The environment means surroundings in which people, animals and plants exist.
Ecology is a branch of biology which investigate relationships between living beings and their environment.
The most serious ecological problems of today are:
the pollution of air, water and soil,
the destruction of ecosystem, the destruction of tropical rain forests,
disappearance of many species of animals and plants,
the weather changes, acid rains, the warming up of the Earth´h surface,
breaking of the ozone layer.
These damages are caused by the man himself and his technical progress.

Pollution:
The growing number of cars contribute much to the air pollution. Factories, power stations and motor vehicles pump large quantities of waste gases into the air. Factories also pollute rivers because they put there their chemical waste. Also farmers pollute the soil using a lot of pesticides. This pollution can also poison groundwater.
Acid rain:
Acid rain is caused by emissions of sulphur dioxide and nitrogen oxides. Some of them in combination with water make sulfuric acid in the clouds, it later falls as acid rain which kills trees and make soil infertile.

Global warming and green house effect:
In the last 100 years the Earth´s surface has warmed up by more than half a degree. Very small changes in the Earth´s climate can cause very big problems – sea levels rise up. Global warming is caused by the greenhouse affect. A major cause of the green house effect is polluted atmosphere by carbon dioxide from fossil fuels (oil, gas) and chlorofluorocarbons, which are found in refrigerators and aerosol sprays. Normally, heat from the sun warms the earth and then 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.

Deforestation:
Man has destroyed many tropical rain forests, which are so important for the Earth´s climate. They help to control global warming because they absorb carbon dioxide. THey produce oxygen.
The ozone layer:
The ozone layer is a layer of gas high above the surface of the earth that helps to protect it from the sun´s ultraviolet radiation, which can damage our skins and cause cancer.

Scientists have recently discovered holes in the ozone layer, caused by chlorofluorocarbons (CFCs) and halons which are used in refrigerators and air conditioners.
The areas of largest ozone hole are Antarctica, South America, Australia, New Zealand.

How we can defuse the pollution of our Earth?
Recycling: is a processing of used objects and materials so that they can be used again. Recycling saves energy and raw materials and also reduces damage to the countryside. Glass, paper and aluminium can all be recycled very easily.
Alternative energy: most of the energy we use today comes from coal, oil and gas but nowadays we need to look for other ways of supplying energy – we can use solar power, wind power, water power or hydroelectric power.

Environmental groups:
There are several groups all over the world which try to protect the environment. The most famous group is Greenpeace. They have compaigned against hunting whales, pollution in the North Sea, nuclear power, testing nuclear weapons, and many other issues.