From Seafloor to Sustainability: How Blue Carbon Can Save Our Planet

By Vivek Saini 

Something with a significant impact on our daily lives, stored in the planet’s most extensive water system, might be expected to be widely known, right? Not necessarily. Have you ever heard of blue carbon? Oddly, it’s unfamiliar, but you might know more than you think.

Coastal ecosystems, like mangroves and seagrass meadows, play crucial roles for nearby communities, from supporting local diets and fishing industries to safeguarding homes from erosion and storms. However, their advantages extend beyond coastal areas, as healthy ecosystems can contribute significantly to addressing global challenges in climate, biodiversity, and development. Recognizing the importance of blue carbon ecosystems is not just about coastal resilience; it’s a crucial step towards a sustainable future for our planet.

What Is Blue Carbon?

“Blue carbon” denotes carbon captured from the atmosphere and stored in marine and coastal ecosystems, including seagrass meadows, mangroves, and tidal marshes. These ecosystems serve as potent carbon removal systems, storing up to five times more carbon per area than tropical forests and absorbing it from the atmosphere about three times as rapidly. Despite occupying only approximately 0.5% of the seafloor, blue carbon ecosystems might contribute over 50% of all carbon deposited in marine sediments.

These ecosystems excel at carbon removal and storage due to the rapid growth of their plant species, which efficiently absorb CO2 from the atmosphere. Thriving in oxygen-deprived or “anaerobic” soils, these plants impede the decomposition of organic matter, preventing the release of CO2 back into the atmosphere. This allows for long-term carbon sequestration, often spanning hundreds or thousands of years. Moreover, all blue carbon ecosystems feature plants specially adapted to the land-sea interface. These plants can endure fluctuations in salinity and temperature, and their extensive root systems provide resilience against tidal flows and storm surges.

With their distinctive characteristics, these varied and intricate ecosystems offer significant benefits to humanity and the environment despite occupying relatively small areas on the seafloor. Effectively sustainably managing them presents an immediate and feasible approach to addressing climate change, particularly when combined with other measures for climate mitigation.

Blue Carbon Ecosystems: How do they benefit people and the planet?

It’s not all about carbon. Just by existing, these ecosystems provide various “co-benefits” to people and nature, ranging from food, water and economic security to protection from climate change impacts.

1. Biodiversity conservation:

Blue carbon ecosystems function as crucial biodiversity hubs, providing a habitat for various marine and coastal species, including birds, fish, mammals, invertebrates, algae, and microbes. These species play a vital role not only in preserving ecosystem well-being but also in sustaining local diets and supporting fishing industries.

Furthermore, mangroves, seagrasses, and salt marshes act as a protective barrier, shielding adjacent coastal waters from land-based pollutants like nutrient-rich agricultural and wastewater runoff. These pollutants can trigger excessive algal growth and create low-oxygen marine “dead zones.” The dense vegetation within blue carbon ecosystems serves as a natural filter, impeding the coastal water flow and enabling plants and other organisms in these habitats to capture and absorb surplus nutrients.

2. Protecting coastlines:

Rising global temperatures intensify destructive coastal storms, exemplified by the twin Category 4 cyclones that devastated Vanuatu in March 2023. This led to widespread damage, flooding, and power outages, affecting 80% of the country’s population. Blue carbon ecosystems offer a nature-based solution for vulnerable communities and nations grappling with the escalating impacts of climate change.

In tropical regions worldwide, mangrove forests serve as crucial barriers against wave action and storm surges, absorbing storm energy to reduce damage from events like cyclones. The Philippines and other nations invest significantly in mangrove restoration to protect communities and infrastructure. Additionally, blue carbon ecosystems, including seagrasses, help mitigate coastal erosion by stabilizing loose soils and fortifying coastlines, offering vital resilience against the threats of land and habitat loss, as well as damage to homes and infrastructure.

3. Ensuring Food and Water security:

Blue carbon ecosystems play a dual role in enhancing local well-being by improving water quality and ensuring food security. They act as natural barriers against weather-related impacts like flooding and storm surges, preventing saltwater intrusion into freshwater resources, including crucial groundwater relied upon by local communities.

Additionally, healthy blue carbon ecosystems, such as mangroves and seagrass beds, serve as vital nursery grounds for a diverse range of marine and coastal life. These grounds are essential for specific fish and invertebrate species to mature, contributing to artisanal fisheries that play a crucial role in local economies and bolster food security in coastal areas. Notably, a recent study found that fish catch is significantly higher, up to 70%, in areas adjacent to mangroves compared to areas without them.

4. Sustainable Coastal Economy:

In addition to supporting local fishing, blue carbon ecosystems offer recreational and leisure opportunities that attract tourists, generating new jobs in the ecotourism industry and benefiting related sectors like food and hospitality. A case in point is the Florida Keys National Marine Sanctuary, where mangroves and seagrass dominate. A study revealed that tourism linked to the Sanctuary contributes a substantial $4.4 billion annually to Florida’s economy, showcasing the economic significance of these ecosystems in fostering local and regional prosperity.

Blue carbon ecosystems provide a natural solution to extract carbon from the atmosphere, enhance resilience against escalating climate change impacts, and safeguard essential biodiverse habitats. While there is a growing global interest and investment in recognizing blue carbon as a natural solution, these ecosystems are simultaneously facing rapid destruction. Without intervention, there’s a looming risk that they might vanish worldwide within a century.

What puts Blue Carbon Ecosystems in jeopardy

Despite their myriad benefits, coastal blue carbon ecosystems are among the most threatened on Earth, facing annual destruction ranging from 340,000 to 980,000 hectares. Disturbingly, up to 67% of mangroves, along with at least 35% and 29% of tidal marshes and seagrass meadows globally, have already been lost since the mid-twentieth century. If current trends persist, the next century could witness a further 30–40% decline in tidal marshes and seagrasses and the potential loss of nearly all unprotected mangroves. The decline is attributed to the “coastal squeeze” resulting from climate-driven impacts like sea level rise and extreme weather events, coupled with developing coastal areas.

Climate change has heightened the frequency and intensity of hurricanes and storms, impacting coastlines and limiting the space for these ecosystems to thrive. Urban development, commercial use (such as aquaculture and agriculture), and other human activities have further contributed to the degradation and loss of blue carbon ecosystems. Notably, these practices not only destroy these ecosystems but can also release stored carbon into the atmosphere.

The consequences are clear: if this trend persists, the world risks losing a vital ally in addressing climate and biodiversity crises, and coastal communities, particularly in small islands and developing nations, stand to lose a critical resource essential for their livelihoods, food and water security, and climate resilience.

Ensuring Equity and Effectiveness in Blue Carbon Solutions

Governments at various levels, along with project developers, need to take measures to guarantee that projects fulfill their pledged environmental impact and somewhat benefit all parties engaged. Solomon Njenga, climate scientist at the University of Nairobi Institute of Climate Change, Kenya told CFC that, “It is crucial to disentangle climate change action from the realm of partisan politics. The blue economy should not be a platform for “carrot and stick” tactics or the instrumentalization of climate funding for political gain. This sentiment resonates strongly in Kenya, where such practices undermine true environmental progress”.

He also emphasized that “Indigenous knowledge offers invaluable insights for developing blue carbon solutions that effectively address the specific vulnerabilities of coastal communities to climate change. Utilizing and valuing this local wisdom is critical for maximizing the positive impact of blue carbon initiatives on those most affected by environmental challenges.” 

Blue carbon projects are a multifaceted solution to address climate change and biodiversity crises while fostering sustainable development. Rooted in preserving coastal blue carbon ecosystems, these initiatives are crucial in carbon sequestration, climate resilience, and habitat protection. However, their effectiveness hinges on substantial investments. By directing resources into these projects and supporting the communities integral to their success, we not only combat climate change but also promote sustainable development. Recognizing the interconnectedness of environmental and societal well-being, investing in blue carbon becomes a strategic and holistic approach for a resilient and harmonious future.

References 

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17. Image 1: https://twitter.com/oceanpanel/status/1733381008895230009?t=_throe0Q-6s2wlUesE53sg&s=19
18. Image 2: https://www.thebluecarboninitiative.org/

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