Revealed the real size of the largest tropical peat bog

A new study has mapped the full scale of a vast peatland region in the heart of the Congo Basin, revealing it to be 15% larger than previously thought.

An international partnership of scientists from the UK and the Congo has found that peatlands cover 16.7 million hectares, the equivalent of the size of England and Wales combined.

Led by the University of Leeds in the UK and the University of Kisangani in the Democratic Republic of the Congo (DRC), the researchers spent three years visiting scientifically unexplored swamp forests in the DRC.

For the first time, researchers have shown extensive peatlands in the Democratic Republic of the Congo, with peat up to six and a half meters deep. His findings, published today in geoscience of natureshow that peatlands in the central Congo Basin store between 26 and 32 billion metric tons of carbon, roughly the equivalent of three years of global fossil fuel emissions.

The central Congo basin is home to 36% of the world’s tropical forests. peatbog and stores 28% of the world’s tropical peat carbon, according to the new study.

But the researchers show that only 8% of this peat carbon is within nationally protected areas, suggesting vulnerability to future changes in land use.

Bart Crezee, lead author of the paper and a postgraduate researcher at the Leeds School of Geography, says their “findings really highlight the importance of Congolese peatlands as a major global carbon pool.”

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

Mapping of peatlands

Central Congo peatlands were first mapped in a 2017 study also conducted by a team from the UK and Congo. The scientists then spent three years in the neighboring Republic of the Congo (RoC) and estimated that the peat bogs covered an area equivalent to the size of England.

However, two-thirds of this estimated peatland area was in the Democratic Republic of the Congo, where no fieldwork had been conducted, until now.

Mr. Crezee added that “the 2017 study gave us a great foundation for this next phase of research, but we needed to travel to remote peatlands in the Democratic Republic of the Congo to take peat samples and assess whether Central Africa really did host tropical peatland.” biggest in the world”. , and the peatland complex is even bigger than we thought in 2017.”

“After years of work, we have hundreds of field measurements of the depth of the peat across the region, which has allowed us to create the first maps of the depth of the peat, the amount of carbon they store, and an accurate map of the largest tropical peat bogs in the world”.

“We are providing essential information as the world needs to know where carbon is stored in order to protect it.”

The researchers worked with 24 villages in both the Democratic Republic of the Congo and the Republic of China, involving more than 100 field assistants and local guides. This collective effort allowed scientists to make 463 peat depth measurements in the Congo Basin to estimate the amount of carbon found in central Congo peatlands.

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

The scientists found that many peatlands in the Democratic Republic of Congo are located in narrow river valleys along tributaries of the Congo River, in contrast to the wide expanses of peat found between rivers in the Republic of China.

Mr. Crezee says that “to our surprise, the peat in the narrow river valleys of the Democratic Republic of the Congo is at least as deep as in the broader basins of the Republic of the Congo. In the Democratic Republic of the Congo you will find a five-meter-deep peat layer. only four or five kilometers into the swamp. But in the Republic of Congo, you only find a five-meter-deep peat layer after walking more than 20 kilometers into the swamp.”

Protecting peatlands

Peat is partially decomposed plant matter. This wetland soil is most commonly found in cold environments, but year-round waterlogging in the bog prevents decomposition. This means that when trees, leaves and roots die, they do not rot completely and slowly form a layer of peat.

Peat acts as a carbon sink, removing carbon from the atmosphere through past plant growth.

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

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

Due to their remote location, the Congo Basin’s peatlands have so far remained wet because they are relatively calm. Peatland development could have a disastrous effect on managing global climate change.

Parts of the peat bogs have been set aside for oil explorationas well as planned industrial logging concessions and palm oil development, jeopardizing the future of the area.

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

Kisangani University Professor of Forest Conservation Botany Corneille Ewango says “Congolese peatlands are so rich. At one site we count over a hundred species of plants, some of which are almost certainly new to science. “.

“People living near the peatlands are using them quite sustainably, but threats are increasing due to oil extraction, logging and palm oil plantations. These developments put the Congolese peatlands at risk of emitting large amounts of carbon dioxide into the atmosphere, which would put global climate commitments out of reach. attain.”

Professor Ewango added that “in the future, plans are needed to increase the income of local people while improving their skills to protect the peatlands of central Congo, and I hope that our work will help ensure a better future for peatlands.” and your people”.

Professor Simon Lewis, from the Leeds School of Geography, is one of the paper’s lead authors. He says that “this research is a large collaborative effort involving scientists from universities in the DRC and the UK, and is a fantastic example of what can be achieved when we work as partners to tackle global problems.”

Although much of the attention is focused on Coal, we cannot forget that the Congolese peatlands are also home to many species of plants and animals, including bonobos, gorillas and forest elephants. Since this is a flooded landscape, oil spills in particular could contaminate large areas, affecting the health of local people and wildlife that depend on water from peatlands.”

“We are just beginning to understand peatlands and their rich biodiversity. We hope our findings highlight why it is more important than ever to put the scientific study and protection of peatlands high on the international agenda.”