There is growing evidence from scientific studies that many carbon (C)-rich formerly wet soils other than C-rich organic soils (C > 20 %) may have high CO2 emissions when drained. Their emissions are probably being underestimated in Switzerland’s greenhouse gas (GHG) reporting because they are classified as mineral soils. As a medium-term solution to this, we propose introducing additional soil categories for GHG reporting (C-rich mineral soils, C-poor organic soils, and organic soils or C-rich mineral soils covered with a mineral layer) and assigning these categories their own sets of emission factors. This is dependent on there being sufficient measurements in the scientific literature from which emission factors could be derived. Additionally, locating these soils in Switzerland requires substantial research. In the longer term, we recommend that GHG emissions of formerly wet soils are calculated as a function of C content and water level.
