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Marine ecosystems and their role in mitigating climate change

Marine ecosystems, in addition of being reservoirs of biodiversity, store more than half of the planet's CO2, even on a larger scale than the large terrestrial forests.  

Since childhood, we have been taught that preserving forests is important, since trees incorporate CO2 and release O2, vital for life on planet Earth. Likewise, the preservation of forests is also often promoted since they are a large reservoir of CO2, which implies that they are key ecosystems to counteract the greenhouse effect and slow down climate change. However, did you know that the largest carbon pools are not our forests but our marine and coastal ecosystems? They store the so-called blue carbon. 

What is blue carbon?

We call blue carbon to the organic carbon that is captured and stored in oceans and in the marine-coastal ecosystems such as: mangroves, marshes and seagrass meadows. Approximately one third of the total atmospheric CO2 emissions are accumulated as blue carbon through different biological and physicochemical processes. Unlike carbon stored in terrestrial ecosystems such as forests, blue carbon tends to accumulate more and this occurs more efficiently and faster in soil sediments than in plant biomass.

Blue carbon in numbers

The climate change negative effects are considerably mitigated through the formation of carbon reservoirs in the ocean floors, even on a larger scale than in large land forests. 

Approximately 83% of the carbon cycle occurs through the oceans, and even though coastal ecosystems only cover 2% of the total area of the oceans, they store 50% of the carbon sequestered in marine sediments. Therefore, the current losses of 2% of these ecosystems per year are highly significant in the fight against climate change, since just as these ecosystems can function as sinks, they can also be sources of carbon emissions when destroyed. In this case, large amounts of blue carbon return to the surface and accumulate as a greenhouse gas.

How to promote the conservation of marine-coastal ecosystems and promote the storage of blue carbon?

Various governmental and scientific organizations have joined forces to protect marine-coastal ecosystems, encourage the creation of new marine protected areas, and mitigate climate change. These organizations include “The Blue Carbon Initiative” promoted by Conservation International, the Intergovernmental Oceanographic Commission of UNESCO and IUCN; and "Blue Solutions" promoted by IUCN, UNEP, GRID-Arendal and GIZ. 


We invite you to be part of these initiatives!


Written by: Michelle Castellanos

Style and format: Michelle Castellanos

Translated by: Antonieta Parilli

Provita Aug 12, 2020


IUCN Red List of Ecosystems


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