Can Seagrasses Fight Global Warming and Spur Sustainable Development?

As the COP27 climate talks in Egypt wrap up, we have learned more about a frequently overlooked ecosystem in the fight against climate change: seagrasses. While they’re often overshadowed by neighboring coral reefs and mangroves, seagrasses are one of the most valuable coastal ecosystems in the world. They absorb carbon up to 35 times faster than tropical rainforests, soaking up to 10 percent of the ocean’s carbon each year.

Seagrasses belong to the larger set of blue carbon ecosystems. This colorful name refers to carbon captured from the atmosphere by marine and coastal ecosystems. And the tidal marshes, mangroves and seagrasses lining our coasts are a powerhouse for storing carbon. For instance, the protection of blue carbon ecosystems could prevent the equivalent of 670 billion pounds of carbon dioxide (304 billion kilograms) from being released each year. 

Blue carbon ecosystems are champions in fighting climate change. Their protection could provide one of the largest climate benefits on a per-acre basis compared to other land-use projects. Restoring these valuable environments could soak up the equivalent of 841 billion kilograms of carbon per year, or around 3 percent of annual global emissions. This climate change mitigation translates into $1,317 per hectare annually for seagrass meadows.

The environmental and economic benefits of seagrasses

Besides their ability to fight global warming, seagrasses also provide numerous other benefits. Called the lungs of the sea, they release oxygen into the water, while also stabilizing sediments, cycling nutrients and reducing coastal erosion. A range of commercially and recreationally fished species such as cod, snapper, pink shrimp, conch, spotted seatrout and pollock are found in seagrass beds during part of their lifecycle. In fact, these areas support commercial fisheries worth over $4,800 per hectare per year. Finally, charismatic species like sea turtles, manatees, dolphins, stingrays and wading birds feed in seagrass beds. 

What’s threatening seagrass?

Unfortunately, seagrasses are declining rapidly, and about 30 percent of their global presence has been lost since the late 1800s. Densely populated areas often surround seagrasses, which stresses them. Regions most at risk for seagrass loss include Europe, Japan, the western North Atlantic, the northeast Pacific and several locations in Southeast Asia.

A long list of threats is driving seagrass decline including coastal development, dredging, disease and invasive species. In addition, poor water quality, which limits the light available for photosynthesis, is a major threat. Destructive fishing practices such as anchor damage and trawling can also harm seagrass beds. Finally, climate change — including warming waters and ocean acidification — is taking a toll on seagrass meadows.

What’s the solution for saving seagrass? 

The COP27 talks illustrated pioneering work in preserving seagrass. For example, in Madagascar, Blue Ventures supports local fisheries to protect blue carbon ecosystems. The social enterprise helped to establish locally-managed marine areas, where local anglers conduct seagrass mapping and monitor ecological conditions. These community conservation initiatives benefit communities by providing substantial increases in fisheries' yields and income.

Another example comes from Turkey. Along its coastline, the Mediterranean Conservation Society and Flora and Fauna International have developed no-fishing zones, along with a system of community rangers to patrol these areas. These zones protect seagrass meadows from damage and help fish populations recover, while also supporting local communities and anglers by boosting fish yields. 

Blue carbon markets

One way to protect this unique ecosystem is through carbon credits. However, blue carbon credit programs are new, while the ones for seagrasses are in their infancy. The first seagrass project to apply for carbon credit certification did so in 2021. Yet while the market for blue carbon is small, it’s growing exponentially. The overall carbon credit market is estimated to be worth $50 billion by 2030, and project planners hope to claim a slice of that for blue carbon.

While it may be too soon for seagrass carbon credits, some businesses are already offsetting their emissions through other blue carbon credit investments. These credits need to be quantified accurately, independently verified and monitored. Additionally, these programs should be permanent, ensure that the mitigation activity wouldn't have taken place without the carbon credits, and involve locally compensated communities.

Carbon credits are a great investment, but they should be viewed as part of a larger strategy to fight against climate change. Businesses should work to reduce and avoid emissions along with mitigation. Along with carbon credits, embracing more environmentally friendly and sustainable practices will go a long way in protecting our valuable tidal and marine ecosystems — and generate sustainable development opportunities as well.

Image credit: Benjamin L. Jones via Unsplash