Coastal habitats like salt marshes, mangroves, and seagrass beds provide us with countless benefits, from nursery grounds for fish to protection from storms. They also play an important role in addressing climate change by removing greenhouse gases like carbon dioxide from the atmosphere and storing them. The NOAA Fisheries’ Office of Habitat Conservation works to protect and restore these important coastal habitats and the climate benefits they provide.
What is Coastal Blue Carbon?
Coastal blue carbon is carbon that is stored in coastal habitats like salt marshes, mangroves, and seagrass beds.
Just like forests on land, coastal habitats capture and store carbon dioxide from the atmosphere, both in plants and in the soil. But compared to forests, coastal habitats do so on a much larger scale. Research shows that mangroves and salt marshes remove (sequester) carbon from the atmosphere at a rate 10 times greater than tropical forests. They also store three to five times more carbon per acre than tropical forests. This is because most coastal blue carbon is stored in the soil, rather than in above-ground plants.
Coastal blue carbon habitats are also sometimes referred to as “carbon sinks,” because they sequester more carbon than they release. They also hold on to it for long periods of time. Carbon found in coastal soils is often hundreds or thousands of years old.
The Role of Coastal Blue Carbon in Earth’s Climate
Carbon dioxide is a greenhouse gas created by burning fossil fuels like gasoline and coal, as well as solid waste and wood. Increasing levels of carbon dioxide and other greenhouse gases are a major driver of climate change.
Salt marshes, mangroves, and seagrass beds are incredibly efficient at sequestering and storing large quantities of carbon dioxide from the atmosphere. By doing so, these habitats can help decrease the effects of climate change.
When coastal blue carbon habitats are damaged or destroyed, however, their capacity to absorb carbon is lost. In addition, the carbon being stored in these habitats is released. This then increases the levels of carbon in the atmosphere. Coastal habitats around the world are being lost at a rapid rate, largely due to coastal development, meaning the large amounts of carbon they have stored is being released into the atmosphere.
Efforts to conserve coastal habitats play an important role in preserving coastal blue carbon, preventing the release of carbon into the atmosphere, and reducing the effects of climate change. Conservation efforts also protect the many other benefits that healthy coastal habitats provide, such as recreational opportunities, flood protection, and more.
How NOAA Fisheries Protects Coastal Blue Carbon
Collaborative coastal blue carbon efforts are ongoing across NOAA, including within NOAA Fisheries, National Ocean Service, and Oceanic and Atmospheric Research. NOAA strategically invests in foundational work to develop methodologies, create guidelines, and support a national coastal blue carbon community. Our work helps restoration practitioners understand how to account for carbon stored and sequestered in wetlands, seagrass beds, and mangroves.
Within NOAA Fisheries, the Office of Habitat Conservation works to conserve coastal blue carbon habitats, advance the science and management of coastal blue carbon, and collaborate with partners to support a national community of coastal blue carbon experts.
Conserving Coastal Habitats
NOAA Fisheries works with communities and partners across the country to protect and restore habitat for fisheries and protected species. Projects that restore salt marshes, wetlands, and estuaries can sequester and store significant quantities of carbon, while also providing other social and economic benefits to local communities.
For example, our work with partners on the Southern Flow Corridor project in Tillamook, Oregon, helped restore tidal wetland habitat for coho salmon. It also reduced flooding in nearby communities. Monitoring results from the project suggest that, over time, the Southern Flow Corridor site could store 100,000 tons of carbon dioxide. That’s the equivalent of taking 21,000 cars off the road for a year.
Additionally, we have supported several projects that restored wetlands in Washington’s Snohomish Estuary region, including in the Qwuloolt Estuary, on Smith Island, and on Mid-Spencer Island. A NOAA-supported coastal blue carbon assessment of the Snohomish Estuary found that, if the entire estuary were restored, 8.9 million tons of carbon dioxide would be captured over 100 years.
Advancing Science and Management
NOAA Fisheries’ Office of Habitat Conservation plays an active role in supporting a national community of coastal blue carbon scientists, practitioners, and managers. Our work helps build understanding of how coastal blue carbon habitats can support fisheries, and how to use this information in coastal management, restoration, and conservation efforts.
Our work advances awareness and understanding of a variety of aspects of coastal blue carbon, such as:
- How to avoid or minimize the effects of dredging, development, and other actions that threaten coastal blue carbon habitats and the carbon they house
- How to account for carbon stored and sequestered in coastal blue carbon habitats, including factors that drive or influence sequestration and storage rates
- How to identify legal considerations for coastal blue carbon projects on publicly-owned wetlands
We also work with local researchers and partners around the country to understand the coastal blue carbon storage potential of regions and watersheds where we work. For example, we supported a coastal blue carbon assessment in Tampa Bay, Florida. It determined that, by 2100, coastal blue carbon habitats in Tampa Bay are expected to remove 73–74 million tons of carbon dioxide from the atmosphere. That’s equivalent to removing more than 15 million vehicles from the road for one year.
Collaborating with Partners
We work with our federal partners—such as the Environmental Protection Agency, U.S. Fish and Wildlife Service, and U.S. Army Corps of Engineers—through the Interagency Coastal Wetlands Working Group to:
- Better understand the causes of coastal wetland loss
- Develop approaches to address those causes
- Maximize investments in conservation to reverse the decline of coastal blue carbon habitats
The group is also working on more precise and accurate mapping and analysis of these habitats.
We also coordinate with federal partners like the Natural Resources Conservation Service to advance our knowledge of the amount of carbon in the coastal blue carbon habitats we protect. Our work with the National Estuarine Research Reserves helps build our understanding of monitoring methods. We can use these methods to study carbon storage and sequestration at our project sites before and after our conservation efforts.
We also work with non-government partners such as Restore America’s Estuaries to advance coastal blue carbon studies and projects around the world. Our participation in the Coastal Carbon Research Coordination Network helps accelerate scientific discovery, advance science-informed policy, and improve coastal ecosystem management.