gre写作考试范文5:Obtaining Fresh water from icebergs

　　下面是一篇关于Obtaining Fresh water from icebergs的gre写作范文。考生应该从范文中领会到整个文章的结构、用词等，这样才有助于gre写作的提高。

　　GRE 写作范文5：Obtaining Fresh water from icebergs

　　The concept of obtaining fresh water from icebergs that are towed to populated areas and arid　regions of the world was once treated as a joke more appropriate to 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 are a possible source of fresh water that has been overlooked until recently.Three-quarters of the Earths fresh water supply is still tied up in glacial ice, a reservoir of　untapped fresh water so immense that it could sustain all the rivers of the world for 1,000 years.Floating on the oceans every year are 7,659 trillion metric tons of ice encased in 10000 icebergs　that break away from the polar ice caps, more than ninety percent of them from Antarctica.

　　Huge glaciers that 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 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 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 corral　them and steer them to parts of the world where they are needed would not be too difficult.

　　The difficulty arises in other technical matters, such as the prevention of rapid melting in warmer climates and the funneling of fresh water to shore in great volume. But even if the　icebergs lost half of their volume in towing, the water they could provide would be far cheaper　than that produced by desalinization, or removing salt from water.

　　gre写作考试范文只是给考生作为一个参考作用，一方面考生可以背诵这些优秀的gre写作范文，另一方面应该从中举一反三，不要只是一味地背诵。