Antarctica’s Hidden Carbon Sink: Inside the Science of Blue Carbon

What is blue carbon and why does it matter?

I’m sure we’ve all heard about the importance of forests in capturing and storing carbon in order to mitigate climate change, but have you heard of blue carbon? Blue carbon also refers to CO2 being captured, but within oceans and other bodies of water. Essentially the liquid version of what forests do for our planet.

The great appeal of blue carbon is essentially that it is more efficient at capturing carbon than its drier counterpart. The term tends to focus on tropical ecosystems: mangroves, salt marshes, and seagrasses. Doctor Narissa Bax focuses on Antarctic blue carbon, which is the same concept, in the colder climate of the Southern Ocean, a place that has taken on unexpected levels of carbon sequestration.

The Scientist Behind the Research

Dr. Narissa Bax is a polar marine ecologist, originally from New Zealand, who has worked much of her life in Tasmania and is now based in Greenland. Dr. Bax has led expeditions in some of the most remote marine environments on Earth, from the Southern Ocean to the sub-Antarctic, and her work has been recognized by the IPCC, COP27, and Australia’s 100 Climate Conversations. She is also one of the co-authors of an article published in Frontiers in Marine Science titled, “The Growing Potential of Antarctic Blue Carbon.” She is a leading researcher on Antarctic blue carbon and its cycles in the Southern Ocean.

Blue Carbon vs. Antarctic Blue Carbon

To review, blue carbon is carbon that is stored and sequestered by marine ecosystems. Since around 2009, it has become a much more central part of the climate change discussion due to its higher efficiency carbon capture and sequestration, often able to store the CO2 for hundreds of years.

Antarctic blue carbon is essentially the same concept, but in the Southern Ocean and with a longer duration of sequestration.

The key players in the Southern Ocean are the phytoplankton at the surface and the deep-sea corals and sponge fields on the seafloor. Imagine the Great Barrier Reef, but in a cold, dark, Antarctic context. There is quite a lot more animal life down there than you may imagine.

On top of that, with the melting ice in that area, we are seeing phytoplankton blooms on the surface, who are, as a result in direct contact with animals living on the seafloor, leading to faster growth and extended opportunities to feed. We are also seeing some increases in the capacity of those animals to grow and retain carbon in their skeletons.

The phytoplankton living in the surface column consume the carbon and sequester it. If their bodies are buried below the sediment, the oxygenated layer, it ends up being taken out of the carbon cycle for hundreds to thousands of years! This had been happening naturally in the Antarctic and is an incredibly impressive process in the battle against climate change. In response to rising temperatures, this ecosystem is becoming more adaptive and “consuming” more of the carbon that is being output.

Carbon Storage vs. Carbon Sequestration

In order to understand the political and business implications of these findings, it helps to have a clear distinction between carbon storage and carbon sequestration. Carbon storage refers only to capturing and holding carbon without specific definitions of how long it will be held for. Carbon sequestration is the process of removing carbon from the atmosphere and putting it somewhere else, for longer amounts of time, typically over 100 years.

This distinction matters not only factually but also in looking at ecological conservation and quantifying it in monetary terms within a larger business context. Under the Paris Agreement, for example, certain emission limits have been set that businesses need to abide by. If they do not meet the criteria, they are allowed to purchase carbon credits from projects that are removing or reducing CO2 from the atmosphere in order to offset the emissions that they themselves produce.

How Does Blue Carbon Fit Into the Conversation?

The discussion around carbon credits varies on the quality of the credit and the level of removal or sequestration, and is a great topic of debate and, as are many other environmental topics, very politicized.

“In the carbon credit system, only carbon that is permanently removed from the atmosphere for centuries or more is truly considered sequestration. When applied to the ocean, blue carbon projects such as restoring mangroves, seagrass meadows, or salt marshes are increasingly being used in the system. However, the deep sea, where carbon can be stored for thousands of years, operates differently from coastal blue carbon. And because carbon markets are political as much as they are scientific, who gets to claim credit for that sequestration, how it’s verified, and whether it’s really offsetting emissions long term are ongoing debates.”Dr. Narissa Bax, Polar Marine Ecologist (via Pine Forest Media)

Carbon markets are highly politicized spaces that are still developing in terms of regulation. With many large corporations vying for ways to make their image more green, blue carbon and Antarctic blue carbon serve as high topics of interest due to their long sequestration potential.

Protections and Governance in Antarctica

The Antarctic Treaty System is an international framework that governs Antarctic relations and dedicates the space to peace, science, and environmental protection; cutting it off from territorial claims, nuclear waste, and prohibiting military activity below 60 degrees south latitude. This space of land and sea is meant to be a preserve held for the benefit of humankind.

The treaties are very important in terms of environmental protection, but were made in a very different era of time. When they were created they mostly focused on fisheries practices and did not take into account the problems with global warming that we face today. Looking forward, scientists and many others in the environmental space are looking to center on modernizing future treaties and making them more applicable to today’s circumstances.

“So finding ways to make these treaties that are globally applicable and collaborative, and meaningful, is to also understand that biodiversity and climate change are linked.”Dr. Narissa Bax (via Pine Forest Media)

Scientists are looking to adapt what is already in place to be more focused on climate change and upholding Earth’s functions as much as possible.

So much of this area of the world still remains unexplored. There is a big need for continued long-term, collaborative, multi-disciplinary research to take place in order to push us towards a cleaner Earth.

Blue Carbon and Hope for the Future

Blue carbon is not a cure-all, but it is certainly something to be excited about in terms of climate change. (Proceed with cautious optimism.) Antarctic blue carbon is an entity that exists within a protected place, is a system that exists naturally, and is responding and adapting to climate change. This is a rare chance to preserve mostly unharmed, functioning ecosystems before they are degraded.

“…it is an example of working with something that holds a bit of hope because it’s based on protecting areas that are largely intact and biodiverse and functioning in their healthy natural state for the most part, as far as we know. I think it’s incredibly important to protect those areas for the future, obviously, but it’s also really beautiful for and hopeful as a scientist to be able to work in those locations and to hold on to that idea that you’re working on something that will translate into conservation and you’re not necessarily documenting the decline, you’re looking from a collaborative explorative perspective as well.”Dr. Narissa Bax (via Pine Forest Media)

Antarctica’s ecosystems are crucial in connection to global systems that fight climate change worldwide. They provide us with a model of hope to look towards the future with and a way to connect with an utterly critical part of our ecosystem that we know so little about. Antarctic blue carbon is a distant lighthouse of hope in a dark, stormy ocean of bad news.

You can find Dr. Narissa Bax on Instagram, Twitter, or on her website. More than anything, she encourages people to continue engaging in scientific conversations and learning as much as they can!

This article is courtesy of the Oceanography podcast from Pine Forest Media, the only independent podcast network in the world dedicated entirely to environmental science storytelling. Episodes are available wherever you listen to podcasts.

Follow Pine Forest Media on Instagram: @pineforestmedia

Written by: Madelyn Choi Weir

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About the Author

Madelyn Choi Weir is a New York-based freelance journalist, a producer with Pine Forest Media, and a public relations professional. Her work focuses on environmental storytelling and global travel. As an artist and polyglot, she seeks to amplify stories from around the world that have a story worth telling.