By Shannon Hood, Environmental Defense Fund
Terrestrial carbon sequestration is the process by which atmospheric carbon dioxide is taken up by plants through photosynthesis and stored as carbon in biomass and soil. During the process of photosynthesis, plants take carbon dioxide from the atmosphere, coupled with sunlight and water, and turn it into sugar and oxygen, allowing them to act as long-term storage facilities for carbon (“carbon sinks”). Some carbon is re-emitted during the process of respiration, but overall, vegetated areas act as net carbon storage facilities. Utilizing vegetated areas as sinks for carbon allows carbon emissions from other sources (fossil fuel emissions, deforestation, etc.) to be offset. The value of forested lands has been documented for carbon sequestration (e.g., “REDD-Avoiding Planned Deforestation” and “Afforestation and Reforestation of Degraded Lands”), however, until now, the ability of wetlands to capture and store blue carbon hasn’t been formally recognized or quantifiable.
Tierra Resources LLC, an environmental consulting firm based in New Orleans, has developed the first American Carbon Registry-certified methodology for creating carbon offset credits for wetland restoration activities. (In a follow-up post, we will provide information on the methodology and test site). The methodology provides a calculation for determining the number of carbon credits that may be obtained from a wide variety of wetland restoration projects. Never before had wetlands entered the arena for carbon credits, but the potential for credits to be obtained from their restoration is tremendous!
Biologically, wetlands are some of the most highly productive ecosystems in the world, with high rates of photosynthesis. Higher rates of photosynthesis lead to greater carbon capture and storage by trees, grasses and other plants. In addition, wetlands soils are largely anaerobic, meaning that incorporated carbon decomposes slowly and can be stored for long periods of time.
Tierra Resources estimates that if 25 percent of the four million acres of Mississippi River Delta wetlands that are eligible under this methodology are selected for restoration through carbon sequestration, between $5 and $15 billion may be generated over the next 40 years. This creates an additional source of funding for wetlands restoration and adds yet another ecosystem service to the many already provided by the Mississippi River Delta.