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Chapter 7. Raising Water Productivity: A Global Full-Court Press
As fast-unfolding water shortages translate into food shortages, they will signal that we can no longer rely on incremental business-as-usual change. Three factors—the simultaneous drop in water tables, the exponential nature of that fall, and the globalization of water scarcity—ensure that such a response will not be sufficient. As water shocks become food shocks and as falling water tables translate into higher food prices, we will realize that the world has changed fundamentally. As Asit K. Biswas, Director of the Third World Centre for Water Management, notes, "The world is heading for a water crisis that is unprecedented in human history. Water development and management will change more in the next 20 years than in the last 2,000 years."42
Supply-side technological fixes, such as the massive desalting of seawater, do not hold much hope for food production in the foreseeable future. Although the cost of desalting seawater is falling, it is still expensive and thus not yet a viable prospect for irrigation. At present, it costs between $1 and $2 per cubic meter to desalt seawater. Even at the lower cost, producing wheat with desalted seawater would raise its price from $120 to $1,120 per ton.43
Some countries are still focusing on supply expansion when it might be less costly to focus on demand management. To get water to the cities in its industrial northern half, including Beijing and Tianjin, China has devised a plan to move water along three routes from the Yangtze River basin to the Yellow River basin, since the latter has only one tenth the flow of the former. These three routes, designated the East, Central, and West, will cost an estimated $59 billion. Construction on the East route began in December 2002. For China, it might be more economical to invest this $59 billion in urban water recycling and irrigation efficiency in the north rather than trying to transport water from the south.44
With water shortages now threatening so many countries at the same time, we need a global full-court press, to borrow an expression from basketball, to raise water productivity. This begins with improved irrigation practices and technologies, as described in this chapter. It also includes boosting crop yields on both irrigated and nonirrigated land. The former will raise the productivity of irrigation water and the latter will get more mileage out of existing rainfall. Shifting to more water-efficient crops also helps raise farm water productivity. The shift from rice to wheat, already under way in some countries, can continue wherever it is practical. With feedgrain, shifting from corn to sorghum may make sense in countries where there is not enough water for irrigation.
At the dietary level, shifting to more grain-efficient forms of animal protein can raise the efficiency of grain use, and thus the efficiency of water use. This means moving from feedlot beef and pork to more poultry and herbivorous species of farmed fish, such as carp, tilapia, and catfish. For the world's affluent, moving down the food chain also saves water.
At the consumer level, switching to more water-efficient household appliances raises water productivity. For cities and industry, recycling of water becomes the key to achieving large gains in water productivity. Finally, and perhaps most important, for water-scarce countries facing large projected increases in population, accelerating the shift to smaller families reduces the chance of being trapped in hydrological poverty.
42. Asit Biswas, "Water Crisis: Current Perceptions and Future Realities," in Groundwater: Legal and Policy Perspectives, Proceedings of a World Bank Seminar (Washington, DC: Salman, 1999), p. 1-11.
43. Calculation based on Peter Wolff and Thomas M. Stein, "Efficient and Economic Use of Water in Agriculture-Possibilities and Limits," National Resources and Development, vol. 49/50 (1999), pp. 151-59.
44. Erik Eckholm, "Chinese Will Move Water to Quench Thirst of Cities," New York Times, 27 August 2002; "Per Head Water Resources on Decline Along Yangtze," Xinhua News Agency, 31 December 2002.
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