Bruno Kelly / Reuters

Blue Planet, Thirsty World

How to Meet Rising Water Demands

When seen from space, the earth is a blue gem, a water planet. But when it comes to the amount of its water that humans can actually drink—a mere one percent of the total—it is an increasingly thirsty planet.

And even that scant amount of water needs to be made safe to drink. Worldwide, nearly 800 million people—two and a half times the population of the United States—lack access to clean drinking water. In the majority of countries, existing water supplies are insufficient to meet urban, industrial, agricultural, and environmental needs. The UN World Water Development Report predicts that if our water needs continue at its present rate, the world’s demand for water will exceed its supply by 40 percent in 2030.

By then, over one billion people will be suffering from water scarcity. Food shortages and declines in living standards will be unavoidable for many countries. Next to climate change, the water crisis is one of the most urgent priorities of our time. But unlike the much thornier and politicized issue of reducing carbon emissions, providing the world with enough water means efficiently managing the water that we already have. Fortunately, pioneering technologies, based on simple and affordable innovations, have already demonstrated their potential for providing millions of people with the water that they need.

For example, in the 1990s, water contaminated with viruses and bacteria such as cholera and dysentery killed tens of thousands of people in India. Then came a breakthrough in water disinfection: UV Waterworks, a low-cost device that uses ultraviolet light to sanitize water. Introduced in 1995 by Ashok Gadgil, director of the Energy and Environmental Technologies division at Lawrence Berkeley National Laboratory, UV Waterworks now helps provide clean water to over four million people a day across Bangladesh, Ghana, India, and the Philippines.

han_water_rts1jpe.jpg NASA Handout / Reuters

Lake Powell on the Colorado River—which provides water for Nevada, Arizona and California—is seen in a combination of NASA satellite images taken in 1991 (L) and 2015 (R). A severe drought in recent years, combined with withdrawals that many believe are not sustainable, has reduced its levels to only about 42 percent of its capacity.

Although securing access to clean drinking water is critical for billions of people, agriculture is by far the largest consumer of water, using up to 80 percent of the world’s total.

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