- New research mapping out the Angolan Highlands Water Tower (AWHT), a stretch of elevated plateau spanning 380,382 km², finds that a significantly larger portion of the region hosts peatland than previously thought.
- The findings show that the AWHT, named thus because it receives and regulates vast amounts of rainwater, and because it feeds important freshwater systems across southern Africa, is also a critical carbon sink.
- The research can inform national carbon policies and conservation strategies for these peatlands which store thousands of years-old carbon, experts said.
- The biggest threats to the AHWT’s peatlands are human-made including slash and burn agriculture and the unsustainable use of peat — partially decomposed plant material that builds up in waterlogged soils — which result in the release of CO2.
The Southwestern African nation of Angola has much more peatland than previously thought, new research suggests. In a study published on August 20 in Philosophical Transactions of the Royal Society, researchers mapped out peatlands in the Angolan Highlands Water Tower (AHWT). This vast landscape stores and regulates freshwater in central Angola and feeds freshwater systems across southern Africa including the Okavango Basin.
The researchers estimate that overall peatlands cover between 2.28–2.94 % of the of the AHWT. They found 8,662 km² (3,344 square miles) of peatland cover with high certainty (81–100% probability) and 11,167 km² (4,311 square miles) with low certainty (51–100% probability).
Peatlands are areas of land where the surface layer consists of plant material that has partially decomposed. According to the study, they cover around three per cent of the world’s land surface but are estimated to store up to a third of the world’s soil carbon.
In October 2025, Angola designated an area of 53,000 km² (20,463 square miles) in the AHWT as the country’s first Ramsar Site or Wetland of International Importance. The site was selected due to its sponge effect which absorbs, retains, filters, and ultimately supplies freshwater into the rivers that carry water to wetlands far and wide.
A water tower is a highland area that produces a large amount of water, relative to its spatial scope.
One of them is the Okavango Delta in neighboring Botswana, a world heritage site and one of the world’s few inland delta systems that don’t drain into a sea or an ocean, but into the Kalahari Desert.
“[The Angolan Highlands Water Tower] is crucial for water security, development, and ecosystem services in Southern African countries,” lead author Mauro Lourenço, a geospatial ecologist and data analyst at the Wild Bird Trust, told Mongabay via email. “The groundwater-fed peatlands store carbon, regulate river flow and sustain water supplies far beyond Angola, yet remain remarkably understudied.”
He added that until now, decision makers were missing a thorough understanding of where the peatlands are. “Our map provides a timely baseline for protecting them before significant degradation takes place.”
Lourenço, who has been studying the Angolan Highlands Water Tower since 2020, said this research is closing previous research gaps. His earlier study covered an area of 61,590 km² (23,780 square miles) with estimated peatland covering 1,634 km² (631 square miles) of this area— the new study was done across the entire 380,382 km² (146,866 square miles) of the AHWT.
While the previous study mostly relied on remote geospatial data, this time the researchers went on five field expeditions to 51 locations they had identified as potential peatlands. They used imagery from the Sentinel-2 Earth observation satellite and combined it with improved satellite data, in order to locate the drainage lines and low-relief landscapes where peat forms.
The study was a collaborative effort between the Wild Bird Trust and its local non-profit Fundação Lisima, the National Geographic Okavango Wilderness Project and US-based non-governmental organization the Nature Conservancy (TNC). As the region was a conflict hotspot during the Angolan civil war, access to some areas was facilitated by the Halo Trust which maps and clears landmines in Angola.
One of the study’s co-authors, TNC’s Okavango Program Director Sekgowa Motsumi, told Mongabay in a video interview that TNC and its partners are working with the Angolan government to integrate peatlands and their value for carbon storage into the country’s climate agenda.
The peatlands identified in the study face growing anthropogenic stresses that require mitigation in order to prevent the area from becoming a source of carbon emissions, the authors noted.
The AHWT is known as the Lisima Lya Mwono locally, which translates as “The Source of Life” in the indigenous Luchaze language. The area is home to the Luchazi people, an ethnic group of Bantu extraction who hail from eastern Angola and are named after the Luchazi River. They later settled in Zambia and Namibia.
Motsumi said that most communities in the area rely on subsistence farming for their livelihoods, as well as hunting. However, agriculture has been identified as one of the biggest threats to the peat carbon sink. Practices like ditching and draining, which is used to dry out deeper layers of peat soil in order to plant crops, can release a lot of the carbon stored in the peat.
Another threat is the unregulated use of fire for clearing which is the main source of carbon emissions from the peat, Shannon Flaugh, a conservation scientist at TNC, told Mongabay. Flaugh said that samples they took for the study showed that some of the carbon stored in these peatlands is 11,000 years old.
“Once that carbon is lost, we’re not going to sequester it again within our lifetimes,” she said, adding that they are working with communities to co-design solutions and peatland conservation strategies which include the improved management of fires.
More studies are underway to fully understand the relationship between fires and the conditions of the wetlands in the course of the seasons, Flaugh said.
But even though this study provides improved estimates for peat in AHWT, other questions remain. The authors said more measurements are needed to define the characteristics of the peat present in the area.
One of the reasons that Angola’s land features are poorly mapped is the presence of landmines in some region. The researchers also noted that the mapped peatlands are most probably a fraction of Angola’s total extent of peatlands, as other major floodplain systems including the Cameia, Luena, Cuando/Luanginga, Congo tributaries, have not been examined yet.
While the study establishes important data on peatland presence, more research is currently being done to verify the actual amount of carbon the AHWT stores in order to use it for climate action and Angola’s Nationally Determined Contribution (NDC).
Motsumi told Mongabay that he sees an opportunity for Angola to leverage the massive carbon storage potential of its peatlands. Integrating peat carbon storage into its NDC can distinguish Angola from other African countries who mostly focus on adaptation, he said. Currently, the Angolan highlands are not formally protected in national laws, and only about 11% of the country’s terrestrial areas are under protection – which is far from the goal set under the Kunming-Montreal Global Biodiversity Framework, which calls on countries to protect 30% of their land and seas by 2030.
Motsumi added that these peatlands are important for the largest terrestrial transboundary conservation area in the world, the Kavango-Zambezi Transfrontier Conservation Area, which is nourished by water from the Okavango and the Zambezi rivers.
Peatlands and other wetlands in the AHWT help regulate water flow by holding rainwater, which is gradually released feeding channels that feed rivers, providing a steady supply of water.
“Without the Angolan Highlands Water Tower and its peatlands, that water doesn’t drain into the landscape. And without water, there’s no biodiversity — the very biodiversity this region is known for globally,” Motsumi said.
Banner image: Aerial view of the Cuanavale river, which runs through the Angolan Highlands and joins the Cuito River. Image courtesy of Zach Vincent for National Geographic.
Citation:
Lourenco MC et al. 2026 A probabilistic map of tropical peatlands in the Angolan Highlands Water Tower. Phil. Trans. R. Soc. B 381: 20240481. https://doi.org/10.1098/rstb.2024.0481
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