IMPACT Model

Brief model overview

The International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) is a partial-equilibrium economic model that simulates national and global markets of agricultural production, demand, and trade.

IMPACT was developed at the International Food Policy Research Institute (IFPRI) at the beginning of the 1990s to address a lack of long-term vision and consensus among policymakers and researchers about the actions necessary to feed the world in the future, reduce poverty, and protect the natural resource base. Over time, the model has been expanded and improved. IMPACT is now a system of linked models around the core multimarket economic model, and it continues to serve as the basis for research at IFPRI and across the CGIAR.

Model workflow

IMPACT is an integrated system of models that links information from climate models, crop simulation models (for example, Decision Support System for Agrotechnology Transfer), and water models linked to a core global, partial equilibrium, multimarket model focused on the agriculture sector. Crop models use information on the geographical distribution of crops as well as their water management (rainfed or irrigated) from the Spatial Production Allocation Model (SPAM).

Applications

The model covers 62 commodities and 158 countries and supports analysis of long-term challenges and opportunities for food, agriculture, and natural resources at global and regional scales. IMPACT has been employed in a wide range of analyses, from assessing the potential effects of climate change on global food production and nutrition to exploring linkages between agriculture production and food security at the national and regional levels, to evaluating the global effects of biofuels production, to the assessment of economic effects of alternative mitigation policies and the global simulation of technology adoption.

Input data

IMPACT relies on a variety of readily available input datasets. These include supply and demand information for all commodities from the FAO food balance sheets, world prices from the OECD Agricultural Market Access Database (only for the 2005 baseline), and GDP and population data from the International Institute for Applied Systems Analysis (IIASA) to match the Shared Socioeconomic Pathways (SSPs) developed by the Intergovernmental Panel on Climate Change (IPCC).

Output data

The standard outputs of the model include estimates of world prices (global level prices), total production, demand, yields, net trade, and harvested area at national, FPU and regional level. Animal numbers and yields are also available at national FPU and regional level. Food security indicators include kilocalories availability, and number and share of population at risk of hunger.

A selection of IMPACT datasets can be found and downloaded from the IFPRI Dataverse.

Software requirements

The modeling framework is based on GAMS, the General Algebraic Modeling System. Several tools are used for visualization and analysis, including Excel, R and Tableau.

Data processing and visualization of IMPACT results

R-packages are hosted on Github:

The packages are distributed along with the documentation through this IFPRI website:

Accessibility

User documentation

Full documentation for the system of models, including details on input data, output data, and applications, can be downloaded from the IFPRI website.

Additional information is available from the IFPRI IMPACT website.

About IMPACT-SIMM

IMPACT-SIMM is a portable version of IMPACT, designed for analysis of countries or groups of countries. It also allows a more flexible aggregation of commodities available in the global IMPACT model, while keeping a similar mathematical specification. A technical description is available from the link below.

Examples of applications

Rosegrant, Mark W, Timothy B Sulser, Shahnila Dunston, Abhijeet Mishra, Nicola Cenacchi, Yohannes Gebretsadik, Richard Robertson, Timothy Thomas, and Keith Wiebe. 2024. “Food and Nutrition Security under Changing Climate and Socioeconomic Conditions.” Global Food Security 41: 100755. https://doi.org/https://doi.org/10.1016/j.gfs.2024.100755.

Enahoro, Dolapo; Kozicka, Marta; Pfeifer, Catherine; Jones, Sarah K.; Tran, Nhuong; Chan, Chin Yee; Sulser, Timothy B.; Gotor, Elisabetta; and Rich, Karl M. 2023. Linking ecosystem services provisioning with demand for animal-sourced food: an integrated modeling study for Tanzania. Regional Environmental Change 23: 48. https://doi.org/10.1007/s10113-023-02038-x

Wiebe KD; TB Sulser; S Dunston; R Robertson; MW Rosegrant; D Willenbockel. 2022. Modeling biophysical and socioeconomic interactions in food systems with the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT). IN Peters C and D Thilmany (Eds). Food Systems Modelling. Academic Press, London. https://doi.org/10.1016/B978-0-12-822112-9.00008-4

Chan, Chin Yee; Tran, Nhuong; Cheong, Kai Ching; Sulser, Timothy B.; Cohen, Philippa J.; Wiebe, Keith D.; et al. 2021. The future of fish in Africa: Employment and investment opportunities. PLoS ONE 16(12): e026161. https://doi.org/10.1371/journal.pone.0261615

Sulser, TB; KD Wiebe; S Dunston; N Cenacchi; A Nin-Pratt; D Mason-D’Croz; RD Robertson; D Willenbockel; MW Rosegrant. 2021. Climate change and hunger: Estimating costs of adaptation in the agrifood system. Food Policy Report. International Food Policy Research Institute, Washington, DC. https://doi.org/10.2499/9780896294165

Wiebe KD; TB Sulser; S Dunston; MW Rosegrant; K Fuglie; D Willenbockel; GC Nelson. 2021. Modeling impacts of faster productivity growth to inform the CGIAR initiative on Crops to End Hunger. PLoS ONE 16: e0249994. https://doi.org/10.1371/journal.pone.0249994

Kadiyala, M. D. M.; Nedumaran, Swamikannu; Padmanabhan, Jyosthnaa; Gumma, Murali Krishna; Gummadi, Sridhar; Robertson, Richard; et al. 2021. Modeling the potential impacts of climate change and adaptation strategies on groundnut production in India. Science of The Total Environment 776(1 July 2021): 145996. https://doi.org/10.1016/j.scitotenv.2021.145996

Mason-D’Croz, Daniel, Timothy B Sulser, Keith Wiebe, Mark W Rosegrant, Sarah K Lowder, Alejandro Nin-Pratt, Dirk Willenbockel, et al. 2019. “Agricultural Investments and Hunger in Africa Modeling Potential Contributions to SDG2 – Zero Hunger.” World Development 116: 38–53. https://doi.org/https://doi.org/10.1016/j.worlddev.2018.12.006.

Acknowledgements

IMPACT was first developed at IFPRI in the 1990s. The development, documentation, maintenance, application, and enhanced accessibility of the model is supported by the CGIAR Initiative on Foresight, building on earlier support by the Bill and Melinda Gates Foundation, the U.S. Agency for International Development, the CGIAR Research Program on Policies Institutions and Markets (PIM), the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), and others. CGIAR is a global research partnership for a food-secure future, dedicated to transforming food, land, and water systems in a climate crisis. We would like to thank all funders who have supported this research through their contributions to the CGIAR Trust Fund.