An agro-economic model comparison of cropland change until 2050

The future development of land under agricultural production has important implications for environment and climate. Different methods to project future agricultural land use have been published indicating large uncertainty due to different model assumptions and methodologies. In this paper we present a first comparison of global agro-economic models, which have been harmonized on drivers like future population, GDP growth and biophysical yields. The comparison includes four partial and six general equilibrium models, which differ largely according to their modelled land supply and amount of available land. We analyse results of four scenarios: The reference scenario assumes no climate change and a medium pathway of economic growth and population development. The second scenario assumes higher economic growth and population, whereas scenario three and four assume the impacts of climate change on crop yields (HadGEM2, RCP 8.5) and differ according to the used crop model to project the yield changes (DSSAT and LPJmL). Most models (7 out of 10) project an increase of cropland of around 10 to 25% by 2050 compared to 2005, whereas one model projects a decrease. Across all models most of the cropland expansion takes place in South America and Sub-Saharan Africa but also in North America (especially Canada), if the impacts of climate change are considered. In general, the strongest differences in model results are related to differences in the costs or substitution elasticities of land expansion, the endogenous productivity responses and the assumed development of bioenergy demand.