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Addressing Water Security: The Role of Science and Technology Henry Vaux University of California, Berkeley M anaging the worldâs water resources to address problems of water security will be one of the great challenges of the twenty-first century. Problems of water security typically occur on local and regional scales. Yet such problems are so pervasive that it is reasonable to think of them in global terms. Globally, the single largest problem is scarcity. In many regions, existing water supplies are inadequate to serve existing demands for municipal, industrial, agricultural, and environmental uses. This scarcity will intensify as world popula- tion increases by several billion or more over the next 30 years. Moreover, current levels of supply will almost surely be reduced because of groundwater overdraft, which is found in virtually every region of the world; declines in water quality, including soil salinization; and global climate change. Water security can be defined at different levels. The first is the security of supplies needed for drinking, cooking, and sanitation. Although there is ample water to meet the basic personal needs of the entire population of the globe now and for the foreseeable future, a billion people lack access to good-quality drinking water and twice that number or more lack access to adequate sanitation services. This circumstance can be attributed in part to the fact that the avail- ability of water is highly variable over the Earthâs surface. Some regions do not have adequate supplies of adequate quality to provide for personal use in all seasons. The second level of security focuses on the adequacy and sustainability of water for agriculture. Agriculture is the largest consumptive user of water worldwide. Irrigated agriculture is known to be more productive than rain-fed agriculture. As the population grows, increasing numbers of countries will lack the indigenous water supplies necessary to grow the food needed to feed their own populations. 39
40 OBSTACLES AND OPPORTUNTIES IN THE APPLICATION OF S&T A third level of water security is water for the environment. Environmental uses of water yield environmental services such as air and water purification, production of biomass, genetic diversity, and environmental stability, as well as amenity services. Competition for water from urban and agricultural uses t Âhreatens the adequacy of supplies for environmental purposes. Developing coun- tries with high rates of population growth are unlikely to have adequate supplies for environmental services and amenities in the future. Globally, total water supplies are probably insufficient to provide people in every locale and region of the world with complete water security at each of these three levels all of the time. However, in many regions and locales it will be possible to do a better job of providing water security than what is being done currently. At the outset, it is important to acknowledge that there is much existing scientific infor- mation that could be helpful that is not being used. The scientific community needs to find ways of explaining, communicating, and educating that are more effective than in the past. Even significant success at this task will not obviate the need for additional science and technology. Indeed, the development and application of additional science and technology will be crucially important if food and water shortages are to be averted and the various water-based environmental services and amenities are to be protected. The remainder of this paper emphasizes the role and contributions of science in addressing the worldâs water problems. SECURITY OF SUPPLIES FOR PERSONAL USE More than one billion people currently lack access to drinking water supplies of appropriate quality. These people have no alternative but to drink contaminated water, and this results in more than 50 million deaths annually and an incidence of waterborne diseases rarely seen in the developed world. Even in developed countries, advanced water treatment technologies such as chlorination fail to pro- vide complete protection against some pathogens, for example, cryptoÂsporidium. More than 2 billion people lack access to adequate wastewater treatment and sanitation services. Water quality is degraded, resulting in increased incidences of waterborne diseases beyond what can be attributed to simple lack of adequate drinking water supplies. In short, many of the worldâs poor, particularly those in developing countries, pay horrific costs in terms of morbidity and mortality because of the absence of adequate security of water supplies for personal use (Jury and Vaux, 2005). The problem of personal water security can be attributed to scarcity, to the lack of infrastructure to distribute water, and to a generalized failure to protect and enhance water quality. Water and wastewater treatment technologies are expensive, and the need to tailor them to site-specific circumstances makes them even more costly. Such technologies are not viable in the poorest parts of the world because of their cost. The consequence is that small-scale, decentralized technologies are and will be very important. There are a number of âsoft-pathâ
ADDRESSING WATER SECURITY 41 technologies that can increase the overall productivity of water at the basin level. These include treadle pumps, which are manually operated, low-cost diesel pumps, and simple technologies for treating drinking water and managing waste- water. Further efforts to refine and develop new soft-path technologies are likely to have very significant benefits (Rijsberman, 2004). In the developed world, advances in membrane technology are about to culminate in a revolution that will allow larger volumes of water to be treated less expensively than in the past. Although seawater conversion remains too costly for most circumstances, the costs of desalinating brackish waters are now competitive in many of the arid and semiarid portions of the developed world. Bioreactors also offer the prospect of significant gains in the productivity and efficiency of wastewater treatment processes. There may be opportunities to develop applications of these new technologies that are relatively inexpensive and can be easily employed in the developing world. These applications can be realized only through additional investment in research and development, and it appears that only the developed world has the financial resources to make such investments (NRC, 2003). SECURITY OF WATER SUPPLIES FOR AGRICULTURE The security of water for agricultural purposes is a matter of great concern. The projected increase in population would seem to require an expansion of irri- gated acreage at a time when other factors, such as growing urban regions and urgent demands for water for the environment, indicate that agriculture may have to shrink. As previously noted, agriculture is the largest consumptive user of water worldwide and in most individual regions. The problem can be placed in stark perspective by some analyses based on the proposition that each person requires 1,500 m3 of water annually for personal use and for growing the food needed for adequate and healthy nutrition. A common classification scheme defines countries with 1,000â1,500 m3 per capita annually to be under water stress, those with 500 â1,000 m3 per capita annually to be experiencing water scarcity, and those with less than 500 m3 to be experiencing extreme water scarcity (Falkenmark and Rockstrom, 2004; Zehnder, 2004). The distribution of per capita water endowments worldwide for the year 2000 shows that there were a number of countries that had less than 1,500 m3 per capita and were thus unable to grow all of the food needed to feed their populations. Those countries include many in the Middle East and Africa. When the effects of anticipated population growth between 2000 and 2025 are taken into account, the picture changes for the worse. Those countries with less than 1,500 m3 by 2025 would include all of the countries on the Horn of Africa and in southern coastal Africa as well as in North Africa. Furthermore, Afghanistan, Iran, and India fall into this category, and China is likely to unless it can develop virtually all of its surface water supplies (Zehnder, 2004).
42 OBSTACLES AND OPPORTUNTIES IN THE APPLICATION OF S&T In these circumstances, typically countries that are water-short begin to import food. Since it takes some amount of water to grow food crops, import- ing food is equivalent to the act of importing water. This water is often called âvirtual water.â Statistics for Israel show how a country with inadequate water supplies can offset that inadequacy by importing virtual water. When the virtual water is counted, annual per capita supplies move toward the 1,500 m3 figure. The evidence shows that countries with inadequate water supplies also respond by importing cereal grains. This finding is borne out for virtually every country with inadequate water (Zehnder, 2004). This means that the intensifying world water scarcity is likely to affect the water-rich developed countries in the form of increased demands for cereal exports. The largest cereal exporters are the United States, France, Canada, Argentina, and Australia. The ability of these countries to significantly expand cereal exports is a serious issue. The western United States and Australia have their own problems of water scarcity, and it is questionable how much additional water, if any, can be made available for agricultural purposes. Although Canada is water rich, 90 percent of its waters flow north to the Arctic while 90 percent of the population lives within 100 miles of the U.S. border; and agricultural lands are, for the most part, not in the basins flowing north. The result is that the strategy of offsetting water shortages by importing virtual water may not be indefinitely expandable because water-rich countries of the Americas and Europe will ultimately be subject to their own water constraints. The ability of developing countries to generate foreign exchange with which to purchase cereal grains may be quite limited. This could also be a problem. The need is for innovation that will make irrigated agriculture a more effi- cient user of water through increasing the economic productivity of water in agri- cultural use. The first requirement is to pair appropriate crops with appropriate growing environments (e.g., rice is not an appropriate crop for a desert environ- ment). Second, the opportunities for improvements in on-farm water management are large and entail the use of existing information as well as the generation of new science. Advanced irrigation technology that allows growers to apply water with great precision and improvements in irrigation scheduling are among the most promising avenues. In addition, work on the moisture stressing of crops at strategic points in the life cycle or annual cycle has promise of leading to water management regimes that produce high-quality crops with little penalty in terms of quantities. The results of this work may be equally of benefit to developing and developed countries (Jury and Vaux, 2005). ENVIRONMENTAL WATER SECURITY The need for improving the economic productivity of water in agriculture is driven not just by the growing demand for food and fiber but also by the need to preserve some water to allocate for environmental purposes. Historically, water
ADDRESSING WATER SECURITY 43 for the environment has been the supplier of last resort. That is, when additional water was needed for urban areas or to support irrigated agriculture, the resulting impoundments and diversions led to a decline in the quantities of water available for environmental purposes. Today, with widespread recognition of the value of environmental services such as biodiversity and water purification as well as the amenity values of aquatic and associated terrestrial ecosystems, the supplier of last resort is frequently thought of as agriculture. Nevertheless, as the global demand for food and fiber grows, it may be very difficult to find sufficient water to maintain aquatic ecosystems. Indeed, one of the dilemmas of the emerging water situation is that the need for additional water to serve agriculture may result in the loss of environmental stability and sustainability in many parts of the world. Thus, any improvement in the economic productivity of agricultural water use probably means there will be more water for the environment (Jury and Vaux, 2005). One of the great difficulties with environmental uses of water is that so little is known about them. There is some evidence to suggest that damages to ecoÂ system values may not be especially large until some critical threshold is reached. More research is needed to confirm this and to identify that threshold. Interrela- tionships between aquatic ecosystems and terrestrial ecosystems are known to be important, but they have not been clearly identified and described. Science can also contribute to the resolution of conflicts, for example, between water devel- opment and preservation of species. It seems clear that the costs associated with underallocating water to the environment could be very high. However, much more certainty and definition will be required to confirm this supposition. Without such confirmation, learning from experience could be enormously expensive and unpleasant. ADDITIONAL CONCERNS Finally, there are two overarching areas that will need continuing and even increased attention from the scientific community if global water problems are to be addressed successfully. The first is global climate change. The general implications of global climate change for water supply are understood but the implications for specific regions at specific latitudes are more difficult to forecast. It does seem clear that climate change will entail increasing frequen- cies for extreme events such as floods and droughts. With further research the forecasting of climate change impacts should become more reliable, and more detailed information on regional and local implications will become available. Nevertheless, some uncertainty will remain and will have to be managed. As a general rule, the prescription calls for maintaining as much flexibility as pos- sible to enhance adaptation to climate change as it occurs. This points to the importance of devising appropriate institutions and policies, and that leads to the second concern.
44 OBSTACLES AND OPPORTUNTIES IN THE APPLICATION OF S&T For the most part, current institutional arrangements for managing water were developed in different eras to achieve purposes that differ from todayâs pri- mary need, which is to manage scarcity flexibly. Water management institutions around the world suffer from a tendency to focus too narrowly on the achievement of single rather than multiple water management objectives. Institutions tend to be fragmented, and there is minimal coordination among them. The consequence is a general failure to manage water holistically. Existing institutions also tend to divide concerns about water quality and water quantity artificially, contribut- ing further to a lack of holistic management. Finally, most water institutions are not at all suited to deal with problems of scarcity. Despite the need for innova- tive and creative institutional arrangements, financial support of social science research related to the management of water resources has almost disappeared. Research in the social sciences is every bit as important as research in the more traditional physical and biological sciences if water problems are to be success- fully addressed. The picture that emerges from this analysis is that global water problems are now serious and are likely to become more serious as the population grows and as the economies of the world expand. Failure to use existing science and failure to invest in new science will make the problem of managing the intensifying global water scarcity difficult or impossible to address. Finally, as important as scientific research will be, improving the capacity of the scientific community to explain, communicate, and educate may be of equal importance. REFERENCES Falkenmark, M., and J. Rockstrom. 2004. Balancing Water for Humans and Nature. London: Earthscan. Jury, W. A., and H. Vaux, Jr. 2005. The role of science in solving the worldâs emerging water prob- lems. Proceedings of the National Academy of Sciences 102(44):15,715â15,720. NRC (National Research Council). 2001. Envisioning the Agenda for Water Resources Research in the Twenty-First Century. Washington, DC: National Academy Press. Rijsberman, F. 2004. Sanitation and access to clean water. Pp. 498â527 in Global Crises, Global Solutions, Bjorn Lomborg, ed. Cambridge, UK: Cambridge University Press. Zehnder, Alexander. 2004. Feeding a more populous world. Paper presented at Sackler Colloquium on the Role of Science in Solving the Earthâs Emerging Water Problems, Irvine, CA, October 8â10. Abstract available at: http://www.nasonline.org/site/PageServer?pagename=SACKLER_ water_zehnder. Accessed March 30, 2008.