By JOE GROSSMAN, UPI Science News

Aug. 21 (UPI) - - Severe droughts in many regions of the world are giving citizens and national governments a taste of what is widely described as an emerging global water crisis. Increasing standards of living, growing populations and the need for greater food production are driving increased demands for water. Worldwide, agriculture accounts for about 80 percent of all water used each year.

Some areas which normally have limited rainfall and scarce water supplies, such as countries immediately south of the Sahara desert, are experiencing even lower than normal rainfall coupled with expanding populations. Senegal, Mauritania, Mali, Ghana, northern Nigeria, Chad, Sudan, Eritrea and Ethiopia are currently experiencing difficult water situations. Northern India and much of Pakistan are suffering drought. Most of Iran is in the third year of a severe drought. Areas of China have succumbed to years of mismanagement with resultant droughts. The Middle East is also experiencing water scarcity.

Northern Nicaragua, eastern Guatemala, eastern El Salvador and much of Honduras have been hit. Low rainfall on the Canadian prairie is expected to reduce yields of grains by 20 to 30 percent this fall in southern Alberta and Saskatchewan. In parts of the American west, competing environmental and agricultural needs have seen farmers take water by force several times this summer.

Agricultural drought is considered to be occurring when there is not enough water for crops or livestock. Specialists in water resources contacted for this article did not think there was a global drought, however all seemed comfortable with the notion that there is a global crisis.

The Consultative Group on International Agricultural Research (CGIAR), with 8500 scientists and scientific staff working to improve tropical agricultural productivity, states that 25 percent of the world's population will experience severe water shortage sometime by 2025.

Frank Rijsberman, director general of the International Water Management Institute (IWMI), one of CGIAR's 16 affiliated institutions around the world, spoke with United Press International from his office in Sri Lanka. "In the very short term, the fact that people are lacking access to drinking water supply and sanitation services is probably the most urgent symptom and reason for action in this world water crisis. Our organization and the initiative that we have been setting up recently, the Dialogue on Water, Food and the Environment, is focusing on the somewhat longer term issue of the need to increase the productivity of water for agricultural uses, " Rijsberman told said.

IWMI hopes the dialogue, involving some of the world's largest agricultural and environmental organizations, will help to bridge the gap that has grown up between the competing interests of agriculture and the environment

However, with more than a billion people lacking access to clean drinking water and more than two billion lacking adequate water for sanitation, according to reports from the United Nations, it's not just agricultural use of water that is helping to define scarcity. According to Ben Wisner, who specializes in sanitation issues related to water, many of the rapidly growing cities in the developing world have populations that are essentially unserved. "In a place like Caracas or Bogota or Mexico City or Bombay or Mumbai anywhere between 40 and 60 percent of the population living in what's known as informal settlements, self-built, uncontrolled settlement, strictly speaking illegal settlements. They really have no sanitary provisions whatsoever," Wisner told UPI.

Several sources told UPI that between 5 and 10 million people a year die from drinking unclean water and as many as 250 million fall ill.

While withering crops and dying cattle are the usual images of drought, defining water scarcity is more of an academic exercise. This has to do with the way in which water scarcity is defined. Most of the water resource community contacted appears to accept the definitions provided by Malin Falkenmark, a Swedish hydrologist. Falkenmark says is that if a country has more than 1700 cubic meters (1.7 million liters or 449,000 gallons) of renewable water resource per year per person then that country is unlikely to experience water stress. If less than 1000 cubic meters ( 264,000 gallons) per person per year are available, then "severe" water stress may occur.

Using these numbers, the World Resources Institute projects that the percent of the world's people with less than 1700 cubic meters per year, that is "water stressed," will grow by 2025 to about 48 percent from the current level of about 42 percent.

But making comparison between widely variant cultures can be a problem."The standard numbers are useful when comparing one place with another but when you get to absolute numbers people can argue. Water is such a variable resource that exact numbers are not possible," Leonard Berry, a professor at Florida Atlantic University who is an expert on water resources and is director of the Florida Center for Environmental Studies, told UPI.

While it may be possible to argue about absolute numbers used to define the situation, there is a deep concern about long term trends. According to Juha Uitto, who monitors and evaluates water management projects around the world for the Global Environment Facility, told UPI, "The current water use trends are certainly not sustainable."

Uitto, and a number of other experts contacted, believe that global warming will also play a role in the crisis. "Places like the Middle East, the Sahel (Africa immediately south of the Sahara), and some of the areas in central Asia and western China and northern India will be facing drier conditions which can be disastrous unless there is really good management of land and water, whereas other areas, such as the southeast Asia region is probably going to have even more than they have now and they are already very wet areas, so there will be increasing amounts of typhoons and storms where they have major floods."

Cooperative planning to avoid disaster is going to be key. According to Aaron Wolf, an associate professor at Oregon State University who specializes in international water policy agreements, "If the world is to get ahead of the crisis curve, the trick is to identify the basins that have a lack of some type of cooperative agreement and help the parties work together to develop some kind of mechanism for managing their resources, " Wolf told UPI. The ten countries that comprise the Nile River basin have signed an agreement to work cooperatively.

Water shortages have emerged this summer in the western United States. Peter Gleick, president of the Pacific Institute for Studies in Development, Environment, and Security in Oakland, Calif. sketched out the need for more efficient use, a problem that will need to be addressed worldwide. "Part of the problem in the western United States is that we've developed all of the reasonable water resources in the region . . . The challenge in the western United States is, how can we get smarter about using the water resources that we have?," Gleick said.

Because agriculture uses about 80 percent of water worldwide, many of the answers are going to need to come from new and more efficient methods of irrigation. Irrigation canals will need to be lined to prevent leakage, drip irrigation at low cost will need to be developed, low-cost pumps will need to be distributed widely, forestry practices will need to change in some areas. Crops that use less water may need to be substituted. Many experts believe that charging farmers more money for irrigation water will reduce use.

In Bangladesh, treadle pumps that sell for 35 dollars can be operated by pushing pedals. Some farm families spend four to six hours a day pumping and have increased their annual income, which hovers around $100 a year according to water expert Sandra Postel. It is easy to think of societies where people are not going to view physically pumping water four to six hours as the path to improvement, yet each part of the world is going to need to find ways to make better use of their water resources if what is what is widely perceived as a looming water crisis is to be averted.