Space Intelligence scientist use satellites to map world ‘s largest peat deposit, in central Africa

Space intelligence scientist Dr Edward Mitchard led satellite data analyses to reveal the most extensive peat deposit in the tropics, in central Africa. Dr Mitchard worked with a team of scientists from the Universities of Leeds, University College London, St Andrews, Leicester and Université Marien Ngouabi, Brazzaville; to estimate an area of peat of 145,500km2, and up to 5.6 m in depth. This is over five times the extent that was previously thought possible for the area of peat in the Congo basin.

Known as the Cuvette Central depression, the finding has important implications for the global climate. The team estimated that these peatlands store some 30.6 Peta grammes of carbon below ground – startlingly this is similar to the total above ground carbon stocks of tropical forests the entire Congo basin. For the moment, these peatlands are relatively undisturbed due to their remote location, and are also vital for supporting remaining megafauna – Africa’s last large animals including elephants and gorillas. However, as we have seen in South East Asia, especially the island of Sumatra in Indonesia, the pressure to access land for agricultural development projects and timber access can place enormous pressure on swamp forests. As this part of Africa develops, the integrity of these peat swamp forests needs now to be considered, particularly in terms of their carbon content.  This will require sustainable management and development, and will require the kinds of datasets that can be provided by the new generations of satellite sythetic aperature radar (SAR) satellites such as the Japanese Space Agency’s ALOS-2 PALSAR-2, and European Space Agency’s Sentinel-1 satellites.

Dr Mitchard said:

 “the swamps of Congo and DRC are among the most difficult landscapes in the world to explore. Having found peat in a few locations through field surveys, the only way to produce good maps of where peat is likely to be found across the basin was to use satellite data. Optical satellite data could tell us where the forest was, but was of little use for mapping the peatlands because it cannot see below the forest canopy. Therefore we used radar satellite data, as the pulses of microwave radiation can penetrate the canopy and give information on the soil surface beneath.”

The original article can be found here https://www.nature.com/articles/nature21048.