PNNL

The Science                                

Growing crops for food and other necessities consumes water at their point of origin, but some of these crops get traded elsewhere. The consumed water is embedded in the traded crop commodities through a concept known as virtual water. Researchers used a multisector long-term global model, the Global Change Analysis Model (GCAM), to explore the potential effects of agriculture trade on virtual water trade and total water consumption. They found that across a set of increasing and decreasing future global trade scenarios, the amount of water virtually traded changes by +400% and -20%, respectively. Additionally, they found that the global demand for water for agriculture may vary by up to the volume of Lake Michigan from 2020 – 2100.

The Impact

This work highlights the need for integrated water management strategies around the world in the face of future multi-sector uncertainties. Recent literature has started to quantify future virtual water trade patterns, but this study takes the analysis a step further by introducing uncertainty into global trade. This research will enable the identification of regions that may be relied upon for agricultural trade and its associated water demand in differing futures. Future research projects can expand upon the studied scenarios and understand how sensitive water resources are to global agricultural trade evolution.

Summary

The rate of globalization associated with agricultural markets can drastically alter the areas where crop commodities are grown and traded from. As uncertainties surround future socioeconomic growth, energy transitions, and the resulting demand for agricultural commodities, meeting this changing demand will affect energy, water, and land around the world. Previous studies largely focused on the water implications of removing trade barriers or solely examined historical timeframes. Researchers used GCAM to explore future virtual water trade and the associated changes in water resource demands due to various levels of future agricultural trade. The results show that enhancing global agricultural trade saves nearly 6,000 km³ through the end of the century, whereas declining trade may result in more than 6,000 km³ of additional irrigation water withdrawals required to meet demand. Over 65% of these changes occur via nonrenewable groundwater extraction to produce crops in dry regions. This study highlights the need to increase scientific understanding of how trade integration may evolve in the future and potential responses of water resources to maintain food security and limit additional water stress.

PNNL Contact

Marshall Wise, Pacific Northwest National Laboratory, marshall.wise@pnnl.gov

Funding

This research was supported by the Department of Energy, Office of Science, as part of research in MultiSector Dynamics, Earth, and Environmental System Modeling Program. Katherine Calvin, an Earth scientist at Pacific Northwest National Laboratory, is currently detailed to the National Aeronautics and Space Administration. Calvin's contributions to this article occurred prior to her detail. The views expressed are her own and do not necessarily represent the views of the National Aeronautics and Space Administration or the United States Government.