Experts of UN say: as many as 250 million people the world over suffer from the shortage of fresh water. In 20 years from now this figure may soar 16 fold. A way out is in the immense pool of ice resources of the polar regions, the Antarctic first and foremost. Yuri Suprunenko, Cand. Sc. (Geogr), of the RAS Institute of Geography, elaborates on this subject in his contribution for the Russian-language journal Zemlya i Vselennaya (Earth and Universe, No. 1, 2007).

The Antarctic (Antarctica) - also know as the Sixth, or Ice Continent - is a depository of as much as 25 mln cubic kilometers of ice, that is the frozen water of atmospheric precipitation. But because of the persisting global warming that began in the 20th century, the planet's ice

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shield is going to lose up to 1/5 of its mass in the coming 200 to 300 years. The process is already on, Dr. Suprunenko warns, though at this stage only in the form of icebergs, large masses of floating ice broken from glaciers or ice sheets of polar regions (true, bergs have been breaking loose all along, but not as often and abundantly as now. Dropping into the sea, floating fragments of Antarctic ice travel as far as the southern shores of Africa and America to dissolve without a trace in the warm salt water. Besides, icebergs endanger navigation (let us recall the end of the Titanic - though the tragedy occurred in the North Atlantic, it was caused by an iceberg's subwater part, with many such icebergs floating off the Antarctic coasts). If the global warming situation keeps up, the Antarctic ice will melt away, to get the level of the World Ocean up by 100 meters. In that case large coastal zones with great cities in many countries will be submerged. In a nutshell, the situation is bad enough, and it should be considered in good earnest. As Dr. Suprunenko sees it, to begin with one should try to control the icebergs of the Antarctic, which will help inhibit the breaking off and sporadic movement of ice chunks in the ocean. This is quite something!

Now why do ice mountains (bergs) come off from the continental massif of Antarctica (annually about 2 thousand cu. km of such ice is off)?

For the most part bergs are formed above two giant geotectonic faults: one near the shelf Ross glacier, and the other located off the shores of the Weddell Sea. Glaciers are constantly acted upon by ebbs and flows. Huge masses of sea water get under the ice shield, and part of it recedes then. Under the effect of shearing glaciers split up in the process of "calving" when "jerks" of two meters and higher cause them to come apart in crevasses 200 to 400 meters wide. Glaciers closest to the blue deep slowly flow and break off as icebergs setting out on long sea voyages.

Icebergs, Dr. Suprunenko stresses, are also produced by icequakes, which may be violent enough to be registered by seismic detectors. But high tides are the chief culprit. Particularly dangerous is the cumulative action of high oceanic waves and abrupt atmospheric differentials causing ice mounds to resonate; well, the chain is no stronger than its weakest link, as the saying goes.

There are other contributing factors, too. For instance, the meridianal transfer of air in the Southern Hemisphere-it contributes to the buildup of snow on the Sixth Continent and activates cyclones. Rushing towards Antarctica's coast, air masses cause the ice to break off and thus give rise to floating icebergs. Conversely, in the latitudinal transfer of air or climatic cooling in general (the situation is much otherwise today!) the accumula-

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tion of snow in the Antarctic slows down, and so less ice gets onto the continental edge. Be that as it may, the mass of ice built there amounts to half of the global water intake. An impressive figure! We might as well recall that the ice mounds that are thousands and thousands of years old are not contaminated by industrial pollution, i.e. their water is 100 percent good for consumption. But icebergs are not going to be handed down to us on a silver platter, are they?

The idea was born in the 1950s. Dr. Isacke of the United States, an oceanologist and engineer, suggested transporting icebergs by powerful tugboats toward America. Twenty years after, a similar project was advanced by Dr. P. E. Victor of France, who wanted to help Saudi Arabia this way. But these and other suggestions were written off as too costly. Researchers of our RAS Institute of Geography have conceptualized another project tested by Dr. Khodakov and his team in the 1980s on a 1.5x50x10 m ice mound (real sea icebergs are twenty or thirty times as large) located in Lake Bolshoi Khodatinski (Polar Urals): a 20 hp boat tugged it to the farthest end of the lake. However, both practical experience and simulation have shown: ice melts away in warm water while en route. The situation will improve somewhat if ice is heat-insulated with tarpaulin; but this is no radical solution either.

G. Khalilov, an inventor from the Caucasian republic of Daghestan, has come up with an interesting solution: an iceberg should be cut into blocks, each weighing thousands of tons. Thereupon such ice chunks will be loaded into the holds of trimaran iceboats and tugged to the place of destination and unloaded there into special receptacles, or containers. Sunrays and warm air will turn the ice into meltwater pumped to urban consumers. In colder districts there will be no need for costly tanks like that - the ice will be dumped into regular water catchments and sold in retail outlets. (G. Khalilov's idea has been approved by a panel of experts of the Russian Federation's Ministry of Education and Science.)

Clearly, any particular project of this kind should be considered in all its implications by international experts, Dr. Suprunenko concludes. We cannot procrastinate, for procrastination is the thief of time.

Yu. Suprunenko, "Resources of Antarctic Icebergs ", Zemlya i Vselennaya (Earth and Universe), No. 1, 2007

Prepared by Vladimir GOLDMAN