22 March 2012
AGU Release No. 12-17
For Immediate Release
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.
“One of the points the study highlights is we can see that a lot of trading is not driven by water need or food need, it’s driven by economics” — that is, the probability of trading among two countries is proportional to their gross domestic product, regardless of their water need. While that is inevitable to some extent, he adds, policymakers worldwide should become aware of this virtual water trading pattern and consider policies to protect and encourage both local and global water balance.