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     Volume 4 Issue 57 |August 5 , 2005 |

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Should we all be seriously alarmed both by the warnings of the dangerous effects of global warming and also by our individual and collective capacity to ignore such warnings? It seems as if these pessimistic forecasts just go in one ear and come out of the other. So, what is all the fuss about? What is the greenhouse effect and what are greenhouse gases anyway?

What are Greenhouse gases? Can it be possible that some people out there still do not know what greenhouse gases are?
Greenhouse gases are certain gases in the Earth's atmosphere some of which occur naturally while others are only produced in industrial processes. They allow incoming radiation from the Sun to pass through the atmosphere of the Earth. The Earth absorbs the radiation and then reflects it back but the wavelength of the radiation is changed. When this outgoing radiation collides with particles of a greenhouse gas, the radiation is absorbed by the particle. This makes the particles move and stretch and the movement warms up the greenhouse gas. On a large scale, all the greenhouse gases around the Earth form a warm blanket around the planet, raising global temperatures. This is known as the greenhouse effect.

How much do you already know about global warming?

1. Which of the following are greenhouse gases?

2. Which of the above gases does not occur naturally in the Earth's atmosphere?
Answer TRUE or FALSE for the following statements
3. The greenhouse effect is a natural process which is necessary for human life.
4. Scientists have proved that the Earth's temperature is rising.
5. This temperature increase is caused by a build-up of greenhouse gas emissions.
6. Changes in global climate are affecting animal behaviour.
7. The Sun might also be responsible for global warming.

Now continue reading and check your answers to the questions.
Greenhouse gases include carbon dioxide, methane, water vapour and nitrous oxide. They appear naturally but are also made through industrial processes. CFCs or chlorofluorocarbons are another form of greenhouse gas but are only produced in industrial processes. Greenhouse gases absorb some of the sun's energy, warming the atmosphere near the Earth's surface. This keeps the Earth warm enough to support life. Some scientists believe that increased emissions of greenhouse gases are causing too much energy to be trapped, inside the Earth's atmosphere, increasing global temperature. They suggest that the greenhouse effect is working too well.

It is a fact that the UK is warmer now than at any time in the past 200 years. Average global temperatures have risen by 0.6°Celsius. October 2001 was the warmest October since records began in 1659, and summer 2003 was Europe's hottest for 500 years. The changes in global climate might even be affecting the behaviour of some animals. In the UK, birds are laying eggs earlier in the year than usual and inhabiting more northerly areas. Animal behaviour is affected by many other things, such as competition between species, so these events may not be due to climate change.

A study by UK researchers carried out in the year 2001 compared recent satellite readings with data from 27 years ago and found that less radiation is now escaping into space. This suggests that the greenhouse effect has increased at a rate in line with rising greenhouse gas production. However, no-one has yet succeeded in proving that the main cause of climate change and global warming is related to human industrial activity and more specifically to the increase in greenhouse gas emissions.

Another explanation is that climate change might not be entirely our fault. It has been suggested that changes in the solar wind (electrically-charged particles coming from the Sun) affect the Earth's cloud cover thereby increasing global temperatures. This would have a far stronger effect on global temperatures than greenhouse gas emissions.


Grammar Note

We use linking words when we describe or explain actions or processes. The following are some of the most common linking words:
and, also - to give additional information
but, although - to describe contrasts
because - to give the reason or cause
so, therefore - to describe consequence
if, unless - to introduce conditional clauses
Now use the most appropriate linking word given above to join the two parts of the following sentences together.
8. The Earth's polar ice caps are melting __________ the global temperature is rising.
9. The UK is warmer now than at any time in the past 200 years _______ average global temperatures have risen by 0.6°C.
10. CFCs are only produced industrially ________ they are easier to cut down than gases like carbon dioxide and methane.
11. The Kyoto Treaty calls on richer nations to cut greenhouse gas emissions by around 5% over the next decade ________ some experts calculate that cuts of 60% are necessary to prevent climate change.
12. ________ richer nations do not reduce the production of greenhouse gases the poorer countries will suffer.
13. _________ richer nations act soon to reduce the production of greenhouse gases we could face an environmental disaster.

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