Exploring Blue Carbon

We must address the climate crisis, if we're going to address the ocean. The number one issue with the ocean is acidification and the number one issue with acidification is carbon. Number one, and first and foremost, we must all become netzero. Every company, every country, every organization, every individual must commit now to becoming net-zero.

Marc Benioff, Chair and Chief Executive Officer, Salesforce

What is Blue Carbon?

Blue Carbon refers to the carbon stored in coastal and marine ecosystems such as mangroves, seagrasses, salt marshes, kelp forests and even within the majestic whales. These ecosystems are not just beautiful and biodiverse but also play a crucial role in mitigating climate change by acting as carbon sinks. These coastal habitats capture and store vast amounts of carbon dioxide (CO2) from the atmosphere, helping to regulate our planet’s climate.

The term "blue" highlights the aquatic nature of this carbon storage, differentiating it from the "green carbon" stored in terrestrial forests. According to the NOAA National Ocean Service , these ecosystems are among the most efficient carbon sinks, capable of locking away carbon for centuries, sometimes even millennia. The importance of preserving and restoring these ecosystems cannot be overstated, as they offer a powerful tool in our fight against climate change.

The Significance of Coastal Ecosystems

Coastal ecosystems, including mangroves, seagrasses and salt marshes, are essential not only for carbon storage but also for the invaluable services they provide. These ecosystems support fisheries, protect coastlines from storms and erosion and maintain biodiversity.

Despite covering just 5.8% of the Earth's surface, these ecosystems can store five times as much carbon as tropical forests and absorb it three times more rapidly (Sources: United Nations , Project Drawdown and Cambridge University Press & Assessment ).

The Significance of Coastal Ecosystems However, these ecosystems are under threat. According to the U.S. NOAA National Ocean Service , wetland habitats around the world are disappearing at an alarming rate—three times faster than forests—due to development, pollution and climate change. When these ecosystems are degraded, they release significant amounts of carbon back into the atmosphere, contributing to global warming.

DID YOU KNOW?

Mangroves, salt marshes and seagrasses are found along the coastlines of every continent except Antarctica. Source: The Blue Carbon Initiative.

Mangroves: Guardians of the Coast

Mangrove forests are mostly found in warm areas with calm coastlines, shallow water and soft ground. They are excellent at storing carbon—it’s estimated that they store more than 6.23 gigatons of carbon (Source: 联合国粮农组织 ).

However, 30-50% of mangroves have been cleared globally in the last 50 years. The destruction of mangroves has dire consequences. Not only do we lose the carbon storage capacity of these forests, but their destruction also contributes to approximately 10% of global deforestation emissions, despite mangroves covering only 0.7% of the world’s tropical forest area (Source: The Blue Carbon Initiative).

Salt Marshes: Coastal Buffers and Carbon Storehouses

Salt marshes are coastal habitats, with muddy and peaty soils, flooded twice daily by tides. These tidalmarshes sequester significant amounts of carbon, particularly in warmer regions like Australia and the Gulf of Mexico; with most carbon stored in deep soils. However, salt marshes face threats from construction, coastal development and sea level rise, with a loss rate of 1-2% a year (Sources: The Blue Carbon Initiative, NOAA: National Oceanic & Atmospheric Administration and Phys.org ).

Seagrasses: The Underwater Carbon Warriors

Seagrass meadows are one of the most powerful tools in our arsenal against climate change. These marine flowering plants, found in shallow coastal waters, are exceptional at capturing and storing carbon. Although they cover less than 0.1% of the ocean floor, seagrass meadows account for up to 18% of oceanic carbon storage.

Despite their importance, seagrasses are declining at a rate of 7% annually due to pollution, dredging and climate change. This loss translates to the equivalent of a football field of seagrass being destroyed every 30 minutes (Source: UNEP-WCMC / The Blue Carbon Initiative).

Kelp Forests: The Rainforests of the Sea

Kelp forests, often referred to as the "rainforests of the sea," are vast underwater ecosystems that play a significant role in carbon sequestration. These towering brown algae can grow up to 150 feet tall and are incredibly efficient at absorbing carbon dioxide through photosynthesis (Source: BBC and Oceana ).

When kelp dies, some of it sinks to the ocean floor, effectively locking away the carbon it contains for centuries. However, kelp forests face severe threats from climate change, pollution and overfishing. In some areas, like California, kelp forests have declined by over 90% due to a combination of factors, including marine heatwaves and overgrazing by purple sea urchins (Source: Sierra Club ).

Coastal Ecosystems: From Sinks to Sources

When coastal ecosystems are degraded or drained, they can quickly become carbon sources. The exposure of blue carbon (coastal ecosystem) soils to oxygen accelerates microbial decomposition, releasing stored carbon back into the atmosphere as carbon dioxide.

Protecting these ecosystems is crucial to preserving their role as carbon sinks and mitigating climate change (Source: NOAA: National Oceanic & Atmospheric Administration ).

Efforts to protect and Restore Blue Carbon Ecosystems

Efforts are underway around the world to restore these critical coastal ecosystems.

• In Tampa Bay, Florida, significant efforts to reduce pollution have led to a remarkable recovery of seagrass meadows, with coverage now exceeding 41,000 acres (Sources: (Sources: Bay Soundings and Springer Link).
• In Australia, initiatives like " OzFish Unlimited " are working with local communities to replant seagrass meadows
• In the UK, a major seagrass restoration project is underway to restore 30 km2 of seagrass by 2030 (Source: Water Magazine ).

Whales: Giants of Carbon Storage

Whales play a surprisingly important role in our climate system. Throughout their lives, whales accumulate large amounts of carbon in their bodies. When they die, their bodies sink to the ocean floor, where the carbon is stored in deep-sea sediments for centuries.

Moreover, whales contribute to nutrient cycling in the ocean through the "whale pump” As they dive deep for food and return to the surface, they release nutrient-rich waste (whale poo) that stimulates the growth of phytoplankton. These tiny organisms are responsible for producing half of the oxygen we breathe and play a crucial role in carbon sequestration (Source: NOAA: National Oceanic & Atmospheric Administration ).

Whale Poo and Phytoplankton

DID YOU KNOW? Whales contribute to nutrient cycling in the ocean through a process known as the "whale pump." As they dive deep for food and return to the surface, they release plumes of nutrient-rich waste (whale poo).

Actions to Protect Blue Carbon Ecosystems

• Support Conservation Efforts: Consider donating to or volunteering with organisations dedicated to restoring blue carbon ecosystems, such as The Ocean Foundation , Project Seagrass or the Global Mangrove Alliance .
• Raise Awareness: Use your voice on social media to share the importance of these ecosystems.
• Tighter Environmental Governance: Contact your local and national government representatives to push for stronger environmental policies and regulations
• Make Climate Positive Choices: Switch your pension or bank to those that don’t support fossil fuels. Opt for a heat pump instead of a gas or oil boiler at your next upgrade. These choices help combat climate change and protect blue carbon ecosystems from global warming.
• Advocate for Stronger Marine Protections: Join campaigns that advocate for Marine Protected Areas (MPAs) to safeguard these vital ecosystems. Push for stronger environmental governance and better resourcing for protected areas.

Thanks for reading and have a great weekend!

The Green Fridays Team

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