University of York: Research reveals true size of world’s largest tropical peatland

A vast region of peatland in the heart of the Congo Basin is 15% bigger than previously thought, a new study mapping the full scale of the area has revealed.

The study, which involved Congolese and UK researchers including from the University of York, shows that the peatlands in the central Congo Basin store between 26 and 32 billion tonnes of carbon – roughly equivalent to three years’ worth of global fossil fuel emissions.

With only 8% of the peatland currently falling with nationally protected areas and one million hectares already scheduled to be auctioned for oil development by the DRC government next week, the researchers are calling for urgent action to protect the region.


Co-author of the study, Dr Aida Cuni-Sanchez, from the Department of Environment and Geography at the University of York, said: “Our study highlights not only that the Congolese peatlands are larger than previously thought, but also that only a small percentage of them lie within nationally protected areas.

“We have to engage with governments, logging companies, mining companies, conservation organisations and local communities, to determine how best we can find a balance between carbon storage and development goals. The plans to auction one million hectares of the peatland for oil development next week should definitely not proceed forward.”

For the study, researchers spent three years visiting scientifically unexplored swamp forests in the DRC. They discovered that the peatlands span 16.7 million hectares – equivalent to the size of England and Wales combined – with the peat up to six and a half metres deep.


Lead author of the study, Dr Bart Crezee, from the University of Leeds said: “Our findings really highlight the importance of the Congolese peatlands as a globally important store of carbon.

“As much carbon is stored in this relatively small area of peatland as is found in all the trees of the entire Congo Basin rainforest. The critical importance of keeping this carbon safely stored in tropical peatlands cannot be underestimated in the battle to tackle climate change.”

In order to map the peatlands, the researchers worked with 18 villages across both the DRC and RoC involving over 100 field assistants and local guides. This collective effort allowed the scientists to make 463 measurements of peat depth across the Congo Basin to estimate how much carbon is held in the Central Congo peatlands.

The researchers used satellite data to predict peat depth in areas where there were no measurements. Combining the peat depth estimates with peat carbon content from peat samples allowed them to calculate the total amount of carbon stored across the region.


Peat is partially-decomposed plant matter and acts as a carbon sink, removing carbon from the atmosphere though past plant growth.

If peatlands dry out, either through changes in land use such as drainage for agriculture or reduced rainfall, peat decomposition can accelerate, releasing the stored carbon into the atmosphere.

The central Congo peat swamp forests are currently one of the most carbon-dense ecosystems on earth, storing an average of 1,712 tonnes of carbon per hectare in peat.

Due to their remote location, the peatlands in the Congo Basin so far have been kept wet because they are relatively undisturbed. Development on the peatlands could have a disastrous effect on managing global climate change.

When the researchers overlaid the new peatland map with plans for changes in land use, they found that a quarter of the carbon stock is threatened by industrial logging, mining or palm oil development.


Professor of Botany of Forest Conservation at the University of Kisangani Corneille Ewango said: “The Congolese peatlands are so rich. At one site alone we counted more than one hundred plant species, some of which are almost certainly new to science.

“People living near the peatlands are using them fairly sustainably, but threats are growing from oil drilling, logging and palm oil plantations. These developments risk the Congolese peatlands emitting vast quantities of carbon dioxide into the atmosphere, which would put global climate commitments out of reach.

“Going forward, plans are needed to increase the incomes of local people while enhancing their abilities to protect the central Congo peatlands, and I hope our work will help secure a better future for the peatlands and its people.”