– CHANGES IN WORLD CLIMATE –
(Global Warming – Changing Climates – Changing Air Conditions – Changing Weather Conditions)
Although the weathermen’s forecasts for a month ahead are only a little better than guesswork, they are now making long-term forecasts into the next century with growing confidence. For the dominant trend in the world’s climate in the coming decades will, scientists say, be a predictable result of man’s activities.
At the start of the industrial revolution nearly two centuries ago, man innocently set off a gigantic experiment in planetary engineering. Unaware of what he was doing, he spared no thought for the consequences. Today, the possible outcome is alarmingly clear, but the experiment is unstoppable. The danger: Global Warming
Within the lifetimes of many of us, the earth may become warmer than it has been for a thousand years. By the middle of the next century, it may be warmer than it has been since before the last Ice Age. And the century after that may be hotter than any in the past 70 million years. The danger: Changing Climates
Superficially, a warmer climate may seem welcome. But it could bring many hazards – disruption of crops in the world’s main food-producing regions, famine, economic instability, civil unrest and even war. In the much longer term, melting of the great ice-caps of Greenland and Antartica could raise sea-levels throughout the world. The danger: Changing Air Conditions
The average sea-level has already risen a foot since the turn of the century, and if the ice-caps disappear entirely, it would rise by nearly 200 feet. Complete melting might take many centuries, but even a small increase in sea-level would threaten low-lying parts of the world such as the Netherlands.
The man-made agent of climatic change is the carbon dioxide that has been pouring out of the world’s chimneys in ever-increasing quantities since the industrial revolution began. And in the past few years, scientists have begun to suspect that there is a second man-made source of carbon dioxide which may be as important as the burning of fossil fuels, namely the steady destruction of the world’s great forests. Trees and other vegetation represent a huge stock of carbon removed from circulation like money in a bank. The danger: Changing Weather Conditions
As the vast tropical forests are cut down, most of the carbon they contain finds its way back into the atmosphere as carbon dioxide. The amount of CO2 (carbon dioxide) in the atmosphere is still tiny. But it has climatic effects out of all proportion to its concentration. It acts rather like the glass in a greenhouse, letting through short-wave radiation from the sun, but trapping the longer-wave radiation by which the earth loses heat to outer space. Computer studies have suggested that if the concentration of carbon dioxide in the atmosphere were to be twice that of today’s, there would be a rise of between 2°C and 3°C in average temperature.
A. What do the following refer to?
1. ‘they’ (line 2):
2. ‘it* (line 15):
3. ‘if (line 22):
B. Mark the best choice.
1. Line 16, ‘hazards’ probably means .
a) advantages b) benefits c) problems d) precautions
2. Line 39, ‘trapping’ probably means .
a) not allowing to pass b) making easier to pass c) letting through a surface d) losing heat
3. Which of the following cannot be one of the results of a warmer world climate?
a) An increase in food production.
b) Wars between countries.
c) The death of millions of people from starvation.
d) Economic instability.
4. Scientists predict that, in the long term, .
a) there will be a Third World War
b) all countries will be flooded
c) the sea-level will not rise noticeably
d) the polar ice-caps might melt completely
5. Man has changed the world’s climate by .
a) building chimneys b) using up more carbon dioxide
c) decreasing industrialisation d) destroying forests and burning fossil fuels
6. If the amount of CO2 in the atmosphere increases considerably,
a) the world will become warmer
b) we can expect colder weather
c) plants will tend to grow faster
d) we will have to destroy more forests
7. Weathermen believe that our future climate will be the direct result of
a) clever long-term forecasts
b) scientific experiments
c) planets’ changing course
d) man’s activities