ICEBERG-A SOURCE OF FRESH WATER

Icebergs towed from Antarctica to the Red Sea could provide an economic source of fresh water for Saudi Arabia. There are no technical problems, to which we cannot find a solution.

In France a detailed plan for towing the icebergs, each weigh­ing 100 Mt, across the Indian Ocean, and through the Gulf of Aden to the mouth of the Red Sea was developed. There they would be chopped into manageable pieces (about 1 Mt each), us­ing heated cables and towed through the shallow Bab el Mandeb Straits to the Saudi coast.

Even in tropical temperatures, natural thawing of the icebergs would not be quick enough to match demand for fresh water and the problem is of working out ways of speeding up formation of the fresh-water pools by induced melting. That is the last of the problems to be solved, and it should not be a difficult one.

The giant icebergs must be wrapped in an insulating jacket to cut down melting losses on their 8,000 km journey. At an esti­mated towing speed of 1 knot, it will take 6-8 months for five tugs to pull the icebergs along a computer plotted route, taking advan­tage of prevailing currents and winds and dodging high ways.

Without protection, over half of the ice would melt en route, but there is a way of cutting this to 20% or less by using a huge iceberg "coddler", made from a 50 mm-thick sheet of plastic-coated felt, which will be drawn under the base of each 250 m-deep berg. A massive skirt of the same material will then be un­rolled around the 3-4 km perimeter, with weights holding its base 100 m or more below the water line.

No top protection will be needed. The pool forming naturally on top of the iceberg will itself limit melting. Similarly, water lay­ers inside the skirt and bottom protection will provide their own insulation against progressive thawing.

Once the bergs reach the Gulf of Aden, the jackets will be re­moved and heated cables will slice them into about 100 individual pieces, each no thicker than 15 m. These slices will then be floated through the Bab el Mandeb Straits. Inside the Red Sea, another skirt will be fixed to each berg, to separate the fresh water from the salt-water sea, and a pipeline will connect the offshore reser­voirs to the mainland.

French scientists have now developed all the technology needed to wrap an iceberg in its protective jacket, tow it halfway across the world, and deposit it in sections in the Red Sea.

The idea of using icebergs as a source of fresh water is not new. After all, 99% of the fresh water in the world is in the form of ice, and 90% of it is in the Antarctic. It seems natural that we should look at ways of using it.

The source has another important advantage — it is infinitely renewable. About 1,000 km³ of ice forms every year in Antarc­tica — and it is all free for the taking.

On the basis of this conception other plans have been drawn up for towing icebergs to Western Australia. Though the unit cost of water from these proposals is highly favourable, the authorities have so far not come to fruition because of the very high initial in­vestment needed to develop and build the size of tug needed and the risk of failure. A scheme to tow giant icebergs to California to provide water for Los Angeles also seems to have been aban­doned.

But all these schemes relied on the huge initial size of the ice­berg to overcome melting losses. Losses of 50% or more were considered acceptable, because the remaining ice would still con­stitute a massive reservoir. The French plan to insulate the ice­bergs before their journey makes the idea economic for much smaller bergs. Existing tugs can be used for towing and the finance becomes possible.

For Saudi Arabia the cost of the iceberg water is well below the cost of desalination. A side benefit for the Saudi Arabia is that a line of melting icebergs 1.5 km offshore would be a giant air-conditioning system, dropping local temperatures by as much as 5°C.

Cold? Britain Is Actually Getting Hotter

Most Britons could be forgiven for thinking a new Ice Age is upon us. Small comfort, then, as we struggle through snowdrifts and cope with burst pipes, that the present cold is a sign the British climate is generally getting milder.

Ironically, most scientists now believe the short sharp shock of severe cold that has struck Europe for three winters running is an indicator that the world is growing warmer. The burning of fossil fuels is building up a blanket of carbon dioxide in the atmosphere, creating a "greenhouse" effect.

Britain and Europe have certainly experienced weather this cold before. In the 17th century, the Thames froze solid so of­ten that it became a regular winter sports attraction. The weather then was so severe that it is sometimes referred to as the Little Ice Age. Even in the early 19th century, Britain's cli­mate was still colder than it is today. We still have a cherished picture of Charles Dickens's Christmases — although, in fact, snow at Christmas has been a rarity in southern England for 150 years.

Studies of temperature trends around the world show that it has been warming up since the middle of the 19th century. Most experts agree that this is a result of human activities. By burning coal and oil, we are putting carbon dioxide into the air. This acts like a blanket round the earth, trapping heat that would otherwise escape into space. As long as we keep burning fossilfuel, the trend is likely to continue. So why have we had such severe cold spells in Europe recently? According to researchers at the University of East Anglia, it is all part of the same process. When the climate of the globe changes, it doesn’t do so evenly. Britain and Western Europe are just unlucky in being in the path of a particularly significant wind shift.

By comparing the weather in different seasons, during the warmest and coldest years of the 20th century, the researchers have built up a picture of what is going on. Their key new discovery is that although spring, summer and autumn are all warmer, severe cold spells in winter are most likely over the whole of central Europe. So then, short cold spells mean it's generally getting warmer — but the bad news is it could get TOO warm. If the predictions come true — and the present changes are exactly in line with computer forecasts — within the next 40 or 100 years we shall see a change in climate as dramatic as the shift which ended the last Ice Age.

Date: 2016-01-03; view: 953