Earth in Peril

Freshwater Resources, 2000
Water covers roughly 70 percent of Earth's surface, but only 2.5 percent of it is freshwater, which humans need for irrigation, drinking water, and other everyday uses. According to the United Nations, the scarcity of freshwater due to overuse and contamination will be the second most pressing global concern in the 21st century, after population growth. On the map above, countries with less than 5,000 cubic meters of freshwater per capita are considered short of water. Experts believe that people may be able to replenish water tables with new water-saving irrigation methods, bioengineered crops that require less water, rainwater harvesting, and public information campaigns, but it will be centuries, if ever, before freshwater is plentiful again worldwide.