West Bengal sees five-fold increase of cyclones in 50 years: Study

The frequency of cyclones in 15 West Bengal districts, home to nearly 7.2 crore people, has increased five-fold between 1970 and 2019 for which priority should be given to preserving the mangrove forests of Sunderbans which act as a natural coastal defence against flooding, an environmental think tank said on Thursday.

The study says roots of mangrove trees known as pneumatophores which grow upward from the soil to get oxygen supply act as a shock absorber against violent storm surges and floods in the Sunderbans which lie on the delta of the Ganges, Brahmaputra, and Meghna rivers on the Bay of Bengal.

The Sundari is the dominant mangrove tree species of the Sunderbans. To curtail the spurt of cyclones, the country also needs to build climate resilience at multiple levels, the study said.

The hotspot for cyclones and storms in West Bengal includes districts like Howrah, Kolkata, North 24 Parganas, Paschim Medinipur, and South 24 Parganas.

According to the study, after 2005, the yearly average of Indian districts affected by cyclones has tripled and the cyclone frequency has doubled.

In the last decade alone, 258 districts were affected.

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In east coast districts, the frequency of cyclones and storm surges has increased seven-fold in the last 50 years.

"The combined effect of micro-climatic shifts occurring in various parts of Indias east coast has triggered more cyclonic disturbances in the Bay of Bengal, leading to storm surges, incessant rainfall, and floods", the Council on Energy, Environment, and Water (CEEW) CEO Arunabha Ghosh said.

Two cyclones, Tauktae and Yaas, have struck India in quick succession in the middle of a pandemic. Given the increase in frequency and intensity of such extreme climate events, the country needs to build climate resilience at multiple levels, he said.

"Coastal states like West Bengal should invest in climate-proofing their infrastructure, following standards that will ensure protection from the compounded impacts of cyclones and other extreme weather events.

"Also, West Bengal should accelerate implementation of the National Cyclone Risk Mitigation Project, approved for the state in 2015," Programme Lead at CEEW Abinash Mohanty said.

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Ghosh suggests India should create a national Climate Risk Commission with statutory authority to convene key stakeholders and publish periodic climate risk assessments.

Mohanty said livelihoods and infrastructure can be protected better by carrying out micro-level climate risk assessments using a Climate Risk Atlas and by issuing impact- based public warnings.

The study which captured detailed data between 1970 and 2019 also found that extreme flood events have also risen seven-fold affecting over 7.08 million people in West Bengal each year, especially in hotspots like Birbhum, Cooch Behar, Hooghly, Malda, and Nadia.

The study said climate change impact has extended to drought-like situations also with West Bengal witnessing a two-fold increase in droughts in the last ten years.

According to the CEEW analysis, even flood-prone regions like Bankura and Purulia have witnessed a shift towards drought events in the past decade.

Once irregular occurrences, droughts (or drought-like conditions) have affected more than 40 per cent of the districts of the state in recent times.