GreenhousePeat: a model linking CO₂ emissions from subsiding peatlands to changing groundwater levels

• Main Authors: K. Koster, A. Frumau, J. Stafleu, J. Dijkstra, A. Hensen, I. Velzeboer, J. Esteves Martins, W. J. Zaadnoordijk
• Format: Article
• Language: English
• Published: Copernicus Publications 2020-04-01
• Series: Proceedings of the International Association of Hydrological Sciences
• Online Access: https://www.proc-iahs.net/382/609/2020/piahs-382-609-2020.pdf

<p>Oxidation of organic matter in peat above the phreatic groundwater table causes subsidence and carbon dioxide (<span class="inline-formula">CO₂</span>) emissions. Because 25&thinsp;% 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 <span class="inline-formula">CO₂</span> emissions under changes in groundwater levels. Furthermore, it is important to reduce greenhouse gas emissions in view of international agreements.</p> <p>We are developing GreenhousePeat: a nationwide model that synthesizes information on peat organic carbon content, land subsidence, and <span class="inline-formula">CO₂</span> emission monitoring to model present-day and future <span class="inline-formula">CO₂</span> emissions from subsiding peatlands.</p> <p>Here, we discuss the approach and input data of GreenhousePeat. GreenhousePeat is based on a UNFCCC approved model to predict <span class="inline-formula">CO₂</span> 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 <span class="inline-formula">CO₂</span> emissions measured at four different locations. We found that for one site the upper bound of the model reproduces the measured <span class="inline-formula">CO₂</span> emissions. The modelled emissions at two sites have a relative deviation of approximately 73&thinsp;% to 29&thinsp;% from the measured emissions. Whereas one site is a net <span class="inline-formula">CO₂</span> sink, although low emissions were modelled. Finally, we conclude on the suitability of the model for <span class="inline-formula">CO₂</span> emission forecasting and suggest improvements by incorporating groundwater level information and land use type.</p>