A new kind of carbon market - a blue one.

By Anna Talken

04/26/2022

 Just below the surface of Santa Barbara’s coastal waters, seagrasses wave in the currents and kelp forests reach for the sun, providing critical habitat for an abundance of marine life including juvenile fish and invertebrates. Thousands of miles away in Florida, the coastline looks a little different. Thickets of mangrove forests line the edge of brackish waters, with roots embedded in the salty soil that provides habitat for oysters and protects the coast from erosion. While nearshore ecosystems vary in form across the globe, from mangrove forests and salt marshes to dense underwater kelp forests and seagrass beds, they all serve a similar important function in today’s changing climate: carbon sequestration. 

What is blue carbon?

Blue carbon refers to carbon that is sequestered in the marine ecosystem, such as in mangroves and seagrasses, as well as in coastal sediments. The term also refers to the carbon sink created when marine life, including plankton, fish and whales, die and sink – carbon-rich bodies that are eventually sequestered for millennia on the ocean floor. Occupying less than 2% of the ocean, coastal habitats contain nearly half of the sequestered carbon that exists in ocean sediments. Nearshore ecosystems are not only effective at removing carbon dioxide from the atmosphere, but they also provide a myriad of ecosystem services, including pollution remediation and storm buffering.

Yet these coastal ecosystems are in peril. According to one study, nearly 30-40% of tidal marshes and seagrass beds and nearly 100% of mangroves could disappear in the next 100 years based on the current rate of coastal conversion to aquaculture, dams, industrial use, deforestation, and sea level rise. When coastal biogenic habitats are degraded, carbon that has been stored mainly in plant material and coastal sediment is released into the atmosphere – contributing an estimated 0.45Pg of carbon annually, or roughly the amount of CO2 from fossil fuels that the United Kingdom releases every year. Some research suggests that economic costs related to releasing this stored coastal carbon is estimated at between $6 and $42 billion every year.

            In the destruction of coastal habitat lies opportunity. Companies seeking to offset their emissions purchase carbon credits, investments in projects that either prevent the release of CO2 in the atmosphere or sequester it. Until recently, the vast majority of carbon sequestration projects have been land-based, including protecting areas of habitat or reforesting areas that have been degraded. However, coastal mangroves and salt marshes store 3-5 times more carbon than tropical rainforests, suggesting it may be time to invest in our coastlines.

Blue carbon projects

Adding blue carbon credits to the list of options for companies looking to offset emissions may provide substantial benefits to coastal ecosystems that are in a degraded state. A new study showed that about 20% of the world’s mangroves can be protected through entering into the blue carbon market, which would mitigate climate change by sequestering roughly 26 Mt of CO2 every year. However, the potential for impact can be scaled based on how carbon is valued. If carbon prices increase, then there is greater potential to expand the blue carbon market and invest in restoring more mangrove and seagrass ecosystems.

Blue carbon projects throughout the world have come to fruition with varying levels of success. A Kenyan project, Mikoko Pamoja, is an example of a successful community-based blue carbon project. Funds from carbon credits go directly towards the community for mangrove restoration and conservation. Despite some limitations, this program is an example of a small-scale blue carbon project that actually yields benefits not only for climate mitigation but also for the local community.

One project that was carried out in Senegal from 2008-2012 invested millions of dollars to plant 150 million mangrove trees on 12,000 acres. Nearly 300,000 people, mostly women from local communities, were hired to perform the restoration work. Unfortunately, the project saw many drawbacks, including that only one type of species was planted despite being a historically biodiverse area with many mangrove species. In addition, many of the community members felt underpaid and restricted from accessing and using resources or fishing in areas where they historically could. This project illustrated the importance of not only raising the price of carbon to increase funds for restoration workers, but also in creating community-based carbon projects to increase equity.

The Controversy

While blue carbon credits have the potential to yield notable benefits for carbon sequestration and coastal ecosystems worldwide, critics are afraid these credits distract from the real problem – burning fossil fuels in the first place. Some consider this solution to be like slapping a band-aid on a much bigger problem, as companies will continue business as usual, creating more pollution despite purchasing carbon credits. Moreover, carbon fluxes in coastal ecosystems are very difficult to accurately measure, creating huge unknowns around the true sequestration impact of these projects.

Nevertheless, habitat restoration in addition to increased carbon sequestration make blue carbon projects increasingly appealing. Blue carbon credits alone won’t keep warming below 1.5 degrees C, but there is no denying that they can aid climate mitigation efforts and restore critical ecosystems that support an abundance of marine and terrestrial species. As market-based climate solutions begin investing in the high-sequestering potential of the coastal zone, one thing is certain – local coastal communities need to be at the heart of these projects. Creating strong relationships with local communities to promote blue carbon projects that are both sustainable and equitable will ultimately determine the success of the projects. In the face of a changing climate with rising sea levels, increased storms and continued human development on the coastline, restoring our blue carbon ecosystems has never been more important.