Small clique of nations found to dominate global trading web of food, water

WASHINGTON - It's not easy, or economically feasible, to ship freshwater across the globe. But when scientists use food as a proxy for that water - taking into account how much crops are irrigated and livestock are fed - they can get a glimpse of the flow of freshwater between countries. When one research group studied this "virtual water network," they found that the interconnectedness between countries has almost doubled over the last two decades - potentially lending some resiliency to the water trade. Still, a handful of nations control a majority of the freshwater flow, and some regions, including much of Africa, are left out of the trading loop.

"In general, we have more trade going on, and more and more countries are now connected," said Joel Carr, an ecohydrologist with the University of Virginia in Charlottesville and one of the authors of the new study. "But these increases in trade and connections are not equally spread among countries."

Food production is one of the primary uses of fresh water, and as countries grow in population, they need more food, and therefore more water, to support their residents. If they don't have the water to grow crops or raise livestock but have money to spend, countries can import food - essentially importing water. The virtual water network is a way to look at the global balance of this freshwater trade, Carr said. Read More