World’s largest tropical peatland found in Congo basin

Carbon-rich peatlands could store three years’ worth of world’s total fossil fuel emissions, say scientists

Georgia Brown

Scientists have discovered the world’s largest tropical peatland in the remote Congo swamps, estimated to store the equivalent of three year’s worth of the world’s total fossil fuel emissions.

Researchers mapped the Cuvette Centrale peatlands in the central Congo basin and found they cover 145,500 sq km – an area larger than England. The swamps could lock in 30bn tonnes of carbon that was previously not known to exist, making the region one of the most carbon-rich ecosystems on Earth.

The UK-Congolese research team, co-led by Prof Simon Lewis and Dr Greta Dargie, from the University of Leeds and University College London, first discovered the swamps five years ago. Their research, published in Nature on Wednesday, combined three year’s worth of peat analysis with satellite data to estimate that the Congo basin peatlands store the equivalent of nearly 30% of the world’s tropical peatland carbon.

The new study found that the central Congo peatlands cover 145,500 square kilometres – an area larger than England. Photograph: Simon Lewis/University of Leeds

Lewis said: “Our research shows that the peat in the central Congo basin covers a colossal amount of land. It is 16 times larger than the previous estimate and is the single largest peatland complex found anywhere in the tropics.

“We have also found 30bn tonnes of carbon that nobody knew existed. The peat covers only 4% of the whole Congo basin, but stores the same amount of carbon below ground as that stored above ground in the trees covering the other 96%.

“These peatlands hold nearly 30% of the world’s tropical peatland carbon, that’s about 20 years’ of the fossil fuel emissions of the United States of America.”

Peat is an organic wetland soil made from part-decomposed plant debris, more commonly found in cool environments, such as northern Russia, Europe and Canada. Healthy peatlands act as carbon sinks, removing carbon from the atmosphere through plant growth. Further decomposition of the peat is prevented by its waterlogged environment, locking up carbon. Year-round waterlogging is needed for peat to form in the tropics.

If peatlands dry out, either through changes in land use such as drainage for agriculture or reduced rainfall, further decomposition resumes, releasing carbon dioxide into the atmosphere…

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