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One of Africa's most valuable carbon sinks is beneath our feet



Mauro Lourenco has successfully created the first-ever map of the peatlands in the Angolan Highlands. Africa's peat, he explains, is a massive, unrecognised, carbon sink, with the potential to store more carbon than forests.


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Peatland ecosystems create almost mystical environments. Spongy, water-logged peat shifts as one moves across the surface, threatening to swallow an individual moving through vegetation above the unstable ground.


Surplus water from the saturated peat forms small, meandering streams that flow towards larger accumulations of water.


Beyond their unique physical attributes, peatlands, as it turns out, also serve a vital ecological function.


They are filled with deep accumulations of slowly decomposing plants and other organic, which over time become known as the flammable, energy-dense material known as peat. The resulting peatlands are huge carbon sinks, absorbing more carbon than they release into the atmosphere, and have been crucial in slowing planetary warming.


The International Union for Conservation of Nature estimates that peatlands store more carbon than all the world's forests combined. Peatlands also conserve biodiversity, purify water and reduce flooding and soil erosion.


And Africa, it turns out, is home to many peatland areas, including the world's largest tropical peatland, identified beneath the Congo Basin forests, and spanning 145,000 km².


With so much carbon at stake, the danger arises when peatlands are burned or drained. Their peat is exposed to air and releases its carbon in the form of carbon dioxide - which heats the planet.


About 5% of global emissions are attributed to damaged peatlands, thus the underlying need to preserve them.


However, mapping and inventory gaps have stood in the way of preserving these areas, especially those in Africa.


Mauro Lourenco, a PHD student at the University of Witwatersrand in South Africa, set out to change that. He has developed the first map of peatlands in the Angolan Highlands, an ecologically rich area.


Working alongside his supervisors, Professor Jennifer Fitchett and Professor Stephan Woodborne, he utilised Google Earth Engine and remote sensing technology to estimate the extent of peatlands in the Angolan Highlands.


With similar skills in wetland monitoring and soil carbon quantification in his masters and undergraduate projects, Lourenco notes the project “aligns with my passion for conservation.”


Lourenco believes academic knowledge can be used to provide practical solutions to boost climate action and biodiversity conservation in Africa.


He spoke with bird story agency about his experience in the Angolan Highlands and the relevance of his study in climate action.


How did you get involved in this project?


I was initially invited by my two supervisors working on the Okavango Wildness project under the Wild Bird Trust and National Geographic. During their first expedition in 2015, they discovered peatland deposits and peat soils around some source lakes and some close to the Okavango Delta.


So I was offered the opportunity to be part of the larger quantification of these peats as part of my PhD.


I just completed the programme; all my revisions have been accepted. I haven't graduated yet, but I will receive my PhD from the University of Witwatersrand in Johannesburg, SA.


**Why is it important to save and educate people about the peatlands?**


In Angola, most farming areas have Kalahari sand. These are not mineral-rich, so people target the peatlands for agricultural practices.


Due to drainage issues, some farmers dry the peat before planting, while others burn surface vegetation for planting. These practices are currently at a subsistence level and should be maintained as such to prevent damage to the peatlands.


In Southeast Asia, peatlands have been converted into land and exposed to burning, releasing carbon into the atmosphere. We want to avoid that in African peatlands.


**How much peatlands did you map in your study?**


Our estimate of peatland covered is 1634 km square kilometres, 2.65% of a mapped area spanning approximately 61590 square kilometres. This represents just about 16% of the Angolan Highlands and 4% of Angola.


I limited my study area to only 16% because I limited myself to sites that the people I relied on had visited and looked into now that I didn't have early access to.


We, however, need to have the entire Highlands mapped so that peatland areas are known before we can move into the preservation phase.


**What needs to be done so that mapping is done on the remaining areas for total preservation?**


We will have to go into areas we haven't and extend our estimates by collecting more samples.


We also need to do more to quantify the amount of carbon stored or sequestered annually to do more accurate monitoring going forward. With these, we can then extrapolate the results to the whole area.


These details will be helpful to paint a larger and more compelling picture not only for Angola but for other regions such as east Zambia and the Congo. However, all these will need a lot more scientists and logistical support, but it is attainable.


**The trade-off between conservation and economic development is usually a problem. Other than farming, did you witness any scenarios that could potentially pose such conflicts in the future?**


There seemed to have been some small-scale artisanal mining attempts for diamonds, but the mines were abandoned. This could be because they did not get what they were looking for. This lack of whatever they were searching for was good for the lands because they would have exploited the peatlands exposing carbon.


However, the use of peatlands to boost the agricultural value of the local communities can be allowed. We noted that small-scale farming activities build the peatlands rather than destroy them.


**How will the research findings inform policy and decision-making on peatland conservation in Africa and beyond?**


We found some interesting results. Firstly although the peatland quantity is huge, as we reported, it can be greater. Policies should facilitate more mapping to discover the rest.


Also, we did study how peatlands respond to fire and drought. The study covered about 40 years of rainfall and at least 20 years of fire. We used historical satellite images to check whether the peatlands responded in a good or wrong way to the two.


It was essential to assess the two because water table drops and peats are exposed to the atmosphere when we have droughts. Fire, in much the same way, damages the peats themselves.


Results show that the ecosystem is highly buffered against both events. So there are natural mechanisms within peats that protects them against these extremes. Therefore, there shouldn't be many external efforts focusing on protecting peats in these scenarios.


**What do you see as the next steps that other researchers need to focus on?**


The accuracy of defining peatlands and peat ecosystems is the major gap. In Africa, there is a lack of good data and maps. This is for researchers to find out more and accurately map peatlands in the continent.


We can then ask more detailed questions, for instance, if they are actively growing, how much carbon they store if they are degraded, among others.


After all these, we can begin pushing for action around conservation.


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