Debate
Water supply: the world's next challenge.

Water is a finite resource: there is a fixed amount on the planet which can be neither increased nor decreased; however, water is continually recycled and purified by the hydrological cycle. An increasing scarcity of fresh water is now a major threat to global agriculture, food security, health and peace among nations. There are growing fears that large dams and irrigation programmes are a technological dead end, impoverishing the countries they are supposed to set on the path to prosperity. How we manage our rivers, and even larger stocks of fresh water, is likely to become one of the major technical and political issues of the next few decades. As the wells run dry, the politics of water will become as important as the politics of oil. Two things can be done to reduce water scarcity; the first is to increase supplies; the other is to use water more efficiently. In both cases the human factor is crucial. According to the World Meteorological Organisation (WMO) water use has risen six fold since 1900, more than double the rate of population growth. With the world's population projected to top 8bn by 2025 from 5.7bn now, freshwater supplies will not be able to keep pace. New Agriculturist brings you the latest figures and predictions about water and the looming crisis.

Scarcity and misuse of fresh water poses a serious and growing threat to sustainable development and protection of the environment. Human health and welfare, food security, industrial development and the ecosystem on which they depend, are all at risk, unless water and land resources are managed more effectively, in the present decade and beyond, than they have in the past.
Statement from the Dublin Conference on Water and Sustainable Development, which led up to the Rio Earth Summit

In Asia, where most of the world's population growth, and thus additional food needs, will occur, many rivers run dry for all or part of the dry season - including the mighty Ganges. In 1995, the lower stretch of China's Yellow River was parched for a third of the year. Africa now has nearly 300 million people living in water-stressed countries, many of which are already heavily dependent on food imports.
Worldwatch Paper 132. Dividing the waters: Food security, Ecosystem Health, and the New Politics of Scarcity. Sandra Postel

Countries with freshwater resources in the range of 1,000-1,600 cubic meters per capita per year face water stress. Currently, 28 countries with a total population of 338 million are considered water stressed, and 20 of these countries are water scarce. Water shortages will increase dramatically in the next 30 years.
Food, Agriculture, and the Environment Discussion Paper 20. IFPRI. Water Resources in the Twenty-First Century: Challenges and Implications for Action. Mark W. Rosegrant

In Dakar, the capital of Senegal, the water supply often has to be cut for hours as the demand for water greatly exceeds the supply (a deficit of 100,000 cubic metres per day). The water extraction cannot be easily increased due to the danger of salinating the water as the sea-water front encroaches as the freshwater levels drop.
Botswana Daily News, "Tapping into the old and the new" by Susanna Thorp

At least 214 rivers flow through two or more countries, but no enforceable law governs the allocation and use of international waters. As world population expands by 2.6 billion over the next 30 years, water problems will intensify.
Food security, Ecosystem Health, and the New Politics of Scarcity. Sandra Postel

The Tigris and Euphrates Rivers rise in Turkey and flow through or along Syrian territory before entering Iraq. Tensions escalated with the construction by Turkey of the Greater Anatolia Project (GAP) on the Euphrates in south-east Anatolia. GAP will include 21 dams irrigating 1.65 million hectares. The centrepiece of the project is the Ataturk Dam. In order to begin filling the reservoir behind the dam, Turkey stopped the flow of the Euphrates entirely for one month, rekindling tensions with Iraq and Syria.
McCaffery SC 1993. Water, politics, and international law. quoted in Food, Agriculture, and the Environment Discussion Paper 20. IFPRI. Water Resources in the Twenty-First Century: Challenges and Implications for Action. Mark W. Rosegrant

At global level, it is clear that, as water becomes progressively more scarce in the major crop producing nations, international trade in agricultural commodities will increasingly be determined by the amount of water required to produce crops. Carruthers (1993) contends that, in the future, the Asian nations will become the greatest exporters of industrial products while the western nations will specialize in food exports. The economic logic of water lends support to that hypothesis.
The New Era of Water Resources Management: From "Dry" to "Wet" Water Savings by David Seckler CGIAR

Most of the growth in food production needed to meet population increases over the past four decades has resulted from an expansion of the area of irrigated agriculture. More than a third of all crop production now comes from the one-sixth of arable land that is irrigated.
Water for life, World Food Day, Food and Agriculture Organisation of the United Nations

One way of using scarce water resources more efficiently is to use lower-quality water, such as drainage water and treated waste water from towns, cities and industry. This practice is being increasingly applied in a number of developing countries, particularly those in arid areas such as parts of China, Egypt, Israel, Jordan and Kuwait, where it is proving cost-effective. Israel's national policy is now to reuse all waste water.
Water for life, World Food Day, Food and Agriculture Organisation of the United Nations

In many irrigation systems, water is lost at every stage between the source and the crop. In Asia, for example, 20 percent of irrigation water is typically lost between reservoir and irrigation area, a further 15 percent of what remains is lost in distribution and 25 percent of even that is wasted in the field. This gives an overall efficiency of about 40 percent; this means that 2,500 cubic metres of water may have to be used to produce a tonne of cereal.
Water for life, World Food Day, Food and Agriculture Organisation of the United Nations

The challenge is to find ways of making more water available for agriculture without exceeding natural refill rates. Farmers in areas where water conservation has always had to be a priority have developed systems that could act as a model in those regions where water scarcity is a recent threat. The most promising new technical solutions are those which have improved upon these traditional farming systems.
Spore no 57, CTA

Water harvesting, the capture and diversion of rainfall or floodwater to fields to irrigate crops, has been used for centuries in traditional agriculture. The improvement and expanded use of such techniques can increase production and farm income in some environments.
Food, Agriculture, and the Environment Discussion Paper 20. IFPRI. Water Resources in the Twenty-First Century: Challenges and Implications for Action. Mark W. Rosegrant

"Water is emerging as a major constraint on efforts to expand food production in Central Northern China, in parts of India, the Southern Great Plains of The United States, throughout North Africa and the Middle East. As the demand for water in countries pushes up against the limits of supply, as it now is in Central and Northern China for example, then in the competition between cities and countryside, which the cities almost always win, farmers lose the irrigation water. As they lose the irrigation water then that loss has to be offset by grain imports. To import a ton of wheat is. in effect. to import a thousand tons of water, so grain becomes the most efficient way to import water if you are a country facing acute water scarcity. And that's what we are beginning to see all over the world now."
Dr Lester Brown, President of the Worldwatch Institute in Washington speaking on The Farming World, BBC World Service

The history of hydropolitics along the rivers of the Middle East exemplifies both the worst and the best of relations over international water. While shared water resources have led to, and occasionally crossed, the brink of armed conflict, they have also been a catalyst to co-operation between otherwise hostile neighbours, albeit rarely and secretively.
Middle East Water Conflicts and Directions for Conflict Resolution by Aaron T. Wolf. Food, Agriculture, and the Environment Discussion Paper 12, IFPRI

Agriculture is by far the biggest consumer of water world-wide. In Asia it accounts for 86% of total annual water withdrawal, compared with 49% in North and Central America and 38% in Europe. Irrigated rice, in particular, is a heavy consumer of water: it takes some 5,000 litres of water to produce 1 kilogram of rice. Compared with other crops, rice production is less efficient in the way it uses water. Wheat, for example, consumes only 4,000 cubic metres per hectare, while rice consumes 7,650.
Water, a looming crisis - IRRI, International Rice Research Institute

The watering of crops currently uses something like 3300 cubic kilometres of water a year - roughly six times the requirement for industrial and domestic uses..... Irrigation is a wasteful process. Less than half of all irrigation water reaches the crop it is designed to water."
Water: the International crisis by Robin Clarke, Earthscan Publications

"We can talk about irrigated land as a future strategy, beginning to invest in irrigated land. Now those who say this cannot be one - it is too expensive - are not necessarily correct. Because it's a question of priority. You can see in Southern Africa - it is not the wettest part of Africa - yet South Africa has been able to feed itself for a very long time because they have invested in irrigation dams in Zimbabwe, in Botswana and also within South Africa itself."
Michael Foster of the Sasakawa African Foundation speaking on The Farming World, BBC World Service

Water was a critical input to the Green Revolution, through irrigation, flood control, and drainage, and it has contributed most to the growth in rice production for the past 30 years. But this expansion has been bought at a cost to the environment: a proportion of the chemicals applied as fertilizer and as pest and weed control pollutes rivers and lakes through runoff, or groundwater through leaching.
Water, a looming crisis - IRRI, International Rice Research Institute

Sustainable agricultural development depends on sustainable water use and food security depends on water security. Policy makers, water engineers and the end-user on-farm have to give greater thought to the wiser use of water. From the commercial farmer pumping water to irrigate high value export crops to the woman carrying water on her head, raised from a distant well in order to water the vegetable plot, water is too valuable to waste.
Spore no.57, CTA

"We need a Blue Revolution in water supply and sanitation like the Green Revolution in food production. But even new approaches to water use can only outrun population growth for so long. We need to address demand as well as supply."
Pamela LeRoy, policy analyst at Population Action International - USA and co-author of Sustaining Water: Population and the Future of Renewable Water Supplies

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