Greenhouse Gases (Edexcel IGCSE Biology (Modular))

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 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