MODELING THE GLOBAL SOCIETY-BIOSPHERE-CLIMATE SYSTEM .1. MODEL DESCRIPTION AND TESTING

This paper describes the IMAGE 2.0 model, a multi-disciplinary, integr ated model designed to simulate the dynamics of the global society-bio sphere-climate system. The objectives of the model are to investigate linkages and feedbacks in the system, and to evaluate consequences of climate policies. Dynamic calculations are performed to year 2100, wit h a spatial scale ranging from grid (0.5-degrees x 0.5-degrees latitud e-longitude) to world regional level, depending on the sub-model. The model consists of three fully linked sub-systems: Energy-Industry, Ter restrial Environment, and Atmosphere-Ocean. The Energy-Industry models compute the emissions of greenhouse gases in 13 world regions as a fu nction of energy consumption and industrial production. End use energy consumption is computed from var-ious economic/demographic driving fo rces. The Terrestrial Environment models simulate the changes in globa l land cover on a grid-scale based on climatic and economic factors, a nd the flux of CO2 and other greenhouse gases from the biosphere to th e atmosphere. The Atmosphere-Ocean models compute the buildup of green house gases in the atmosphere and the resulting zonal-average temperat ure and precipitation patterns. The fully linked model has been tested against data from 1970 to 1990, and after calibration can reproduce t he following observed trends: regional energy consumption and energy-r elated emissions, terrestrial flux of CO2 and emissions of greenhouse gases, concentrations of greenhouse gases in the atmosphere, and trans formation of land cover. The model can also simulate long term zonal a verage surface and vertical temperatures.