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Thematic Guide to Integrated Assessment Modeling



Who Develops Integrated Assessment Models

Essay prepared for SEDAC by:

Peter Morrisette
Environmental Research Consultant
P.O. Box 684
Victor, ID 83455



Integrated assessment models or IAMs have emerged in recent years as one of the key tools for helping scientists and decision makers assess the problem of global climate change. Climate change has proven to be a very difficult problem for scientists and decision makers to deal with because of the uncertainties about the science of the problem, the affects climate change might have on the environment and human activities, and the potential costs of responding to the problem.

In order to better understand the problem of global climate change, scientists and decision makers have turned to IAMs as a tool for integrating and assessing many of the complex interrelationships between natural and social factors that underlie the climate change problem. Most climate change IAMs, for example, are composed of sub-models that cover the climate, economy, and ecosystems. Indeed, the key strength of an IAM is its ability to combine and integrate information about different systems. Such an effort requires an interdisciplinary approach.

Other MVA Usage Guide essays explore the purpose, structure, and uses of IAMs, this essay offers a look at some of the institutions and individuals who are currently working on the development of IAMs. A brief overview of the IAM field is provided followed by a more detailed review of selected IAM programs. Information about projects, backgrounds of model developers, and funding sources is provided. In assessing the uses of the different IAMs, it is helpful to understand who develops the models.


Overview of the IAM Field

The IAM field is large and diverse. There are over two-dozen efforts to develop IAMs that are either underway or have been completed in past few years. Many of these IAMs efforts are described in SEDAC's Thematic Guide essay In Search of Integrated Assessment. Some of these modeling efforts are large and complex, involving collaboration between two or more institutions and many scientists and researchers. Others are quite small, involving only a few individuals. For the most part, IAM efforts are undertaken by researchers at universities, public and private research institutions, and government agencies.

The development of IAMs is an international effort with major programs located in North America, Europe, and Asia. Europe has been the center of much activity. Probably the most high profile European models are the IMAGE models (IMAGE 1.0 and IMAGE 2.0) developed by the National Institute of Public Health and the Environment (RIVM) of The Netherlands. The European Community supported the development the ESCAPE model which was a joint project between the Climatic Research Unite (CRU) at the University of East Anglia in the UK and RIVM in The Netherlands. Other examples of IAMs developed in Europe include the PAGE model developed at Cambridge University and MAGICC model developed at CRU at the University of East Anglia in the UK.

A similar array of IAM efforts is underway in the United States. For example, Pacific Northwest Laboratory is developing the MiniCAM model and its larger, and more complex cousin ProCAM. Researchers at Carnegie Mellon University have developed the ICAM family of models which includes versions 0, 1, and 2. Researchers at the Electric Power Research Institute (EPRI) and Stanford University have developed the MERGE model, and a large-scale IAM effort is underway at the Massachusetts Institute of Technology. In addition, individual researchers or small teams of researchers have also developed IAMs. Notable among these efforts is the DICE model developed by William Nordhaus at Yale University. The major IAM effort in Asia is the AIM or the Asia-Pacific Integrated Model which is being developed in Japan.

The developers of climate change IAM come from a wide range of backgrounds. Some of the more common disciplines among model developers are economics and public policy, the atmospheric sciences, engineering, and ecology and other biological sciences. IAM programs and research teams are almost always interdisciplinary. The profiles of selected IAM programs provided below illustrated the breath of disciplines and backgrounds of the individual researchers involved with the development of IAMs. Some model developers have worked on other integrated assessment activities in the past such as the work done on acid rain in the 1980s, others come from a computer science and modeling background, and still others come from specific disciplinary backgrounds in economics, climatology, etc. This diversity in backgrounds is necessary in order to establish the knowledge base to build an IAM that covers the climate, economy, and biosphere.

The majority of IAM projects are independent efforts; however, there is much collaboration within the IAM field. For example, model developers frequently meet at conferences and workshops to discuss their results and share information. In addition, some IAMs such as the ESCAPE model noted above are collaborative efforts between two or more institutions. A number of modeling efforts also involve combining two or more IAMs. For example, the ESCAPE model uses components of the IMAGE model developed at RIVM combined with the STAGGER model developed at CRU, and the MiniCAM model developed by PNL combines the MAGICC model with an integrated energy model (the ERB model) developed by Jae Edmonds and John Reilly. Recently, the IAM field has come together to produce two major papers which review the state-of-the-art of climate change IAMs (see Rotmans, Dowlatabadi, and Parson 1996; Weyant et al. 1996). Also, the Energy Modeling Forum (EMF) at Stanford University has recently organized two studies that have focused on climate change IAMs--EMF-12 and EMF-14. The EMF is a collaborative effort among energy reseachers to study specific issues and problems.

Funding for developing IAMs comes from both the public and private sector. Dowlatabadi (1995) notes that IAM program support has tended to be stronger in Europe than the United States. Major funding in Europe has come from the European Economic Community (support for ESCAPE and PAGE) and the government of The Netherlands (support for IMAGE). In the United Sates, EPRI has been a major contributor to IAM efforts supporting not only its own activities, but also other IAM efforts such as the development of ICAM at Carnegie Mellon University. Support has also been provided by government agencies such as the National Science Foundation (e.g., ICAM and DICE) and the Department of Energy (e.g., MiniCAM and ProCAM).


Profiles of Selected IAM Groups

Below are profiles of some of the institutions and programs that are involved in the development or support of climate change IAMs. Each profile highlights the focus of the program, identifies funding sources, and provides at least a partial list of researchers. Every effort has been made to provide the most current information; however, the IAM field is evolving rapidly and changes in program structure and staffing occur frequently. You are encouraged to check with individual programs for the most up-to-date information.


Carnegie Mellon University


The Department of Engineering and Public Policy (EPP) at Carnegie Mellon University (CMU) is home to the Global Climate Change Integrated Assessment Program. This program represents one of the larger and more active IAM efforts in the United States. The program was established in 1990 and consists of a large, interdisciplinary research team that conducts research in three main areas: integrated assessment modeling, perception and understanding of the climate change problem by public and private decision makers, national and international policy making. The program is funded by the National Science Foundation and the Electric Power Research Institute.

Researchers at EPP have developed a series of IAMs referred to as the ICAM (Integrated Climate Assessment Model) family of models. There are currently three generations of ICAM--versions 0, 1, and 2. ICAM emphasizes the role of uncertainty in the climate change decision-making process. For example, ICAM-0 explored the role of uncertainties versus subjective perspectives about climate change in policy making. The most recent version, ICAM-2, explores mitigation and adaptation strategies for seven geo-political regions.

The Global Climate Change Integrated Assessment Program at CMU also publishes a Newsletter--Degrees of Change. For more information about the program visit the EPP web site. A more detailed discussion of ICAM is available online in the Thematic Guide essay In Search of Integrated Assessment and in the ICAM Model Guide.

Research Team (partial list):

Hadi Dowlatabadi, Program Coordinator -- Physics
Cliff I. Davidson, Professor -- Atmospheric Science
Paul Fishbeck, Professor -- Decision Science
Brauch Fischhoff, Professor -- Decision Science
Milind Kandlikar, Research Fellow -- Science and Public Policy
Granger Morgan, Professor and Department Head -- Applied Physics
Spyros Pandis, Assistant Professor -- Atmospheric Chemistry
James Risbey, Research Fellow -- Climatology/Public Policy
Mitchell J. Small, Professor -- Mathematical Modelling of Environmental Systems
Program Address:

Department of Engineering and Public Policy
Carnegie Mellon University
Pittsburgh, PA 15213

Electric Power Research Institute

The Electric Power Research Institute (EPRI) was established in 1973 by U.S. electric utilities as a research consortia for exploring global energy issues. EPRI researchers work on numerous issues related to the generation, delivery, and use of electrical energy. A major focus of EPRI's research is the environmental implications of electrical energy use. In addition to conducting research, EPRI also funds research activities at other institutions.

EPRI operates the Global Climate Research program within its Environmental Business Group. This program focuses on a number of issues including integrated assessment modeling. EPRI researchers have collaborated in the development of several important energy models and climate change IAMs, including Global 2100, MERGE, and CETA. Global 2100, developed by Alan Manne of Stanford University and Richard Richels of EPRI, is a macro-economic model of economic activity combined with an energy-technology model. The MERGE model, also developed by Manne and Richels, adds a climate component to the Global 2100 model, extends it time horizon to the end of the 22nd century, and covers five global regions. The CETA model, developed by Stephen Peck of EPRI and Tom Teisberg, is a set of models based on the Global 2100 model that includes component models for the carbon cycle, climate change, and impacts.

In addition to its own efforts to develop IAMs, EPRI has been a major source of funding for other IAM efforts. Currently, EPRI is supporting the development of IAMs at Carnegie Mellon University, Pacific Northwest Laboratories, and the Massachusetts Institute of Technology. EPRI is supporting this work as part of its efforts to develop an integrated assessment framework that will aid analysts and decision makers in comparing the costs and benefits of policy proposals for responding to climate change.

For more information about EPRI and its climate change program visit the EPRI Web site. Also, an article about EPRI's climate change work--Global Climate Research: Informing the Decision Process--appeared in a recent issue of EPRI Journal.

Research Team (partial list):

Dr. Richard Richels, Technical Executive -- Economist
Dr. Chuck Hakkarinen -- Global Climate/Plume Models
Dr. Louis F. Pitelka -- Plant Ecology
Dr. Larry Williams -- Integrated Assessment
Dr. Tom Wilson -- Global Climate, Risk Management
Program Address:

Electric Power Research Institute
3412 Hillview Ave.
Palo Alto, CA 94304-1395

Energy Modeling Forum
The Energy Modeling Forum (EMF) was established in 1976 at Stanford University to provide a forum for collaborative research on energy issues. EMF is under the direction of Stanford Professor John Weyant, and is supported by funding from the Department of Energy, Environmental Protection Agency, National Science Foundation, Electric Power Research Institute, and industrial affiliates. EMF studies bring together researchers from universities, research institutions, and industry in collaborative efforts to address key energy modeling issues.

Over the past two decades EMF has supported 15 studies and assessments of energy modeling issues, including two recent efforts concerning climate change and integrated assessment modeling. EMF-12 focused on policy options for controlling global carbon emissions by examining the results of 14 energy models. EMF-14 focused specifically on integrated assessment modeling by comparing the usefulness of different modeling approaches for policy making and research.

For more information on the Energy Modeling Forum visit the EMF web site. Also, the MVA Usage Guide essay How to Select an Integrated Assessment Model and the Thematic Guide essay In Search of Integrated Assessment discuss EMF-12 and -14.

Program Address:

Prof. John P. Weyant
Energy Modeling Forum
Stanford University
406 Terman Building
Stanford, CA 94305-4022

National Institute of Public Health and the Environment (RIVM), The Netherlands

The Dutch National Institute of Public Health and the Environment or RIVM is a leader in the development of climate change IAMs. A large interdisciplinary team of researchers at RIVM has developed several IAMs including IMAGE (Integrated Model to Assess the Greenhouse Effect) 1.0, IMAGE 2.0, and TARGETS (Tool to Assess Regional and Global Environmental and Health Targets for Sustainability).

IMAGE 1.0 was the first climate change IAM. It coupled an emissions model with a biogeochemistry, climate, sea level, and impacts model to assess potential climate change impacts and response strategies for The Netherlands. IMAGE 2.0 is a detailed model of a linked global society-bioshpere-climate system. It is based on three main sub-models covering energy and industry, the terrestrial environment, and the atmosphere and oceans. The Dutch government based a recent proposal for global greenhouse gas emission controls on the results of IMAGE 2.0. The TARGETS model is RIVM's most recent IAM effort. It examines global climate change in the context of the larger issue of sustainable development.

The IAM work at RIVM is supported by the Dutch government, with additional funding from the United Nations Environment Programme, International Geosphere-Bioshpere Programme, the World Wildlife Fund, the World Health Organization, and the International Human Dimensions Programme. For more information about RIVM visit the RIVM web site. The Thematic Guide essay In Search of Integrated Assessment discusses IMAGE 1.0, IMAGE 2.O, and TARGETS, and also see the IMAGE 2.0 Model Guide.

Research Team (partial list):

Dr. Rik Leemans, Leader IMAGE Project
Dr. Bert de Vries, Leader TARGETS Project
Program Address:

National Institute of Public Health and the Environment, RIVM
P.O. Box 1
NL-3720 BA Bilthoven
The Netherlands

Pacific Northwest Laboratory

Pacific Northwest Laboratory or PNL is a large national laboratory operated for the Department of Energy by Battelle. PNL works on a wide range of issues including nuclear technology, energy, the environment, and the economy. Researchers at PNL have an established track record in climate change and energy research, and are currently working on a variety of issues related to global climate change including the development of IAMs.

An interdisciplinary team of researchers in PNL's Global Environmental Change Program are working on two IAMs--MiniCAM and ProCAM. MiniCAM combines the Edmonds-Reilly energy model with the MAGICC model to explore the potential for using advanced energy technologies to reduce greenhouse gas emissions. The ProCAM model is a much larger and more complex model of human activities and climate change based on a calculable general equilibrium model (called the Second Generation Model or SGM) that is composed of twenty regional models. ProCAM also utilizes the MAGICC and SCENGEN models and GCM output to derive regional patterns of climate change. Support for PNL's modeling effort is provided by the Department of Energy and EPRI.

For more information about Battelle and the Pacific Northwest Laboratory, visit the PNL web site. Further discussion of MiniCAM and ProCAM can be found in the Thematic Guide essay In Search of Integrated Assessment and in the MiniCAM Model Guide.

Research Team (partial list):

Jae Edmonds, Energy Economics
Hugh Pitcher
Steve Rayner, Anthropology
Norman J. Rosenberg, Agricultural Climatology
Marshall Wise
Program Address:

Global Environmental Change Program
Pacific Northwest Laboratories
901 D Street, SW, Suite 900
Washington, D.C. 20024-2115


Dowlatabadi, H. 1995. Integrated assessment models of climate change: An incomplete overview. Energy Policy 23: 289-296.

Rotmans, Dowlatabadi, and Parson. 1996. Integrated assessment of climate change: Evaluation of methods and strategies. In Human Choices and Climate Change: A State-of-the-Art Report. Forthcoming.

Weyant, J., O. Davidson, H. Dowlatabadi, J. Edmonds, M. Grubb, R. Richels, J. Rotmans, P. Shukla, W. Cline, S. Fankhauser, and R. Tol. 1996. Integrated assessment of climate change: An overview and comparison of approaches and results. In Climate Change 1995--Economic and Social Dimensions of Climate Change. Contribution of Working Group III to the Second Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), eds. J. Bruce et al. Cambridge: Cambridge University Press. Forthcoming.





Suggested Citation

Center for International Earth Science Information Network (CIESIN). 1995. Thematic Guide to Integrated Assessment Modeling of Climate Change [online]. University Center, Mich.


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