India's Mangroves Store More Carbon Than Rainforests, And Coastal Deforestation Is Erasing Them Fast

A single hectare of mangrove forest stores up to 1,000 tonnes of carbon in its soil, roughly four to five times more than a comparable patch of tropical rainforest. The reason is structural. Mangroves grow at the edge of land and sea, in anoxic, waterlogged soils where organic matter decomposes almost not at all. Dead leaves, root fibres, and sediment accumulate over centuries without releasing their carbon back into the atmosphere. Scientists call this "blue carbon," and it is among the densest biological carbon storage on earth.
India holds roughly 4,992 square kilometres of mangrove cover, concentrated in the Sundarbans of West Bengal, the Gulf of Kutch in Gujarat, and the Andaman and Nicobar Islands. The Sundarbans alone, the world's largest contiguous mangrove forest, shared between India and Bangladesh, stores an estimated 34 million tonnes of carbon in its above-ground biomass and soil combined, according to research published in Forest Ecology and Management. That number does not include the carbon locked in the deep peat layers beneath, which can extend several metres down and represent centuries of sequestration.
Global mangrove cover has declined by 30 to 50 percent over the last five decades. In Asia, the rate of loss has consistently outpaced rainforest deforestation, in some periods running at twice the speed. India's own Forest Survey of India data shows net gains in some states through plantation drives, but these figures mask the loss of old-growth, structurally complex mangroves replaced by monoculture plantings that carry a fraction of the biodiversity and carbon value of natural stands.
The pressures are specific. Aquaculture, particularly shrimp farming, has converted vast stretches of mangrove in coastal Andhra Pradesh, Odisha, and Tamil Nadu. Port expansion and coastal infrastructure projects have cleared mangrove buffers in Gujarat and Maharashtra. Urban encroachment along the Konkan coast and in the creeks around Mumbai has reduced mangrove extent even where legal protections exist on paper. The Supreme Court of India has repeatedly upheld mangrove protection orders, yet enforcement at the state level remains inconsistent.

A 2020 study in the journal One Earth estimated that the destruction of mangroves globally releases between 0.07 and 0.42 billion tonnes of carbon dioxide annually, equivalent to the annual emissions of a mid-sized industrialised nation.
The biodiversity argument for mangrove conservation is as strong as the carbon argument, though it receives less attention. Mangroves function as nurseries for over 1,300 species of fish, crustaceans, and molluscs across their global range. In India, the Sundarbans supports the Bengal tiger, one of fewer than 100 individuals estimated to live in the Indian portion of the delta, alongside the Irrawaddy dolphin, the estuarine crocodile, and the Gangetic river shark, a critically endangered species.

The prop-root architecture of mangroves creates a three-dimensional habitat that no other coastal system replicates. Mudskippers, amphibious fish that breathe through their skin and climb roots, are found almost exclusively in mangrove zones. Fiddler crabs aerate the sediment, accelerating the very carbon burial processes that make mangroves such effective carbon stores. The biology is circular: the creatures that live here help the forest do what it does.
The 2004 Indian Ocean tsunami offered a brutal natural experiment. Villages behind intact mangrove belts in Tamil Nadu and the Andaman Islands suffered significantly lower casualties and structural damage than those where mangroves had been cleared for aquaculture or development. A study published in Science after the tsunami quantified the effect: areas with dense mangrove cover saw wave energy reduced by up to 90 percent before it reached inhabited land.

Cyclone Amphan in 2020 tested the Sundarbans again. The mangrove belt absorbed a significant portion of the storm surge before it reached the populated delta interior, though the weakening of the forest edge, from both natural die-back and encroachment, meant the protection was less complete than it would have been thirty years ago. The economic value of this storm buffering, calculated by researchers at the Nature Conservancy, runs to hundreds of millions of dollars annually for India's coastline alone. That value is never entered on any balance sheet when a shrimp farm is approved.
Community-based mangrove management has produced documented results in India. In the Bhitarkanika National Park in Odisha, forest department partnerships with local fishing communities have reversed mangrove loss over two decades, with cover increasing measurably since the 1990s. The model works because local fishers understand that the nursery function of the mangrove directly feeds their catch. When the forest goes, so does the fish stock.
The Compensatory Afforestation Fund Act and various coastal regulation zone notifications provide a legal scaffold for mangrove protection, but plantation drives, the government's preferred metric, continue to count monoculture plantings of a single Avicennia or Rhizophora species as equivalent to natural, multi-species stands. They are not. A planted mangrove row along a highway median sequesters carbon and shelters nothing like what a 200-year-old Sundarbans stand does.
The carbon market offers one pathway. Blue carbon credits from verified mangrove conservation projects are now tradeable under voluntary carbon standards, and several pilot projects are underway in Odisha and Gujarat. Whether those credits reach the communities who actually protect the forest, or get absorbed by intermediaries, will determine whether the mechanism works.
The mangrove sits at the intersection of every crisis India's coast faces, rising seas, intensifying cyclones, fishery collapse, carbon debt, and it addresses all of them simultaneously, without any infrastructure budget. The tragedy is that its value only becomes legible after it is gone.