Malaysia

Deforestation is usually followed by massive soil erosion with valuable topsoil washed away into rivers. This is a loss of a most vital resource required for agriculture and at the same time a siltation of the river systems causes widespread floods.

(Khor Kok Peng, 1989)

Kenya

Kenya fells up to 20,000 hectares of trees a year but … thanks to efforts at grassroots level, encouraged by government, the country now has a record unparalleled in the developing world of efforts to eventually planting more trees than it fells.

(UNEP News, 1987)

South America

In other regions pristine tropical forest has been converted on a massive scale to cattle pasture. Ironically even small farmed plots in cleared tropical forest areas are often converted to pasture after two or three years because of declining yields on poor soils. Perhaps 90% of tropical moist forest soils are completely unsuitable for any kind of annual agriculture. The only people that have evolved sustainable agroecosystems in these areas are the indigenous and tribal peoples who inhabit many of the still intact rainforests. (Ecoforum, 1988)

India

The variety of forest resources available and used by the rural people are neither recorded nor appreciated by the government foresters. Arttabandhu Mishra, a researcher … in the eastern coast of Orissa, has recorded that rural people in Orissa get almost all their needs in the forest without destroying it. “There are at least 30 to 40 varieties of roots and rhizomes collected by the villagers from the hill slopes and by asking the old ladies in the villages I learned of 40 types of spinaches and edible flowers …”, Mr Mishra reported. So abundant is the resource that in certain seasons people taking cattle for grazing in the forest rarely take lunch with them because fruits, berries, mushrooms etc. Are so readily available.

(Ravi Sharma, Ecoforum, Dec. 1989)

12. Read the text The Greenhouse Effect and think what consequences of this phenomenon can be. Name them.

The greenhouse effect

There is an increasing amount of scientific evidence to suggest that the average temperature of the earth is increasing due to the ‘greenhouse effect’. This would appear to be bad news for all those parts of the world already suffering from serious desertification. Surely a rise in temperature will make the problems caused by drought much more severe.

The events following the warming of the earth’s climate by even a few degrees would be far more complicated than you might think. For example, it is predicted that by the year 2060 the earth’s temperature will have increased by an average of three degrees centigrade but that the actual increase will only be about one degree at the equator and as much as seven degrees at the poles. A rise of seven degrees at the poles could cause the melting of a tremendous amount of ice. If only a small proportion of the 26 million kilometres cubed of ice in Antarctica melted, the seas would rise and there would be a lot more water, which could evaporate and form rain clouds. Changes in the temperature would also affect the paths and direction of wind and water currents around the planet earth. So we cannot be certain what all the consequences of the greenhouse effect would be.

One prediction is that there would be tremendous changes in the pattern of the world’s climate, which would make some areas wetter than they are now and other areas much drier than they are at present. The tropical rainforest areas of the world would become drier and many of the desert areas would become wetter. Large areas of Africa (including the Sahara), South America, and Australia would receive more rain and might be able to grow more crops and provide more grazing for animals. In the great grain growing areas of the USA and Russia the rainfall would decrease and many of the crops would die of lack of moisture. In these areas desertification would become more and more of a problem and perhaps we would see a return of the great dust bowls which rendered great tracks of land infertile in the 1920s and 1930s. Countries which were once big exporters of grain might not have enough to feed themselves. Indeed, they could become dependent on the countries which today are poor and stricken by famine.

Another consequence of the melting of the ice at the North and South Poles would be a rise in the level of the sea. Many coastal cities would be flooded and many hectares of fertile land on coastal plains and valley bottoms would be permanently inundated with water. Most of the Netherlands, for example, would be permanently flooded. Forty per cent of the world’s population lives in coastal areas and would have to move inland as the seas rose and this might well result in millions of people unable to earn a living or grow their own food.

Nobody knows if there would be a total decrease or increase in the food supply as a result of the greenhouse effect but what is certain is that there would be tremendous changes in the areas where food is produced at the present time. Farmers all over the world would have to learn to grow different crops and millions of people might be forced to change their traditional diets.

Even if people all over the world were successful in adapting to a different climate, the problems of desertification would remain with them if they continued to neglect the soil and ignore the need to carefully cultivate and nourish those precious few inches of topsoil. Changes in the climate might just give some people living in the drier areas of the world a better chance to grow their crops and the years of drought might cease, but water as well as wind can carry away fertile soil and once lost it is gone for ever.

The greenhouse effect is not difficult to understand if you know how hot a greenhouse can get when the sun shines on it. The glass lets the sun’s energy into the greenhouse and then traps it so the air gets hotter and hotter. Carbon dioxide in the earth’s atmosphere has much the same effect as the glass in the greenhouse, and the more carbon dioxide there is, the hotter the earth’s climate will become. Since 1850 the amount of carbon dioxide in the atmosphere has increased by almost 30 per cent. This is because our consumption of energy from fossil fuels has reached such a peak that we now burn almost five billion tonnes of fossil fuel each year. Coal fired electric power stations produce large amounts of carbon dioxide which is released into the atmosphere. The burning of tropical rain forests also produces a great deal of carbon dioxide. Trees also use carbon dioxide so the destruction of forests also means less carbon dioxide is used up in the atmosphere.

13. A) Read the text Shenandoah National Park and answer the questions given before each part of the text.