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Coastal Blue Carbon

What is Coastal Blue Carbon?

Healthy coastal habitat is not only important for seafood and recreation, it also plays an important role in reducing 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.

Using more scientific lingo, 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

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.

Carbon Storage Abilities of Different Habitat Types (please click on the image to enlarge)

Carbon Storage Abilities of Different Habitat Types

*Data is per unit area, where tCO2eq/ha is tons of carbon dioxide equivalents per hectare

Source: Murray, Brian, Linwood Pendleton, W. Aaron Jenkins, and Samantha Sifleet. 2011. Green Payments for Blue Carbon: Economic Incentives for Protecting Threatened Coastal Habitats. Nicholas Institute Report. NI R 11-04.

What is NOAA Doing to Protect “Blue Carbon”?

NOAA is raising awareness about the value of mangroves, salt marshes, and seagrasses in carbon sequestration and storage to encourage conservation of these valuable habitats. Besides serving as a carbon sink, these habitats provide feeding, breeding, and nursery grounds for a wide variety of fish and wildlife species; recreational opportunities such as fishing and bird watching; and protection from coastal storms and extreme weather events. By considering the carbon value of these habitats in policy and management decisions and supporting the development of market-based incentives for conservation, NOAA is seeking to create additional protections for these important habitats and the services they provide for future generations. For more details on NOAA’s coastal blue carbon work, click here.