Seekell, D.A., P. D’Odorico, and M.L. Pace. 2011. Virtual water transfers unlikely to redress inequality in global water use. Environ. Res. Lett. 6(2011) 024017(6pp) doi:10.1088/1748-9362/6/2/024017
Some countries do not have enough freshwater resources within their control to support their current population and standard of living. The proponents of “virtual water” argue that these countries can balance their water needs by importing “virtual water” through the international trade of agricultural and industrial products.
“Vitural water” is the volume of water used to produce, but not necessarily contained within, a unit mass of agricultural and industrial goods.
Proponents claim that “Virtual Water” transfer will ‘save’ water because crops could be grown in wateruse efficient environments and exported to other countries with greater water-use requirements for the same crop. This would supposedly prevent wars over freshwater resources because it is less expensive to participate in international trade than to battle for water resources.
In reality, water is not the dominant factor in the majority of trade decisions. As a result, the “virtual water” concept has not been actively applied as a policy tool. These authors examine the feasibility of applying “virtual water” by comparing United Nations statistics on both social and human development with water usage statistics for a range of countries.
Figure 3 of their study (below) is informative. The first panel (A) represents the relative contributions of different water uses to overall water-use inequality among nations. Internal agricultural water usage dominates the overall inequality. Panel (B) represents the average internal agricultural water usage per capita and average volume of virtual water (sum of external agricultural and external industrial water footprints) per capita (black bars). The volume of water needed to be transferred to create an equal distribution, as determined by the Hoover coefficient, is displayed in the red bars and is denoted ‘Hoover volume’.
The authors state:
“Here we assess inequality in water use between nations. We quantify the contribution of different water-use categories to the overall inequality and the inequality within and between social development classes. We conclude that virtual water transfer is not sufficient to equalize water use among nations primarily because internal agricultural water use, the main contributor to inequality, dominates national water needs and cannot be completely compensated by current volumes of virtual water transfers.”
It troubles me that throughout the article “differences” are interpreted as “inequality.” This use of language implies that differences are somehow “wrong” and they must be corrected so that there is equality. Water resources and water use patterns are not uniformly distributed across and between countries, nor should there be an expectation that they should be. The agricultural component is very important in the big picture and perhaps a different paradigm than the “virtual water” approach describe here is needed.