More Mangroves: Protecting Tropical Coastal Areas from Cyclone Damage

By Jerri-Lynn Scofield, who has worked as a securities lawyer and a derivatives trader. She is currently writing a book about textile artisans.

Just over a month ago, cyclone Fani struck the Indian states of and Odisha and West Bengal, and then Bangladesh. Fortunately, the number of deaths reached only dozens, rather than the tens of thousands killed in Odisha alone in 1999 by a similar storm, and the half a million people who died as a result of cyclone Bhola in 1970. The small death toll was due to the trajectory Fani took and the effective public policies both India and Bangladesh have implemented over recent decades, both in improving the system for forecasting cyclones – and crucially, moving vulnerable populations out of harm’s way (see my immediate take on the cyclone; I happened to be visiting Calcutta and witnessed it firsthand, Climate Change: The Wrath of Cyclone Fani).

Fani’s aftermath has been severe. Many homes were destroyed. While destruction of industrial plant was limited – largely because the Indian state of Odisha has little heavy industry, and the storm missed the more industrialized parts of West Bengal – some areas  have yet to see their power fully restored, according to The Times of India, A month after cyclone ‘Fani’, 1.64 lakh families still without electricity in Odisha. The monsoon has yet to arrive, so many of the affected areas are still enduring extreme temperatures, with high and continuing humidity. The damage to wildlife reserves is still being assessed; initial reports were pessimistic (see this account in The Hindu, Odisha’s wildlife sanctuaries ravaged by Fani; and this more more recent take in OrissaPost, ‘Need for collaborative approach to restore Odisha post-Fani, which emphasizes that the environmental impact reaches far beyond destruction of nature reserves).

Fani makes clear that it will not be enough for countries at the forefront of future climate-change superstorms to implement effective measures to shield their populations from their immediate impacts. These countries must also move onto the next challenge: boosting policies to protect against other harms such storms can inflict on their infrastructure and ecosystems.

What Can Be Done to Protect Against Cyclones

This week, a study published in the Proceedings of the National Academy of Sciences, provides some small basis for optimism in what seems to be the never-ending drumbeat of despair about what we can expect to see from climate change. According to a report in The Conversation, How mangroves protect people from increasingly frequent and powerful tropical storm:

Jacob Hochard and colleagues use global data covering nearly 2,000 coastal communities in 23 countries and 194 mangrove areas. Meticulous statistical analysis of cyclones from 2000 to 2012 provides a convincing model of how economic activity is impacted and recovers. …

The area of mangrove protecting a community is divided by the length of coastline to give an average extent of mangrove per metre of coast. The authors compare how typical communities protected by smaller areas of mangrove (6m per metre of coastline average) fared over the long term versus communities with larger areas of mangroves (25m per metre average).

So, what does this mean (same source):

Losses per cyclone for communities with 6m of mangroves per metre of coastline were double that of communities protected by 25m per m of mangroves. In the former group, losses are somewhere between 5.5 and 6.5 months of economic activity. In the latter, the extra mangroves kept cyclone impacts down to between 2.5 and 5.5 months.

And, not only do mangroves help reduce the economic damage of cyclones, they have another positive effect. Over to The Conversation again:

Mangrove forests cover just 0.5% of the world’s coasts but account for an estimated 10-15% of coastal carbon capture. As we try to stop CO₂ levels rising and put the brakes on climate change, protecting mangroves for their blue carbon value is key.

The Sundarbans: Failure of Bangladesh and India to Safeguard this Crucial Bulwark Against Storms

Alas, what is happening to the world’s mangrove forests? The answer: they’re shrinking. As Ars Technica reports in More mangroves? Economies recover faster after tropical cyclones:

From the 1970s to 1990s, about 35% of the world’s mangroves were lost due to urbanization, aquaculture, timber, and reductions of the freshwater flows that keep these swamps alive. The rate of loss has slowed down greatly since then, but it hasn’t fallen to zero.

Let’s focus here on the Sundarbans, the largest mangrove forest in the world, situated in the delta formed by the confluence of four rivers – the Brahmaputra, Ganges, Meghna and Padma. Both India  Bangladesh have created protected wildlife sanctuaries here, and Unesco has designated each as a separate world heritage sites.

The area is the home of the royal Bengal tiger, a fearsome beast that reputedly drinks salt water. I’ve made four visits to the Sundarbans, which I can attest is a paradise for birdwatching. I’ve yet to see a royal Bengal tiger.  As I wrote in an article in The National, India and Bangladesh’s mysterious mangroves: The Sundarbans, the state of West Bengal changed its tourist promotion campaign – from promising a glimpse of the elusive tiger that most visitors would never see – to emphasizing the area’s other wonders, including the many endemic birds, the monitor lizards, and two types of freshwater dolphins, the Ganges river, and the Irrawaddy, not to mention the mangroves themselves. Otherwise, many visitors returned from their visits  a wee bit dismayed over what they’d failed to see, rather than thrilled without reservation by what they had.

While visitors rarely see a tiger, fatal encounters with the king of cats occur all too frequently for those who participate in the local economy, especially shrimp harvesters, and honey collectors – mouley. Since the big cats attack from behind, mouley wear special masks on the back of their heads, to confuse the tigers, and divert them towards other targets.

While the increase in local economic activity is somewhat reducing the health of the Sunderbans ecosystem – especially shrimp harvesting – far more damaging is the impact of increased industrial activity, and boat traffic, on this unique ecosystem.

As The Third Pole reported in 2018 in Rapid industrialisation poses pollution risk to the Sundarbans:

Mongla port is a hive of activity. Several oceangoing vessels are anchored in the harbour and there is a steady bustle of barges hauling cargo. Defunct for a long time, a deepening of the shipping channel around the turn of the century has led to a dramatic turnaround, making Mongla one of the fastest growing ports in South Asia.

Strategically located in south-western Bangladesh, the success of Mongla is due to the frenetic industrialisation in its hinterland. Within a radius of 10 kilometres there are several cement factories, a petrochemical refinery, and many gas bottling plants – with scores more being built, among them a massive USD 21.5 million leather processing plant and the contentious Rampal thermal power plant. They are part of Bangladesh’s growth story, whose GDP has been growing at a rate of over 5% annually for the past several years.

This humming industrial hub, however, carries with it an environmental cost that may be high enough to endanger the economy of the entire region. Situated as it is on the edge of the Sundarbans – a world heritage site and a biodiversity hotspot – the risk of pollution to its unique ecosystem is quite high, environmentalists fear.


The Mongla Export Processing Zone is expected to be the main economic hub of the southern region of the country, Mohammed Habibur Rahman Khan, Executive Chairman of the Bangladesh Export Processing Zones Authority (BEPZA), said in a meeting last year. The industrial units already operating within the ECA in Mongla include four cement factories, one soybean oil refinery, one crude oil refinery, four gas bottling companies, and one cigarette factory, Mallick Anwar Hossain, director of the department of environment at Khulna, was quoted as saying in a media report.


It seems that the authorities in Bangladesh have learnt no lessons from the impact of industrialisation in the neighbouring state of West Bengal in India. Researchers have found that industrial units located on the Gangetic delta in the Haldia port-cum-industrial complex on the Hoogly River, and in the eastern metropolis of Kolkata and its outskirts, are polluting the fragile ecosystem of the Sundarbans, home to over 4.5 million people in India alone.

Industrial activity near to the Sundarbans raises the number of boats who ply its ‘protected’ waters – thus damaging the ecosystem – and increasing the possibility of even more catastrophic damage (see Another Nail in the Sundarbans coffin?). As the Dhaka Tribune reports in Environmental group calls for restricting ship movements in Sundarbans river routes:

While discussing, BARCIK researcher Pavel Partho said, frequent accidents are seriously harming the flora and fauna and putting total eco-system at risk as well as breaking the food-cycle in the world’s largest mangrove forest, also the largest harbour of Irrawaddy dolphin. He said the eastern side of the forest has been declared as a World Heritage Site and the frequent incidents of fire and ship capsize are putting the heritage site in great danger.

The Bottom Line

I’ve spent much more the last decade in developing countries than in elsewhere, so I am well familiar with the appeal of arguments about the necessity of facilitating economic growth so as to lift people out of poverty.

The problem is that the planet is dying – and that Bangladesh and India are on the front lines of where climate change will have catastrophic effects on the day to day weather.

Preserving the Sundarbans ecosystem is one way to mitigate the wider effects of this impact.

What needs to be done? And, is this a problem that Bangladesh and India need to solve – and pay for – on their own?

And surely, the problem isn’t limited to the sub-continent: preserving mangroves is something that must be undertaken – and urgently – to prepare coastal areas for the impact of climate change.


Print Friendly, PDF & Email


  1. Colonel Smithers

    Thank you, J-LS.

    Over the past dozen years, Mauritius has been restoring its mangrove swamps. In addition to protection from cyclones, they serve as havens for wildlife and, in some places, can host tourists in kayaks and canoes.

    This said, the government is also building more solid defences along the coast where erosion is too advanced.

    As there is some affinity between Mauritius and Louisiana, Creole countries, Mauritians like me who visit la belle Louisiane are puzzled at the environmental destruction of swamps, coastal and further inland.

    1. John Zelnicker

      @Colonel Smithers
      June 7, 2019 at 11:10 am

      Thanks for mentioning Louisiana, Colonel.

      As I was reading the post that was the first thing that came to mind. The swamps along the southern coast of Louisiana have been destroyed by the oil and gas industry cutting channels through them in order to reach the oilfields that extend from the mainland into the Gulf. I’m in Mobile and we have a similar problem along our short piece of coast, although there are some protected areas such as the Bon Secour National Wildlife Refuge.

      The continuing destruction of these barrier swamps, which play a critical role in degrading hurricanes when they make landfall, before they reach populated areas, is causing a big increase in the damage wrought by such storms. IIRC, Louisiana has lost hundreds, possibly thousands, of square miles of protective swamps along its coast.

    2. upstater

      Louisiana’s coastal marsh problem is one that can only be solved on a geological time scale now. While there are number of active restoration projects, the scale is limited and expenses in the billions.

      I would expect the mangroves in India and Bengaladesh are equally challenging to restore.

  2. PlutoniumKun

    Its very depressing that something as useful as Mangroves can be under threat. They don’t just protect in storms, they are vital nurseries for sea fish and (along with associated wetlands) are very good as ‘natural’ urban wastewater treatment systems in countries where conventional systems are too expensive to build and run.

    I’d also be concerned that rising sea levels may itself be a threat to mangroves – they usually establish where net deposition of silts and sand is higher than erosion – with climate change this dynamic is likely to be severely altered in many areas in favour of erosion, so exacerbating localised sea level rises. It may be that in the longer term more than preservation is needed – governments may have to invest in coastal protection schemes to enhance and develop new suitable mangrove habitat.

    1. rd

      They would naturally move inland unless we prevented them. 20,000 years ago, the oceans were 400 feet lower. Mangrove swamps, coral reefs all adapted fine to the subsequent ocean rise, sometimes with large short-term surges of several feet when a big ice dam would break causing a massive release from inland lakes.

      Mother Nature is very adaptable to change. However, we keep pretending that things are static and resist that change.

  3. rd

    Mangrove swamps, temperate coastal wetlands, coral reefs, and oyster reefs are all critical systems for mitigating storm surges and near-shore water quality. all are under threat. Another Tragedy of the Commons problem.

  4. juliania

    Just wondering and a foolish question here – isn’t the latest flooding in the midwest of the US a sign that nature will not accept the current system of dykes and catchment basins all the way down to coastal regions – those rivers want to run to the sea and they want to take sediment with them. Surely we have to encourage them to do that? Then deltas could be reconstituted, and mangrove swamps, tall grasslands stopped from eroding away.

    Or is it now too late?

    1. Synoia

      The US Economy, and much of the world’s economy, appears to be built on the monetization of the current status quo.

      Which works until it does not, thus much money and effort are spent on maintaining the status quo.

Comments are closed.