Biofuels: a new methodology to estimate GHG emissions from global land use change
This study implements a new methodology developed by the JRC IES and IE for estimating changes in greenhouse gas (GHG) emissions from soil and above- and below-ground biomass resulting from global land use changes caused by the production of biofuels. The methodology is based on the Tier 1 approach as developed under the IPCC 2006 Guidelines for National Greenhouse Gas Inventories. Under this approach GHG emissions are estimated from comparing the pre-land use change carbon stocks with the carbon stocks after the conversion. The study incorporates the output from global economic models on land use change as input data to calculate the related GHG emissions. Used are cropland demands from the general equilibrium model MIRAGE (run by IFPRI) and from the partial equilibrium model AGLINK-COSIMO (run by JRC-IPTS). A novelty of the study is the development of a harmonized spatial data set and advanced analysis methods for all aspects of estimating GHG emissions. In the spatial allocation process cropland demands from the output of the economic models are processed for a global raster layer with approx. 10 km grid spacing. The outcome of the spatial allocation process allows computing changes in land use, which are the related changes in soil carbon stock and N2O emissions and the changes in carbon in the affected biomass. The output from IFPRI-MIRAGE analysis was available to the study for two scenarios: one assuming conditions of