Agua virtual

China’s Water Scarcity and Virtual Water
Junguo Liu * SIAM, EAWAG, Ueberlandstrasse 133, CH-8600 Duebendorf, Switzerland e-mail: Junguo.liu@eawag.ch Hong Yang SIAM, EAWAG, Ueberlandstrasse 133, CH-8600 Duebendorf, Switzerland e-mail: Hong.yang@eawag.ch ABSTRACT In this paper, we highlight the interrelation between water, food production and virtual water trade in China. The literature reviewshows that there will be 10 % of the food deficit unsatisfied by the domestic food production if the agricultural water is balanced in 2010 and 2030. Virtual water strategy seems to be a prominent perspective to fill in this gap. It is concluded that most of the grains fall into the categories of median or high water intensive crops and have low unit water value (UWV), while fruits and vegetableshave lower virtual water content (VWC) and higher unit water value in China. Therefore, China has a comparative advantage of water use in fruits and vegetables and a comparative disadvantage in grains. A strategic restructuring in agriculture should take the comparative advantage into account because increasing water scarcity may likely constrain future domestic food production in China. Virtualwater has already played an important role in militating China’s water scarcity for long. There is an average annual net virtual water import flow of 31 Gm3/yr coming into China during the period of 1992 to 2001. This accounts for 8 % of the total agricultural water use. If taking the agriculture water efficiency of 45 % into account, this percentage will be much higher A more free internationalmarket after China’s accession to WTO will inevitably lead to more virtual water entering China’s territory through importing more grains. Keyword: water scarcity, food security, virtual water, trade, China 1. INTRODUCTION Water scarcity and food security are closely interrelated in China. To guarantee the food security with such a huge population of nearly 1 billion, agriculture has been given high .3priority in China (China Agenda 21, 1994). As population continues its fast pace and land resources remain declining, many measures have to be taken to improve the agricultural output per unit of land considering China’s basic agricultural policy of food self-sufficiency. Water has played, and will continue to play, a paramount important role in improving the food production. In the past,irrigation has been crucial in increasing crop yields and facilitating the shift to new technologies and more intensive cultivation (Huang et al., 2002) . The yield and income, including those of poor, are raised by between 30 and 100 % when cultivated area is irrigated (Huang et al., 2002). At present, about three fourth of China’s grain
*Corresponding author.

production comes from irrigated land,accounting for 40% of China’s total arable land (Zhang, 1999). In the near future, China has to depend on the irrigation instead of the rain-fed agriculture to support the annual population growth of 12 million over the first half of 21st century considering the higher crop yields from irrigated areas. However, increasing sever water shortages may constrain future yield rises (Huang et al.,2002).With the rapid economic growth, domestic and industrial water demand is experiencing an unprecedented increase, which leaving the water uses among sectors more competitive. The result has typically been a reallocation of agricultural water to the industrial and domestic sectors and a compromise of environmental water needs (Yang and Zehnder, 2001). It is indicated that the share of agriculturalwater use has declined from 83.4 % of the total water uses in 1980 to 69.2% in 1999 (Liu and Chen, 2001). The increasing water scarcity in many areas and the large water consumption in agricultural sector provoke the question whether China should produce all water-demanding products domestically or it can import part of water-intensive products from other water rich countries. Because of the large...