Comparison of CH4 emission inventory data and emission estimates from atmospheric transport models and concentration measurements

Abstract

Abstract CH4 emissions from two sources of emission inventory data i.e. the National Communications and the EDGAR/GEIA database, are compared with emission estimates from six global and two regional atmospheric transport models. The emission inventories were compiled using emission process parameters to establish emission factors and statistical data to derive activity data. The emission estimates were derived from an evaluation of atmospheric transport modelling results and measured concentrations of CH4. The comparison of emission inventories and the emissions derived from atmospheric transport models shows the largest differences on the global scale to occur in biogenic CH4 emissions, i.e. by wetlands and biomass burning. Anthropogenic CH4 emissions due to oil and gas production and distribution, also appear rather uncertain, especially with respect to the spatial distribution of the sources. A comparison of CH4 emissions on a smaller scale (NW Europe) showed a fair amount of agreement between National Communications, EDGAR data and results of inverse atmospheric modelling. Because most of the CH4 emissions in this area come from reasonably well-known CH4 emission sources like ruminants and landfills, this is a good argument. CH4 emission from some areas in the North Sea was underestimated by inventories. This could be due to CH4 emissions of oil production platforms in the North Sea.