Blue Carbon

The overarching goal of this team-based Master’s Project is to determine and evaluate the economic, policy, and logistical issues involved with potential blue carbon offset projects, specifically in Louisiana and North Carolina. The new field of blue carbon offsets aims to restore or prevent the loss of coastal wetlands, including: mangroves, salt marshes, and seagrass beds, which are known carbon sinks. Unlike traditional carbon offsets – namely, preventing deforestation – blue carbon projects exploit the carbon that is sequestered within the sediments as well as the living plants. This particular project will research the feasibility of blue carbon offset projects and provide suggestions to guide Duke’s development of a blue carbon decision.

Wetland carbon storage potential compared to other ecosystems (Tierra Resources 2012).












Duke University’s interest in blue carbon offsets was spurred by its promise to become carbon neutral by 2024 through their Climate Action Plan (Duke Campus Sustainability Committee 2009). Duke’s Carbon Offsets Initiative (DCOI) is attempting to determine available carbon offset options in order to help reach this goal of carbon neutrality in a cost effective manner. Blue carbon has great potential for carbon offsets and can provide additional benefits in the form of ecosystem services by preserving existing wetlands that would otherwise erode away or become developed without action (Laffoley and Grimsditch 2009).

To determine the economic viability of a blue carbon project site, in terms of being a cost effective carbon offset, the first step is looking at previous research and the ecology of viable regions. Many areas around the world have started to include mangrove stands as possible carbon offsets, but only based on what is above ground in the trees themselves, not including the carbon sequestration capacity of the soil. Blue carbon initiatives seek to incorporate this important underground aspect in order to make wetland preservation an economically viable offset possibility. Blue carbon is especially necessary in areas like Louisiana where mangroves are not widely present but marshland abounds, as marshes have very little above-ground sequestration but great opportunity for carbon sequestration below the water (Sifleet et al. 2011). Blue carbon projects in Louisiana would also serve a second purpose through erosion control and wetland restoration along a coastline that is losing several acres of land each year.

In the United States, the Atlantic and Gulf of Mexico coastlines offer the greatest potential for blue carbon projects. The Gulf of Mexico coast is the premier area for domestic blue carbon offset projects because it is lined with marshland from Texas to Florida, where seagrass beds and mangrove forests become abundant. The southern half of the Atlantic coast is predominantly wetland as the wide continental shelf minimizes wave action, promoting soft sediment habitats rather than rocky shorelines. Georgia and South Carolina have the highest acreage of marshland on the eastern seaboard, composing approximately 400,000 hectares combined (Bertness 2007). Marshland is present all the way to Maine but is much less prevalent north of New York, where colder temperatures and a narrower continental shelf limit wetland habitat potential.

The coastal watersheds of the continental United States. Blue carbon projects are being researched along the Gulf of Mexico (light green) and the South Atlantic (purple), where salt marshes, mangrove forests, and seagrass beds are the dominant coastal habitats. The rocky shorelines found in the North Atlantic, the Pacific Northwest, and California are not suitable for blue carbon initiatives as carbon sequestration is limited (EPA 2012).

This project expanded upon the progress made by previous Duke environmental students, looking at the economic feasibility of blue carbon as a broader offset initiative while also factoring in the benefits gained from the ecosystem services that blue carbon efforts could provide. When considering the economic feasibility, it is necessary to take into consideration the opportunity costs of what the land could possibly be used for instead of blue carbon projects (Murray et al. 2011).  As Murray et al. (2010) discuss, blue carbon is currently unable to economically outcompete the construction of hotels or other real-estate endeavors that will net large amounts of revenue. However, if the offset market is priced high enough, blue carbon initiatives will likely be financially competitive with coastal agriculture and aquaculture.