Mangroves: The foundation of coastal resilience

Mangroves are living shields that protect shorelines, absorb carbon, sustain fisheries and livelihoods, and offer a vital line of defence against an increasingly unpredictable climate. For India, protecting these green barriers is not merely an environmental responsibility — it is an investment in national resilience and human survival

In a period of rapid climate change, rising sea level, increasing storms and coastal disasters, mangroves have become not just forests but natural life support systems that protect humans and the environment as well.

In case of a large country like India, which has more than 7,500 kilometers of coastline and millions of people who live in coastal regions of India, the conservation of mangroves is no more an issue of the environment; it is an important step towards creating resilience of the nation against disasters and climate change, providing ecological security and sustainable development. While nations spend billions on building protective structures such as sea walls, embankments etc., nature has created an efficient, self-renewing and inexpensive defence system in the shape of mangrove forests.

The mangroves are one of the best examples of Nature-based Solutions (NbS) and Ecosystem-based Disaster Risk Reduction (Eco-DRR). They show how ecosystem conservation can help in safeguarding biodiversity, improve livelihoods, reduce disaster risks, and even mitigate climate change at the same time. Each hectare of healthy mangrove forest represents an example of living green infrastructure that provides much more than any engineering structure.

Mangroves include a special type of plants represented by salt-resistant trees and shrubs growing in the transition area between the land and the sea. Being located in the tidal zones, river deltas, lagoons, and bays, mangroves are special organisms that have developed amazing adaptation mechanisms that allow them to live in such specific conditions. Their intricate prop roots are very helpful in providing stability against powerful currents and surges. Pneumatophores are breathing roots growing upwards, allowing them to breathe in the oxygen in the oxygen-deficient sediment. This adaptation leads to the formation of extensive and dense root systems, which bind sediments and help stabilize the shorelines, besides providing shelter to a multitude of aquatic creatures. Ecologically, mangroves serve as an important interface between the terrestrial, freshwater, and marine ecosystems.

Rich Mangrove heritage of India

India is blessed with some of the most abundant mangrove vegetation in the world, which spans an area of around 5,000 square kilometres along the east and west coasts and islands of the country. Mangroves have been found growing in varied climatic and geomorphological zones, each unique in its biodiversity.

Notable among Indian mangroves is the Sundarbans, which is the largest continuous mangrove forest in the world, shared by India and Bangladesh, and home to the majestic Royal Bengal Tigers. Another equally important site of mangroves is that of Bhitarkanika in Odisha, the river delta areas of Godavari, Krishna and Mahanadi, Pichavaram mangroves of Tamil Nadu, Gulf of Kachchh in Gujarat, and Andaman and Nicobar Islands. The mangrove forests house many plants, fish, crustaceans, mollusks, reptiles, amphibians and migratory birds.

In terms of climate action, mangroves are very special ecosystems as they are blue carbon ecosystems. They absorb carbon dioxide in the atmosphere through the process of photosynthesis and accumulate very high amounts of carbon in their biomass and soil. Scientific evidence suggests that mangroves are capable of storing several times more carbon per hectare than many tropical forests. Therefore, protecting mangroves is one of the best ways of mitigating the effects of climate change.

Their socio-economic importance is also immense. Millions of coastal people make their living through fishing, gathering of crabs, honey collection, eco-tourism, sustainable harvesting of forest products and the services provided by mangroves. However, perhaps their greatest contribution is the ability to safeguard human lives and property from the destructive effects of cyclones, storm surges, and even tsunamis — a potential that only becomes visible in times of crisis. With increasing frequency of natural disasters along coastal areas due to global climate change, these natural green walls have become an integral part of the solution. As a consequence of rising sea levels and warming of oceans, people residing in low-lying coastal areas are becoming vulnerable to many risks. Under such conditions of increased risk, mangrove forests have become one of the best defences that mother nature provides. Concrete seawalls offer resistance against waves. On the other hand, mangroves not only offer resistance but also dissipate wave energy due to their trunk, branches and root system. Mangroves lower the wave height and velocity and protect the shorelines by stabilising them and by reducing coastal erosion. The role of mangroves during the occurrence of cyclones and storm surges is that of a natural bio-shield that reduces flood impact and protects life, agriculture, infrastructure and livelihoods. Studies after some cyclones and 2004 Indian Ocean Tsunami indicate that the areas with degraded mangrove belt were heavily impacted while those protected by mangroves suffered little and recovered faster.

In case of India, with 7,500-km long coastline and coastal districts being densely populated, mangroves play an important role in terms of environmental conservation as well as strategic investment.  There has been increasing appreciation of Eco-Disaster Risk Reduction (Eco-DRR), making the conservation of natural ecosystems a crucial part of disaster management. In contrast to traditional grey infrastructure like seawalls and embankments, mangroves are living green infrastructure that becomes stronger over time, does not need much maintenance, and provides several co-benefits including conservation of biodiversity, carbon sequestration, improved fish stocks, and sustainable livelihoods. The combination of mangroves and artificial measures of protection results in a more sustainable and cost-efficient system of disaster management of coastal areas. This approach is entirely consistent with Sendai Framework for Disaster Risk Reduction, Paris Agreement, and the Sustainable Development Goals that view healthy ecosystems as a key part of climate change resilience and sustainable development.

Lessons from major disasters

Perhaps none of the events has highlighted the role of mangroves better than the tsunami that hit the Indian Ocean in 2004. More than 230,000 people lost their lives in fourteen different countries due to the deadly tsunami. However, post-disaster analysis showed a clear trend where coastal villages having dense mangroves forests witnessed much less devastation than those areas where mangroves had been cleared out for any kind of developmental work such as aquaculture and urbanisation.

Some of the coastal stretches in Tamil Nadu with intact mangrove forest witnessed lower wave energy impact and consequently low devastation from the deadly waves. The same was seen in some regions in Andaman and Nicobar Islands, Sri Lanka, and Indonesia.

Another lesson from major disasters where mangrove has played an important role is the super cyclone in 1999. During the 1999 super cyclone in Odisha, the mangrove forests in Bhitarkanika acted as natural bio-shield against the cyclone by lowering the speed of wind and storm surge before they hit inland areas.

Such experience shows an essential lesson that restoration of one hectare of mangroves before disasters is always cheaper than restoration of infrastructure destroyed in the process.

Development of effective disaster management policies in coastal areas is impossible without the integration of engineering solutions with ecosystem protection. It is necessary to build shelters, embankments, early warning systems, resilient houses and plan evacuations, but all this will be much more efficient if there are healthy mangrove belts as a first line of defence.

In light of the growing threats brought about by climate change, governments need to start looking at mangroves as an important part of natural infrastructure that needs to be planned, developed and protected just like roads, ports and energy networks. The cost involved in protecting mangroves is negligible when compared to the huge losses human beings could suffer due to coastal disasters in the future.

While mangroves hold great ecological and economic significance, they continue to be subjected to greater pressure because of urbanisation, industrial growth, aquaculture, development of coastal infrastructure, pollution, reckless tourism and climate change impacts such as sea level rise and salinisation. The conservation and protection of this fragile ecosystem need to go beyond just plantation to scientific management and conservation on a landscape scale.

Initiatives like the Mangrove Initiative for Shoreline Habitats and Tangible Incomes (MISHTI), Integrated Coastal Zone Management, Green India Mission and state-wise restoration projects have been initiated in India. Yet, their success in the future will be dependent upon the incorporation of mangrove conservation in coastal development plans, disaster management planning and climate change policy-making. Advanced technologies like remote sensing, GIS, drones, Artificial Intelligence and satellite-based monitoring could transform the process of mangrove mapping, health assessment and restoration. An equally important aspect would be community engagement that holds the key to conservation of these ecosystems. Sustained livelihood through fishing, ecotourism, honey and blue carbon funding could provide strong economic motivation for conservation. The protection of the mangroves is imperative and should be seen as vital natural infrastructure. Every coastal region should include the protection and restoration of the mangroves in their Disaster Management Plan, Climate Action Plan, and Coastal Zone Management Plan. Investment in the restoration of the mangroves should be seen as an investment in reducing disaster risks, climate resilience and economic security.

The writer is the former Executive Director, National Institute of Disaster Management, Government of India; Views presented are personal.