Preserving Congo peatland vital for climate

The Cuvette Centrale peatlands are big. Really big. Covering an area of 145,500 square kilometers in the Congo Basin, they are bigger than the whole of England, and are the largest known tropical peatlands. But until a few years ago, nobody knew they existed.

"Our 2012 discovery of the Congo Basin peat gave us just enough insight to refine our searches," explains Greta Dargie, from University College London. "When we found the deepest peat deposits in the most remote areas of swamp we realized the importance of the Cuvette Centrale peatlands. The sheer expanse of these peatlands makes central Africa home to the world's most extensive peatland complex."

A British-Congolese research team, led by Dargie and Simon Lewis of the University of Leeds spent three years exploring and mapping the tropical swamp forests, combining soil analysis with satellite data. Their findings were published in the current issue of Nature.

"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," said Lewis.

What makes this discovery important to the rest of the world is the fact that peatlands are very efficient at storing carbon. In fact, peatlands only cover about 3 percent of the earth's surface but store one third of the soil carbon on the planet.

"These peatlands hold nearly 30 percent of the world's tropical peatland carbon, that's about 20 years of the fossil fuel emissions of the United States of America," Lewis explained.

That makes preserving the ecosystem vital not just to the region but to the planet as a whole. As long as the peat soils remain waterlogged, they act as carbon sinks because the water prevents organic decomposition. But if the peat dries up, the decomposition picks up again and CO2 is released into the atmosphere, contributing to climate change. 

"If the Congo Basin peatland complex was to be destroyed, this would release billions of tonnes of carbon dioxide," Lewis said.

This could happen if people drain the peatlands to use them as farmland. But ironically, climate change could threaten the wetlands as well since rising temperatures increase evaporation and rainfall patterns might change, potentially leaving the peat to dry out.

"The discovery of the Cuvette Centrale peatlands could have a large impact on the climate and conservation policies of the Congo," said study co-author Ifo Suspense, from the Université Marien Ngouabi in Brazzaville. "The maintenance and protection of this peatland complex, alongside protecting our forests, could be central Africa's great contribution to the global climate change problem."