CReScenDo · Combining Remote Sensing Technologies for Peatland Detection and Characterization

Combining Remote Sensing Technologies for Peatland Detection and Characterization

Peatlands hide a treasure in their soils. It is the enormous amount of organic carbon that is stored belowground and preserved by the constant or cyclical presence of water. The source of carbon is the mixture of organic material that is produced by wetland plants and that is left in the wet soil as they die. The presence of water slows down the oxidation of dead and decaying plant material, leading, over time, to the accumulation of peat. This mechanism is so efficient that peatlands are among the most carbon-dense environments in the world, storing up to 70 kg of carbon per cubic meter. Peatlands continue to extract carbon dioxide from the atmosphere and to store it unless the water is removed and the soil is drained. Unfortunately this is an extremely common practice, mainly related to land reclamation for agricultural purposes. Once water is drained, aerobic microorganisms attack the organic matter in the soil and quickly decompose it, releasing carbon dioxide. Land reclamation is just part of the problem: the degradation of peatlands is currently accelerating due to the higher frequency of droughts caused by global warming and to natural and man-induced fire events. Unfortunately, the speed at which peat is degrading is alarming. It is estimated that the total emissions from degraded peatlands and peat fires correspond to about 2 billion tons of carbon dioxide equivalent per year, which is about 6% of total anthropogenic greenhouse gasses emissions. The conservation of peatlands is one of the main measures indicated by the Intergovernmental Panel on Climate Change (IPCC) to mitigate climate change. The European Commission has recently added the preservation of carbon-rich soils such as peatlands and wetlands among the environmental objectives of the future CAP (Common Agricultural Policy, 2019). This type of actions necessarily needs a precise assessment of the avoided potential emissions linked to conservation strategies and accurate methods to monitor peatland changes over time. Hence, a precise map of peatlands at the regional scale is urgently needed. However, the identification of the territories with the presence of peatlands is not sufficient for a proper quantification of the carbon stored in these systems. We need to determine how thick peatland soils are in order to quantify their volume and the amount of organic carbon they store. This was the main objective of CReScenDo: quantifying the extent and thickness of peat deposits, from the local to the regional scale, to accurately define their importance in the global carbon cycle. In the process, the project developed a radically new observational methodology making use of remote sensing and airborne geophysical sensors.

Data: CORDIS, © European Union