The role of blue carbon to achieve a green transition


Terrestrial forests are well known for their capacity to absorb our carbon dioxide emissions (CO2), however, the similar role that plays the Ocean has been overlooked. The Ocean covers two thirds of the planet’s surface and absorbs more than one fourth of our world CO2 emissions, representing up to 34 billion tons per year. Hence, the Ocean constitutes an incredible natural carbon sink. This is the result of two phenomenon. On one hand, there is a physico-chemical dissolution process of atmospheric CO2 when it interacts with seawater. And on the other hand, the presence of marine and coastal micro-organisms and ecosystems is decisive, when it comes to carbon dioxide absorption and storage.

From coastal areas to High Seas…. Several Ocean's ecosystems and organisms are very performant in absorbing atmospheric CO2

Mangroves, salt marshes, and seagrass meadows are marine and coastal ecosystems capable to capture and store atmospheric CO2 in the sediments through photosynthesis. They are therefore labelled as blue carbon ecosystems. Blue carbon ecosystems have a critical role to play against global warming, as they can absorb CO2 up to 4 times faster than tropical forests, and 10 times faster than temperate forests! In total, salt marshes and seagrass meadows store each year about 200 million tons of CO2, which is equivalent to the emissions generated by 150 million individual automobiles.

And when it comes to High Seas? Phytoplankton, also called vegetal plankton provide half of the Ocean sedimentary carbon. Composed of microscopic and unicellular algae, phytoplankton are able to capture carbon dioxide and to transform it into oxygen during photosynthesis. From littoral zones to High Seas, the Ocean is therefore key to the stability of our entire climate system.

Beyond their climate mitigation potential : blue carbon ecosystems produce vital services to human communities   

The benefits provided by blue carbon ecosystems are way beyond the absorbtion of atmospheric CO2, as they generate numerous ecosystemic services, which are essential to the well being of human societies. Indeed, mangroves, salt marshes and seagrass meadows provide good water quality, sustainable fishing areas, a healthy biodiversity and they also protect populations against coastal risks (e.g storms, coastal erosion phenomenon, flooding events). According to a recent study*, the ecosystemic services generated by mangroves for coastal populations all over the world, are estimated to be worth a total of 1.6 billion US dollars.  

However, blue carbon ecosystems are facing major threats today, due to anthropogenic pressures. It is time to act for their protection ! 

Climate change, unsustainable coastal projects, overexploitation of marine ressources, pollution... Multiple factors are responsible for the deterioration and destruction of blue carbon ecosystems at the global scale. What are the negative consequences? Firstly, mangroves, salt marshes and seagrass meadows cannot fulfill their crucial climate mitigation and adaptation role. And secondly, once destroyed, these ecosystems release the CO2 they had stored in the atmosphere, thus reinforcing global carbon dioxide emission.   

Protecting and restoring mangroves, salt marshes and seagrass meadows represents a major global stake, as 151 countries over the world count at least one of these three ecosystems. International climate and biodiversity events, such as the United Nations Biodiversity Conference’s COP 15 in October (Remote) and COP 26 in November in Glasgow (United Kingdom) are therefore a great opportunity to highlight the role of carbon blue ecosystems - and hence the role of the Ocean - in advancing sustainable and prosperous societies. Investing in oceanographic research, developing more Marine Protected Areas (MPA) and fighting against coastline artificialization represent necessary solutions to better understand and protect these inestimable ecosystems.  

Convinced that the biodiversity of our Ocean is both unique and fragile, Surfrider Foundation Europe has created various coastal protection projects, such as the Ocean Initiatives, or the Ocean Friendly Gardens Program. Surfrider Foundation Europe’s Coastal Defenders collective is also mobilized on the ground, in order to fight against the deterioration of our coasts.

 To learn more about Surfrider Foundation Europe’s missions, click here.

The Blue Carbon Initiative

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