Angola’s peatlands trap carbon and clean the region’s water — how we mapped this newly found landscape

Prime quality peatland extent information are solely obtainable for a small number of international locations and areas

Ask most individuals what they image when enthusiastic about pure “carbon sinks” — ecosystems that soak up and retailer greenhouse gases — they usually’ll most likely describe a forest. Reforestation is a standard function of local weather change plans.

However there’s one other equally essential, usually ignored sort of pure carbon sink: Peatlands. These are a specific sort of wetland ecosystem by which darkish, loamy peat soil is produced. Peatlands retailer more carbon than all of the world’s forests mixed.

And so they do greater than retailer carbon. They preserve biodiversity, purify water and scale back flooding and soil erosion. Additionally they play an essential function in agriculture — they’re good for planting certain crops, equivalent to potatoes and carrots.

Regardless of this, even international scientific our bodies haven’t paid a lot consideration to peatlands till very recently. International maps and inventories of peatlands are inconsistent, although there’s extra information for the northern hemisphere in comparison with the southern hemisphere and the tropics.

Prime quality peatland extent information are solely obtainable for a small number of international locations and areas, together with Canada, Sweden and West Siberia.

This hole must be stuffed urgently: discovering, quantifying and defending new peatland deposits is important in an unsure local weather future that depends upon intact, pure carbon sinks.

That’s why, for my PhD, I set out to quantify and map just lately found peatland deposits within the drastically understudied Angolan Highlands. This area is hydrologically and ecologically essential.

One of many causes is that it’s the first supply of water flowing into the Okavango Delta, a UNESCO world heritage website, in north-west Botswana.

The Okavango is a flat, in depth and seasonally flooded alluvial fan that’s one among only a few massive inland delta methods that don’t drain into the ocean. As a substitute, it drains into the desert sands of the Kalahari Basin.

I labored alongside my PhD supervisors, Professor Jennifer Fitchett and Professor Stephan Woodborne, utilizing distant sensing to estimate that there are about 1,634 km² — that’s roughly 230,000 full-sized soccer fields — of peatland within the Angolan Highlands.

It’s a conservative determine, because the mapped space spans simply 16 per cent of the Angolan Highlands and 4 per cent of Angola. For comparability, the biggest tropical (and African) peatland deposit, which was additionally recently mapped within the Democratic Republic of the Congo within the Congo Basin, spans 145,000 km².

That is the primary estimate of peatland protection in Angola. And the research reveals doubtlessly extra tropical peatland deposits to find within the highlands area and surrounding river basins.

Distant mapping

In 2015 the National Geographic Okavango Wilderness Project was launched to create a community of newly protected areas to preserve the size of the Okavango Catchment.

It has been surveying and accumulating scientific information on the river system and dealing with native communities; NGOs; and the governments of Angola, Namibia and Botswana to safe everlasting, sustainable safety for the larger Okavango Watershed.

The Okavango Delta depends on precipitation occurring within the highlands of central Angola, the place water flows south into the Okavango River from two tributaries: the Cuito River and Cubango River.

The larger Okavango Catchment encompassing these three rivers covers roughly 112,000 km² and spans three international locations — Angola, Namibia and Botswana.

The supply waters originate from areas which skilled historic conflicts and wars and stay unprotected by laws.

The Nationwide Geographic Okavango Wilderness Mission was created due to considerations about threats to the Angolan area of the Okavango catchment and the potential downstream penalties to the Okavango Delta.

Throughout groundbreaking scientific explorations, the venture staff recognized in depth peatland deposits within the Angolan Highlands. These had been the primary identified scientific explorations of those rivers and supply lakes; new plant and animal species were discovered.

The peatland identification was additionally a primary. In June 2022, I used to be invited to be a member of the analysis staff on the Lungu Bungu River expedition in Angola.

The writer at work (after Covid lockdowns) extracting peat soil on the Lungu Bungu river transect. Picture: Jen Guyton

For my PhD, which I began in January 2020, I deliberate to conduct in depth fieldwork within the Angolan Highlands to quantify the newly found peatlands. However by April 2020, the world was largely locked down by the COVID pandemic. It seemed like I had no probability of attending to my research website.

Then I used to be launched to Google Earth Engine, a strong cloud computing platform for Earth statement, science and evaluation and found that I may gather an unbelievable quantity of geospatial information about my research website from residence.

Peatlands have distinctive traits that distinguish them from terra firma. Geospatial scientists use multisensory approaches. Optical, radar and LiDAR satellite tv for pc imagery are all employed to establish and distinguish peatland from different wetland options.

Peatlands have additionally been mapped in accordance with their geophysical properties, together with vegetation cowl, topography and the presence of standing water. I drew these classes of knowledge for the Angola Highlands from Google Earth Engine. Then I labored by them iteratively over quite a lot of Zoom calls with my supervisors.

All this information was overlaid and Google Earth Engine’s machine studying algorithms had been used to provide the primary classification map of peatlands within the Angolan Highlands.

Invaluable info

Angola, like many different African international locations, is extremely weak to local weather change. Preserving these essential peatland deposits will assist facilitate carbon seize. It will permit nature to scale back greenhouse gasoline concentrations within the environment without cost.

The identification and mapping of those peatland deposits may also assist to facilitate preservation of the Angolan Highlands area. The well being and ecological functioning of those peatlands has direct implications for native communities who depend on the peatlands for water purification, fishing, cultivation and gasoline.The Conversation

Mauro Lourenco, PhD pupil, University of the Witwatersrand

This text is republished from The Conversation below a Inventive Commons license. Learn the original article.


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