Advocating for the extraordinary benefits of blue carbon

The last decade has shown me that team effort and perseverance are powerful tools for creating change.

Not long ago, in December 2019, I was in Madrid for the 25th UN Climate Change Conference, to speak as part of a roundtable session. On the stage with me were five government ministers who wanted to include “blue carbon”—carbon dioxide absorbed by the world’s coastal ecosystems—in their climate commitments. Next to us, there was a panel of countries explaining how they were committed to achieving this goal. The room was packed, with conversations humming in every corner. It was a remarkable scene: a gathering of success stories and success stories in the making.

I had arrived with a small group of ocean scientists, who would later become close friends. We had a beautiful naïvety to us. We thought we would just turn up, share our strategy on blue carbon, and the world would start paying attention. Our panel was scheduled to take place in a massive auditorium that could hold hundreds of people. There were five of us on stage. It would be generous to say there were five people in the audience. And although no one was impolite, each of them pointed out in turn that such a harebrained idea was likely to go nowhere.

The important question

A specific chain of events and discoveries brought me to Cancún that year.

In the run-up to the 2010 climate negotiations, I had been finding my feet in a new role as Conservation International’s resident ocean scientist. With a Ph.D. in environmental engineering, I was the first non-marine biologist they had hired for their ocean work. I cared deeply about this opportunity. When you grow up next to the ocean, as I did in the Australian city of Perth, you feel a visceral connection to it. I hoped to make a difference by applying my scientific knowledge to real-life projects. My first two years at Conservation International were hectic and inspiring in equal measure. I was advising on technical matters relating to marine programs, and my work took me from country to country.

A few years later, just before going on maternity leave, I published a report on coastal wetlands—distinct ecosystems flooded by seawater, such as mangroves, salt marshes, and seagrasses. My theory was that in the context of addressing climate change, these wetlands could be just as important as forests on land, if not more. When I returned to work, I was surprised and pleased to find a handful of people had contacted me to say they were inspired by the report, and that we should develop it somehow.

Working with a small group of fellow conservationists, I scraped together enough funding for a meeting of a few international experts on coastal wetlands, where we would ask the important question: if we worked to preserve coastal wetlands, would they be a game changer? We put our heads together and immersed ourselves in every relevant piece of research we could lay our hands on. At the end of two days confined to the bowels of UNESCO Headquarters in Paris, we reached a conclusion.

A treasure trove of blue carbon

From sculptural mangrove trees hugging the coasts, to green carpets of seagrass in shallow waters, coastal wetlands are the unsung climate heroes. They are the only habitat on Earth that can continuously take carbon out of the air and ocean and lock it away—and keep doing so for millennia. We realized how important this was, because when these wetlands are degraded or destroyed, the carbon they store is released as carbon dioxide into the atmosphere, contributing to the rising levels of greenhouse gases that are heating up our climate. Today, coastal wetlands are being lost at a tremendous rate, making them some of the most threatened ecosystems on Earth. From a climate change perspective, we knew we should be taking notice of them.

Mangroves are a critical example of this trend as since 1980, we have lost a staggering 35 percent of these trees. They are often cleared to make room for shrimp ponds, or their salty habitat is drained to create rich plots for agriculture. Increasingly, coastal development is also proving detrimental. Not only do ports often have a direct impact on surrounding mangroves when they are built, but the secondary effects can be the most devastating—ports attract tens of thousands of people who need materials to construct homes for themselves, and subsequently wood is frequently taken from mangrove trees.

This pattern of demolition goes against the extraordinary benefits that mangroves bring to our climate. Astonishingly, mangroves are up to 10 times more efficient at absorbing carbon than non-aquatic trees. A very thin ecosystem that gets wet every time the tide comes in, mangroves are like a skin wrapping around the edge of a continent.

They shelter populations from storm surges—waves of water caused by severe cyclones—and reduce the impact of flooding. They are also essential for the health of coastal fisheries, as many of the fish we picture in coral reefs or offshore actually live in the intricate network of mangrove roots for the first part of their life cycle. When we demolish these habitats, and the fish disappear, we threaten the immediate and long-term food security of coastal communities.

Presented with these ecological and pragmatic gifts, why do we not give mangroves the love they deserve? I often joke that I am now a mangrove hugger by profession. I get offended when people think of mangrove forests as just dark, damp, and muddy—as places no one wants to explore. The mud is exactly what makes mangroves so special, as it is where you will find a treasure trove of blue carbon. I endlessly enjoy my connection to the mud. You notice the smell, like sulfur. The unique colors and textures in different countries surprise you: gray-green clay in Brazil; pale sand in Mexico and northwestern Australia; black tar in western Indonesia and on the Pacific coast of Colombia. When you move through mangrove mud, you have to concentrate like a young child learning to walk. It sucks you in with every step, and all your senses are flooded.

The next step

When no one in Cancún was interested in how blue carbon had to be an essential part of addressing climate change, it was not a disappointment, but rather a call to action. For our little team, it was a crucial turning point. The experience told us that more work was needed, both in terms of the science and on the ground. Mangroves were not mainstream. The research did exist in scientific circles, but it was scattered across different locations, and the right questions had not yet been asked. Besides, when someone tells you why your goal is impossible, they are in fact explaining to you what the next step will be.

So the core group who first met in Paris started developing the science around mangroves, and coastal wetlands in general. We focused on solutions that would feed into both broad policy and small-scale management. Since then we have grown to be the Blue Carbon Scientific Working Group, and there are now 31 experts in blue carbon and climate change who are regularly part of our discussions, as well as dozens more we work with every year, based on every continent around the world. Each scientist has solved different pieces of the puzzle. Key elements of the process have been forging close ties with the Intergovernmental Panel on Climate Change producing guidelines so that nations can include coastal ecosystems in their emissions reduction targets.

As well as working toward scientific objectives, I have spent time partnering with the communities who live alongside, and within, mangrove forests. It is these communities who have educated me on the necessity of these trees for the millions of people who live along vulnerable coastlines. Acting as a buffer, mangroves provide a means of surviving the impacts of climate change. Today, our team at Conservation International works to understand how a healthy mangrove forest protects shorelines from tropical storms, and how communities can build solutions based on this knowledge. And when I think of climate events damaging livelihoods, nowhere comes to mind more strongly than the Philippines.

The need for innovation

It was November 2013 when Typhoon Haiyan, the first truly “super” typhoon, swept through the Philippines. Haiyan’s power was colossal, leaving behind a trail of destruction. The Visayas were badly damaged, with almost two million people made homeless. Six months after the cyclone hit, I went to visit Iloilo, a province in the Western Visayas region. Once almost entirely covered in lush mangroves, since the 1990s the trees on Iloilo’s coastline have been lost to timber and shrimp farms. Along with our executive director for Conservation International in the Philippines, Enrique Nuñez, or Ricky, I hoped to explore mangrove restoration as a way of buffering the island against future storms.

I remember one day in particular. We had traveled to a tiny village flattened by the typhoon, to speak with the people who lived there. Families’ wooden homes were built on the beach, as close as possible to the boats that were hauled up on the shore. It was unbearably hot. The sun was beating down on the dazzling water as we stood on the pristine white sand. Communication was an intricate dance. While Tagalog is the dominant language in the Philippines, most Visayan islands have their own language, so each time I asked a question, we would embark on several rounds of translation. First, Ricky would translate what I had said into Tagalog, before a native speaker passed it on in the local Visayan language, and then eventually the response would come back in the other direction.

I had a question for one of the men from the village: how high was the storm surge created by Typhoon Haiyan? Pointing to the top of a nearby coconut tree, perhaps six meters tall, he gave a reply that transcended language. Ricky and I just stared up at the tree. This image needed no translation. A wall of water had washed over this man’s village, and no amount of mangroves could have stopped it.

In that moment I felt a deep sense of humility, almost shame, from wanting to come to this place and presume we had the answers.

We realized that to stand a chance of protecting villages like those in Iloilo, we needed to become more innovative. Mangroves were essential for lessening the impact of storm surges, but they would never fully safeguard villages from the worst tropical cyclones. So we went in search of an adaptable solution. What we have designed is a combination of two well-established resources, nature and engineering—a “green-gray” approach. “Green” stands for the mangroves, while “gray” relates to more conventional structures like sea walls. We are also encouraging sustainable fisheries, building resilience in the community against climate events while restoring marine biodiversity. We are hopeful that together, the two concepts will bring more long-term security to affected areas in the Philippines. If it works, this green-gray approach will provide a model for other countries that are similarly vulnerable to storms. The beauty of this story extends outward. We will all benefit from any newly thriving mangroves, because by making a home for carbon, these mangroves are helping to change the course of climate change.

Hands in the mud

To have gone from a nearly empty room at the Cancún climate negotiations, to successful outcomes for blue carbon in Madrid and community-based cooperation all around the world, feels phenomenal. The blue carbon movement has truly begun to thread its way around the globe, and there are hundreds, if not thousands, of scientists, leaders, and individuals—across all parts of society—who have come to appreciate the treasures hidden in the salty stems of these unique ecosystems.

There is still a great deal of work to do. Together with my colleagues at Conservation International and in the Blue Carbon Scientific Working Group, we want to cultivate connections with coastal communities to help their mangroves flourish. We will continue to team up with visionary engineering companies to advance green-gray solutions, and with conservation partners and regional and national governments to ensure funding and forward-thinking policies, like incorporating blue carbon into nationally determined contributions for climate change mitigation. We will continue to work on an international level to increase public awareness of the value of coastal ecosystems. I think we do our best work when we integrate all of these pieces.

Whenever anyone asks me what they can do, I give them the same answer: look for a salt marsh near to you. Look for a bay of mangroves, a bed of seagrass, a fen, or a bog. And when you get there, dive your hand into the mud. What does it feel like? We need to demystify these profound areas where earth and water are combined, ones that so many people have never visited. The carbon stored deep inside the mud is offering us a chance: take care of it, and coastal wetlands will go a long way toward protecting our planet from climate change. I hope you will fall in love with mud just as I did. Trust me when I say it is worth it. Your hands will be sinking into carbon absorbed into these systems over thousands of years. History—and, in a way, the future of humanity—will be squelching between your fingers.