Growing World Population Faces Shrinking Water Supply
Environment News Service
WASHINGTON, DC, (ENS) - Increasing water shortages may lead to global hunger, civil unrest and even war, according to Sandra Postel, director of the Global Water Policy Project and senior fellow with the Worldwatch Institute. In her new book, "Pillar of Sand: Can the Irrigation Miracle Last", Postel joins the growing ranks of experts warning the world to reduce water use now to avoid serious problems later.
With population growing rapidly in many of the world,s most water short regions, water problems are bound to worsen. The number of people living in water stressed countries is projected to climb from 470 million to 3 billion by 2025, Postel notes. Many countries do not have a coherent national water policy, and there are few international agreements on sharing water from rivers and lakes that cross international borders.
In March, the United Nations and many world governments celebrated World Water Day, drawing attention to world water needs and examining ways of addressing those needs. Sri Lanka based International Water Management Institute (IWMI), a research center of the Consultative Group on International Agricultural Research, released a study predicting that a third of the world's population will experience severe water shortages within the next 25 years.
Access to clean water can mean the difference between health and disease for millions of children.
The United Nations Environment Programme (UNEP) announced that the number of people without access to safe drinking water will jump from 1.4 billion to 2.3 billion in 2025 unless governments take faster action to address water shortages.
UNEP calculates that safe water and sanitation could be provided throughout the world for an estimated $50 to $105 per person per year. Unless governments commit to spending money on cleaner water supplies, three million to five million people, most of them children, will continue to die each year from diseases carried in dirty water.
The UN estimates the price of bringing safe water to those who need it would be $23 billion to $25 billion per year over eight to 10 years. Current world investment in clean water supplies is only $8 billion. The $15 to $17 billion shortfall is about the same amount spent every year on pet food in the U.S. and Europe. "This is the absolute minimum that the world community must provide to the world's poor without water," said Hans van Ginkel, rector of United Nations University.
In her book, Postel focuses on the dangers to the world,s food supply from water shortages. Water tables are dropping steadily in several major food producing regions as groundwater is pumped faster than nature replenishes it, she says. The world's farmers are racking up an annual water deficit of some 160 billion cubic meters - the amount used to produce nearly 10 percent of the world's grain.
Traditional spray irrigation loses about a third of the water to evaporation and winds.
About 60 percent of the increased food production needed to sustain a projected world population of eight billion by 2025 will be produced using irrigation, the UN Food and Agriculture Organization said in March. Rain fed agriculture will not be able to keep pace with growing needs. Irrigation currently accounts for two thirds of global water use, but less than half that water reaches the roots of plants. "Without increasing water productivity in irrigation, major food producing regions will not have enough water to sustain crop production," says Postel.
"Some 40 percent of the world's food comes from irrigated cropland," said Postel, "and we're betting on that share to increase to feed a growing population." But the productivity of irrigation is in jeopardy from the over pumping of groundwater, the growing diversion of irrigation water to cities, and the buildup of salts in the soil.
Water short countries are increasingly turning to the world grain market. Jordan imports some 91 percent of its grain, Israel 87 percent, Saudi Arabia 50 percent, and Egypt 40 percent. Postel suggests some simple, inexpensive solutions to help these countries and others double their water productivity and agricultural yields.
Some of these techniques are already being used. Farmers in India, Israel, Jordan, Spain and the U.S. have shown that drip irrigation systems that deliver water directly to crop roots can cut water use by 30 to 70 percent and raise crop yields by 20 to 90 percent.
In low energy spray irrigation, water is directed at the ground instead of the air, retaining more than 90 percent for the plants.
In the Texas High Plains, farmers using highly efficient sprinklers raised their water efficiency to more than 90 percent while simultaneously increasing corn yields by 10 percent and cotton yields by 15 percent.
Rice farmers in an area of Malaysia saw a 45 percent increase in water productivity by better scheduling their irrigations, shoring up canals, and sowing seeds directly in the field rather than transplanting seedlings. In Australia, 233 communities are getting upgraded water supply systems powered by solar energy.
These projects are rays of hope in an otherwise bleak situation. As IWMI director general David Seckler says, "Water scarcity is now the single greatest threat to human health, the environment and the global food supply."