Reading

Task 4. Read and translate the text. Find in the box the synonyms to the italicized words from the text.

raise, component, breathing, reason, suppose, discovery, occurrence, over a period of, research, widespread, currently

Carbon dioxide

Carbon dioxide is a colourless and non-flammable gas at normal temperature and pressure. Although much less abundant than nitrogen and oxygen in the Earth's atmosphere, carbon dioxide is an important constituent of air.

Carbon dioxide makes up less than one percent of the Earth's atmosphere. It is a minor component of the Earth’s atmosphere, formed in combustion of carbon-containing materials and in respiration of animals. The presence of the gas in the atmosphere keeps some of the radiant energy received by the Earth from being returned to space, thus producing the so-called greenhouse effect.

The processes involving carbon dioxide affect our climate in ways that are difficult to understand. World temperatures increased about six-tenths of a degree Celsius in the last one hundred years. The best information about climate in the past comes from tests of ice many kilometres deep in Antarctica and Greenland. The tests show changes in temperature during the past four hundred thousand years. These tests show that levels of carbon dioxide today are the highest ever measured. These findings have led scientists to believe that carbon dioxide is a major cause of climate warming.

Carbon dioxide is released into the atmosphere when fuel is burned. Oil, coal down, it also releases carbon dioxide. However, plants use carbon dioxide in the process called photosynthesis. Plants and other organisms convert light energy, normally from the sun, into chemical energy that can be used to fuel the organisms’ activities.

Forests and trees are able to capture large amounts of carbon dioxide from the air. Some scientists even suggest that an increase in carbon dioxide could cause plants and trees to grow faster. But the researchers found the effect appears to last for only three years. Another study showed that much of the carbon dioxide that is taken in by trees is released within three years. The study noted that leaves release carbon dioxide when they fall from trees and break down in the soil. Plants also naturally release carbon dioxide through the process of respiration.

The natural balance of gases in the atmosphere is a complex scientific issue. The debate over carbon dioxide is only one part of efforts to understand world climate change.

Task 5. Answer the following questions to the text.

1. What is carbon dioxide?

2. What gases in the Earth's atmosphere are more abundant than carbon dioxide?

3. How much of the Earth's atmosphere does carbon dioxide make up?

4. In what way is carbon dioxide formed?

5. In what way is greenhouse effect produced?

6. How did world temperatures increase in the last one hundred years?

7. What shows changes in temperature during the past four hundred thousand years?

8. How is carbon dioxide released into the atmosphere?

9. Why do some scientists suggest that an increase in carbon dioxide could cause plants to grow faster?

10. When is carbon dioxide taken in by trees released according to some scientific suggestions?

Task 6. Decide which of the following statements are true (T) or false (F). If the statement is false, explain why.

1.	Nitrogen and oxygen are less abundant in the Earth's atmosphere.
2.	Carbon dioxide is formed in combustion of carbon-free materials and in respiration of animals.
3.	The greenhouse effect is caused by the presence of carbon dioxide in the atmosphere.
4.	The processes involving carbon dioxide affect our climate.
5.	Carbon dioxide is a major cause of climate warming.
6.	World temperatures decreased about six-tenths of a degree Celsius in the last one hundred years.
7.	The tests of ice show changes in temperature during the past four hundred thousand years.
8.	In photosynthesis plants and other organisms convert chemical energy into light energy.
9.	Carbon dioxide taken out by trees is given off within three years.
10.	The process of plants respiration results in releasing of carbon dioxide.

Task7. Match the columns to make up phrases and translate them.

1) climate	a) levels	1)
2) world	b) cause	2)
3) natural	c) effect	3)
4) carbon	d) issue	4)
5) large	e) atmosphere	5)
6) major	f) warming	6)
7) the Earth's	g) temperatures	7)
8) greenhouse	h) dioxide	8)
9) scientific	i) balance	9)
10) highest	j) amounts	10)