What is blue carbon?

What is blue carbon and why is it important?

The term ‘coastal blue carbon ecosystems’ refers to three main types of vegetated coastal habitats – mangroves, tidal marshes and seagrasses. These ecosystems are important for addressing climate change and securing social, economic and environmental outcomes. Coastal blue carbon ecosystems sequester two to four times more carbon than terrestrial forests (Murray et al, Nicolas Institute, 2011).

Improved management of these ecosystems can enhance food security, secure livelihoods, increase resilience, and contribute to delivering Nationally Determined Contributions through carbon sequestration.

When degraded or lost, coastal blue carbon ecosystems can become significant emission sources. Mangrove deforestation is estimated to be around as much as 10 per cent of emissions from deforestation globally (Donato et al, Nature Geoscience 2011).

Mangroves

Mangroves are evergreen shrub lands or forests that occur in tropical and subtropical shores and estuaries. They generally grow from mean sea level to the highest spring tide. Countries with the largest areas of mangroves include Australia, Bangladesh, Brazil, Cuba, India, Indonesia, Malaysia, Mexico, Mozambique, Myanmar, Nigeria and Papua New Guinea.

Tidal marshes

Tidal marshes are dominated by dense salt-tolerant plants such as succulent herbs and low shrubs, and grasses. They are found on soft sediments on sheltered coastlines, from the sub-arctic to the tropics, though most extensively in the temperate zones of Europe, North America, and Australia and in the higher latitudes of South-America and Africa.

Seagrasses

Seagrasses are communities of underwater-flowering plants. They are generally restricted to habitats with sediments comprised of sand, silt and mud and high light availability. Seagrasses prefer wave sheltered conditions and are found in coastal waters of all continents except Antarctica.

More information on blue carbon can be found in the Partnership’s Coastal blue carbon: an introduction for policy makers.