The greenhouse effect
Some Energy travelling as waves in the form of changing electrical and magnetic fields. from the Sun passes through Earth's The layers of gases that surround the Earth. The important gases in the atmosphere are nitrogen, oxygen and carbon dioxide.. This includes Electromagnetic radiation emitted from a hot object., visible light and Electromagnetic radiation with a frequency between that of visible light and X-rays.. This warms the Earth.
The warm Earth emits infrared radiation. Some gases absorb this radiation and re-emit it in all directions.
Gases which can absorb the infrared radiation are called The gases responsible for global warming - carbon dioxide, methane, nitrous oxide and CFCs (chlorofluorocarbons).. These include carbon dioxide, water vapour and methane.
More energy is absorbed than is radiated back into space. This creates a warming effect that is called the The retention of heat in the atmosphere caused by the build-up of greenhouse gases..
The diagram gives more details about this process.
- electromagnetic radiation at most wavelengths passes through the Earth's atmosphere
- the Earth absorbs most of the radiation and warms up
- the Earth radiates energy as infrared radiation
- some of the infrared radiation goes into space
- some of the infrared radiation is absorbed by greenhouse gases in the atmosphere
- the lower atmosphere warms up
Without the greenhouse effect, Earth would probably be too cold for life.