从冰山获取淡水作文
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 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。
【从冰山获取淡水作文】相关文章:
冰山底之谜作文900字04-03
淡水人生作文700字04-05
淡水生活作文350字04-03
最后一块淡水冰作文06-14
用冰山难靠造句05-02
冰山南极读后感400字07-24
中考英语作文获取高分写作指导12-02
从?到!作文03-16
在痛苦中获取救赎作文500字10-19
关于获取知识读后感07-06