"For millions of years, the atmosphere, the hydrosphere, the lithosphere and the biosphere have been in balance on the Earth. These four parts make up what we call the Earth's environment.
ATMOSPHERE - all the gases that make up the air including the weather systems, the greenhouse gases and the ozone layer.
LITHOSPHERE - all the rocks in and on the Earth.
HYDROSPHERE - all the water in the seas, rivers, lakes and soils.
BIOSPHERE - all the living organisms on the Earth. 'Organisms' include viruses and bacteria right up to plants and animals (including humans).

ENVIRONMENT
Environment is a big problem. People long influenced environment, but their activity never hadn´t as disastrous effects as today. Environmental issues are a concern for everyone. The Earth bears to the prejudice of our comfort. We need electricity so we have power stations which burn million and million coal and make a big pollution.
Four million years ago, humans first walked on the Earth's surface. We have a highly developed brain. We learn quickly and can plan for the future. Weapon began to change the balance of the environment in our favour. The number of people on the Earth is growing each year making our environmental problems worse. The main ones are:

GLOBAL WARMING
Background: The earth has a thin atmosphere that is like a transparent blanket that keeps us warm. In a process called the greenhouse effect high energy radiation from the solar system is trapped by gases such as carbon dioxide. This heat energy keeps Earth temperatures too high to support life.
The greenhouse effect
The atmosphere keeps the surface of the Earth warm. Without it the average temperature on Earth would be around minus 18°C. With this atmospheric blanket the average temperature is actually around plus 14 degrees Celsius. The energy from the Sun, in the form of ultraviolet radiation, streams in through the atmosphere and warms the surface of the Earth. In a similar way, the energy is reflected back out into space as infrared radiation and absorbed by the gas molecules, which trap the heat inside, like in a greenhouse. This is called the greenhouse effect."