Water comes in bottles, pours out of skies and faucets and laps at the sand on beaches, covering more than two-thirds of the planet. A recent study also pointed out that the amount of land ice lost annually from glaciers and ice caps is enough to make the global sea level rise by half an inch. Unfortunately the sheer volume of water around is not the kind of water needed to perform tasks such as cleaning, cooking and helping crops grow, much less the water needed for use by industry or as an energy source.
To help alleviate water shortage concerns, many researchers are working on developing crops that are tolerant of drought or salt, and seeds that use water more efficiently. Water security itself was one of the topics discussed at the recent 14th Asian Security Conference in New Delhi.
In his speech to the conference attendees on Feb. 13, the Indian defense minister was quoted as saying that, “Water is actually fast emerging as a major source of insecurity and a potential issue for conflict among nations. Thus, nations need to cooperate on sharing water and efficient water usage and harvesting and initiate collective action for preserving our common environment.”
One method of tracking water usage to more efficiently use this resource came from a report released the same week as the Asian security conference. Engineers from the Netherlands calculated the water usage in every country between 1996 and 2005. To measure what they called the “water footprint of humanity,” they considered how much water is being used in the home, in agriculture and in industry, and factored in each country’s use of rainwater, which they referred to as “green” water, groundwater and surface water, which they called “blue” water, and polluted or “gray” water.
Varying water usage
Based on their data, they found that China, India and the United States have the largest water footprints worldwide, but the makeup of each country’s water usage varied widely. For example, a quarter of the world’s gray water is used by China, while India uses a quarter of the world’s blue water, primarily to grow wheat, rice and sugarcane.
For every country, the researchers noted, the largest factor in the water footprint was agricultural production. However, another factor they considered was what they called the “virtual water flow,” or how goods and services made in one country were then exported rather than used locally. They reported that the top three gross virtual water exporters were the United States, China and India and that the top three gross virtual water importers were United States, Japan and Germany.
More than 40 percent of the products involved in the virtual water flow turned out to be oil-producing crops such as soybean and sunflower. Another 17 percent was dedicated to cereal crops and 8 percent was utilized for coffee, tea and chocolate. Beef products, according to the report, accounted for almost 7 percent of the water flow.
“For governments in water-scarce countries such as in North Africa and the Middle East,” the engineers wrote in their report, “it is crucial to recognize the dependency on external water resources and to develop foreign and trade policies such that they ensure a sustainable and secure import of water-intensive commodities that cannot be grown domestically.”
The study was published online the week of Feb. 13 in the journal Proceedings of the National Academy of Sciences USA.
E-mail the author at massie@massie.com.