Carbon Dioxide & Methane

  • 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 hold the radiation.
  • Carbon dioxide, methane and water vapour are gases that have this effect, and although present in only small amounts, they are causing significant upset to the Earth’s natural conditions by trapping extra heat energy.
  • This process is called the Greenhouse effect.

The Greenhouse effect, IGCSE & GCSE Biology revision notes

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.


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

The Greenhouse effect

  • Caused by the increased concentration and effect of Greenhouse gases, mainly methane and carbon dioxide.

AQA GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.