Congo Basin's Peatlands are More Than 42,000 Years Old, New Study Reveals
Jul 29, 2025
The central Congo Basin contains the world’s most extensive tropical peatland complex, spanning 16.7 million hectares. Until now, radiocarbon dating of ancient peats has been limited to 14 samples with poor coverage, and suggested that peat typically initiated during the Holocene. New research indicates that peat initiated in the central Congo Basin at multiple locations in the Late Pleistocene. The oldest date determined by the authors is 42,300 years before present, making this one of the world’s oldest extant tropical peatlands, and twice as old as previously believed.
The central Congo Basin straddles the equator, containing 360,000 km2 of wetland that is shared between the Republic of the Congo and the Democratic Republic of the Congo. Of this wetland area, an estimated 167,600 km2 is swamp forest underlain by peat deposits, with a median thickness of 1.7 m. These peatlands are some of the most carbon-dense ecosystems on Earth, storing an average of 1712 Mg C ha−1, with a total of 29 Pg C−1 stored in the peat.
However, research into the establishment and development of this large carbon stock, including the dynamics of peat initiation and expansion across the basin, is in its early stages. “These peat swamp forests are a globally important carbon store, holding the equivalent of three years of global fossil fuel emissions,” said University of Leeds researcher Greta Dargie. “We now know that they are among the most ancient tropical peatlands on the planet.” The study began with research teams trekking through remote and inaccessible Congolese peat swamps, using hand-operated equipment to collect samples of the peat from up to 6 m below the forest floor.
Back in the laboratory, tiny amounts of the peat were dated using radiocarbon, to determine when the peat began to form in each sampled location. Over a period of 10 years the researchers collected and dated more than 50 cores from across the central Congo Basin, from which they were able to build up a picture of the development of the peatlands through time. It is not just the great age of the peatlands which came as a surprise to the scientists. “One of the most unexpected findings which came from our new data is that some of the older peatlands in central Congo Basin began forming during periods of the past when we think that the regional climate was a lot drier than it is today,” said University of Marien Ngouabi’s Professor Ifo Suspense.
https://www.sci.news/biology/congo-peatlands-14101.html