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The term ‘blue carbon’ is gaining currency in global climate talks and national policy circles. But what does it really mean, and what should we be doing about it?

Research is ongoing into the distribution and extent of blue carbon around the world, and how protecting the ecosystems that store it can contribute to efforts to mitigate climate change.

In celebration of World Water Day on 22 March, we take a look at the developing science on blue carbon, and what it suggests for managing forests, water, people and a changing climate.

What is blue carbon?

‘Blue carbon’ refers to the carbon captured and stored in oceans and coastal ecosystems. It’s ‘blue’ because it is formed underwater.

It also includes coastal carbon stored in tidal wetlands, such as tidally influenced forests, mangroves, tidal marshes and seagrass meadows, within soil, living biomass and non-living biomass carbon pools. Mangrove forests are carbon-rich ecosystems that can hold up to three times as much carbon per hectare as terrestrial forests.

When protected and restored, with organic matter locked in their soils, mangroves and other wetlands act as effective ‘carbon sinks’, offering great potential to mitigate climate change.

   Once considered ‘wastelands’, mangroves are increasingly being appreciated for their potential as blue carbon sinks, among other values. CIFOR Photo/Mokhamad Edliadi

Why is blue carbon important?

Because blue carbon ecosystems are such effective carbon sinks, they can play a major role in meeting national and global targets on climate change.

Standing coastal wetlands hold vast stores of blue carbon, while cleared wetlands release those stores into the atmosphere. Because of this, good management of blue carbon ecosystems is important for countries to make progress toward their nationally determined contributions to the Paris Agreement, among other climate goals. Action is also underway to meet Sustainable Development Goal number 14, to “conserve and sustainably use the oceans, seas and marine resources.

Until recently, wetlands were in many places considered to be ‘wastelands’, waiting to be cleared for development. But as the value of these water-based ecosystems to climate mitigation becomes clearer — not to mention their value as international bargaining chips, with possible financial value to boot — policies are changing to conserve and even expand them.

This is having knock-on effects for even more of the underappreciated values held by these ecosystems, such as their ability to provide habitats for threatened species on land and in water, improve water quality, and protect coastal areas from tsunamis, storms and erosion.

Where can blue carbon be found?

Blue carbon is stored in open ocean carbon pools, as well as in coastal wetland ecosystems like mangroves. Research is ongoing into the exact distribution and extent of blue carbon ecosystems around the world, especially in the tropics.

New findings are emerging all the time from Asia, Africa and Latin America, bringing to light vast areas of wetland carbon stocks that had previously gone unnoticed.

A worldwide initiative is underway to map the world’s wetlands, including blue carbon ecosystems like mangroves. Scientists from the Center for International Forestry Research (CIFOR) together with partners at the United States Forest Service as part of the Sustainable Wetlands Adaptation and Mitigation Program (SWAMP), are leading the data-sharing effort to create an interactive, online map.

The Global Wetlands Map is a tool for plotting wetlands, histosols and carbon stocks around the world, using a combination of global topographic and weather datasets, satellite imagery and on-the-ground research data added by registered users.

By showing carbon stock data in spatial terms, it is designed to help identify priority areas for conservation and restoration, among other aims.

How is blue carbon being managed?

Just like other types of forests, water-based forests where blue carbon is stored depend on landscape-scale management to maintain their values for biodiversity, ecosystem services, economic development, human well-being and more.

But while the biophysical aspects of blue carbon ecosystems are gaining attention, the details of their governance and management are relatively unexplored.

In Tanzania and Indonesia, countries with some of the world’s greatest areas of mangrove forests, recent research as part of the CIFOR-led Global Comparative Study on Forest Tenure Reform (GCS-Tenure) found that as in terrestrial forests, mangrove forests can greatly benefit from the devolution of tenure and management rights to local communities.

When local communities have ownership over blue carbon ecosystems and are involved in their management, they become better positioned to conserve those ecosystems, while benefitting from their goods and services.

Both studies made the case for expanding and strengthening tenure rights of local communities to mangroves as a first step toward sustainable management, conservation and global climate change mitigation.

   Studies in Tanzania and Indonesia have made the case for greater local control over blue carbon ecosystems. CIFOR Photo/Ulet Ifansasti

What next?

As research continues to drive home the importance of blue carbon, national and global policy processes are beginning to pay attention.

In 2015, an International Partnership for Blue Carbon (IPBC) was established at the Global Landscapes Forum in Paris, on the sidelines of COP21. In 2016, oceans and coastal ecosystems were added to the agenda of global climate talks for the first time at COP22. By 2017, conservation and restoration of wetlands was gaining recognition as a key nature-based strategy for climate action at COP23.

At regional and national levels, blue carbon is also gathering momentum. Talks are underway this week in Perth, Australia at the IORA Indian Ocean Conference on Blue Carbon, with more to follow in July in Jakarta at the Blue Carbon Summit.

Members of the IPBC will join talks on mangroves and blue carbon in Yogyakarta, Indonesia, in a few weeks’ time as part of the third Asia-Pacific Rainforest Summit.

And as the research shows, much of the important work going forward will be done at the ground level – policies that support the right of local communities to manage and benefit from their wetland ecosystems could make all the difference.

For more information on this topic, please contact Daniel Murdiyarso at
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Topic(s) :   Blue carbon, mangroves and peatlands Peatlands Wetlands