Scientists search for a way to avert world water crisis Severe shortage could affect one-third of global population - 2.7 billion people - by 2025, according to predictions By Steve Connor Science Editor 14 August 2001
http://news.independent.co.uk/uk/environment/story.jsp?story=88564
Traditional technology offers hope to the poorest A worldwide water shortage is likely to worsen severely over the next 25 years with billions of people affected by an unprecedented global crisis affecting the Earth's most precious natural resource.
As scientists, agriculturalists and environmentalists from around the world gather at the Stockholm Water Symposium this week, the latest predictions on freshwater availability portray a bleak future for the children of today.
Already some 450 million people in 29 countries face serious water shortages affecting the wealthiest and poorest nations, whose expanding economies and populations are chasing fewer sources of fresh water.
Professor Frank Rijsberman, director general of the International Water Management Institute, which helped to organise the Stockholm summit, said: "If current trends continue, the shortage of water will extend well beyond the semi-arid and arid regions. Expanding demand for water will drain some of the world's major rivers, leaving them dry throughout most of the year.
"Urban centres will experience severe water shortages. But the rural poor will suffer the most serious consequences. Many already lack access to potable water and to the quantity and quality of water needed to grow food and generate income."
The Stockholm meeting is one of several planned before the World Water Forum in Kyoto in 2003. The aim is to produce agreement between the leading international bodies on food, agriculture and the environment.
The water shortages have been spreading over recent decades as more land is swallowed up for farming and irrigation and growing populations produce more water-borne pollution.
Agricultural scientists say irrigated farmland has to expand by up to 20 per cent over the next 25 years to feed a rising population. But environmental scientists have warned that water consumption has to fall by at least 10 per cent on current levels to protect rivers, lakes and wetlands.
The crisis will be made worse because what little freshwater there is is becoming polluted with industrial effluent and a rise in water-borne diseases caused by raw sewage.
The International Water Management Institute predicts that by 2025 about 2.7 billion people – a third of the world population – will live in regions faced by regular and severe water scarcity. Asia and sub-Saharan Africa will be hit hardest.
Vast areas of the world already face shortages of varying severity, including the entire Mediterranean region, Pakistan, parts of India and China, most of southern Africa, and major regions in North and South America.
A report published earlier this year by the American Association for the Advancement of Science found that fresh-water sources were dwindling or becoming contaminated at an unsustainable rate. The association's report says: "Water withdrawals from rivers and underground reserves have grown by 2.5 to 3 per cent annually since 1940, significantly ahead of population growth.
"Water tables are falling on every continent. Shortages are having an increasing effect on global grain markets, as arid countries that rely on irrigation for crop production are switching to food imports."
Irrigation causes a build-up of salts in the soil which eventually leads to salinity levels rising to a point where crops can no longer be grown. Farmers, if they can, then move on to pollute other land with further irrigation schemes.
William Cosgrove, vice- president of the World Water Council, says: "It is clear that more irrigation cannot be the only solution ...In developing countries, irrigation today accounts for more than 80 per cent of the water consumed, so that the debate among agriculturalists and environmentalists on how to manage water for agriculture is of paramount importance to the very poor."
Half the irrigated land of Asia is used to grow rice, a thirsty crop for which 2,000 tons of water are needed to grow just one ton of grain. Yet by 2025, more than half of the world's population will depend on rice at its staple food. In parts of Africa, Tanzania for example, mangrove swamps are being cut down to make way for rice production. But after five years the soil becomes infertile and new mangroves have to be cut down to maintain yields.
The International Water Management Institute says: "Irrigation projects often do not generate the benefits they promise. Irrigation schemes in the Senegal river [Mauritania] and the Waza river [Cameroon] have not met their targets for agricultural production by far.
"In Mauritania, an area once teeming with birdlife, researchers counted exactly two birds in 1994.
"In both Mauritania and Cameroon, the local communities, fishermen and nomadic herders bore the costs: no fish or grazing grounds were to be found, and local communities were forced to emigrate from the floorplan."
In parts of south-east Asia, the stories are the same. In Vietnam alone, the area of land that is now irrigated had doubled over the past 20 years, most of it for rice paddies. Nearly of third of this land, however, has deteriorated to a point where yields are diminishing.
But it is not just rice; cereal crops are also causing problems. Groundwater levels in parts of Spain have fallen by up to five metres because of farmers irrigating wheat, maize and vegetable crops. The underground aquifer of La Mancha is currently being used at between two and three times the rate at which it is recharged.
In many areas of the world, over-extraction of groundwater has prompted inundation by saltwater, leading to contamination of remaining freshwater supplies. Scientists estimate that in Florida, which is 90 per cent dependent on groundwater, water is being extracted three times faster than its replenishment rate.
http://news.independent.co.uk/uk/environment/story.jsp?story=88564
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