47. Fresh Water from Icebergs

The concept of obtaining fresh water from icebergs are moved to 1) populated areas and barren regions of the world was once treated as a joke more appropriate to 2) cartoons than real life. But now it is being considered quite seriously by many nations, especially since scientists have warned that the human race will outgrow its fresh water supply faster than it runs out of food.

Glaciers(冰河) are a possible source of fresh water that has been 3) overlooked until recently. Three-quarters of the Earth’s fresh water supply is still tied up in glacial ice, a reservoir of untapped fresh water so large that it could 4）maintain all the rivers of the world for 1,000 years. Floating on the oceans every year are 7,659 trillion metric tons of ice stored in 10000 icebergs that 5 break away from the polar ice caps, more than ninety percent of them from Antarctica.

Huge glaciers that 6） stretch over the shallow continental shelf give birth to icebergs throughout the year. Icebergs are not like sea ice, which is formed when the sea itself 7） freezes, rather, they are formed entirely on land, breaking off when glaciers spread over the sea. As they drift away from the polar region, icebergs sometimes move mysteriously in a direction opposite to the wind, pulled by subsurface currents. Because they 8） melt more slowly than smaller pieces of ice, icebergs have been known to drift as far north as 35 degrees south of the equator in the Atlantic Ocean. To move them to parts of the world where they are needed would not be too difficult.

The difficulty 9） arises in other technical matters, such as the prevention of rapid melting in warmer climates and the storing of fresh water in great 10）volumn. But even if the icebergs lost half of their volumn in moving, the water they could provide would be far cheaper than that produced by removing salt from water.