GCAM is a partial equilibrium model of the world with 14 regions. It is used to project energy consumption and greenhouse gas emissions, and to investigate the impact of climate change policies and technologies for emissions mitigation. GCAM includes an agriculture land-use module and a reduced form carbon cycle and climate module in addition to its incorporation of demographics, resources, energy production and consumption. It operates in 15 year time steps from 1990 to 2095.