Kategorie: Biológia (celkem: 966 referátů a seminárek)

Informace o referátu:

  • Přidal/a: anonymous
  • Datum přidání: 01. července 2007
  • Zobrazeno: 1675×

Příbuzná témata


The environment is all around us. It consists of the flora, fauna, the water, the air, and the earth. However, humans do not always care for the environment as they should. People tend to prefer their own convenience and luxury over a healthy natural environment. People want more cars, bigger houses, the latest computer technology, and packaged foods, etc. to make their life more comfortable.
The most serious ecological problems of today are the pollution of air, water and soil, the destruction of ecosystem, disappearance of many species of animals and plants, the weather changes, acid rains, the warming up of the Earth’s surface, the destruction of tropical rain forests and the breaking of the ozone layer. These damages are caused by the man himself and his technical progress. Factories, power stations and motor vehicles pump large quantities of carbon dioxide and other waste gases into the air. Some poisonous gases dissolve in water in the atmosphere and then fall to the earth as acid rains. Acid rain damages trees, buildings and kills fish. Rivers can also be polluted by industrial waste from factories and chemical fertilizers and pesticides used by farmers.
Global warming is caused by the greenhouse effect. Normally, heat from the sun warms the earth and escapes back into space. But carbon dioxide and other gases in the atmosphere trap the sun’s heat, and this is slowly making the earth warmer.
The ozone layer is a layer of gas high above the surface of the earth than helps to protect it from the sun ultraviolet radiation. Scientists have recently discovered holes in the ozone layer, caused by substances called CFCs. CFCs are used in refrigerators, aerosol cans and in the manufacture of some plastic products. Now don’t use these things and these are marked “ozone-friendly”.
Rainforest help to control global warming because they absorb carbon dioxide. In recent years, large areas have been destroyed for wood or for farming. Many rainforest grow on poor soils, and when they are cut down or burned, so that the area may turn to desert. Many plant and animal species that live there could become extinct.
People should use the alternative energy. Electricity made from solar, wind or water power don’t damage environment like the electricity made from coal, gas or oil. But solar, wind or water power is still too expensive. People should use recycling, when used objects and materials so that can be used again.

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