Large amounts of carbon are stored in soils. However, depending on the soil type, climate and management, a soil can either function as a CO2 sink or as a CO2 source. Soils that function as a CO2 sink make an important contribution to climate mitigation via carbon sequestration. In addition, the carbon content has a positive influence on the soil quality and this also contributes to climate adaptation. However, it is currently unknown whether all Flemish soils together produce net CO2, store CO2 or are CO2 neutral.