World Oceans Day: Harnessing the Power of ‘Blue Carbon’ in Mitigating Climate Change – International Atomic Energy Agency
The IAEA joins hands with the leading experts from all over the world to study organically absorbed carbon, known as Blue Carbon, captured and stored especially by coastal ecosystems, such as seagrass meadows, mangrove forests and tidal marshes to understand the natural mechanisms of organic carbon sequestration and catalyse sustainable solutions to the problem of climate change and corresponding ocean degradation.
These ecosystems are very efficient in accumulating and storing large quantities of CO2 in both plants and the sediment below. They absorb and store carbon at a much faster rate than other ecosystems such as forests.
Despite being much smaller in area and body mass than that of terrestrial forest ecosystems, their global carbon sequestration potential is comparable. Seagrass meadows cover less than 0.2% of the ocean floor, but accumulate about 10% of the carbon buried in the oceans each year, mostly in underlying sediments. Mangrove soils have a tremendous capacity to accumulate and retain carbon stocks over millennia. Understanding the sequestration of organic carbon in these ecosystems will help clarifying how the ocean is coping with human-made CO2 emissions and what its absorption capacity is.
The ocean has already absorbed a quarter of global CO2 emitted into the atmosphere over the last century, but most of this CO2 has not made it to the coastal vegetated ecosystems that can absorb it. Mainly accumulated on the surface of the ocean, these greenhouse gases therefore make the water more acidic and hostile to fragile marine life such as coral reefs and shellfish. The increasing level of the surface water acidity, known as ocean acidification, has emphasized the need to better understand the ocean’s capacity to cope with CO2 emissions.
In-depth knowledge on carbon sequestration can help expand the natural carbon sinks in coastal ecosystems to absorb CO2 entering the ocean and thus reducing the surface water acidity and store CO2.
“Coastal Blue Carbon constitutes an important component of nature-based solutions that are providing to be essential to offset the negative impacts of climate change,” says Florence Descroix-Comanducci, Director of the IAEA Environment Laboratories. “However, when these ecosystems become damaged or disrupted by human activities, their capacity to sequester carbon can be compromised. As these ecosystems degrade, an enormous amount of carbon that has been accumulated for thousands of years can potentially be released as CO2 , further exacerbating climate change.”
Recognition of the important role of these unique ecosystems has been growing in the past decade, but there is still a need for more scientific research and data to aid policymaking, she added.