The Earth's atmosphere is all around us. It is the air that we breathe and move about in. Some of the atmosphere is made up of gases called Greenhouse Gases. They include carbon dioxide, nitrous oxide and methane. These gases occur naturally, and are important because they trap energy from the Sun in the Earth's atmosphere.

This is called the Greenhouse Effect because the gases behave in the same way as the panes of glass in a greenhouse. Sunlight enters the Earth's atmosphere and passes through the greenhouse gases. When it reaches the Earth's surface, the land and water absorb energy from the sunlight. Once absorbed, this energy is sent back into the atmosphere. Although some energy escapes back into space, some of it gets trapped in the atmosphere by the greenhouse gases and causes the Earth to heat up. This greenhouse effect is very important, because without it the Earth would be too cold for us to live on.

However, if the greenhouse effect becomes stronger, the Earth could get even warmer than usual. This is called Global Warming.