While international trade results in carbon emissions thanks to the fossil fuels burned by planes, trucks and ships, a Princeton University research team has found that world trade could also mean more efficient water use as a side benefit. And since water is a key resource in the production of climate-friendly energy sources, including hydroelectric and nuclear power, that could at least partially offset trade’s negative impact.
Focusing on agriculture, which accounts for 80 percent of freshwater consumption worldwide, the researchers examined trade through the lens of what they call “virtual water” — a measure of how much water goes into the production of a bushel or a kilogram of a given crop. “It’s like the carbon footprint concept, but for water,” Princeton civil and environmental engineering graduate student Carole Dalin, lead author of a paper on the topic in Proceedings of the National Academy of Sciences, said in an interview.
Watering soybeans, Keya Paha County, Nebraska.
According to Dalin and her colleagues, it turns out that nations with inadequate water resources also have lower crop yields per acre. In these places, in other words, it takes more water to produce the same amount of corn or soy or barley. Food exported from water-rich areas to water-poor areas, therefore, amounts to a transfer not just of food, but of water efficiency. Overall, Princeton civil and environmental engineering professor Ignacio Rodríguez-Iturbe said, “This lowers the average water footprint of the whole world population.” Read more
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