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TOEFL Directory > TOEFL writing > 44.Obtaining Fresh water from icebergs
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 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.
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