A topical question now is how much economic damages of Amphan the Sundarbans has actually helped Bangladesh avoid. The avoided economic damages of Amphan by the Sundarbans can be defined as the additional economic damages that would occur if the forest was not present.
Sepul Kanti Barua: A powerful tropical cyclone called Amphan made landfall in Eastern India and Southwestern Bangladesh on 20 May 2020, causing huge devastation in both countries.
An initial assessment by the Bangladesh government puts the damages of the cyclone in the country to about US$130 million. It will take some time before the full extent of the damage can be assessed because of ongoing corona pandemic, and as the cyclone has made widespread disruption to communication lines and destroyed roads and bridges in affected areas making them still partly inaccessible.
The economic damage figure in Bangladesh is likely to go up when the full extent of the damages appears which is also hinted by the government of Bangladesh.
Before hitting the populated areas of Bangladesh, the cyclone had to pass through the Sundarbans, the world’s largest mangrove forest on a single tract that spreads in 1 million hectare (ha) of land in Bangladesh and India. By reducing the wind speed and height of the resultant tidal surge, the Sundarbans is believed to have reduced both the devastation power and economic damages of the cyclone substantially.
A topical question now is how much economic damages of Amphan the Sundarbans has actually helped Bangladesh avoid. The avoided economic damages of Amphan by the Sundarbans can be defined as the additional economic damages that would occur if the forest was not present.
For making a precise estimate of avoided economic damages mentioned above, a field-based approach with data collected through household and community surveys in affected areas would be the best. Such an approach, however, is time and resource consuming, and thus making a field-based estimate of avoided economic damages of Amphan by the Sundarbans may take months if not years. A desk-based approach is useful in making a rapid estimate of such avoided economic damages.
Multiple tropical cyclones of varying magnitude are formed in Bay of Bengal every year and some of them do make landfall in Bangladesh. The Sundarbans and the coastal plantations most often act as the first line of defense for the country against these cyclones.
By analyzing data in relevant literature, a recent article published by me with two co-authors in the journal Ecosystem Services (https://www.sciencedirect.com/science/article/abs/pii/S2212041620300115) estimated that the economic value of avoided storm damage in Bangladesh by the Sundarbans mangrove forest ranged from US$ 13 per hectare (ha) per year to US$ 720 per ha per year (in 2017 constant price).
The average value was US$ 284 per ha per year. Considering that the Bangladesh part of the Sundarbans covers about 0.6 million ha of land and applying the US$ inflation rates, the annual avoided storm damage value of the forest comes between US$ 8.3 million and US$ 458 million with the average of US$ 181 million (in current price).
According to various historical records, just over 500 cyclones were formed in the Bay of Bengal in the past 100 years (prior to 2017), and about 17 percent of them made landfall in Bangladesh. This gives, on average, one successful tropical cyclone landfall per year in the country. This means the annual avoided storm damage value range derived above is applicable to Amphan, i.e. the Sundarbans helped avoided between US$ 8.3 million and US$ 458 million of worth of damages from Amphan in Bangladesh.
The range is wide, and thus trying to ascertain a more precise avoided damage value is worthwhile. The average avoided damage value of the Sundarbans of US$ 181 million that is reported above is unlikely to apply to Amphan simply because it was not an ordinary cyclone to hit Bangladesh.
It was one of the most powerful cyclones to have made landfall in Bangladesh in the past few decades, it was categorized as super cyclone until not long before making landfall.
The more powerful a cyclone is, the more is the economic value of damages of it avoided by any barrier like a tract of forest. Although Amphan caused the most devastation in nine districts (out of 64) in Khulna and Barisal divisions, if the Sundarbans was not there more districts could have been severely affected, and Dhaka, the heart of Bangladesh economy, could have easily been hit with a deadly wind speed.
Above suggests that the economic value of avoided damages of Amphan by the Sundarbans in Bangladesh is the most likely to be in the upper end of the spectrum, i.e. US$ 458 million (in current price). This is over three times higher than the actual economic damages of the cyclone estimated by the Bangladesh government.
The above points us to one thing that most people including many decision makers in Bangladesh do not realize or if realize tend to ignore: the Sundarbans mangrove forest is immensely important for the economy of entire country. If Bangladesh continues destroying the forest as it has been doing for long, the tropical cyclones, which it cannot avoid because of geographical location, will mount incremental damages to the economy of the country each year. Sound conservation of the Sundarbans as well as sustainable expansion and management of coastal plantations should be among the top priorities of the country.
The writer currently works as a senior consultant in NIRAS International Consulting, a multinational development consultancy based in Helsinki, Finland. Prior to joining NIRAS, he worked as an environmental economist at the Food and Agriculture Organization of the United Nations (FAO).
