New study on peatlands in Angola highlights urgent need to protect key southern Africa freshwater source

• First of its kind high-resolution mapping suggests four times more peat in Angolan highlands than previously estimated

• Carbon-rich wetlands sustain rivers, economies, and wildlife across 7 countries

• More cost-effective to protect Africa’s carbon sinks now than restore them later

  

New research published today suggesting Angola’s central highlands hold at least four times more peat than previously thought underscores the urgent need to conserve one of southern Africa’s most important freshwater ecosystems from unsustainable development, drainage, and fire.

Published in Philosophical Transactions of the Royal Society B, the study identifies thousands more square kilometres of potential peatlands that store carbon, regulate river flows,nourish wildlife habitat including the Okavango Delta, and sustain millions of people’s daily needs and key economic sectors across seven African countries.

The findings give Angola its clearest picture yet of these ecosystems and a practical roadmap to support local communities to protect peat where they live, farm, fish, and forage. The research can help prioritise scant international conservation funding, and inform policy and planning over infrastructure, agriculture and other livelihood practices, and water use by Angola, its neighbours, and regional bodies like the five-country, 520,000-sq km Kavango Zambezi (KAZA) Transfrontier Conservation Area.

Angola’s highland plateau is the source of some of Africa’s mightiest rivers and their basins, including the Zambezi, Congo, the Cuanza, Kunene, and the Cuito and Cubango, which join to become the Okavango that spills into the Okavango Delta. Millions of people and billions of dollars of business in Angola, Botswana, the Democratic Republic of the Congo, Mozambique, Namibia, Zambia, and Zimbabwe rely on freshwater systems that rise in central Angola.

The newly mapped wetlands store groundwater during the rainy season and release it gradually, helping to maintain water flow throughout the year. This sustains rivers during dry seasons while also locking away carbon in permanently waterlogged soils. The new study mapped the whole 380,382 sq km Angolan Highlands Water Tower in higher resolution for the first time, estimating that between 8,600 sq km and 11,100 sq km may hold peat.

This is four to five times more than estimates drawn from earlier data that was not specific to Angola. Much of the newly identified peat lies in valley bottoms and along rivers where farming is most intense, or close to areas intended for large-scale infrastructure projects including new hydropower plants, expanding commercial agriculture, and the Lobito Corridor linking inland mines to Atlantic ports. Once drained or repeatedly burned, peat loses its ability to regulate water and could begin releasing thousands of years of stored carbon into the atmosphere. Once released, this carbon is not easily replenished.

The findings show why accounting for these key ecosystems should become integral to development and climate mitigation planning rather than being purely an issue of environmental conservation, said Sekgowa Motsumi, KAZA Landscape Director for The Nature Conservancy (TNC) and a co-author of the study.

He said: “Protecting these wetlands is not about stopping development; it’s about using science to help guide where agriculture, infrastructure, and other investments can best be located. The encouraging news is that most of these peatlands are still functioning naturally for now. That allows Angola, many countries no longer have: to protect these ecosystems before they become degraded, when it’s much more costly to act. Angola should not carry this burden alone. These peatlands provide ecosystem services far beyond Angola’s borders – there is no Okavango Delta or KAZA without Angola’s peat – so downstream countries and the wider international community also have a role in helping finance their protection.”

Peatlands cover only around three percent of the Earth’s land surface but store roughly one third of the world’s soil carbon while purifying water, regulating floods, and providing wildlife habitat. The Congo Basin contains the world’s largest known tropical peatland complex. The new study begins to plug gaps in what was known about the far-less studied Angolan deposits.

Angola’s peatlands function because of the relationship between the intact upland miombo forests, which help regulate the local climate and water cycle, and the Kalahari sand aquifers. The peatlands form along water drainage lines at the interface between the forests and these water-bearing sands. Protecting the peat therefore means protecting the wider system, including both the trees and the sediments beneath them. Together, these natural systems sustain the peatlands and safeguard carbon that has accumulated over thousands of years.

The findings underscore the approach taken by the Government of Angola and partners, including TNC, to protect the Angola Highlands Water Tower as a foundation for long-term water security, climate resilience, and sustainable development.

TNC is the technical lead supporting Angola’s National Source Water Protection Strategy and is advising on climate policy, including discussions to include peat carbon within Angola’s Nationally Determined Contributions. The organization is working with local communities in the highlands and downstream to identify ways to conserve freshwater while continuing to support people’s livelihoods and daily needs. Communities are helping map important freshwater habitats, establish locally managed freshwater reserves, and develop their own plans for managing them.

TNC is also exploring how changing the timing of fires traditionally used in these landscapes for livelihood activities could reduce greenhouse gas emissions. Until now, much of this region had remained effectively invisible to scientists because previous global maps lacked the resolution needed to detect the narrow, groundwater-fed peatlands that follow many of the region’s river valleys.

Researchers designed computer models that analysed satellite imagery to identify landscape characteristics most closely associated with peat, including vegetation that remains green through the dry season, persistently wet soils, and flat, groundwater-fed valley bottoms and floodplains.

They combined this with ground samples from 51 peat deposits collected during five expeditions between 2019 and 2023, in a landscape where old landmines still restrict access decades after Angola’s civil war. Specialists from the demining nonprofit The Halo Trust were needed to help researchers reach key study sites safely.

The ultimate output was the first map with a resolution of 10m of the whole 380,382 sq km Angolan Highlands Water Tower. The researchers estimate that at least 8,662 sq km almost certainly contains peat in small pockets across the study area, while the total could be as much as 11,167 sq km in areas where the evidence is less certain.

Mauro Lourenco, lead author of the paper and geospatial ecologist at the Wild Bird Trust and National Geographic Okavango Wilderness Project, said:

“To protect, manage, and restore peatland ecosystems, we must know where they exist and map them. Peatlands could shift from carbon sinks to carbon sources if they are not managed carefully. This mapping effort shows communities, governments, and other conservation leaders where action can be taken to safeguard them.”

The researchers emphasise that the new map identifies where peatlands are most likely to occur, rather than providing a definitive inventory. Further fieldwork will now be needed to verify peat depth, measure carbon stocks, and better understand the condition of these ecosystems.

The full study, “A probabilistic map of tropical peatlands in the Angolan Highlands Water Tower,” is published in Philosophical Transactions of the Royal Society B. The research was facilitated by The Nature Conservancy, with funding support provided by the Bezos Foundation and Grantham Foundation, and by Okavango Eternal, a partnership between National Geographic and De Beers, through the Wild Bird Trust. Ideas expressed do not necessarily reflect the views of any funder.

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