The aim of the land and food submodel is to simulate the key features of the global changes in land use and land cover that result from demand for food and the requirements of forestry. The submodel can reproduce the major historical trends in land use and land cover, food demand and supply, fertiliser use, etc. This is done, to a large extent, by employing of exogenous policy scenarios. The interaction with the other submodels, in particular CYCLES, allows the exploration of linkages between population growth, water availability and climate change on the one hand and food production on the other.

Introduction

The Earth's vegetation patterns have always changed in response to natural changes in, for example, geology, biology and climate. However, over the last few centuries human activities have made a considerable contribution to such changes. Natural ecosystems, forests, savannahs and wetlands have all been severely affected. The combination of growing populations and higher per capita food consumption has led to the gradual expansion of the land area used for food production and grazing. Increasing population density has led to forms of permanent agriculture which make more intensive use of land and this trend towards intensification is likely to continue in the decades to come. The growing demand for food may cause an imbalance between what can be produced and what is needed.