Greenhouse Gases (Edexcel GCSE Chemistry)

Greenhouse Gases

• When shortwave radiation from the sun strikes the Earth’s surface it is absorbed and re-emitted from the surface of the Earth as infrared radiation

• Much of the radiation, however, is trapped inside the Earth’s atmosphere by greenhouse gases which can absorb and store the energy

• Carbon dioxide, methane and water vapour are gases that have this effect

• Increasing levels of carbon dioxide and methane, although present in only small amounts, are causing significant upset to the Earth’s natural conditions by trapping extra heat energy

• This process is called the enhanced greenhouse effect

Greenhouse gases trap some of the Sun's radiation causing the Earth to warm up

Carbon dioxide

• Sources: Combustion of wood and fossil fuels, respiration of plants and animals, thermal decomposition of carbonate rocks and the effect of acids on carbonates

Methane

• Sources: Digestive processes of animals, decomposition of vegetation, bacterial action in swamps and in rice paddy fields