By Mark J. Spalding, President, The Ocean Foundation
Last week, Enric Sala of the National Geographic Society spoke about the Society’s Pristine Seas program, which has visited an array of countries to highlight the important marine regions that need protection. In 2012, Sala led an expedition to the Pitcairn Archipelago, which is famous as the refuge of the HMS Bounty mutineers. On this trip, Sala’s team discovered a coral “paradise,” where as much as 90 percent of the sea bottom is covered with healthy coral, providing a habitat for a kaleidoscopic variety of dazzlingly colored fish and lightning-quick reef sharks.
Here at The Ocean Foundation, we would like to see a world in which all of our ocean systems were as healthy. And, we believe that we can all share in that vision and take steps towards that goal as a community of those who strive for healthy oceans. Because of our focus on ocean habitats, we are developing a ways to enhance the natural ways in which we can offset greenhouse gas emissions in the ocean – an exciting concept that helps to address climate change and promotes ocean health. The natural coastal ecosystems of seagrasses, tidal marshes, and mangroves take up and sequester large quantities of carbon in both the plants and in the sediment below them. This sequestration capacity is referred to as “Blue Carbon.”
When these ecosystems are degraded or damaged by human activities, such as boating and dredging, their capacity as carbon sinks is lost. Recent studies on mangrove forests, salt marshes, and seagrass meadows even suggest that these areas could play significant roles in future climate mitigation—if they are restored and protected. Obviously, restoring coastal habitats is good for oceans and for humans. However, we must answer many questions before the opportunity that blue carbon systems present can be fully evaluated.
For example, how much carbon do coastal ecosystems store compared to other ecosystems? Are carbon storage rates different in different parts of the ocean? And based on this, how economical are investments in blue carbon ecosystem options for climate mitigation? Does it have a place in the potential carbon markets? Could preserving blue carbon options also significantly contribute to promoting habitat protection and thus biodiversity?
Today more people are investing in finding answers to these questions, and are beginning to get results. Confirmation of key blue carbon attributes includes:
- Coastal seagrass beds store up to 83,000 metric tons of carbon per square kilometer in the plants and in the soil below them, which is more carbon storage per square kilometer than forests! (1)
- Seagrass meadows can protect nearby coral reefs and other calcifying organisms, including mollusks, from the effects of ocean acidification. (2)
In 2008, to jump-start this cutting edge focus on these natural coastal ecosystems, SeaGrass Grow! was created. It is a project to restore seagrass habitat that offers a protective buffer from destructive storms and prevention of shoreline erosion, and also locally fixes carbon (to slow ocean acidification) and stores carbon (with long-term sequestration). Healthy seagrass meadows also support tourism, food security, and both commercial and recreational fishing. And, in addition to providing nurseries for fish and other creatures, seagrass meadows also offer grazing opportunities for sea turtles, manatees, and dugongs.
A new addition to SeaGrass Grow! is the Blue Carbon Calculator. This first ever Blue Carbon Calculator allows those who care about the ocean to calculate how to naturally offset greenhouse gas emissions in the ocean through seagrass restoration and protection. For now, this is a voluntary offset. And, we are working along side Restore America’s Estuaries to seek verifiable carbon sequestration that is eligible for certification through VCS, or Verified Carbon Standard.
The Verified Carbon Standard is a greenhouse gas accounting program used by projects around the world to verify and issue carbon credits in voluntary markets. It is designed to make sure that when a program or project offers carbon offsets (say, through planting trees or seagrass meadows), its claims are matched to a consistent standard that is credible and verified.
Columbia Sportswear and Absolut Vodka, founding partners of Seagrass Grow!, have been critical to efforts to raise awareness of just how important the role of blue carbon (and the all-important coastal habitats on which it depends) can be. Replanting seagrass meadows, marsh grasses, and mangrove forests are good for the ocean now and in the future.
(1) For, “Seagrass ecosystems as a globally significant carbon stock” Nature Geoscience 5, 505–509 (2012)
(2) Unsworth, Richard et. al. “Tropical seagrass meadows modify seawater carbon chemistry: implications for coral reefs impacted by ocean acidification” 2012 Environ. Res. Lett. 7 024026 (Published 28 June 2012)