The Coast is Clear for Blue Carbon

Emily Pidgeon is attending the United Nations Framework Convention on Climate Change in Cancun, Mexico. Read other posts about CI’s engagement at COP16.

As a marine scientist, I have spent most of my career thinking about the habitats that lie out of sight below the surface of the ocean. But in recent years, my attention has been turning increasingly upward, to the atmosphere above us. Working with some of the world’s most vulnerable communities has made me acutely aware of how, as levels of greenhouse gas emissions rise, climate change already is having a profound and devastating impact on the natural systems on which we all depend for survival.

Which is why I started thinking about the mitigation opportunities in the 70 percent of the world that lies between the continents we live on: the oceans. We know that oceans contain approximately 90 percent of carbon stores on Earth and play a huge role in climate regulation, but they also provide us with food, transportation and livelihood options that billions of people rely on to survive. So, as countries come together in Cancun to discuss climate change and measures to slow it, it seems only natural that oceans should be part of the solution. Frankly, it’s been a bit puzzling to me that they aren’t already.

Enter “blue carbon.” Over the last year, I have been studying the capacity of coastal marine ecosystems to sequester and store carbon from the atmosphere. It turns out that the mangroves, tidal salt marshes and seagrasses that blanket the ocean floor are phenomenally efficient at doing this — with sequestration rates of up to 50 times those of tropical forests. What’s more, these carbon stores are maintained for centuries at a time in the sediment below them. When we destroy these coastal systems, we not only lose their capacity to absorb carbon from the atmosphere, we release centuries or millennia of accumulated carbon — perhaps the natural equivalent of popping the top off a champagne bottle (except with no cause for celebration!)

As development speeds ahead, with little regard for sustainability or management of natural resources, these coastal systems are being lost at an alarming rate; up to 2 percent of coastal systems are being destroyed or degraded each year, approximately four times the estimates of tropical forest loss. So far, we’ve lost at least 29 percent of the world’s seagrasses and 35 percent of mangroves. More than 35,000 square kilometers (13,500 square miles) of mangroves — an area the size of Taiwan — is gone for good.

This ecosystem loss results in a double whammy to our planet: first, the rapid emission of carbon stores that in many cases have built up over centuries (combined with decreased sequestration in the future), and second, a critical loss of habitat that we need for protecting coastal communities, maintaining the world’s fisheries and providing other services to help us adapt to climate change. All that is to say that reversing the loss of coastal marine ecosystems is essential to addressing climate change — and not only that, it’s likely to be one of the few efficient, low-cost methods of turning the tide.

That’s why CI, in partnership with several other major organizations, has formed the Blue Carbon Initiative — to ramp up and centralize our understanding of the science, economics and required policies needed for countries to properly manage, value and account for the carbon sequestered in their coastal ecosystems, and provide guidance on mechanisms for doing so.

We made this exciting announcement during a well-attended presentation in Cancun this week, where delegates from every nation have gathered to try to design a climate agreement that can put our planet back on track with global climate solutions. As the science on blue carbon develops, we may find that an international framework that values these coastal ecosystems for the carbon services they provide may help us to conserve and restore them. But for now, we need countries to join us by starting to think blue in their green development plans, and by investing in coastal marine systems to support our climate.

Emily Pigeon, from Conservation International, talks about blue carbon

We look forward to telling you more about our efforts in the coming year.

Emily Pidgeon is the director of CI’s marine climate change program. Read more about CI and blue carbon (PDF – 554 KB).



    Yes I wholeheartedly support this motion.Use this vast resource to remedy some of the carbon in the hemisphere above us.Here in New Zealand it’s illegal to remove mangroves from the foreshore for development or reclamation.We also have a thriving algae and kelp harvesting industry.Say why eat seaweed products in our food diets,we can be healthy and make more food grow for generations to come.Fish breeding hasn’t really began and predatory species are on the decline.I love shrimps,crabs and shellfish.P roduction of these may give species like tuna and sharks time to recover.The oceans are really a gigantic food basket for fish and our species.

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  6. Drew Martin says

    I agree with the premise of storing co2 in coastal estuaries. Some have suggested that this creates methane gas another greenhouse gas. I would like to know if other greenhouse gases are included in this research.

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