Land-use - WITCH

From IAMC-Documentation
Jump to navigation Jump to search

Model Documentation - WITCH

Corresponding documentation
Previous versions
Model information
Model link
Institution European Institute on Economics and the Environment (RFF-CMCC EIEE), Italy,
Solution concept General equilibrium (closed economy)
Solution method Optimization

Land-use in WITCH is taken into account through soft-linking the model to the GLOBIOM model. Given the importance of land use emissions, of the link between agriculture, biomass energy and forest management, modelling land-use is of key importance in integrated assessment models. Rather than being modelled in its full detail, land-use in WITCH is represented by the mean response functions produced by the Global Biosphere Management Model (GLOBIOM) land-use model (Havlik et al. 2014). GLOBIOM is a partial equilibrium model that covers agriculture and forestry, including bioenergy. It is used for analysing land-use scenarios over many years. In GLOBIOM, the world is divided into 30 economic regions, in which consumer behaviour is modelled through isoelastic demand functions. Commodity uses “Simulation Units”, which are aggregates of 5 to 30 arcmin pixels belonging to the same altitude, slope, and soil class in the same country. For crops, grass, and forest products, Leontief production functions covering alternative production systems are calibrated from biophysical models including EPIC (Izaurralde et al. 2006). Economic optimization is based on a spatial equilibrium approach and regional price-quantity equilibria are computed.