From healing the sick to infecting the healthy to fomenting conflict, there doesn't seem to be much that water can't do. Test your knowledge with eight questions on humanity's favorite liquid.
Answers to the FP Quiz
1) A, 37. As populations grow and societies become wealthier, water consumption swells, leading many to predict that the future will be filled with conflicts over water. There is reason for optimism, however. In the past 60 years, some 400 international water agreements have been signed, compared with 37 documented violent clashes between countries over water, according to researchers at Oregon State University.
2) C, 47 percent. The Tibetan plateau is Asia's principal source of water, feeding 10 of its major rivers and providing water for nearly half the world's people. Glaciers in the area, which feed rivers, are melting at unprecedented rates, and the Intergovernmental Panel on Climate Change predicts 80 percent of Himalayan glaciers will be gone by 2035. With more than one fourth of China classified as desert, the geopolitical implications could be ugly.
3) C, 1,000 liters. One thousand liters might sound like a lot, but it's nothing compared with the 15,000 liters or so necessary to produce a kilogram of beef. As more people rise out of poverty and into the middle class, meat consumption also rises. It takes about 2,000 liters per day to support the typical vegetarian in Asia or Africa, but about 5,000 liters daily for a carnivore in Europe or the United States.
4) B, 3.7 miles. In developing countries, women and girls walk an average of 3.7 miles (6 km) a day carrying 5.3 gallons (20 liters) of water, according to UNICEF. In rural Africa, women often walk 6.2 miles (10 km) daily, and twice that during the dry season, all while carrying as much as 50 pounds. The onerous task-which puts females at risk for sexual assault when they venture far from home-reduces the time girls can attend school and women can devote to other work.
5) C, 38 percent. Sanitation has been one of the greatest advances in public health, but 2.6 billion of the world's people-around two out of five-lack basic sanitation. That unfortunate fact contributes to 5,000 deaths of children every day from infectious diarrhea.
6) C, 80 percent. Shockingly, unsafe water accounts for four fifths of all illnesses in developing countries, according to a U.N. study. Thirty percent of deaths in developing countries are attributed to poor water quality.
7) C, $0.45. Slum dwellers in many developing countries-from Peru to India to Indonesia-pay far more for water than wealthier people. The well-to-do get government-subsidized water from metered connections while the poor must buy it from trucks that regularly drive through shantytowns and haul brimming jerry cans home.
8) C, 3 liters. Producing 1 liter of bottled water requires 3 liters of water-1 liter to go inside the bottle and 2 liters used in the production process-according to a 2006 estimate by the California-based Pacific Institute. The amount of oil needed to fill the bottles with water, transport them, chill them, and dispose of or recycle them can amount to one fourth a bottle's volume.