Unit3 environmental protection text 3.1 Our Common Threats

I. Read the text thoroughly and point out the most important facts.

The new level of technology, the results of modern scientific knowledge made people realize that the time came for humans to take responsibility for preserving the quality of life for the future generations. The conservation movement was trying to protect endangered species. But suddenly water, air and soil became the most endangered parts of this planet. Unfortunately people did not realize that until some drastic events happened. Science can not always predict the result of human activity. The real struggle for banning nuclear tests in the atmosphere began only after the scientists discovered radioactive strontium-90 in cattle that fed on grass and in cows' milk. Both American scientists and Soviet scientists were sure that there was no ground for worry because the radioactive materials would remain in the stratosphere for many years. A more alarming discovery showed that each link in the food chain contains greater levels of concentration of radioactivity than the link below it. As soon as everybody realized that no matter who does the testing it increases the level of radioactivity on the whole planet, nuclear testing in atmosphere was banned by most countries.

The environmental movement has a global prospective now. In the 1970s environmental movement crossed the borders and became the international one. Concerns over environment were the subject of a UN conference in 1972 attended by 114 nations. Out of this conference developed the United Nations Conference on Environment and Development Environmental issues can be resolved only if all the countries cooperate. There are very positive and encouraging results in such a global cooperation Ten years ago a historic event, a landmark in environmental movement took place in Montreal. 24 countries signed a treaty on Substances That Depleted Ozone Layer.

Later on 150 countries ratified the treaty. The treaty put very strict restrictions on the use of chemicals that damage the ozone layer — a 10-15 kilometers layer in the stratosphere that protects the earth from harmful ultraviolet (UV) radiation. Governments from different countries were participating in the talks — rich developed nations as well as poor developing ones. We see the results of this treaty now — 10 years later. The production of the most dangerous chemical substance — chlorine-containing chlorofluorocarbons (CFCs) went down 76 percent. In 1996 industrial countries stopped producing CFCs for domestic use. It is inspiring to know that countries can work together in the face of common danger. It would be much better if we had not allowed it to happen. Scientists warned us in time and governments acted promptly. Otherwise the results of radiation could have been grave for humanity. But if humans want to survive, they need to solve the problems that humanity faces now.

The Earth Summit on Environment in Rio de Janeiro in 1992 was unproductive. Barriers are too strong. The economies are too different; the level of problems facing each country is very different too. We as humans are facing several environmental problems that need to be solved if we want to survive. One of the big problems is the increase of carbon dioxide (C0₂) in the earth's atmosphere. The amount C0₂ in atmosphere remained stable for centuries, at about 260 ppm (parts per million), but over the past 100 years it has increased to 350 ppm. The significance of this change is its potential for raising the temperature of the earth through the process known as the "greenhouse effect." Carbon dioxide in the atmosphere prevents the escape of outgoing long-wave radiation front the earth to outer space; as more heat is produced and less escapes, the temperature of the earth increases.

Global warming of the atmosphere would have profound environmental effects. It would speed the melting of polar ice caps, raise sea levels, change the climate regionally and globally, alter natural vegetation, and affect crop production. Since 1850 there has been a mean rise in global temperature of about 1°C. Some scientists have predicted that rising levels of C0₂ and other "greenhouse gases" will cause temperatures to continue to increase up to 6°C by the middle of the 21^s' century

Another problem - acid rains - is associated with the burning of fossil fuels, which is caused by the emission of sulphur dioxide nitrous oxides into the air from power plants and motor vehicles. These chemicals interact with sunlight, moisture, and oxidants to produce what is known as acid rains. Acid rain is a major global problem. They corrode metals, stone buildings and monuments, injure and kill vegetation, and acidify lakes, streams, and soils. It is known already that low level air pollution results in general increase in the incidents of bronchitis and emphysema.

Pesticides present another environmental threat. Pesticides resist biological degradation. They are insoluble in water; they cling to plant tissues and accumulate in soils, at the bottoms of streams and ponds, and the atmosphere. Pesticides are a great threat to humans. Animals that eat plants absorb them; we eat the meat of these animals. Pesticides are absorbed directly through the skin by fish. Because of that a lot offish-eating birds became extinct.

A lot of toxic poisoning that presents a risk to human health occur at dump sites. When toxic substances seep into soil and water, the chemicals can contaminate water supplies, air, crops, and domestic animals, and have been associated with human birth defects and diseases. We know about the dangers but the problem is widening. In a recent 15-year period, more than 4 million new synthetic chemicals were manufactured, and new ones are being created at the rate of 500 to 1000 each year. Power plants constitute a great danger to the environment. A lot has been achieved through common efforts in banning atmospheric testing of nuclear weapons by most countries. But nuclear radiation still remains an environmental problem. Power plants always release a certain amount of radioactive waste. Nuclear accidents, which unfortunately happened not than once, release a lot of radiation into the environment. This happened in 1986 in Chernobyl and scientists still can not comprehend the full effect of this catastrophe.

The world is also experiencing a permanent decline in water quality and water availability. In a lot of places water supplies are contaminated with toxic chemicals and nitrates. Waterborne diseases kill 10 million people a year.

We, the human race, are involved in a large experiment - an experiment to see what will happen to our planet, its health and the health of its inhabitants. The experiment is a dangerous one. Life itself is at stake. Can we preserve the life? Can we preserve the quality of life necessary for future generations? When we are sick we try to take care of ourselves. There is nobody but us, humans, to take care of the Earth that is sick because of our actions. Can we do something? — YES, we can! We proved that. Is it difficult? Extremely! There are so many of us and we are so different — socially, economically, culturally, traditionally. But the Earth does not know that all these differences exist, that there are borders we created. We are just one of the life forms that the Earth supports. And we are the only life form that is able to destroy our life support system. Let's believe that we are also the ones, who can maintain it for the many generations to come.

link	звено
food chain	пищевая цепочка
deplete	истощать
ozone layer	озоновый слой
acid rain	кислотный дождь
insoluble	нерастворяемый
absorb	поглощать
extinct	вымерший
contaminate	заражать
waste	отходы,отбросы
decline	ухудшение, v снижаться, приходить в упадок