Yaas, a severe cyclone, caused massive damage in the state of West Bengal on May 26, 2021. Earthen dams at the Sundarbans were breached resulting in huge devastation, human displacement and irreparable loss.
Global warming is responsible for the increased frequency and intensity of natural disasters. Fires rage in India’s arid and semi-arid forest regions while cyclones and storm surge batter the tropical and subtropical coastlines.
Coastal regions cover only 4 per cent of the world’s land area but are home to around one-third of the people. The Ganges-Brahmaputra delta is extremely vulnerable to population displacement due to the rise in sea level. This large and densely populated region is protected by salt-tolerant, disaster-resilient Sundarban mangrove forests. The Sundarbans are also the world’s only abode of mangrove tigers.
Two curses are destroying this unique ecosystem. The first is the colonisation of these islands by cutting down the mangroves. The second is the increased frequency of natural disasters due to climate change.
The Sundarbans are spread over 4,000 square kilometre with 102 islands. Of these, 54 are colonised by humans with a dense population of 4.5 million. These islands are newly formed and unstable. They have always been the home of mangroves.
Human colonisation over the last two centuries resulted in the wiping out of mangroves from more than half of the area. Without mangroves, these unstable islands are at the mercy of the devastations caused by natural disasters.
Most of the arable land in this region is below the surface waterlevel. Earthen dams and levees were built along the banks to stop the villages from being inundated during high tides. Breaching of these earthen dams and intrusion of saltwater in the villages are the major impacts from recent cyclones, namely Aila (2009), Bulbul (2019), Amphan (2020) and Yaas (2021). Cyclone Yaas has flooded several islands of the Sundarbans, destroying standing crops, killing fish in the ponds and devastating homes. It has infused the arable soil with salt, rendering it unproductive for years to come.
River dams are the lifelines for the communities residing in these disaster-prone islands. There has been a call to construct concrete dams all along the Sundarbans. Such concrete structures would damage the mangrove ecosystem. Mangrove reforestation along the river banks is the only sustainable method to stabilise the banks. The natural mangrove barrier of the Sundarbans had reduced the wind speed of Cyclone Bulbul by 20 kilometre per hour in 2019. Mangroves, with their extensive root system, can consolidate the soil and resist erosion by tidal waters. Mangroves can stabilise the banks and render ecosystem services such as protecting against disasters, increasing fish catch, remediating pollution and sequestering carbon.
Another issue plaguing these low lying deltaic islands is the increased frequency and intensity of natural disasters, due to climate change. Between 1970 and 2019, India was battered by 117 cyclones, resulting in the loss of about 40,000 lives. A model indicates that by 2100, the sea level in the Asia-Pacific region can rise by 0.4-0.6 metre, while the temperature can increase by 2.6-4.8 degrees. The UN’s Intergovernmental Panel on Climate Change predicted that by the end of this century, the maximum intensities of hurricanes or cyclone can increase by 5 per cent. This indicates more powerful storms and intense natural disasters along the tropical coasts.
Policymakers must understand the uniqueness of the Sundarban islands and devise sustainable, eco-friendly methods to protect and conserve the islands’ ‘one of a kind’ mangrove ecosystem. The Centre should enact and implement strong policies to reduce GHG emissions, consistent with the nation’s commitment to the 2015 Paris Agreement to combat climate change. Sustainable development, reforestation and nature conservation are the only ways forward to protect the Sundarbans.
(The writers are associate professor and dean, respectively, at Jindal School of Environment & Sustainability, O P Jindal Global University, Haryana)