Coastal ecosystems — including mangroves, seagrasses and tidal marshes — are some of the most valuable ecosystems on Earth, offering innumerable benefits to the climate, people and nature.
Coastal wetlands sequester and store vast amounts of what is known as “blue carbon.” In fact, in a single square mile, mangroves hold as much carbon as the annual emissions of 90,000 cars. However, when these ecosystems are degraded or destroyed large amounts of blue carbon are released into the atmosphere, accelerating climate change.
Mangrove forests and other blue carbon ecosystems protect hundreds of millions of people worldwide by providing natural buffers against sea-level rise, storm surges and erosion. They play a critical role in improving and maintaining water quality and provide habitats for fish, which are essential to the food security and incomes of millions.
Blue carbon ecosystems, encompassing mangroves, seagrass beds, and salt marshes, are indispensable in preserving biodiversity, offering vital habitats for a myriad of species, including fish such as snook and red drum, crustaceans like blue crabs, nesting grounds for sea turtles, and migratory stopovers for waterfowl like herons and egrets.
But blue carbon ecosystems are at risk:
How we protect blue carbon
For over 15 years, Conservation International has been at the forefront of researching, protecting and conserving blue carbon ecosystems. Together with our partners, we are developing the strategies and tools needed to protect and fully-value coastal ecosystems — and equipping governments to develop policies that protect blue carbon ecosystems and promote their potential for supporting climate change adaptation and resilience.
We believe partnerships — big and small, public and private — are essential to the growth and success of blue carbon as a climate mitigation and adaptation tool. Conservation International leads and engages with a robust, multi-disciplinary network of partners through the following initiatives:
The Blue Carbon Initiative — This initiative brings together governments, research institutions and non-governmental organizations from around the world to advance the management approaches, financial incentives and policy mechanisms needed to ensure the conservation, restoration and sustainable use of blue carbon ecosystems as tools for climate change mitigation and adaptation. Learn more.
The Global Mangrove Alliance — An initiative to halt loss, restore half of recent loss and double protection of mangroves globally by 2030. Since its launch in 2018, the Global Mangrove Alliance has worked to implement a comprehensive and coordinated approach to mangrove conservation and restoration at an unparalleled scale. Learn more.
The International Partnership for Blue Carbon — A 54-member strong network supporting countries in protecting their blue carbon ecosystems through learning and knowledge-sharing. The partnership provides a forum for governments, non-governmental organizations, intergovernmental organizations and research institutions to connect, share and collaborate to build solutions, take actions, and benefit from the experience and expertise of the global blue carbon community. Learn more.
The Blue Carbon Buyers Alliance and Blue Carbon Suppliers Alliance — These groups coordinate buyers and suppliers committed to funding or purchasing credits from high-quality blue carbon projects, and assist capital providers in understanding where their support would be most impactful. Learn more.
Knowledge and tool building
Conservation International and our partners are building a robust, scientific basis for effective blue carbon policy, financing and management. We work with global experts to develop and synthesize knowledge for standards and tools needed to realize on-the-ground impact.
- In partnership with the government of Singapore and others, Conservation International launched the International Blue Carbon Institute, which focuses on developing global blue carbon knowledge and building the capacity to scale blue carbon projects. The institute plays a vital role in effectively translating cutting-edge science into practical tools and methodologies that are harnessing the potential of blue carbon for climate action.
- Conservation International coordinates the International Blue Carbon Scientific Working Group, an expert group that is advancing essential science for blue carbon. In 2014, the working group developed the Blue Carbon Field Manual, which provides standardized recommendations for carbon measurements and analysis and is translated into Spanish and Mandarin. The working group also co-founded the Coastal Carbon Research Coordination Network to share knowledge on ecosystem processes and carbon cycling in coastal wetlands globally.
Creating innovative funding mechanisms
In close partnership with local communities and governments, Conservation International implements blue carbon projects and financing approaches that are tailored to achieve long-lasting benefits for climate, people and nature.
- At the 2022 United Nations Climate Change Conference, Conservation International and a global coalition of ocean leaders launched the High-Quality Blue Carbon Principles and Guidance. Informed by our experience in pioneering global high-quality blue carbon credits, this first-of-its-kind resource is designed to guide the development and purchasing of high-quality blue carbon projects and credits.
- In 2018, Conservation International and partners launched a blue carbon crediting project on Colombia’s Caribbean coast that fully measures and monetizes the carbon stored by a 11,000-hectare (27,000-acre) mangrove forest. The carbon stores were fully certified in 2021 using the Climate, Community & Biodiversity Standards developed by Verra. The vast majority of revenues — 92 percent — generated from the sale of blue carbon credits is invested in Cispatá Bay’s conservation management plan to protect the mangroves and support the sustainable livelihoods of the 12,000 people who live near the project site. Critically, Vida Manglar provided proof of concept to bring blue carbon markets to scale, with Colombia’s government seeking to replicate this project elsewhere and six other countries exploring similar projects.
Accelerating global policy action for blue carbon
Conservation International works at all levels of government to help create and strengthen policies needed for the effective, long-term conservation and restoration of coastal blue carbon ecosystems.
- Countries all around the world are committed to combating climate change and its impacts. Increasingly, the conservation and restoration of coastal blue carbon ecosystems is being recognized as a high-impact mechanism for countries to reach their
individual and collective climate mitigation and adaptation goals.
Approximately 151 countries contain at least one blue carbon ecosystem, and roughly one-third of all countries contain all three — mangroves, seagrasses and tidal marshes. However, less than half of these countries have integrated blue carbon ecosystems in their climate mitigation commitments under the Paris Climate Agreement, leaving significant untapped potential.
- The 195 signatories of the Paris Agreement are required to submit plans for reducing emissions through a mechanism called Nationally Determined Contributions (NDCs). As each country’s NDCs are updated every five years, it is crucial that governments are equipped with all the newest, science-backed information necessary to increase the ambition of their plans. Conservation International and our partners published Guidelines for Blue Carbon and Nationally Determined Contributions to advise countries on the ways coastal blue carbon ecosystems can contribute to achieving their national climate adaptation and mitigation goals. We have worked with the governments of Colombia, Costa Rica, Kenya, Liberia and Madagascar to include blue carbon commitments in their NDCs — and many other countries are following their example.
- Conservation International and the International Union for Conservation of Nature (IUCN) developed an International Policy Framework for Blue Carbon Ecosystems, which details how blue carbon ecosystem conservation and restoration can be accelerated and strengthened by aligning international polices across the United Nations Framework Convention on Climate Change (UNFCCC), the Sustainable Development Goals and other UN-level goals. The framework seeks to raise countries’ ambitions for protecting their blue carbon ecosystems, accelerate project implementation and align on how collective impacts are measured. We also work with our partners to maintain a Blue Carbon Policy Hub that contains framework updates and a library of policy guidance documents.
On the ground
Blogs about 'blue carbon'
New study reveals seaweed’s hidden climate benefits
Humble seaweed is having a moment. It’s been heralded as a sustainable superfood, a biodegradable replacement for plastic packaging and a feed supplement to cut cows’ methane emissions. Now, new research shows that seaweed forests — such as massive underwater towers of kelp — may play a bigger role in fighting climate change than previously thought.
A study by researchers at Conservation International and the University of Western Australia found that seaweeds absorb as much climate-warming carbon as the Amazon rainforest. But not all seaweed forests are created equal — some offer much better climate benefits than others.
To learn why, Conservation News sat down with the study’s lead author Albert Pessarrodona, a post-doctoral researcher at Conservation International.
Conservation News: What did your research find?
Albert Pessarrodona: For years, we’ve suspected that seaweed is an underappreciated ally in the fight against climate change. Our research set out to examine that potential. We looked closely at seaweed forests, like those made up of fast-growing kelp, and found that the conservation and restoration of those forests around the world could help keep roughly 36 million metric tons of carbon out of the atmosphere. That’s roughly the same amount of carbon captured by between 1.1 and 1.6 billion trees.
But not all seaweed forests play an equal part in sequestering carbon. Location makes a big difference. Seaweed forests in temperate and polar regions absorb more carbon than those in warmer, tropical waters. That’s because cool, nutrient-rich waters support the tallest forests, which are better at absorbing carbon.
Kelp forest off the coast of Northern California. © Keith A. Ellenbogen
Given the right conditions, could seaweed be a climate game-changer?
AP: It’s complicated. We know seaweed forests absorb large amounts of carbon, but to make a difference in terms of climate change that carbon needs to be kept out of the atmosphere for a long time.
Again, location matters. Like most plants, seaweed absorbs carbon as it grows. Then, when it dies, some of it can drop to the bottom of the ocean or be buried into layers of sediment. That’s where the carbon can be sequestered for up to hundreds of years. Seaweed forests growing near the deep ocean, such as in oceanic islands and canyons, or near fjords, where lots of sedimentation occurs, have greater potential for carbon sequestration.
Until now, it has been difficult to quantify the amount of carbon seaweed forests lock away because of the challenge of measuring carbon in hard-to-reach deep sea areas. To help, we created a framework as part of this study that categorizes coastlines based on their carbon sequestration potential — and identifies areas that are among the most critical for conservation. For example, Chile’s coastline, which has many fjords, cool water and prolific seaweed forests, is going to have greater carbon sequestration potential than a coastline in the tropics that doesn’t have the same conditions.
How can these findings be applied to marine conservation?
AP: Scientists studying “blue carbon” — meaning the carbon sequestered by oceanic and coastal ecosystems — have largely focused on tropical mangroves. They’re climate superstars, but far from the only marine ecosystem that stores large amounts of carbon. Our research shows that ecosystems in other parts of the world, which have typically taken a backseat in the blue carbon space, can also play a role in protecting the climate.
It’s encouraging to see evidence that kelp forests in areas like Australia’s Great Southern Reef or off the coasts of Norway, Chile and Japan — places we previously thought had limited opportunities to combat climate change — have the potential to sequester significant amounts of carbon. But we only get those benefits if we protect these underwater forests or restore the ones that have been lost. Seaweed forests are disappearing at alarming rates around the world because of pollution and ocean warming. For example, in Tasmania and Northern California kelp forests have declined by 95 percent.
We hope that this research will bring attention to the importance of seaweed forests — from storing carbon to increasing biodiversity to supporting fish habitats worldwide. There’s no silver bullet when it comes to curbing climate change — it’s an all-hands-on-deck effort that needs as many solutions as possible. Our research proves that protecting and restoring seaweed forests belongs in the world’s climate toolkit.
Kelp forest and coral reef off the coast of Northern California. © Keith A. Ellenbogen
Resources & publications
- High-Quality Blue Carbon Principles and Guidance (PDF)
- International Policy Framework for Blue Carbon Ecosystems
- Blue Carbon Policy Hub
- Guidelines for Blue Carbon and Nationally Determined Contributions
- Blue carbon pathways for climate mitigation: Known, emerging, and unlikely (ScienceDirect)
- Carbon sequestration and climate change mitigation using macroalgae: a state of knowledge review (Biological Reviews)
- The Ocean as a Solution to Climate Change: Updated Opportunities for Action (Ocean Panel)
- Blue Carbon Handbook — A guide to managing blue carbon ecosystems as a nature-based solution for supporting sustainable development. (Ocean Panel)