26 FEBRUARY 1983, Page 14

Acid rain and tidal waves

Nigel Sitwell

In 1970 I volunteered, in print, to throw myself under the bulldozers if work should ever start on the third London air- port at Foulness (later they called it Maplin, perhaps to make it sound more acceptable). I don't suppose my threat caused much anxiety in Whitehall but it certainly made me feel better. I also felt pretty good about joining the then recently formed Friends of the Earth on a march through the West End of London that culminated in our dumping a load of bottles on You Know Who's front doorstep.

Those were the days when everything seemed possible and the Friends looked all set to form the next government. I am con- fident that apart from feeling self-righteous we had our priorities right. However, as the years have passed I am no longer so sure that the environmental lobby always fights the right battles. Sometimes campaigning issues are chosen because they are popular, not necessarily because they are the most important. These reflections are provoked by the Sizewell inquiry. It may be un- fashionable to argue that nuclear power is environmentally the best option, but here goes.

Let us dispose of a few obvious points first. Certainly there are valid grounds for questioning the need for any new power sta- tion, of whatever kind. And there are legitimate fears about safety, involving the reactor itself, the disposal of radioactive wastes, and the possibility that fissionable material might fall into the wrong hands, At the back of everyone's mind, however, seems to be the idea that conventionally fuelled power stations are OK. They are not.

The problem is not what goes into a coal- burning or oil-fired power station, but what comes out. And what comes out is very dangerous indeed. Take sulphur dioxide, for example, which is emitted in large quan- tities. This reacts with water in the at- mosphere to form sulphuric acid, and falls to earth, often many hundreds of miles away, as acid rain (or acid snow or acid fog). Nitric oxides cause a similar problem, but they are mostly the product of vehicle emissions.

Some complain that the phrase 'acid rain' is too emotive. But this may be just as well, for although there is much scientific uncertainty surrounding the subject, there is general agreement that power stations are the main source and that the effects are ex- tremely damaging.

An American government report in 1979 estimated that architectural damage from acid rain in the United States amounts to about $2 billion a year. A host of famous buildings are steadily crumbling, from the Taj Mahal to the Colosseum, from the Par- thenon to the churches of Cracow. Acid rain reduces crop yields, kills trees, and wipes out freshwater fish. Soils are damag- ed as increased acidity leaches out nutrients and replaces them with toxic metals.

The normal measurement of acidity is the pH scale, ranging from 0 to 14, with lower values representing greater acidity. Seven is neutral and 'average' rainfall has a value of 5.6. When water in a lake or a river drops below 4.5, all the fish are dead and virtually no living matter remains barring an unat- tractive mat of algae, moss and fungus. The water itself is deceptively clear.

Unfortunately, very little research has been done in this country, but the available information is far from encouraging. The worst affected areas in Britain are thought to be Cumbria, and the southern uplands and west central highlands of Scotland, where acid levels approach those of parts of Scandinavia and the eastern United States. There are only two sampling points in south-eastern England, in rural Berkshire and Surrey, bilt both record an average rainfall acidity of 4.1. Apparently a pH of 4.0 is quite usual in the Solway area. There is evidence of a reduction in fish stocks in the Lake District as a result of acid rain, and crops and woodlands in the East Mid- lands and in Cambridgeshire may be at risk from power stations in the Trent Valley.

For a time Britain held the world record for super-acid rain. A storm at Pitlochry in 1974 brought rain with a pH of 2.4, which is slightly more acid than vinegar. This dubious achievement was wrested from us by the Americans in 1978, when Wheeling, West Virginia, recorded rain with a value of 2.0, which is virtually battery acid.

In Sweden, toxic metal concentrations in tap water have led to corrosion of cooking utensils, diarrhoea in children, and blond hair turning a punk-like green after washing in water with a high copper content. In southern Norway, 80 per cent of the lakes and streams are dead or dying. Residents in the Adirondack area of New York State have been warned to flush out their household pipes each morning to remove the metals that have been leached from the pipes during the night.

(-liven the general agreement that coal- V fired power stations are the major culprit, what are we doing about them? Suitable technology does exist to 'clean' the coal before use, and to clean the flue gases after combustion. However, it appears that modification of existing power stations us- ing today's methods would be very expen- sive if not impossible. So Britain is planning to await development of newer techniques that are expected to be much less costly. Ex- pedient? Yes. But sensible? No, because in the meantime soils and forests in manY places are likely to suffer irreversible damage. The Europeans are not happy that the prevailing winds will continue to deliver our highly acid rain to them for many years to come.

But power stations release something else which in the long term will prove manY times more dangerous. That something is carbon dioxide. Admittedly much of the carbon dioxide spewed out is quickly ab- sorbed by plants and the oceans, but there has been a net increase in atmospheric car- bon dioxide over the last century of perhaps 15 per cent. And most scientists agree that atmospheric carbon dioxide has risen in just the last 20 years from 315 parts per million to 335 parts per million, or 6.3 per cent.

What are the effects of this increase? One is that carbon dioxide combines with water to form carbonic acid, thus adding in a small way to our acid rain problems. More important is the 'greenhouse effect'. Car- bon dioxide allows short-wave solar radia- tion to reach the earth, but tends to absorb the long-wave radiation reflected off the earth's surface, thus preventing it from be- ing dissipated in outer space. So the more carbon dioxide in the atmosphere, the more of this heat that will be trapped and the greater the consequent warming.

As with acid rain, there are great gaps in our knowledge about the carbon dioxide problem. Even so, there are several points on which the scientists are in broad agree- ment. One, carbon dioxide is produced when fossil fuels are burned. Two, it is vir- tually impossible to remove it from flue gases. Three, predicted growth rates for fossil fuel consumption suggest a doubling of the natural level of atmospheric carbon dioxide by the middle of the next century, or even before. This doubling will cause a global temperature rise of between 1.5°C and 4.5°C.

A temperature increase of this magnitude will have profound side-effects. There will be an increase in humidity and cloud cover. There will be changes in wind systems, distribution of precipitation, and oceanic currents. Some areas are likely to be wetter and some drier than they are today. There will certainly be drastic effects on world food production. Perhaps most alarming of all, parts of the polar ice-caps will melt, causing gigantic tidal waves as enormous chunks of ice fall into the sea, and widespread flooding in coastal areas as the sea level rises.

It has been calculated that a temperature rise of 2°C would cause the west Antarctic ice sheet to melt, leading to a rise in the sea level of five metres. To put this in perspec- tive, the Thames Barrier has a safety margin of three metres above the highest tides we currently expect. Without doubt carbon dioxide levels will continue to increase and will bring widespread havoc sometime between now and a hundred years hence. The scientific consensus is that it is no longer a question of if but when all this will happen.

Erik Eckholm of the International In- stitute for Environment and Development writes in his book Down to Earth: 'The human-caused build-up of atmospheric car- bon dioxide is the quintessential global en- vironmental issue. A continuation of recent trends will probably have momentous im- pacts on world climate and thus on world society . . . Essential as better scientific knowledge is, the response to the carbon

dioxide challenge must involve more than research. We already know enough to war- rant serious concern. The urgent need for research cannot be used as an excuse for ir- responsibly ignoring the consequences of today's decisions. Waiting another decade or two quite likely amounts to imposing great hardship on a future generation.'

So what can be done? About all we can do is to reduce as fast as possible our dependence on fossil fuels. This will involve energy conservation but that alone will not be nearly enough. We simply have to switch to alternative sources of energy. Regret- tably Britain spends a pathetic amount on research into things like wind, wave, tidal, and solar power. We should spend more, and in time these alternatives may make a significant contribution. But given the time scale and the size of the problem, we have to take nuclear power seriously. With all its hazards, the nuclear option still looks a bet- ter bet than sitting back complacently and waiting for tidal waves to engulf our coasts — assuming that they haven't already been rendered lifeless by vinegary downpours.

I believe that the environment lobby, of which I count myself a member, should stop putting on funny masks and posturing in front of the television cameras, and start to address the long-term, fundamental problems.