Why Blue Carbon Ecosystems Are Disappearing

Coastal ecosystems like mangroves, seagrasses, and salt marshes do far more than paint a beautiful backdrop for a day by the sea. These blue carbon ecosystems capture and store enormous amounts of carbon, protect shorelines from storms, and support fisheries and tourism around the world. Yet despite the numerous benefits that blue carbon ecosystems bring to people, nature, and the economy, they are among the most threatened ecosystems. 

Our world’s blue carbon ecosystems are rapidly shrinking in size, as up to 2.4 million acres are destroyed each year. From resort construction to pollution and agriculture, the pressures on blue carbon ecosystems are mounting as coastal populations and tourism grow. Their decline not only threatens marine life but also puts communities, economies, and the climate itself at risk.

In this article, we’ll explore the leading causes of blue carbon loss, the consequences of this destruction, and what can be done to protect these natural climate defenders.

Coastal Development 

Mangroves, seagrass, and wetlands are often removed or drained to construct resorts, golf courses, ports, and other shoreline infrastructure. In the Caribbean, it is common for hotels to clear mangroves or seagrass to create “pristine” beaches and swimming areas for tourists. The irony is that these habitats are what keep the water clear, nurture marine biodiversity, and protect the very beaches visitors come to enjoy.

Venice, Italy, offers a clear example of how coastal development can degrade blue carbon ecosystems and lead to unintended consequences. Built on the marshy islands of the Venetian Lagoon, centuries of canal dredging, river diversions, and embankment construction have reduced its salt marshes to less than a quarter of their former size. Their loss has weakened the lagoon’s natural defenses, accelerating erosion and increasing Venice’s exposure to flooding.

Resource Extraction 

Mangroves are often cut down for their timber, as the wood is a cheap source of fuel and a durable building material used for homes and boats. This demand has led to widespread deforestation in some coastal regions.  In Kenya, for example, about 20% of the country’s mangroves were lost between 1985 and 2010, with rates reaching up to 70% in some peri-urban coastal areas due to overharvesting for charcoal, construction, and household energy. The Mikoko Pamoja project is helping to halt and reverse this loss by introducing clean energy stoves, establishing community woodlots, and restoring mangrove forests through planting efforts.

Beyond cutting down trees, the harvesting of species like shellfish that inhabit them can also severely damage blue carbon ecosystems. Digging for clams in seagrass meadows, for instance, can tear up the plants and their roots, reducing the meadow’s ability to stabilize sediment and store carbon. Mussel dredging has a similar effect, churning up sediment and clouding the water.

Climate Change Impacts

Blue carbon ecosystems help fight climate change by capturing carbon and protecting coastal communities from flooding and storm surges. Yet they are also vulnerable to the very impacts they guard against. Rising sea levels, stronger tropical storms, and warming ocean temperatures all pose serious threats.  

Salt marshes and mangroves can drown if sea levels rise too quickly. In the Maldives, rising seas outpaced the mangrove trees’ ability to grow and stay above water. This resulted in about 25% of islands with mangroves experiencing a major die-off in 2020 due to salt stress. 

Rushing temperatures also threaten blue carbon ecosystems. Marshlands can dry out during prolonged heat and drought. These changes can release the carbon stored in wetland soils, turning them from carbon sinks into carbon sources. It’s well known that heat stress causes coral bleaching, and some studies suggest that warmer waters may also be linked to seagrass leaf bleaching.

Hurricanes can uproot mangroves, erode shorelines, and bury seagrass meadows under displaced sediment. In 2019, Hurricane Dorian struck The Bahamas with winds reaching 185 miles per hour, accompanied by powerful storm surges and waves. The storm destroyed roughly three-quarters of the mangrove habitat on Grand Bahama.

Land Conversion for Food Production 

Coastal ecosystems are frequently cleared to make way for croplands, such as rice paddies and oil palm plantations, as well as aquaculture ponds. These low-lying areas provide reliable access to water for the flooding and drainage cycles needed in rice cultivation and shrimp farming. Their nutrient-rich soils also support high crop yields. 

In Indonesia, large areas of mangroves were historically converted into shrimp ponds known as tambak. This destroyed nearly 800,000 hectares of mangroves in just three decades. Many of these tambak are now abandoned or produce very little, illustrating how unsustainable expansion can lead to long-term loss. 

Destructive Fishing Practices

Fishing can also harm coastal habitats. One of the most damaging methods is bottom trawling. This involves dragging large, heavy nets across the seafloor to catch everything in their path. As they move, the nets uproot seagrass meadows and disturb sediments that settle back onto the plants. 

In Tunisia’s Gulf of Gabès, illegal bottom trawling is having a devastating impact on marine ecosystems and local livelihoods. The seagrass meadows here are the largest in the Mediterranean and serve as important nurseries for juvenile fish. As bottom trawlers destroy these habitats, fish stocks decline. This leaves the region’s 45,000 fishers—about three out of every four of them small-scale artisanal fishers—to face shrinking catches or turn to the same destructive practices to survive.

The time it takes for seagrass to recover varies widely. Fast-growing species can grow back within a year or two, while slow-growing ones, such as those found in the Mediterranean, may take nearly a century.

Boating and Trampling

Boat anchors, hulls, and propellers also pose a danger to delicate seagrass beds. As boats shift with wind and waves, their anchor chains drag across the seafloor. Propellers and hulls can cause similar harm when boats enter shallow areas. These actions can tear up seagrass, leaving behind bare patches, or stir up the sediment that blocks the sunlight seagrass needs to grow.

When this happens, the damage can be costly. Nearly a decade ago, a catamaran ferry ran aground in the Florida Keys, tearing up part of a protected seagrass meadow. The operators were fined more than $2 million to fund restoration. Today, efforts are underway to heal the scarred seabed by planting thousands of new seagrass shoots.

Coastal vegetation can also be damaged when people repeatedly walk over it. This often happens when swimmers, snorkelers, or divers wade through shallow areas. In salt marshes, trampling can kill grasses and other plants while compacting the soil beneath them. Building boardwalks or creating designated pathways helps protect these fragile habitats.

Water Pollution

Nutrient-rich runoff from agriculture, untreated sewage from coastal resorts, and discharges from boats all contribute to the formation of harmful algae blooms. These blooms can smother seagrass beds, as seen with the massive sargassum invasions in Mexico and the Caribbean. In recent years, thick mats of this floating seaweed have piled up along shorelines, releasing foul odors as they decompose and disrupting tourism and marine life.

In high-use swimming areas, chemicals from sunscreen can also accumulate in the water. These pollutants add further stress to seagrass and can hinder its growth and recovery.

Consequences of Ecosystem Loss

When blue carbon ecosystems are degraded or destroyed, their enormous carbon stores are released into the atmosphere. Studies show that these ecosystems are being lost twice as fast as terrestrial forests at a rate of 0.03 to 1% annually. This loss releases up to 1 billion metric tons of carbon dioxide each year. That’s the same amount of carbon that is emitted by driving 2.6 trillion miles, or 104 million laps around the Earth. 

The consequences aren’t only environmental but also economic. A study published in May 2025 warned that seagrass loss alone could lead to more than $200 billion in climate-related damages from the release of stored carbon. Communities that depend on tourism and fishing lose both income and food security as these habitats vanish and their biodiversity declines. The disappearance of vegetation leaves coastal destinations and communities unguarded against the powerful waves that strike their shores. 

If we continue on our current path of destruction, scientists warn that we could lose 30-40% of tidal marshes and seagrasses, as well as almost all of our mangroves, within the next 100 years.

How to Protect and Restore Blue Carbon Ecosystems

Safeguarding blue carbon ecosystems requires both local action and global awareness. Here’s how you can help keep these habitats healthy:

Protect marine habitats through responsible travel.  Download our Sustainable Marine & Coastal Tourism Tips for practical guidance on everything from low-impact boating to respectful snorkeling.

Purchase carbon offsets through our Climate Impact Portfolio to fund projects that protect blue and restore blue carbon ecosystems and fight climate change at its source.

Join our Member Community to access tools and resources that help your business engage in sustainable tourism, reduce your footprint, and contribute to global restoration efforts.