Planet Earth

Numbers: Water, From Precipitation to Irrigation to Sanitation

By Jeremy JacquotJan 23, 2010 12:00 AM

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70 Percentage of global freshwater use that is devoted to irrigation. Industry soaks up 22 percent, and the remainder goes to households. About 20 percent of all cropland worldwide is irrigated; that land yields 40 percent of the world’s food supply.

528 Minimum amount of water, in gallons, required to produce a day’s worth of food for one person, according to United Nations estimates. One pound of rice takes about 240 gallons of water; 1,680 gallons go into creating one pound of grain-fed beef.

4.4 billion Amount of human waste, in pounds, entering global watercourses each day, according to the U.N.’s World Water Assessment Programme. In developing countries, 70 percent of industrial waste is dumped into the water supply with no treatment.

2 million Number of child deaths worldwide caused by diarrhea each year, as estimated by the World Health Organization. Of those deaths, 88 percent are due to lack of sanitation facilities and insufficient clean water for drinking and hygiene.

5.3x10^16

The total amount of freshwater on earth, in gallons, that can be used by humans and ecosystems, according to the U.N.’s Environment Programme. This represents just 0.01 percent of all water on the planet. Some 97 percent of available freshwater is underground, but in many parts of the world (including the United States as a whole), groundwater is being depleted as we consume freshwater more quickly than it is replenished.

50 Projected percentage increase in water use in developing countries by 2025. Water use has grown twice as fast as population over the past century.

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