The Power of Mangroves Over Seawalls

Source: The Hindu

Summary

The landfall of Cyclone Dana near Bhitarkanika on the Odisha coast has spotlighted the protective role of coastal mangroves against storm surges and cyclones, in contrast to costly engineered seawalls and groynes. The editorial argues that India should pivot from “grey” hard infrastructure toward Ecosystem-based Adaptation (EbA) — using mangroves, seagrass meadows, and coral reefs as dynamic, self-sustaining buffers for its long coastline and large coastal population.

Key takeaways:

• Coastal stakes: ~11,000 km coastline and ~250 million people living near it are exposed to cyclones, storm surge, and sea-level rise.
• Spending mismatch: States spent ₹2,641 crore in a decade on hard engineered protection, even as the National Coastal Mission budget fell from ₹195 crore (2022-23) to ₹50 crore (2024-25).
• Why mangroves work: Aerial roots break wave energy, trap sediment, build coastline, store “blue carbon,” and self-repair over time.
• Why seawalls fall short: Expensive, rigid, degrade under stress, shift erosion downstream, and offer no biodiversity or livelihood co-benefits.
• EbA: A nature-centric adaptation strategy promoted by the CBD and UNFCCC.
• India’s edge: A global hotspot for coastal EbA — mangroves here protect more people per hectare than almost anywhere else.

Background & Concept

What is the issue? After Cyclone Dana, the debate over coastal protection has reopened: should India keep investing in “grey” engineered defences (concrete seawalls, groynes), or shift to “green/living” defences (mangroves, seagrass, reefs)?

Hard structures are static and rigid, while coastlines are dynamic — they move, erode, and accrete. Living ecosystems, by contrast, grow, adapt, and regenerate. The editorial frames this as a case for Ecosystem-based Adaptation (EbA): harnessing ecosystem services to buffer climate hazards while also delivering carbon, biodiversity, and livelihood benefits. Cyclone Dana’s Bhitarkanika landfall, where mangroves visibly shielded the coast, is presented as field evidence for this shift.

Key Facts

Indicator	Detail
Trigger event	Landfall of Cyclone Dana near Bhitarkanika, Odisha
India’s coastline	~11,000 km
Coastal population at risk	~250 million people
Spent on hard protection (decade)	₹2,641 crore
National Coastal Mission budget	₹195 cr (2022-23) → ₹50 cr (2024-25)
Core recommendation	Shift to Ecosystem-based Adaptation (EbA)
Key living buffers	Mangroves, seagrass meadows, coral reefs
Nodal ministry (Coastal Mission)	Ministry of Environment, Forest & Climate Change

Mangroves vs Seawalls

Parameter	Mangroves (Green/Living)	Seawalls (Grey/Engineered)
Wave energy	Dense aerial roots break surge energy	Reflect/absorb waves but rigidly
Sediment	Trap sediment; build coastline upward	Often deflect erosion downstream
Durability	Self-repairing; strengthen over time	Degrade under repeated cyclone/tidal stress
Cost	Low build & maintenance	Expensive to build and maintain
Adaptability	Move with the dynamic coastline	Rigid; coastlines shift around them
Co-benefits	Carbon storage, biodiversity, livelihoods	None

Why Mangroves Work as Climate Shields

Function	Detail
Wave attenuation	Dense aerial/stilt root networks break incoming wave energy
Coastline building	Trap organic sediment at roots, raising coasts against rising seas
Carbon storage	“Blue carbon” sinks — lock carbon at rates far above tropical rainforests
Resilience	Self-repairing; strengthen rather than degrade over time
People protected	India is a hotspot — mangroves shield more people per hectare than most countries

India’s Major Mangrove Ecosystems

Site	State / Region	Note
Sundarbans	West Bengal	World’s largest mangrove forest; UNESCO World Heritage Site
Bhitarkanika	Odisha	Saltwater crocodiles; Olive Ridley turtles
Pichavaram, Muthupet	Tamil Nadu	Among India’s notable mangrove patches
Coringa	Andhra Pradesh	Second-largest mangrove in mainland India
Mahanadi, Krishna, Godavari deltas	Odisha / Andhra Pradesh	Major deltaic mangroves
Gulf of Kutch & Khambhat	Gujarat	Arid-zone mangroves
Andaman & Nicobar Islands	UT	Island mangrove systems

Key Initiatives India Has Taken

Initiative	Detail
MISHTI	Mangrove Initiative for Shoreline Habitats & Tangible Incomes — announced in Union Budget 2023-24, for mangrove plantation along coasts and salt-pan lands
ICZM Project	Integrated Coastal Zone Management — World Bank-supported, in selected states
CRZ Notification	Coastal Regulation Zone — regulatory framework for activities along the coast
NAPCC	National Action Plan on Climate Change, under which the National Coastal Mission sits

Key Bodies & Concepts

National Coastal Mission — A central scheme under the Ministry of Environment, Forest and Climate Change (MoEFCC) to protect and manage coastal areas (mangroves, coral reefs, biodiversity, communities). Funds mangrove restoration, reef protection, capacity building, awareness, and shoreline management. It is one of the missions linked to the NAPCC.

Ecosystem-based Adaptation (EbA) — A nature-centric climate strategy using biodiversity and ecosystem services to help communities adapt to climate change. It deploys living habitats (mangroves, seagrass, reefs, salt marshes, wetlands, forests) as self-sustaining buffers, as opposed to static “grey” infrastructure. Promoted by the Convention on Biological Diversity (CBD) and the UNFCCC.

Keywords & Definitions

▸ Ecosystem-based Adaptation (EbA): Using biodiversity and ecosystem services as dynamic, self-sustaining buffers against climate hazards; promoted by the CBD and UNFCCC.

▸ Mangroves: Salt-tolerant trees and shrubs of tropical/subtropical intertidal zones whose aerial and stilt roots trap sediment and break waves; rich biodiversity habitats.

▸ Blue Carbon: Carbon dioxide captured and stored by coastal/marine ecosystems (mangroves, seagrass, salt marshes, tidal flats); their soils act as long-term carbon sinks, storing more per unit area than most terrestrial forests.

▸ Seagrass Meadows: Submerged flowering-plant beds that stabilise sediment, support fisheries, and store blue carbon.

▸ Groyne: A rigid hydraulic structure built out from a shore to limit sediment movement and erosion.

▸ National Coastal Mission: Central scheme under MoEFCC for coastal protection and management; linked to the NAPCC.

▸ MISHTI: Mangrove Initiative for Shoreline Habitats and Tangible Incomes (Budget 2023-24) for coastal and salt-pan mangrove plantation.

▸ ICZM: Integrated Coastal Zone Management — World Bank-supported coastal management project.

▸ CRZ Notification: Coastal Regulation Zone framework regulating activities along India’s coastline.

▸ Sundarbans: World’s largest mangrove forest (West Bengal); a UNESCO World Heritage Site.

▸ Bhitarkanika: Odisha mangrove ecosystem known for saltwater crocodiles and Olive Ridley turtles.

Question Section (MCQs)

Q1. Ecosystem-based Adaptation (EbA) is promoted as climate-adaptation best practice by which of the following?

1. Convention on Biological Diversity (CBD)
2. UNFCCC
3. World Trade Organization (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Q2. With reference to “Blue Carbon,” consider the following statements:

1. It refers to carbon captured and stored by coastal and marine ecosystems.
2. Mangrove soils act as long-term carbon sinks.
3. Per unit area, mangroves store less carbon than most terrestrial forests. Which are correct? (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Q3. Consider the following statements about why mangroves act as climate shields:

1. Their aerial root networks break incoming wave energy.
2. They trap sediment and help coastlines build up against rising seas.
3. Being rigid concrete structures, they degrade rapidly under tidal stress. Which are correct? (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Q4. Match the mangrove site with its State/UT: A. Sundarbans — 1. Odisha B. Bhitarkanika — 2. Tamil Nadu C. Pichavaram — 3. West Bengal D. Coringa — 4. Andhra Pradesh (a) A-3, B-1, C-2, D-4 (b) A-1, B-3, C-2, D-4 (c) A-3, B-2, C-1, D-4 (d) A-4, B-1, C-2, D-3

Q5. The “MISHTI” programme, associated with mangrove plantation, was announced in: (a) Union Budget 2021-22 (b) Union Budget 2022-23 (c) Union Budget 2023-24 (d) Union Budget 2024-25

Q6. The National Coastal Mission functions under which ministry? (a) Ministry of Earth Sciences (b) Ministry of Environment, Forest and Climate Change (c) Ministry of Jal Shakti (d) Ministry of Ports, Shipping and Waterways

Q7. Which of the following are valid limitations of engineered seawalls highlighted in the context?

1. They can shift erosion to neighbouring stretches.
2. They are rigid while coastlines are dynamic.
3. They provide strong biodiversity and livelihood co-benefits. (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Q8. Cyclone Dana, referenced in the editorial, made landfall near: (a) Sundarbans, West Bengal (b) Bhitarkanika, Odisha (c) Pichavaram, Tamil Nadu (d) Gulf of Kutch, Gujarat

Q9. Consider the following statements:

1. The Sundarbans is the world’s largest mangrove forest and a UNESCO World Heritage Site.
2. India is described as a global hotspot for coastal Ecosystem-based Adaptation.
3. The Integrated Coastal Zone Management (ICZM) Project is World Bank-supported. Which are correct? (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

Q10. Which of the following are correctly described as “blue carbon” ecosystems?

1. Mangroves 2. Seagrass meadows 3. Salt marshes 4. Tidal flats (a) 1 and 2 only (b) 1, 2 and 3 only (c) 2, 3 and 4 only (d) 1, 2, 3 and 4

Answer Key with Explanations

▸ Q1 → (a) 1 and 2 only. EbA is promoted by the CBD and the UNFCCC. The WTO is a trade body and is unrelated — Statement 3 is wrong.

▸ Q2 → (a) 1 and 2 only. Blue carbon is stored by coastal/marine ecosystems, and mangrove soils are long-term sinks. Statement 3 is wrong — mangroves store more carbon per unit area than most terrestrial forests.

▸ Q3 → (a) 1 and 2 only. Aerial roots break wave energy and trap sediment. Statement 3 wrongly describes mangroves as rigid concrete — that describes seawalls; mangroves are living and self-repairing.

▸ Q4 → (a) A-3, B-1, C-2, D-4. Sundarbans — West Bengal; Bhitarkanika — Odisha; Pichavaram — Tamil Nadu; Coringa — Andhra Pradesh.

▸ Q5 → (c) Union Budget 2023-24. MISHTI (Mangrove Initiative for Shoreline Habitats and Tangible Incomes) was announced in the 2023-24 Budget for mangrove plantation along coasts and salt-pan lands.

▸ Q6 → (b) Ministry of Environment, Forest and Climate Change. The National Coastal Mission is a central scheme under MoEFCC, linked to the NAPCC.

▸ Q7 → (a) 1 and 2 only. Seawalls can shift erosion downstream and are rigid against dynamic coasts. Statement 3 is wrong — seawalls offer no biodiversity or livelihood co-benefits; mangroves do.

▸ Q8 → (b) Bhitarkanika, Odisha. Cyclone Dana made landfall near Bhitarkanika on the Odisha coast, where mangroves played a clear shielding role.

▸ Q9 → (d) 1, 2 and 3. All three are correct — Sundarbans is the largest mangrove forest and a UNESCO site; India is a coastal EbA hotspot; and the ICZM Project is World Bank-supported.

▸ Q10 → (d) 1, 2, 3 and 4. Blue carbon ecosystems include mangroves, seagrass meadows, salt marshes, and tidal flats.