Mangroves can help countries reduce their carbon emissions

Geographers at the National University of Singapore (NUS) found that coastal vegetation, such as mangroves, seagrass beds and salt marshes, could be the best way to reduce carbon emissions.

The study, conducted by researchers from the Department of Geography, NUS Faculty of Arts and Social Sciences, indicates that countries with large coasts could expand these ecosystems to further reduce their fossil fuel emissions. These results were published in the journal of the Royal Society. Letters of biology October 24, 2018. With the recent agreement in Paris to all countries aim to become carbon neutral in the future, the use of these natural ecosystems could contribute to achieving this goal.

The impact of coastal vegetation

Coastal vegetation, known as the "blue carbon" ecosystem, can grow rapidly and can accumulate organic carbon in the saturated soil surrounding it. Therefore, a blue carbonaceous vegetation such as mangroves is able to store carbon more efficiently, in a way that other ecosystems such as tropical rainforests can not.

On a global scale, the impact of blue carbon is reduced due to the small size of these coastal regions. In fact, only 0.42% of global human-induced carbon emissions in 2014 have been mitigated by these ecosystems. However, in countries with extensive coastlines, moderate carbon emissions and limited deforestation, these habitats could be effective in controlling some fossil fuel emissions caused by human activities.

Blue carbon change between countries

The study found that for Nigeria, Colombia and Bangladesh, among the top 50 fossil fuel producing countries in the world, mangroves alone have mitigated more than 1% of their national carbon emissions.

"In 2014, Colombia occupied an area of ​​mangroves of about 1,700 km2 and generated 23 million tonnes of carbon emissions each year.Our study suggests that mangroves would mitigate nearly 260,000 tonnes of these emissions. If the national carbon emissions were reduced and restored, this percentage would become even larger, "said Dr. Pierre Taillardat, the first author of the study who conducted the research at the Department of Geography of NUS and in collaboration with the NUS Tropical Marine Science Institute.

"We thought this approach would be interesting for countries like Indonesia and Malaysia, because of their vast mangrove-occupied coastlines, but the high rate of deforestation of mangroves in both countries actually reduces the number of mangroves." 39 importance of this process of natural carbon sequestration "Taillardat continued.

As such, mangroves have been considered a source of carbon in the atmosphere in Malaysia, because when converted to other land uses, it will remobilize stored carbon in the long run and produce carbon emissions. . Similarly, in Indonesia, mangrove forests have reduced only 0.4% of national carbon emissions in 2014, as deforestation of mangroves has offset much of the carbon consumed by this ecosystem.

However, Assistant Professor Massimo Lupascu of the Geography Department of NUS, and one of the co-authors of the study, says that if deforestation of mangroves was stopped, they could potentially limit about 1.6% of natural carbon emissions from Malaysia. In Indonesia, the impact would be even greater, as it would reduce about 2.6% of the carbon emissions of human origin.

Restore mangroves to limit environmental impacts

The results suggest that conserving and restoring blue carbon ecosystems is a direct means of mitigating the effects of climate change, in addition to all the other benefits these ecosystems provide to people. The revelation that mangroves and other blue carbon ecosystems are such efficient carbon collectors has prompted scientists to conduct the study to claim their protection.

"Restoring the mangrove should not be difficult, if done correctly, it only takes a few years to start growing a forest of new trees." By creating conditions similar to those found in a natural forest, for example, tidal floods, it is possible to expand mangrove habitats and absorb more carbon, "said Associate Professor Daniel Friess of the NUS Geography Department, who is another co-author of the study .

Ultimately, this research could influence how countries respect the purpose of the Paris Agreement, which states that countries must eliminate as much carbon as they emit by 2100. Researchers believe that Expansion of blue carbon ecosystems could make this goal more achievable.

Mr. Taillardat said: "Given the strong competition between land uses and the time needed for economies to become independent of fossil fuels, the conservation and expansion of ecosystems with high carbon sequestration potential are an inexpensive option that can contribute to this commitment of the Paris Agreement. "

Explore further:
Blue carbon mapping in mangroves around the world

More information:
Pierre Taillardat et al. Blue carbon mangrove strategies for mitigating climate change are the most effective nationally, Letters of biology (2018). DOI: 10.1098 / rsbl.2018.0251