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.

9.13 You are going to read a newspaper article about a man who teaches survival techniques. Eight sentences have been removed from the article. Choose from the sentences A-I the one which fits each space (1-7). There is one extra sentence which you do not need to use. There is an example at the beginning (0).

THE MAN WHO CAN SURVIVE ANYWHERE

Ray Mears tells Graham Hardley how learning survival skills can help us rediscover nature.

Armed with little more than a hunting knife and a cooking pot Ray Mears can survive anywhere. He loves nothing more than spending days, weeks or even months alone in the wild, and he will talk passionately about any aspect of the natural world, from his favourite trees to endangered species of animals. (0 – I) Those who sign up for the courses range from children to grandparents, with a large number of twenty to thirty-year-olds looking for a taste of adventure.

“People might see it as survival skills,” he says, “but I aim to teach a little more than that. (1) Some who have participated on the course have experienced a very profound change in their life. They develop a greater awareness of nature. They return to the cities and notice the seasons change for the first time. (2) The city and their life in it are transformed.”

The Woodlore courses take participants to experience tribal life with the native people of Namibia, or to shiver through an Arctic survival course in Lapland. (3) These are the places to fulfil the schoolboy dream of lighting fires with just a couple of sticks.

(4) “There are lots of simple survival tips, like it’s often better to avoid anything which is green. More energy is used up eating it than you get out of it. Roots are best because you need carbohydrates.”

There is a very serious purpose to what Mears does. “All around the world cultures are losing ancient skills as the latest generation is attracted away from the land to an easy life through technology,” he explains. “We live in a world where we can have whatever we want, but along the way we have lost contact with the natural world. (5) Without them, there’s a danger we could lose sight of where we’ve come from.”

“The area around London is particularly threatened. (6) People need places where they can get close to nature.”

But Mears is not against the latest technological developments and is well aware of the benefits. (7) “In this way people can become part of a global tribe, one which lives both for and from the natural world.”

(www.raymears.com)

► A) Mears even takes groups to visit a highly-protected reserve in Canada to watch bear cubs being born and raised.

B) He has just hired an Internet consultancy firm to design a website which will give people all over the globe access to his knowledge.

C) I try to show people how to reconnect with nature, how to see it in a different light.

D) This experience, and others like it, led Mears to write The Survival Handbook, which was published in 1989.

E) The ancient woodlands should be left alone, and areas not needed for agriculture should be planted with trees and allowed to grow wild.

F) They see the geese, the pigeons, the edible plants growing between the cracks in the pavement.

G) These ancient skills help to put us back in touch with nature, and to understand our place in the world.

H) He also teaches how to identify edible plants for food.

I) His passions are reflected in Woodlore, a series of courses in which he passes on survival techniques to people of all ages.

9.14 Read the text “Desert Plants” and find the correct answer.

DESERT PLANTS

Desert plants have adapted to the arid climate by using both physical and behavioral mechanisms. Some plants have developed to take advantage of the seasons when moisture is at a premium and / or when it is coolest. One of this category of plants are ‘annuals’, plants that live for only a season. The term ‘annuals’ implies blooming yearly, but since this is not always the case, desert annuals are more accurately referred to as ‘ephemerals’. Many of them can complete an entire life cycle in a matter of months, some in just weeks.

Desert plants must act quickly when heat, moisture and light inform them it’s time to bloom. Ephemerals are the sprinters of the plant world, sending flower stalks jetting out in a few days. The peak of this bloom may last for just days or weeks, depending on the weather and difference in elevation. The higher one goes, the later blooms come. Different varieties of plants will be in bloom from day to day, and even hour to hour, since some open early and others later in the day.

Ephemerals such as Desert Sand Verbena, Desert Paintbrush and Mojave Aster usually germinate in the spring following winter rains. They grow quickly, flower and produce seeds before drying and scattering their progeny on the desert floor. These seeds are extremely hardy. They remain dormant, resisting drought and heat, until the following spring – sometimes two or three springs – when they repeat the cycle, germinating after winter rains to bloom again in the spring. There are hundreds of species of ephemerals that thrive in the deserts of the American Southwest, and if you examine the desert ground closely, you will likely find dozens of annual seeds in every handful of soil.

1 Which of the following best describes the main point of the passage?

a) The desert soil is full of drought-resistant annual seeds.

b) Annual winter rainfall allows the ephemerals to bloom.

c) Different plants flower at different times.

d) Ephemerals have adjusted to the weather conditions.

2 It can be inferred from the passage that ephemerals

a) flower more quickly than other plants.

b) need to have high temperatures before they can flower.

c) only bloom at high altitudes.

d) are at their peak when they have flowered for a few days.

3 According to the passage, the seeds of the ephemeral

a) germinate every year.

b) are very sturdy.

c) bloom every spring.

d) do not live long on the desert ground.

4 What do some plants take advantage of?

a) The autumn seasons.

b) The drought each summer.

c) The temperature and humidity.

d) The winter rains and very cold temperatures.

5 According to the passage, the seeds on the desert floor remain

a) there for two or three years in every handful of soil.

b) inactive until conditions are suitable for them to flower.

c) on the desert floor drying out.

d) thriving in the deserts of the American Southwest.

9.15 Read the text “Ecotourism in the Highlands of Ecuador” through and complete the table after it.

Date: 2014-12-22; view: 3141