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Model Report

INTEGRATED GLOBAL SYSTEM MODEL

Last Revision Date: 08/25/2009 View as PDF
General Information Back to Top
Model Abbreviated Name:

IGSM
Model Extended Name:

INTEGRATED GLOBAL SYSTEM MODEL
Model Overview/Abstract:
The MIT Integrated Global System Model (IGSM) is designed for simulating the global environmental changes that may arise as a result of anthropogenic causes, the uncertainties associated with the projected changes, and the effect of proposed policies on such changes. As described in numerous publications, the IGSM is a comprehensive research tool that is applied to questions regarding potential anthropogenic global climate change and its social and environmental consequences. The current IGSM formulation includes an economic model for analysis of greenhouse and aerosol precursor gas emissions and mitigation proposals, a coupled model of atmospheric chemistry and climate, and models of terrestrial ecosystems. All of these models are global but with appropriate levels of regional detail.
The climate system component of the IGSM was designed to provide the flexibility and computational speed required to handle multiple policy studies and uncertainty analysis while representing to the best degree possible the physics, chemistry and biology of the more computationally intensive coupled atmosphere-ocean-land general circulation models. Also, within the IGSM the earth system components are linked to a model of human interactions. The nature of the analysis that such a facility can provide is illustrated by its use to analyze key aspects of the climate issue.
Keywords:
Model Technical Contact Information:
EPA contact: Brooke L. Hemming, Ph.D.
Tel: 919-541-5668
E-mail: hemming.brooke@epa.gov

Other:
MIT Joint Program on the Science and Policy of Global Change
http://web.mit.edu/globalchange/www/
Tel: (617) 253-7492
E-Mail: GlobalChange@mit.edu
Model Homepage: http://web.mit.edu/globalchange/www/if.html Exiting the EPA Site

User Information Back to Top
Technical Requirements
Computer Hardware
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Compatible Operating Systems
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Other Software Required to Run the Model
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Download Information
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Using the Model
Basic Model Inputs
The IGSM is a comprehensive research tool for analyzing potential anthropogenic global climate change and its social and environmental consequences. The IGSM includes consideration of climate science, technical change, and economic and social science, in an interacting set of computer models designed for study of the sensitivities and uncertainties that are crucial to policy evaluation. The MIT Joint Program maintains an archive of modeling datasets (input and output) utilized in the Program's studies, as well as technical details regarding the many modeling components. Access to datasets used in particular studies are available by request. Research colleagues, students, and others interested in gaining access to the data used in a specific study should contact the lead author of the study, or globalchange@mit.edu.
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Basic Model Outputs
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User Support
User's Guide Available?
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Model Science Back to Top
Problem Identification
The MIT Integrated Global System Model (IGSM) is designed for analyzing the global environmental changes that may result from anthropogenic causes, quantifying the uncertainties associated with the projected changes, and assessing the costs and environmental effectiveness of proposed policies to mitigate climate risk. It includes an economic model for analysis of greenhouse gas and aerosol precursor emissions and mitigation proposals, a coupled atmosphere-ocean-land surface model with interactive chemistry, and models of natural ecosystems. In this global framework the outputs of the combined anthropogenic and natural emissions models provide the driving forces for the coupled atmospheric chemistry and climate models. Climate model outputs then drive a terrestrial model predicting water and energy budgets, CO2, CH4, and N2O fluxes, and soil composition, which feed back to the coupled climate/chemistry model.
Summary of Model Structure and Methods
In the integrated model, the combined anthropogenic and natural emissions model outputs are driving forces for the coupled atmospheric chemistry and climate model. the essential components of which are chemistry, atmospheric circulation, and ocean circulation. The climate model outputs drive a terrestrial ecosystems model predicting land vegetation changes, land CO2 fluxes, and soil composition, which feed back to the coupled chemistry/climate, and natural emissions models.
The economics model computes predictions of anthropogenic emissions of the key gases and aerosols generated from the world's economies and energy usage, and converts them into distributions by latitude where needed. Special provision is made for analysis of uncertainty in key influences, such as the growth of population and economic activity, and the pace and direction of technical change. The model also supports analysis of emissions control policies, providing estimates of the magnitude and distribution among nations of the costs, and clarifying the ways that changes are mediated through international trade. The model also supports examination of potential feedbacks of climate change onto predicted emission rates.

Refer to the Model Homepage for more information.

Model Evaluation
Further information about the IGSM and its component models, as well as sample applications and related details, are described in numerous publications and reports.
  • Integrated Global System Model (IGSM) Version 2: Model Description and Baseline Evaluation MIT JOINT PROGRAM REPORT 124 Sokolov et al., 2005. [PDF: 1.1 MB]
  • Integrated Global System Model for Climate Policy Assessment: Feedbacks and Sensitivity Studies CLIMATIC CHANGE 41(3/4): 469-546 Prinn et al., 1999. [PDF: 880 kB]. This article provides a description of the MIT IGSM as of 1998. Many changes since then are documented in MIT Joint Program Report 124 (above).


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