What is Blue Carbon?
Blue Carbon is about mitigating climate change through coastal ecosystem management.
Healthy coastal habitat is not only important for seafood and recreation, it also plays an important role in moderating climate change. Salt marshes, mangroves, and seagrass beds absorb large quantities of the greenhouse gas carbon dioxide from the atmosphere and store it, thus decreasing the effects of global warming. These types of habitat are known as carbon sinks and contain large stores of carbon accumulated over hundreds to thousands of years.
Coastal blue carbon is the carbon captured by living coastal and marine organisms and stored in coastal ecosystems. Salt marshes, mangroves, and seagrass beds play two important roles:
- Carbon sequestration—the process of capturing carbon dioxide from the atmosphere, measured as a rate of carbon uptake per year
- Carbon storage—the long-term confinement of carbon in plant materials or sediment, measured as a total weight of carbon stored
The blue carbon benefits of tidal wetland and seagrass restoration can now be quantified, thanks to a methodology developed by Restore America's Estuaries and Silvestrum.
Why is it Important?
Current studies suggest that mangroves and coastal wetlands annually sequester carbon at a rate two to four times greater than mature tropical forests and store three to five times more carbon per equivalent area than tropical forests. Most coastal blue carbon is stored in the soil, not in above-ground plant materials (biomass), as is the case with tropical forests.
Although coastal habitats provide a great service in capturing carbon, their destruction poses a great risk. When these habitats are damaged or destroyed, not only is their carbon sequestration capacity lost, but stored carbon is released and contributes to increasing levels of greenhouse gases in the atmosphere. As a result, damaged or destroyed coastal habitats change from being net carbon sinks to net carbon emitters. Unfortunately, coastal habitats around the world are being lost at a rapid rate, largely due to coastal development for housing, ports, and commercial facilities.
What is Being Done?
- The Blue Carbon Initiative works to protect and restore coastal ecosystems for their role in reducing impacts of global climate change. To support this work, the Initiative is coordinating the International Blue Carbon Scientific Working Group and International Blue Carbon Policy Working Group, which provide guidance for needed research, project implementation and policy priorities.
- In 2014 the Blue Carbon Initiative released a new manual Coastal Blue Carbon: methods for assessing carbon stocks and emissions factors in mangroves, tidal salt marshes, and seagrass meadows.
- Projects are being developed at sites globally to protect and restore coastal ecosystems for their “blue” carbon value. Learn more about this. A two-year assessment of the potential to develop blue carbon projects on Louisiana's coast estimates that carbon finance revenue can provide up to $1.6 billion in critical funding to assist with wetland restoration over the next 50 years. More on this.
- Research into the sequestration, storage and loss of carbon from blue carbon systems is ongoing. View recent reports and scientific papers.
- In February 2014 Restore America's Estuaries released the findings of a groundbreaking study that confirms the climate mitigation benefits of restoring tidal wetland habitat in the Snohomish Estuary, located within the nation's second largest estuary: Puget Sound. The study, the first of its kind, found major climate mitigation benefits from wetland restoration and provides a much needed approach for assessing carbon fluxes for historic drained and future restored wetlands which can now be transferred and applied to other geographies. The Study, Coastal Blue Carbon Opportunity Assessment for Snohomish Estuary: The Climate Benefits of Estuary Restoration found that currently planned and in-construction restoration projects in the Snohomish estuary will result in at least 2.55 million tons of CO2 sequestered from the atmosphere over the next 100-years. This is equivalent to the 1-year emissions for 500,000 average passenger cars. If plans expanded to fully restore the Snohomish estuary, the sequestration potential jumps to 8.9 million tons of CO2, or, in other terms, equal to the 1-year emissions of about 1.7 million passenger cars.
What Can You Do?
- Check out NOAA's Coastal Blue Carbon Efforts.
- Read the latest Blue Carbon News.
- Learn much more at the Blue Carbon Portal.
- Advocate for the preservation and restoration of coastal habitats that sequester carbon. As a bonus, these same habitats often provide other benefits, including moderating coastal erosion and helping to keep coastal waters clean.
References and Additional Sources of Information
Coastal Blue Carbon - NOAA
Blue Carbon Resources, Restore America's Estuaries
Green Payments for Blue Carbon - Economic Incentives for Protecting Threatened Coastal Habitats, Duke University, Nicholas Institute, April 2011.
North America's Blue Carbon: Assessing the Role of Coastal Habitats in the Continent's Carbon Budget, Commission for Environmental Cooperation.