Blue Carbon: The unexpected hero of the climate crisis?

An unexpected hero is in the waiting – our great oceans.

Trees have always been the champions of climate change – we learn from a young age that we need to plant more of them to keep absorbing carbon dioxide from the air. While true, there's another piece of the puzzle to consider when it comes to sequestering carbon from the atmosphere. 

Even scientists had no idea, until relatively recently, that in Mangrove forests, saltmarshes and seagrass meadows, carbon was slowly but surely being locked up for millennia, creating one of the world’s greatest carbon stores – Blue Carbon.

While we’ve been occupied with conserving the tropical rainforest (and don’t get us wrong, the rainforest is great and in need of protection), marine and coastal habitats have been quietly absorbing and storing carbon in vast quantities beyond our imaginations. 

So what’s so great about carbon in the sea?

To understand this, we need a quick recap on the carbon cycle - don’t worry, we’ll keep this short. Carbon dioxide is absorbed from the air by plants and turned into organic carbon – basically, the plant itself. When leaves or branches drop or that plant eventually dies, two things can happen: either bacteria and other microorganisms start munching on it, digest it and release it back to the atmosphere as carbon dioxide (just like we breathe out), or it gets buried in the soil. Here in the soil, there isn’t much oxygen, so there aren’t so many wee beasties to eat it up. This means that is stays as organic carbon, rather than being turned into CO2, for longer. Eventually – maybe after months, years or centuries, it will become CO2 when it is finally digested. This is where Blue Carbon is special. While terrestrial soil (that’s soil on land) is fairly dry, and so has tiny air pockets where bacteria can live, coastal and marine soils, sands and muds (or ‘sediments’) are soaked with seawater. Not very many bacteria can live here, for much the same reason as you or I can’t live underwater. This means that the organic carbon is converted into CO2 at a much, much slower rate – meaning that carbon can be stored here for thousands of years. That’s less climate-havoc-causing CO2 in the atmosphere over thousands of years.

Additional benefits of blue carbon & coastal ecosystems

It’s not all about carbon, either. Mangroves, seagrass and saltmarsh are all-round pretty special ecosystems. They protect the coast and coastal people from storms and erosion, acting as a natural sea wall. They provide fish and shellfish with a place to live, many of which are relied on by local fishing communities for sustenance and income. The wonderful coastal landscapes that they form and the biodiversity they support attract tourists and visitors, giving local people a source of income.  They clean water, cycle nutrients, provide a natural classroom for everyone from schoolchildren to researchers – we could go on and on!

It sounds like they’re doing a great job.

They are – or were, until we came along and spoiled it all. We’ve cut down mangroves to make way for marinas, smothered seagrass in pollutants, and generally destroyed vast areas of these wonderful coastal ecosystems. Those huge carbon stores so carefully cultivated by Mangrove forests, seagrass meadows and saltmarshes were suddenly exposed to light, air and sunlight – leading to large-scale breakdown of that organic carbon. Without the plants, there’s no hope of it returning. Oh dear...

Blue carbon ecosystems are in danger, so what can we do? 

We need to protect the remaining Blue Carbon ecosystems that we have, and start restoring the areas that we’ve degraded and destroyed. The global population is increasing, cities are growing and the majority of those cities are on the coast – meaning that coastal habitats are under more pressure than ever. On top of that, in developing countries, many people who cut mangroves are also dependent on them for their livelihoods, creating a downward spiral of overexploitation and poverty. We need to find a balance that works for both people and the natural environment, and that will be a huge challenge. Many coastal communities are dependent on the environment and its resources, and this needs to be turned into a reason for them to conserve, not over-exploit, these precious Blue Carbon ecosystems.

Carbon offsetting provides an opportunity to do just that. By funding projects that protect Blue Carbon ecosystems, we can help coastal communities to conserve their natural environment and resources. It gives communities a financial incentive to preserve, not exploit, Blue Carbon ecosystems, and in doing so, compensates for our carbon footprints by preserving and creating habitats that will continue to absorb CO2 for hundreds or thousands of years.

Image: From ACES - Mikoko Pamoja Project - Gazi Bay, Kenya

For this very reason we teamed up with ACES to offer Blue Carbon offsets on our site! If you want to learn more or purchase credits, check out our offset page!