A thirst for meat: changes in diet, rising population may strain China's water supply

Science News, Jan 19, 2008 by Sid Perkins

China's rapid industrialization and increasing population, along with a growing dietary preference among its citizens for meat, are straining the country's water resources to the point where food imports will probably be needed to meet demand in coming decades.

Economic growth in China is brisk: Over the past 2 decades, the country's gross domestic product has risen, on average, about 8 percent per year. That's the highest rate of development in recent world history, says Junguo Liu, an environmental scientist at the Swiss Federal Institute of Aquatic Science and Technology in Dubendorf. Accompanying that growth has been a jump in urbanization and per capita income, both of which have contributed to significant changes in the Chinese diet.

Chinese consumption of staples such as corn, rice, and wheat has changed little in recent years, even dropping somewhat in the last decade, data suggest. However, consumption of more water-intensive fruits and vegetables, now the largest part of the average Chinese diet, has more than quadrupled since the early 1960s. A more significant strain on water resources, says Liu, is the dramatic rise in meat consumption. Since 1980, the Chinese yen for meat has nearly quadrupled, he notes.

While cereal crops such as rice or wheat require between 0.84 and 1.3 cubic meters of water for each I kilogram of yield, it takes about 12.6 [m.sup.3] of water to produce 1 kg of beef. Even though meat and other animal products made up only 16 percent of the typical Chinese diet in 2003, those foodstuffs accounted for more than one-half of the country's food-related per capita water consumption, says Liu. He and colleague Hubert H.G. Savenije of the Delft University of Technology in the Netherlands report their findings in an upcoming Hydrology and Earth System Sciences.

Food-related water consumption per capita in the United States is about 3,074 [m.sup.3] per year, almost four times the Chinese figure. The water needed to produce the typical U.S. citizen's consumption of meat alone exceeds that required to produce the average Chinese diet, the researchers note.

The recent trend toward increased meat consumption in China is aggravating the country's relative shortage of water, says Sandra Postel, director of the Global Water Policy Project in Amherst, Mass. While the nation is home to about 21 percent of the planet's population, it has only 8 percent of its renewable water resources, she notes. More than one-third of the world's population lives in regions where water is considered scarce (SN: 7/20/02, p. 42).

In 2003, production of the food consumed in China required about 1,023 cubic kilometers of water, Liu and Savenije estimate. If current trends in dietary preferences continue, some population-growth scenarios suggest that the total water required for the country's food production could rise more than 11 percent by 2025, even taking into account proposed technological advances that could trim water use more than 1 percent each year.

Now, imports account for only 3 percent of the cereals and meat consumed in China, says Liu. In the coming decades, growing demand for these products--and the county's limited supply of water--may boost that figure to around 8 percent.

Postel agrees: "I absolutely believe they'll need to import more food in the coming decades." That increase in demand, in turn, will probably boost prices in commodity markets worldwide, she notes.