Angola’s peatlands entice carbon and clear the area’s water – how we mapped this newly discovered panorama

Ask most individuals what they image when occupied with pure “carbon sinks” – ecosystems that soak up and retailer greenhouse gases – and so they’ll most likely describe a forest. Reforestation is a standard characteristic of local weather change plans.

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

They usually do greater than retailer carbon. They preserve biodiversity, purify water and scale back flooding and soil erosion. In addition they play an necessary position in agriculture – they’re good for planting certain crops, resembling 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 knowledge for the northern hemisphere in comparison with the southern hemisphere and the tropics. Prime quality peatland extent knowledge are solely out there for a small choice of nations and areas, together with Canada, Sweden and West Siberia.

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

That’s why, for my PhD, I set out to quantify and map lately found peatland deposits within the drastically understudied Angolan Highlands. This area is hydrologically and ecologically necessary. 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 certainly one of only a few massive inland delta programs that don’t drain into the ocean. As an alternative, 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, for the reason that mapped space spans simply 16% of the Angolan Highlands and 4% of Angola. For comparability, the most important 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 examine 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 gathering scientific knowledge 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 nations – 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 Undertaking was created due to considerations about threats to the Angolan area of the Okavango catchment, and the potential downstream penalties to the Okavango Delta.

Learn extra: Botswana’s Okavango Delta is created by a delicate balance, but for how much longer?

Throughout groundbreaking scientific explorations, the mission crew recognized in depth peatland deposits within the Angolan Highlands. These have 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 crew on the Lungu Bungu River expedition in Angola.

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 likelihood of attending to my examine website.

Then I used to be launched to Google Earth Engine, a strong cloud computing platform for Earth remark, science and evaluation, and found that I might gather an unbelievable quantity of geospatial knowledge about my examine website from dwelling.

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 keeping with their geophysical properties, together with vegetation cowl, topography, and the presence of standing water. I drew these classes of information for the Angola Highlands from Google Earth Engine. Then I labored via them iteratively over numerous Zoom calls with my supervisors.

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

Invaluable info

Angola, like many different African nations, is extremely susceptible to local weather change. Preserving these necessary peatland deposits will assist facilitate carbon seize. This can enable nature to cut back greenhouse fuel concentrations within the ambiance totally free.

Learn extra: How we discovered the world’s largest tropical peatland, deep in the jungles of Congo

The identification and mapping of those peatland deposits will even 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.