Global Change Analysis Model (GCAM)

The Joint Global Change Research Institute (JGCRI) of the Pacific Northwest National Laboratory (PNNL) is the home and primary development institution for GCAM, a multisector tool for exploring consequences of and responses to global change. Climate change is a global issue that impacts all regions of the world and all sectors of the global economy. Multisector tools such as GCAM capture these interconnected impacts in an economic framework in order to explore interactions between regions and sectors.

GCAM has been developed at PNNL for over 20 years and is now a freely available community model and documented online (See below). The team at JGCRI is comprised of economists, engineers, energy experts, forest ecologists, agricultural scientists, and climate system scientists who develop the model and apply it to a range of science and policy questions and work closely with Earth system and ecosystem modelers to integrate the human decision components of GCAM into their analyses.

Model Overview

GCAM is a dynamic-recursive model with technology-rich representations of the economy, energy sector, land use and water linked to a climate model that can be used to explore climate change mitigation policies including carbon taxes, carbon trading, regulations and accelerated deployment of energy technology. Regional population and labor productivity growth assumptions drive the energy and land-use systems employing numerous technology options to produce, transform, and provide energy services as well as to produce agriculture and forest products, and to determine land use and land cover. Using a run period extending from 1990 2100 at 5 year intervals, GCAM has been used to explore the potential role of emerging energy supply technologies and the greenhouse gas consequences of specific policy measures or energy technology adoption including; CO2 capture and storage, bioenergy, hydrogen systems, nuclear energy, renewable energy technology, and energy use technology in buildings, industry and the transportation sectors. GCAM is an Representative Concentration Pathway (RCP)-class model. This means it can be used to simulate scenarios, policies, and emission targets from various sources including the Intergovernmental Panel on Climate Change (IPCC). Output includes projections of future energy supply and demand and the resulting greenhouse gas emissions, radiative forcing and climate effects of 16 greenhouse gases, aerosols and short-lived species at 0.50.5 degree resolution, contingent on assumptions about future population, economy, technology, and climate mitigation policy.

Community guidelines for peer-reviewed journal articles using GCAM

This section outlines some suggested language which the GCAM user community can employ to describe GCAM in papers in peer-reviewed journal articles using GCAM or versions of GCAM. GCAM is under continuous development. The suggested language for the opening paragraphs of a methodology or introduction section of a paper describing GCAM is as follows:

"The Global Change Analysis Model (GCAM) is a multisector model developed and maintained at the Pacific Northwest National Laboratorys Joint Global Change Research Institute (JGCRI, 2023) <include additional citations to previous GCAM studies as relevant>. GCAM is an open-source community model. In this study, we use GCAM v NN. The documentation of the model is available at the GCAM documentation page (http://jgcri.github.io/gcam-doc) and the description below is a summary. GCAM includes representations of: economy, energy, agriculture, and water supply in 32 geopolitical regions across the globe; their GHG and air pollutant emissions and global GHG concentrations, radiative forcing, and temperature change; and the associated land allocation, water use, and agriculture production across 384 land sub-regions and 235 water basins. <If using GCAM-USA, include without quotes: "This study uses a U.S.-focused version of GCAM called GCAM-USA that includes representation of energy, economy, and water systems for the fifty states and the District of Columbia in addition to 31 regions outside of the United States.>. The version of GCAM used in this study is available along with full source code and instructions for use in a public repository <include citation including link to the GCAM repository with doi used in paper>.

Subsequent paragraphs of the description might expound on particular capabilities, systems, or sectors of focus in the paper. Details in the GCAM documentation page can be used as a reference to develop these paragraphs.

Community users of GCAM might also undertake their own model developments and/or assumptions for papers. It is recommended that these departures from the publicly available version of the model be clearly described. In addition, if these developments are substantial, we suggest making this clear by including an additional phrase (e.g. region name or name of institution) in the name of the model and explicitly calling it out in place of or immediately following the italicized portion in the above paragraphs. For example: "This study uses a modified version of GCAM/GCAM-USA called GCAM-<institution name>/GCAM-USA-<institution name>. GCAM-<institution name>/GCAM-USA-<institution name> incorporates additional details and modified assumptions from GCAM v NN as described subsequently".

Documentation

• GCAM Documentation
• Getting Started with GCAM
• GCAM Community
• GCAM Videos and Tutorial Slides
• GCAM Citation and Co-authorship Guidelines

Selected Publications

Calvin, K., Patel, P., Clarke, L., Asrar, G., Bond-Lamberty, B., Cui, R. Y., Di Vittorio, A., Dorheim, K., Edmonds, J., Hartin, C., Hejazi, M., Horowitz, R., Iyer, G., Kyle, P., Kim, S., Link, R., McJeon, H., Smith, S. J., Snyder, A., Waldhoff, S., and Wise, M.: GCAM v5.1: representing the linkages between energy, water, land, climate, and economic systems, Geosci. Model Dev., 12, 677698, https://doi.org/10.5194/gmd-12-677-2019, 2019.

Edmonds, J., and J. Reilly (1985)Global Energy: Assessing the Future (Oxford University Press, New York) pp.317.

Edmonds, J., M. Wise, H. Pitcher, R. Richels, T. Wigley, and C. MacCracken. (1997) An Integrated Assessment of Climate Change and the Accelerated Introduction of Advanced Energy Technologies, Mitigation and Adaptation Strategies for Global Change, 1, pp. 311-39

Kim, S.H., J. Edmonds, J. Lurz, S. J. Smith, and M. Wise (2006) The ObjECTS Framework for Integrated Assessment: Hybrid Modeling of Transportation Energy Journal (Special Issue #2) pp 51-80.

Full list of GCAM publications