-
(单词翻译:双击或拖选)
The concept of obtaining fresh water from icebergs1 that are towed to populated areas and arid2 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 outgrow3 its fresh water supply faster than it runs out of food.
Glaciers4 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 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 continental5 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 entirely6 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 steer7 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 funneling8 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.
点击收听单词发音
1 icebergs | |
n.冰山,流冰( iceberg的名词复数 ) | |
参考例句: |
|
|
2 arid | |
adj.干旱的;(土地)贫瘠的 | |
参考例句: |
|
|
3 outgrow | |
vt.长大得使…不再适用;成长得不再要 | |
参考例句: |
|
|
4 glaciers | |
冰河,冰川( glacier的名词复数 ) | |
参考例句: |
|
|
5 continental | |
adj.大陆的,大陆性的,欧洲大陆的 | |
参考例句: |
|
|
6 entirely | |
ad.全部地,完整地;完全地,彻底地 | |
参考例句: |
|
|
7 steer | |
vt.驾驶,为…操舵;引导;vi.驾驶 | |
参考例句: |
|
|
8 funneling | |
[医]成漏斗形:描述膀胱底及膀胱尿道交接区 | |
参考例句: |
|
|