the environment, particularly climate change,” said Hakim, who recently got a second term as mayor.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.