Congo peatlands could emit billions of tonnes of carbon in drier climate

Scientists take a core sample in the Congo peatlands in the DRC. The Congo peatlands turned from a major store of carbon to a source of carbon dioxide emissions thousands of years ago due to a drying climate, according to a new study involving UCL researchers. , the study highlights the potential of the Congo peatlands - the largest tropical peatland in the world - to again release billions of tonnes of stored carbon into the atmosphere in a future warmer world. The study found that a drier climate in central Africa beginning 5,000 years ago led to peat decomposition - triggered by a drop in the water table, exposing the peatlands to the air - which released carbon dioxide into the atmosphere. The peatlands only returned to sequestering and storing carbon as the drying trend stopped and the climate got wetter in the past 2,000 years. The new study highlights that the peatlands are fragile and vulnerable to climatic changes. The researchers say that if they are found to lie close to a climatically driven drought threshold - or tipping point - a positive carbon cycle feedback in the Earth system could be triggered, whereby the peatlands add further carbon dioxide to the atmosphere and induce further, accelerated warming.