GreenhousePeat: a model linking CO ₂ emissions from subsiding peatlands to changing groundwater levels

Oxidation of organic matter in peat above the phreatic groundwater table causes subsidence and carbon dioxide (inline-formulaCO₂) emissions. Because 25 % of the Netherlands has shallow peat layers in its subsurface, it is essential for Dutch policy makers and stakeholders to have reliable information on present day and near future inline-formulaCO₂ emissions under changes in groundwater levels. Furthermore, it is important to reduce greenhouse gas emissions in view of international agreements.

We are developing GreenhousePeat: a nationwide model that synthesizes information on peat organic carbon content, land subsidence, and inline-formulaCO₂ emission monitoring to model present-day and future inline-formulaCO₂ emissions from subsiding peatlands.

Here, we discuss the approach and input data of GreenhousePeat. GreenhousePeat is based on a UNFCCC approved model to predict inline-formulaCO₂ emissions, albeit based on new input data: 3-D organic matter maps, nationwide subsidence rates, and ranges in oxidation fraction. We validate model outcomes with previously documented inline-formulaCO₂ emissions measured at four different locations. We found that for one site the upper bound of the model reproduces the measured inline-formulaCO₂ emissions. The modelled emissions at two sites have a relative deviation of approximately 73 % to 29 % from the measured emissions. Whereas one site is a net inline-formulaCO₂ sink, although low emissions were modelled. Finally, we conclude on the suitability of the model for inline-formulaCO₂ emission forecasting and suggest improvements by incorporating groundwater level information and land use type.