大众英语80篇背诵阅读带翻译(二十二)
"44 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 Earth's 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 10,000 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 subsuITce 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.从冰山中获取海水把冰山拖到世界上生齿浓密的地区和干旱地带，再从中获取海水，这个设法曾一度被以为是一个笑话，更合适于IT画，而非理想糊口。但是现在，良多国家正相称担当地思量这件事变，分外是在迷信家们发出告诫之后。迷信家们以为人类将在耗尽粮食之前首先耗尽海水本钱。冰川是一个直到近来已往不断被轻忽的年夜概的海水源。全球四分之三的海水还锁在冰川的冰块中。冰川便是一个蓄池塘，其中未开发的海水量是如斯庞年夜，足够支撑全世界的江河 1000年。每年有 7，659万亿公吨冰漂泊在陆地中。它们包括在 10，000座从极地冰帽间断裂出来的冰山中。这些冰山的 90百分以下去自南极。一年四季里，笼盖在浅层年夜陆架上的庞年夜冰川生成了众多冰山。冰山和海水的冰不合，后者是海水本身结冰组成的，而冰山则完满是在陆地上组成的。当冰川舒展到海水中时，冰山就断裂上去。当漂离极地地区时，冰山偶尔会在底层洋流的鞭策下颇为秘密地顺风挪动。因为冰山比小块的冰消融要慢，因此有的冰山在年夜泰西中向北飘到了赤道以南 35°的中央。把冰山蓄拦起来并拖到世界上需要它们的中央将不会太困难。有困难的是别的的技能事件。好比，若何防止冰山在较热的气候中敏捷消融以及若何把年夜量的海水搜集到岸上往。可是，即便在拖的历程中冰山失落往了一半体积，如许做也远比从海水中脱盐获得海水廉价。
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