Blue Carbon Rising
It’s likely most people have never heard the term blue carbon. When carbon is stored in coastal wetland ecosystems, including tidal marshes, mangroves and seagrass, it becomes known as blue carbon. Amazingly, blue carbon ecosystems remove four times more carbon dioxide from the atmosphere, per acre, than forests. This means healthy coastal wetlands are considered a carbon sink, and restored wetlands are a largely unrealized solution to the problem of increasing worldwide carbon dioxide levels. In fact, on a per-acre basis, coastal habitat restoration and conservation can provide among the greatest climate benefits compared to forest or all other land-use projects.
Last month at the 2015 Blue Carbon Network event in Silver Springs, Maryland, a group of scientists, policymakers and marketers gathered to discuss how to increase exposure for coastal wetlands — areas that are not only great carbon sinks, but also critically important for ecological and economic value. Globally, coastal wetlands are being lost at an unsustainable rate each year; estimated at 1 to 7 percent, according to Restore America’s Estuaries, an organization whose work is dedicated to the protection and restoration of U.S. bays and estuaries. Unfortunately, if this rate continues, all coastal wetlands may be lost in less than 100 years.
The first Blue Carbon Network workshop was initiated to identify a national network of people and organizations conducting work around blue carbon science, markets, management and policy. The objective of the network is to understand the gaps and challenges for blue carbon efforts in science, policy and environmental credit markets — helping them move toward more concrete action strategies in 2015 and beyond. Much restoration work is being done with seagrasses in the northeast; peatland in the eastern seaboard; as well as coastal wetlands in the Lower Mississippi Valley, California and Puget Sound. However, restoration efforts have not kept up with habitat loss.
Blue Carbon Graph Similar to forests, wetlands store carbon in above and below ground vegetation, but primary carbon storage in wetlands is within soils. Carbon accumulates annually and can be stored for centuries within healthy wetlands; the majority of which is stored in the first meter of soil. Three prominent wetland types globally are Seagrasses (5.10 metric tons of carbon dioxide equivalents per year [tCO2e/ha/yr], Salt Marsh (8.0 tCO2e/ha/yr), and Mangroves (8.3 tCO2e/ha/yr). By comparison, tropical forests are below 0.50 tCO2e/ha/yr).
The Blue Carbon Network also advocates for coastal wetlands restoration projects with the leading greenhouse gas protocols and registries, to illustrate that healthy wetlands need to be included in the growing carbon market. Carbon and other environmental markets (e.g. water quality trading) can assist in financing the preservation and restoration of these coastal habitats—areas of vital importance to the U.S. for both environmental and international commerce reasons.
Presently there are both compliance and voluntary carbon markets in the U.S. The largest compliance market is an active cap-and-trade program located in California and managed by the California Air Resources Board (ARB). The California market is part of a statewide effort to reduce GHGs and promote clean technology. In this system, companies with emissions greater than 25,000 tCO2e/year are regulated. The primary compliance instrument are allowances—permits for covered entities to emit one ton of carbon dioxide issued by the state. Covered entities are also allowed to use credits generated in non-covered sectors, called offsets, for up to 8 percent of their compliance liability. Land-use types, such as forestry and rice, are soon-to-be or have already been approved as part of this regulated system. ARB’s plan is to approve additional land-based offset types in the future; with a potential fit for Coastal Wetlands Restoration. Acceptance of wetlands in this regulated system would likely spur much needed coastal restoration work.
Voluntary carbon markets encourage both corporations and individuals to offset their GHG emissions voluntarily, without regulation. Standards or protocols have been established by independent organizations that ensure environmental efficacy for the credits issued. Examples of leading voluntary standards are the American Carbon Registry (ACR), Verified Carbon Standard (VCS), and Climate Action Reserve (CAR). Each of these standards establish GHG accounting rules for approved project types. Projects must meet specific criteria in order to be awarded or issued carbon credits. Presently, one of the only approved wetland restoration project types or methodologies is the Restoration of Degraded Deltaic Wetlands of the Mississippi Delta.
However, there are other wetland project types being developed under VCS and ACR. The new ACR method is designed to fit California wetland types, and is the first protocol to specifically target at-risk wetlands in the Golden State. Eligible management activities to conserve carbon stocks in threatened wetlands include: Conservation of Intact Wetlands, Rewetting of Drained Organic Soils, and Restoration and Creation of Vegetated Wetlands. The identification of these wetland management activities and emergence of associated GHG standards are an important first step in the use of carbon markets to address rapid wetlands loss and climate mitigation.
One of the more prominent Blue Carbon studies conducted was located in the Snohomish Estuary. This area was selected because the estuary system is representative of the Puget Sound and broader Pacific Northwest Region in terms of land use management issues and geomorphology. The study’s hypothesis was that wetlands in this region will prove restoration can offer a relatively high level of resilience to sea level rise, and also act as an effective sink for carbon sequestration. This is one of the first assessments of carbon fluxes over many decades for historic drained wetlands.
The Snohomish Estuary findings indicated that historic land use change resulted in estimated emissions of 4.5 million tons of carbon (MtC), of which 2.8 MtC was a result of clearing forested wetlands and 1.7 MtC from draining soils. Of the nearly 12,000 acres of converted or drained wetlands, almost 3,500 acres are currently being restored. Full estuary restoration would result in additional carbon stocks of 8.9 million tons of CO2 sequestered over 100 years — equal to the one year of emissions from about 1.7 million cars. Carbon rates on two restoration sites ranged from 0.9 tCha/yr to 3.52 tCha/yr, which is quite high. The next step would be to deliver a carbon project in this geographic region that will produce credits under a new VCS method; eventually expanding with similar projects throughout the region and beyond.
The Blue Carbon Network hopes to illustrate the importance of carbon finance for wetlands in the rapidly diminishing coastal zone. The hope is that Blue Carbon projects will be embraced broadly due to the vital ecosystems services provided; including flood protection, fish and wildlife habitat, improved water quality, jobs and many other economic benefits. Blue Carbon’s role in supporting climate change adaptation and protection of coastal communities cannot be overstated.