Enhanced Greenhouse Effect (Edexcel IGCSE Science (Double Award)): Revision Note

Enhanced Greenhouse Effect

• The greenhouse effect is a natural process by which heat is trapped in the Earth's atmosphere

  1. The Sun emits radiation that enters the Earth’s atmosphere

  2. The Earth’s surface absorbs some of this energy and re-emits it as heat (infrared radiation)

  3. Some of this heat is reflected back into space

  4. Some is absorbed by greenhouse gases (such as carbon dioxide, methane, and water vapour) and trapped within the atmosphere

• This process keeps the Earth warm enough to support life — it is a natural and essential phenomenon

How the greenhouse effect works

The consequences of an enhanced greenhouse effect and global warming

• The enhanced greenhouse effect occurs when increasing levels of greenhouse gases from human activities (such as burning fossil fuels, deforestation, and agriculture) trap more heat in the atmosphere
  As a result, the Earth’s average temperature rises above normal, leading to global warming and climate change

• The consequences of global warming due to an enhanced greenhouse effect include:

  • Ocean temperatures increasing, causing melting of polar ice caps, rising sea levels, flooding and coral bleaching

  • Increasing temperatures causing extreme weather like super storms, flooding, droughts

  • Changes in or loss of habitats due to extreme weather events

  • Decreases in biodiversity as food chains are disrupted and extinction rates increase

  • Increases in migration of species to new places, including increased spread of pests and disease