From global economic modelling to household level analyses of food security and sustainability: How big is the gap and can we bridge it?

Policy and decision makers have to make difficult choices to improve the food security of local people against the background of drastic global and local changes. Ex-ante impact assessment using integrated models can help them with these decisions. This review analyses the state of affairs of the multi-scale modelling of policy interventions, with an emphasis on applications in developing countries and livestock systems. Existing models do not sufficiently capture the complexity of human-environment interactions across different scales, and especially the link between landscape and local market levels, and national and sub-national level policies and markets is missing. The paper suggests a step wise approach with increasing data needs to bridge this gap. Improvements need to be made at the description of effects of the distribution of local markets on price formation and the representation of farm diversity within a landscape. Analyses in contrasting agro-ecological systems are needed to derive generic summary functions that can be used as input for macro level model analyses. This is especially pertinent for macro level descriptions of crop and livestock production in relation to price developments and of the mosaic of different agricultural land use responses in regions with contrasting socio-economic conditions and developments.