ABSTRACT
This chapter examines the prospects for global food supply and demand for the year 2020, in the light of the two most often identified natural resource constraints, land and water. Projections of global food supply and demand have been made using an updated model of IFPRI's International Model for Policy Analysis of Commodities and Trade (IMPACT). The model covers 37 countries and regions, and 17 commodities, including all cereals, roots and tubers, soybeans and meats. Global food production can be increased through expansion of areas and increases in cropping intensity (extensification), or through increases in agricultural productivity (intensification). Crop area harvested, as projected in IMPACT simulations, is expected to grow only slowly. Thus increases in agricultural productivity will have to come from improved yields. The most comprehensive assessment of global land degradation, Oldeman et al., classifies the main types of land degradation as soil erosion from wind and water, chemical degradation and physical degradation.
