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Obtaining Fresh Water from Icebergs The concept of obtaining fresh water from icebergs that are towed topopulated areas and arid regions of the world was once treated as a jokemore appropriate to cartoons than real life. But now it is beingconsidered quite seriously by many nations, especially sincescientists have warned that the human race will outgrow its fresh water supplyfaster than it runs out of food.Glaciers are a possible source of fresh water that has been overlooked until recently. Three-quarters of the Earthsfresh water supply is still tied up in glacial ice, areservoir of untapped fresh water so immense that it could sustain all therivers of the world for 1,000 years. Floating on the oceans every year are7,659 trillion metric tons of ice encased in 10,000 icebergs that breakaway from the polar ice caps, more than ninety percent of them fromAntarctica.Huge glaciers that stretch over the shallow continental shelf givebirth to icebergs throughout the year. Icebergs are not like sea ice,which is formed when the sea itself freezes, rather, they are formed entirelyon land, breaking off when glaciers spread over the sea. As they driftaway from the polar region, icebergs sometimes move mysteriously in a directionopposite to the wind, pulled by subsurface currents. Because they melt moreslowly than smaller pieces of ice, icebergs have been known to drift as far northas 35 degrees south of the equator in the Atlantic Ocean. To corral themand steer them to parts of the world where they are needed wouldnot be too difficult.The difficulty arises in othertechnical matters, such as the prevention of rapid melting inwarmer climates and the funneling of fresh water to shore in great volume. But even if the icebergs lost half of their volumein towing, the water they could provide would be far cheaper than thatproduced by desalinization, or removing salt from water. | 
