It was in Britain that the word 'smog' was first used (to describe a mixture of smoke and fog). As the world's first industrialized country, its cities were the first to suffer this atmospheric condition. In the nineteenth century London's 'pea-soupers' (thick smogs) became famous through descriptions of them in the works of Charles Dickens and in the Sherlock Holmes stories. The situation in London reached its worst point in 1952. At the end of that year a particularly bad smog, which lasted for several days, was estimated to have caused between 4,000 and 8,000 deaths.
Water pollution was also a problem. In the nineteenth century it was once suggested that the Houses of Parliament should be wrapped in enormous wet sheets to protect those inside from the awful smell of the River Thames. In the middle years of this century, the first thing that happened to people who fell into the Thames was that they were rushed to hospital to have their stomachs pumped out!
Then, during the 1960s and 1970s, laws were passed which forbade the heating of homes with open coal fires in city areas and which stopped much of the pollution from factories. At one time, a scene of fog in a Hollywood film was all that was necessary to symbolize London. This image is now out of date, and by the end of the 1970s it was said to be possible to catch fish in the Thames outside Parliament.
However, as in the rest of western Europe, the great increase in the use of the motor car in the last quarter of the twentieth century has caused an increase in a new kind of air pollution. This problem has become so serious that the television weather forecast now regularly issues warnings of 'poor air quality'. On some occasions it is bad enough to prompt official advice that certain people (such as asthma sufferers) should not even leave their houses, and that nobody should take any vigorous exercise, such as jogging, out of doors.
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Every year more and more plants and animals disappear forever. Strangely, it is the most intelligent but most thoughtless animal that is causing most of the problems – man. Nature is very carefully balanced and if this balance is disturbed, animals can disappear alarmingly fast. Every day, thousands of species of animals draw closer to extinction.
In many lakes fish are dying. Fishermen are worried because every year there are fewer fish and some lakes have no fish at all. Scientists are beginning to get worried too. What is killing the fish?
The problem is acid rain. Acid rain is a kind of air pollution. It is caused by factories that burn coal, oil and gas. These factories send smoke high into the air. The wind often carries the smoke far from the factories. Some of the harmful substances in the smoke may come down with the rain hundreds of miles away.
The rain in many places isn't natural and clean any more. It's full of acid chemicals. When it falls in lakes, it changes them too. The lakes become more acidic. Acid water is like vinegar or lemon juice. It hurts when it gets in your eyes. It also kills the plants and animals that usually live in lake water. That is why the fish are dying in lakes.
But dead fish may be just the beginning of the problem. Scientists are finding other effects of acid rain. In some large areas trees are dying. Not just one tree here and there, but whole forests. At first scientists couldn’t understand why. There were no bugs or diseases in these trees. The weather was not dry. But now they think that the rain was the cause. Acid rain is making the earth more acidic in these areas. Some kinds of trees cannot live in the soil that is very acidic.
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The Ozone Layer
The ozone layer is a thin layer of gas about 25 to 40 kilometres above the Earth's surface. The ozone protects us from the sun's radiation. In the 1980s scientists discovered 'holes' in the ozone layer.
The causes include more carbon dioxide (CO2) and the use of CFCs (chlorofluorocarbons).
The holes in the ozone layer might become bigger. Some scientists believe the average temperature of the Earth will increase by between 1.5˚ Ñ and 4˚ C. There will be more droughts and we will change the way we grow our food.
The forests will die. The polar ice will melt and the sea levels might rise by a metre. There will be floods and some big cities might disappear. Some scientists think many thousands of people might die.