Staff at the Joint Institute develop and use models to simulate the economic and physical impacts of global change policy options. The GCAM, for example, gives analysts insight into how regional and national economies might respond to climate change mitigation policies including carbon taxes, carbon trading, and accelerated deployment of energy technology.

  • Global Change Assessment Model – The Global Change Assessment Model (GCAM) is a partial equilibrium model of the world with 32 regions. GCAM operates in 5 year time steps from 1990 to 2100 and is designed to examine long-term changes in the coupled energy, agriculture/land-use, and climate system. GCAM includes a 283-region 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. The model has been used extensively in a number of  assessment and modeling activities such as the Energy Modeling Forum (EMF) , the U.S. Climate Change Technology Program, and the U.S. Climate Change Science Program and IPCC assessment reports. GCAM is now freely available as a community model. See GCAM Community. For more information, contact Pralit Patel ( or Leon Clarke (
  • Hector – An open source, object-oriented, simple global climate carbon-cycle model. It runs essentially instantaneously while still representing the most critical global scale earth system processes, and is one of a class of models heavily used for for emulating complex climate models and uncertainty analyses. For more information on Hector, please contact Corinne Hartin (
  • EPIC – The Environmental Policy Integrated Climate (EPIC) Model is a process-based agricultural systems model composed of simulation components for weather, hydrology, nutrient cycling, pesticide fate, tillage, crop growth, soil erosion, crop and soil management and economics. Staff at PNNL have been involved in the development of this model by integrating new sub-models for soil carbon dynamics and nitrogen cycling. For more information, contact Xuesong Zhang (
  • SWAT – The Soil and Water Assessment Tool (SWAT) is a public domain model jointly developed by USDA Agricultural Research Service (USDA-ARS) and Texas A&M AgriLife Research, part of The Texas A&M University System. SWAT is a small watershed to river basin-scale model to simulate the quality and quantity of surface and ground water and predict the environmental impact of land use, water management practices, and climate change. SWAT is widely used in assessing sustainability of bioenergy cropping systems, soil erosion prevention and control, non-point source pollution control and regional management in watersheds.  Staff at PNNL have been involved in the development of this model by linking carbon cycling along terrestrial-aquatic continuum. For more information, contact Xuesong Zhang (