Assessment report on NRP subtheme “gGeenhouse Gases”: Sources and sinks of CO2CH4 and N2O, databases and socio-economic causes

Abstract The aim of the subtheme Greenhouse gases of the Dutch National Research programme on (NRP) is to quantify the sources and sinks of the major greenhouse gases to enable estimates of the future atmospheric concentration. The major part of the projects in this theme is focused on the Dutch situation, but the results can be extrapolated countries or regions. The information gained will be used for Dutch policy decisions regarding abatement of greenhouse gases. Section 1 deals with the aim and organization of Causes of climate change, and relates the scope to increased awareness of uncertainties in sources and sinks of greenhouse gases: at the start of the National Research Programme the general consensus of the scientific community was that these uncertainties were not extreme large, it is nowadays accepted that these uncertainties are larger than assumed before. The aim the Cluster CO 2 ( Section 2 ) was devoted to study the exchange between terrestrial ecosystems and the atmosphere to gain more knowledge of the “fertilization” flux. The research was mainly focused on the development of a CO 2 exchange model for grassland describing diurnal and seasonal fluxes, and on the validation of this local scale model on a regional and national scale. In both the clusters CH 4 and N 2 O (respectively Section 3 and Section 4 ) anthropogenic and biogenic sources were studied. Major criteria to study sources were the source strength, but also the uncertainty in the source estimate and the potential emission reduction, all projected on the Dutch situation. Exception were the projects on CH 4 emission from rice fields, and the sea/air exchange of N 2 O in oceans; expertise was available in The Netherlands to carry out these studies. As in the sub-theme CO 2 the study of processes in grasslands was given a high priority in the sub themes CH 4 and N 2 O in order to quantify emission the mentioned greenhouse gases. Moreover, in the CH 4 -sub theme projects were performed to evaluate and validate the strength of various sources. The two remaining clusters (limited in extend) were aimed at the development of emission databases and geographic quantification of soil processes controlling greenhouse gas fluxes (cluster Database Development, Section 5 ), and on national inventories (cluster Socio-economic Causes, Section 6 ). In the framework of the first cluster two databases were developed, one was the World Inventory of Soil Emission potentials (WISE), a global gridded database of the primary soil factors controlling soil greenhouse gas emissions, and the other was Emission Database for Global Atmospheric Research (EDGAR) aimed to describe the processes as land use, energy consumption etc, which control the emissions of greenhouse gases and other air pollutants. The goal of the other sub theme was to develop and apply methodologies to compile national inventories of greenhouse gas emissions in The Netherlands, focused on the compounds CH 4 and N 2 O.