Florence in the little ice age, 1601

A force of nature

E&T considers the power of water to enrich or destroy the lives of millions.

It is somewhat ironic that the present interest in water stems from the belief that man is responsible for much of the climate shifts we are currently experiencing. In actual fact, far much more natural and powerful forces are at work. For example, little carbon dioxide was present when the Romans grew grapes near Hadrian's Wall or during the 'Great Warming’ in the early 13th century.

There are some major climatic factors affecting our lives, and a good deal of technology has stemmed from them. Three major forces drive our climate: changing ocean oscillations, solar output and volcanic eruptions.

It was only in the late 19th century that sea temperatures were plotted to show that the great oceans had a temperature rhythm of their own that could be responsible for many of the climatic gluts and troughs being felt. For example, although warm El Niño southern oscillations had been experienced off the west coast of the Americas, there was little to explain periods of famine around much of Asia.

Now, work done by the University of Arizona has shown there are Pacific Decadal Oscillations (PDO) when there are warm and cool periods of around 50 years. When the oceans become cooler, the rain belts move further south and west leaving areas that were previously well-watered much dryer. After a period of beneficial rainfall, the Pacific becomes cool, and the PDO drives much of the associated technology.

The Atlantic began to be unusually cool in the early 1960s, which brought the rain belts further south. However, in 1995 they moved north to force the northern Mediterranean to become very dry. There are also other factors to be considered such as the Sun's output and volcanic action.

The reason for the previous warm and cool periods is an oscillation of around 180 years thought to be caused by movements in the solar system upsetting the forces within the Sun. The cool phases were much more serious, known as 'minima', the most famous being the Maunder Minimum of the early 17th century known as 'the little Ice Age' that affected nations around the globe. It is very possible that we could have another 'minimum' in the second and third decade of this century. Finally, there are volcanoes.

Volcanic eruptions are caused by weaknesses in the Earth's crust through continuous movements of the tectonic plates. Currently, the most active is the Indo-Australian plate, the movements of which caused Krakatoa to blow in 1883 and, more recently, the tsunami and earthquakes in Pakistan and China. Krakatoa exploded with the force of around ten hydrogen bombs, belching 11 million tonnes of debris and gas into the stratosphere that spread around the world, drifting towards the poles and shielding some 70 per cent of the Earth, destroying crops and rendering millions destitute.

Technologies trio

Many of the regions that are presently affected by drought employ irrigation because of the extremely high rates of evaporation and irregularity of the monsoon. Unfortunately, many areas have also overproduced, so that up to one-third of arable land is becoming unusable and will no longer be productive by 2020.

This will demand a major spread of three technologies. These are: the restoration of soil, pioneered by the Israelis for removing saline contamination, resting the land to restore the topsoil and improving access to irrigation; the generation of cultivars that accept brackish water enabling substandard land and water supplies to be used beneficially; and the use of irrigation techniques that reduce evaporation and would help all the regions to be able to feed themselves.

Around half the world's population currently resides in just 23 cities - most of which are within the tropics. As many of these have inadequate sanitation and fresh water supplies, there is a clear need for technologies that improve the efficiency of water treatment systems, including valves, piping, plant, instrumentation, chemicals and so on. There is also the danger of pandemics of water-borne diseases such as cholera, dysentery, typhoid fever and the like. Already hundreds of thousands die every year in China from polluted water.

According to the drought predictions we have, the Middle East will suffer most particularly and threats of Israeli attacks on Iran's nuclear ambitions mean that the Straits of Hormuz, through which around a third of all oil exports pass, will be particularly vulnerable. This will require the development of new technologies such as cold fusion, solar power and even coal electricity generation. For vehicles, the front-runner could be hydrogen.

Cold fusion

Cold fusion, like the philosopher's stone of old the nuclear age, has generated the desire to fuse the atoms of deuterium (heavy water). Like the process that drives the sun, heat is released and the reaction produces tritium, helium and radiation - the controlled reaction of a fusion bomb. The first attempt at cold fusion was made by two researchers - Fleischmann and Pons - in March 1989, but the experiment could not be replicated by other scientists, so it was deemed a programme unworthy for US federal funding. However, more recent laboratory experiments have shown more promise.

Hydrogen

The possibility of using hydrogen, the lightest of all elements, as a fuel only became a reality with the space programme. When burnt with oxygen, it provides the most powerful rocket impulse - far outweighing other propellants. Although widely used industrially, only more recently has its input for a fuel cell become a real possibility. Although hydrogen can be produced from water, biomass, coal and natural gas, over 95 per cent of all the hydrogen is made by steam reforming natural gas - a chemical process whereby one molecule is changed into another having different properties.

However, if hydrogen is to extend its industrial role, it could be formed by electrolysing water using solar power. Currently, around 42 million tonnes of hydrogen are generated every year - most of it being converted to produce ammonia for fertilisers. As a gas it needs to be transported at high pressure at a cost estimated at upwards of $1.20 of a gallon equivalent. There it can be used in a hybrid driven gasoline vehicle or a fuel cell.

The Fuel Cell (FC) works through a process called catalysis - a reverse of electrolysis, one of the techniques for generating hydrogen and oxygen. Instead of an external source of electrical energy, the FC generates an electric current.

Although the voltage is only around 0.7v, a stack of cells would be needed to generate the 48v needed for a vehicle. The great advantage is that its emission is only water and the efficiency is about 45 per cent at low loads - around double that claimed for diesel cars.

Solar power

Solar power has already been mentioned as a means of electrolysing hydrogen as part of an in-line power unit. Sophisticated units drive computer-controlled mirrors or lenses that track the sun focusing the light on heat receivers. This heats fluids to temperatures of up to 1,500°C - hot enough to generate superheated steam turbo generators that supply excess power to the grid by day, then draw power at night.

At a domestic level, great strides are being made to reduce the cost of solar capture and to extend the possibilities for its use outside the sunbelts. One such firm is Zurich-based Flisom AG that plans to market a coated polythene sheet produced in a continuous process. Another company active in this field is the large American corporation Applied Materials, based in California.

Coal-powered generation could also become a possibility through work done by Sasol in South Africa where noxious emissions have been considerably reduced and technologies for extracting oil from coal successfully developed. 

'Water. The Final Resource: How the politics of water will impact on the world' by William Houston & Robin Griffith is published by Harriman House

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