The concept of obtaining fresh wa。ter from iceb。ergs th。at are towed to populated areas and a。rid regions of the world was onc。e treated as a joke more appropriate to cartoons than real life. But now it is being considered quite seriously by many nations, especially since scientis。ts have warned that the human r。ace will ou。tgrow its fresh wat。er supply faster than it runs out o。f food.
Glaciers are a possible source of fresh water that has been overl。o。oked until recentl。y. Three-quarters of the Earth's fresh water supply is still ti。ed 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 tha。t 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 iceber。gs throughout the year. Icebergs are not like sea ice, which is formed when the sea itself freezes, r。ather, they are formed entirely on land, breaking off when glaciers spread over the。 sea。. As they drift awa。y from the polar region, icebergs sometimes move mysteriously in a direction opposite to the。 wind, pulled b。y subsurface currents. Becau。se they melt more slowly than smaller pieces of ice, icebergs have been known to d。ri。ft as far north as 35 degrees south of t。h。e equator in the Atlantic Ocean. To corral them and steer them to parts of。 the worl。d whe。re they are needed would not be too d。iff。icu。lt.
The d。ifficulty arises in other technical matters, such a。s the prevention。 of rapid melting in war。mer climates and the funneling of fresh water to shore in great volume. But even i。f t。he icebergs lost half of their volu。me in towing, the water they could provide would be far cheaper than that produced by desalinization, or removing salt from water。