Unit 4 the greenhouse effect

Exercise 6. Fill in each gap with only one word.

Gases pollute the atmosphere because they are produced 1). too quickly to be cleared away naturally 2). by rain, winds or plant life. These poisonous gases 3). are from several sources such as oil producers, industries which burn fuel, and motor vehicle. When the gases are released, they have two deleterious effects. 4). Firstly, some of the gases are caught by rain clouds and fall as acid rain, 5). hence damages the environment. Secondly, if the amount of carbon dioxide increases, a larger fraction of the incident solar radiation is trapped, keeping the heat of the sun close 6). to the Earth’s surface just 7). as a greenhouse keeps heat in. The increase of carbon dioxide is 8). getting worse by the cutting down 9). rain forests. Trees use carbon dioxide, and the fewer trees 10). are, the more of this gas remains 11). in the air. The USA is now leading an international effort to limit deforestation. In 1996, Washington set goals for industry, and several international agreements 12). have already been effective in reducing the production 13). of harmful gases. Only international cooperation can 14). solve this problem which, if 15). not controlled, may threaten all life on earth.

Exercise 9. Put the sections of the article from the New Scientist into the correct order. The first section is “ a” and the last is “g”.

KEY: a, e, f, b, d, c, g.

Exercise 10. 9 You will hear a lecture on global warming. For questions 1- 15 fill in the missing information.

Tapescript

The director of NASA's Institute for Space Studies James Hansen had a simple message: "Global warming has begun." As evidence he presented not just the atmospheric models that for years have predicted climate change, but also a series of global average temperatures going back to 1880 that show a rise of 0.6 degrees Celsius. And the decade of the nineties, as Hansen pointed out, is by far the warmest ever recorded. The date was June 23, 1998, and human-induced global warming had finally emerged as a worldwide threat and public concern that policymakers could no longer ignore. Although much of the key data had been developed and even published in preceding years, Hansen's testimony was more definitive. A sober government scientist was publicly stating his conclusion that human-induced greenhouse warming is a reality with which modern societies must cope.

Against the background of a persistent North American drought and unusually mild European weather, shock waves emanated quickly from Capitol Hill. Hundreds of reports soon followed in magazines and on television programs around the world. Opinion polls soon showed that climate change had become an issue of major public concern. Since Hansen's testimony, debate has raged in the scientific community and popular press about some of the details of his conclusions.

Hansen brought to public attention what is now a strong and largely undisputed consensus of atmospheric scientists: global tem­peratures are almost certain to warm rapidly during the coming decades, posing a serious threat to societies and ecosystems throughout the world.

The earth's climate is the product of a delicate balance of energy inputs, chemical processes, and physical phenomena. On Venus, a hu­man being's blood would boil. On Mars, a person would instantly freeze to death. This difference in temperature is largely due to the varying compositions of each planet's atmosphere. All three receive huge quan­tities of solar energy, but the amount that is radiated back into space in the form of heat depends on the composition of their atmospheres. Some gases, such as carbon dioxide and methane, tend to absorb this heat in the same way that glass traps heat in a greenhouse, allowing temperatures to build up. The scorching heat of Venus is the product of an atmosphere composed largely of carbon dioxide. Earth, on the other hand, has a nitrogen and oxygen-based atmosphere, only 0.03 percent of which is carbon dioxide. This share has varied only by 40 percent over the past several million years, allowing a relatively stable climate conducive to life.

KEY

1). beginning of the global warming

2). (a series of) global average temperatures

3). the warmest ever recorded

4). June 23, 1998

5). a worldwide thread and public concern

6). Hansen’s testimony was more definitive

7). modern societies must cope

8). an issue of major public concern

9). almost certain to warm rapidly

10).delicate balance of energy inputs, chemical processes, and physical phenomena

11). instantly freeze to death

12). the varying compositions of each planet’s atmosphere

13). the composition of their atmosphere

14). glass traps heat in a greenhouse

15). a nitrogen and oxygen-based atmosphere.