BharatNotes What is Blue Carbon?
Blue carbon is the carbon captured from the atmosphere and ocean and stored by coastal and marine vegetated ecosystems — chiefly mangroves, seagrass meadows and tidal salt marshes. Unlike "green carbon" held in terrestrial forests, most blue carbon is locked away in deep, waterlogged, oxygen-poor sediments where it can remain stable for centuries to millennia. The term was popularised by a 2009 UN report ("Blue Carbon: The Role of Healthy Oceans in Binding Carbon").
The defining feature is efficiency: these ecosystems can sequester carbon several times faster per unit area than tropical rainforests, and over 95% of the carbon in a seagrass meadow is stored in its soil rather than its biomass.
Key Features and Significance
- Disproportionate impact: Globally, blue carbon ecosystems cover roughly 51 million hectares — a tiny fraction of the ocean — yet account for a major share of marine carbon burial. Seagrasses occupy less than 0.2% of the ocean floor but store an estimated ~10% of the carbon buried in the oceans each year.
- Co-benefits: Beyond carbon, they provide coastal protection against storm surges and cyclones, fish-nursery habitats, biodiversity, and livelihoods.
- Vulnerability: When drained, dredged or cleared, these sediments oxidise and release stored carbon — turning a sink into a source. They are being lost faster than almost any other ecosystem.
| Ecosystem | Role in blue carbon |
|---|---|
| Mangroves | Tidal forests; high above- and below-ground carbon; cyclone buffers |
| Seagrass meadows | Submerged flowering plants; very high soil-carbon storage |
| Salt marshes | Tidal grasslands of temperate coasts; dense sediment carbon |
Current Status in India
India's mangrove cover stood at 4,992 sq km (ISFR 2023, released Dec 2024), about 0.15% of the country's geographical area, spread across 12 States/UTs. India hosts the Indian portion of the Sundarbans, part of the world's largest mangrove forest (a UNESCO World Heritage Site and Ramsar site). West Bengal has the largest mangrove cover, followed by Gujarat and Andhra Pradesh.
To restore these habitats, the government launched MISHTI (Mangrove Initiative for Shoreline Habitats & Tangible Incomes), announced in the Union Budget 2023-24 and rolled out from 2023. It targets mangrove restoration along the coastline and on salt-pan lands through convergence with CAMPA, MGNREGS and State schemes. Mangrove and wetland conservation also supports India's enhanced Nationally Determined Contribution target of creating an additional carbon sink under the Paris Agreement.
UPSC Angle
Blue carbon sits at the intersection of climate mitigation, coastal ecology and the blue economy. For Prelims, link it to carbon sinks, IUCN nature-based solutions, Ramsar wetlands and mangrove distribution. For Mains GS3, it supports answers on climate change mitigation, coastal-zone management and disaster resilience; for GS2, it connects to India's international climate commitments. A strong answer pairs the science (sediment carbon storage) with Indian policy (MISHTI, Sundarbans, NDC sink target).
