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We all live in a greenhouse world. Gases in the earth’s atmosphere provide a life-saving blanket of warmth. These gases – known as greenhouse gases – absorb heat directly from the sun but also from the earth’s surface after it has been warmed by the sun’s rays. In other words, the earth is acting as a sort of radiator, which heats the surrounding air. However, some of the heat still escapes back into space. It is the balance of energy coming in and going out that provides the earth with its stable life-preserving temperatures.
The main gases involved in the natural greenhouse effect are carbon dioxide and water vapor. These allow the sun’s short wavelength radiation (visible light) to pass through the atmosphere to heat the earth’s surface. After it has heated up, the earth emits long wavelength radiation (infra-red radiation). Some energy escapes back into space, but a lot is absorbed by the greenhouse gases, causing the air to heat up.
Man’s activities upset the balance of heat coming in and going out, causing the global atmosphere to warm up. Extra carbon dioxide is being added to the atmosphere and other greenhouse gases are being produced. There are over 30 greenhouse gases but five are particularly important because they are very efficient in absorbing infra-red radiation. The main greenhouse gases are: carbon dioxide, methane, nitrous oxide, ozone and chlorofluorocarbons (CFCs).
Carbon dioxide (50%) forms part of the natural cycle of carbon dioxide between the atmosphere, oceans, land and the living world. Our activities are adding to the amount of this gas in the atmosphere: the burning of fossil fuels (in power stations, factories and transport) account for over 75% of these man-made emissions. Plants absorb carbon dioxide during photosynthesis – by chopping down trees we are increasing its emissions by further 23%. Almost a third of the world’s natural forests have been removed in 8000 years. Deforestation is the main problem: even if trees covering an area the size of Western Europe were planted tomorrow they would be able to soak up 15-20% of carbon dioxide produced by human activities.
Methane (18%) is produced by cattle, rice paddies, rotting organic matter in refuse tips, and the burning of wood, other vegetation and fossil fuels.
Nitrous oxide (6%) comes from fossil-fuel combustion (burning), fertilizers, used for growing food, and wood burning.
CFCs (14%) which is a human invention, mostly found in propellants for aerosols, foam blowers, foam trays and boxes and refrigerators. Some long-living CFCs are 25,000 times more efficient at heat absorption than carbon dioxide.
Surface ozone (12%) – the ozone molecules, which form in reaction to pollutants, coming mainly from cars, exhaust.
Some of these are naturally occurring gases, but the sophisticated technology used by humans is increasing the amounts of these gases in the atmosphere. The natural balance of the planet is being affected and the earth is beginning to heat up.
It s difficult to predict what will happen if greenhouse gases continue to build up. However, most scientists agree that the temperature of the atmosphere will rise by between 1,5 degree С and 2,5 degree С. This will affect the world’s climate sea level and agriculture.
A rise of 2,5 degree С may not seem a lot, but it may cause glaciers and polar-caps to melt, sea levels to rise, deserts and arid lands to expand. A generally accepted rule is that the major vegetation types will move 250 km further north and 150 m higher up (hills, uplands) with every 1-degree С rise in mean temperature. The greenhouse effect may be already working. In the 1980s the world experienced the five warmest years since records of weather began.
The “overheating” of the planet could have disastrous effects. These include:
The melting of polar ice caps. An increase of 5% in the earth’s overall heat could melt the Arctic icecap completely, raising the level of the world’s seas.
Coastal flooding. As the world’s seas rise, low-lying countries will be very badly affected. Countries like the Netherlands, the Maldives and Bangladesh could largely disappear.
The world’s climate will change as the heat affects the natural climate patterns. We can expect more and more freak weather like tornadoes, floods, and hurricanes. Warmer weather in normally cool or temperature areas could lead to infestations of insects and droughts.
The world food-growing pattern will change. Disrupted climate means that crops might not grow when we expect them and rainfall will not be soaked up. Food supplies will become unpredictable.
Plants and animals will have trouble adapting to the new conditions as their habitats change. Some species will have to move to survive and others may even become extinct.
The greenhouse effect is recognized as a serious crisis and much research is devoted to it. It will take world action to deal with the greenhouse effect, but there are many basic things every single person can do to reduce it.
What can we do?
Avoid CFCs in aerosols, packaging and refrigerators. Buy aerosols marked “ozone friendly” or “environmentally friendly” – it means that they are CFCs free. Avoid fast-food packaging if it does not say that it is CFCs-free and try to avoid those blown-foam trays used in supermarkets for meat and fruit. Instead, buy unpackaged food when you can. Encourage your families to use fewer paint sprays, de-icers, hairsprays and air fresheners.
Use bicycles and public transport instead of private cars. Public transport is less polluting than cars.
Save paper, which also helps save forests, and use recycled paper as often as possible.
Eat less meat, particularly red meat from methane-producing cattle.
Save energy – make sure that the heat, created in power stations, doesn’t just get lost. Even switching off lights helps.
Help save the forests. Support or join campaigns to save the forests, plant trees yourselves.
Remember, the ozone crisis and the greenhouse effect aren’t somebody else’s…they are affecting you right now!
Ex.4. Arrange the following sentences in the order of appearance in the text:
1) Increased amounts of ozone at ground level are usually caused by a combination of pollutants and local weather.
2) Some gases are particularly harmful to high-level ozone.
3) Ozone is poisonous and damaging – this makes ground-level ozone a problem.
4) Unlike ground-level ozone the high-level ozone does a useful job.
5) The overheating of the planet could have disastrous effects.
6) Ozone is poisonous and can damage people’s health.
7) The main greenhouse gases are: carbon dioxide, methane, nitrous oxide, ozone and chlorofluorocarbons (CFCs).
8) About 90% of the ozone in the earth’s atmosphere is located in the stratosphere – a band 15-50 km above our heads.
9) The ozone layer is fragile and it is being threatened.
10) The depletion of the ozone layer has become a global problem.
Ex.5. State these statements as True or False:
1) The ground-level ozone is dangerous.
2) High-level ozone absorbs 99% of the ultraviolet radiation.
3) Ozone comes directly out of car exhausts and chimneys.
4) Short burst of breathing ozone are not so dangerous as prolonged exposure.
5) Natural and man-made materials are affected by ozone.
6) The high-level ozone is very dense.
7) A thinning ozone layer will allow more ultra violet radiation to reach the earth’s surface.
8) Man’s activities upset the balance of heat coming in and out, causing the global atmosphere to warm up.
9) The greenhouse effect isn’t very dangerous.
Ex.6. Answer the following questions:
1) What kind of oxygen do we need to breath?
2) How is the ozone formed?
3) What are the two kinds of ozone? Which of them is dangerous and which of them is useful?
4) Where can be earth’s ozone found?
5) What are the main pollutants causing ozone?
6) When are high concentrations of ozone formed?
7) What’s the cause of ground-level ozone pollution? How does it affect health?
8) How can be an ozone alert avoided?
9) In which way does ozone affect natural and man-made materials?
10) Why is high-level ozone so important?
11) What gases are harmful to high-level ozone?
12) Describe the process of appearing of greenhouse effect?
13) Which man’s activities contribute to the greenhouse effect?
14) What are the consequences of the greenhouse effect?
Carbon Dioxide and Global Warming
1. Study the vocabulary before reading the text:
Depletion истощение
Nonrenewable resources невозобновляемые ресурсы
Climate warming (global warming) потепление климата
Climate equilibrium климатическое равновесие
Natural variability of the climate изменения климата, вызванные
естественными причинами
The extent and timing of global warming масштаб и время начала потепления
климата
geographic range ареал распространения животного или растения
species вид
habitat место обитания
pattern характер, распределение
fertile lands плодородные земли
proliferate размножаться
greenhouse gases emissions выбросы газов, вызывающие парниковый эффект
buildup накопление
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