Greenhouse Gases (Edexcel IGCSE Biology)

Spec point — 4.13 · understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases

Greenhouse Gases

• A greenhouse gas is a gas that absorbs infrared radiation from the Sun so it remains trapped in the Earth’s atmosphere

• This is important to ensure Earth is warm enough for life, however if levels of these gases in the atmosphere increase it leads to an increase in the greenhouse effect which causes the Earth’s average temperature to rise

• There are many greenhouse gases, the most important are:

  • Water vapour
  • Carbon dioxide
  • Methane
  • Nitrous oxides
  • CFCs

Human Activities & Greenhouse Gases

Spec point — 4.14 · understand how human activities contribute to greenhouse gases

• Human activities have led to increasing levels of carbon dioxide and methane in the atmosphere:

  • Carbon dioxide is produced during the combustion of fossil fuel
  • Methane is produced by cattle as they digest grass and released by rice paddy fields