Greenhouse Gases | Chemistry for Grade 11 (IGCSE) PDF Download

Effects of Greenhouse Gases

• The Sun emits energy in the form of radiation that enters the Earth's atmosphere
• Some thermal energy is reflected from the Earth's surface
• Most thermal energy is absorbed and re-emitted back from the Earth's surface
• The energy passes through the atmosphere where some thermal energy passes straight through and is emitted into space
• But some thermal energy is absorbed by greenhouse gases such as carbon dioxide and methane and is re-emitted in all directions
• This reduces the thermal energy lost into space and traps it within the Earth's atmosphere, keeping the Earth warm
• This process is known as the greenhouse effect
• As the concentration of greenhouse gases in the atmosphere increases due to human activity, more thermal energy is trapped within the Earth's atmosphere causing the Earth's average temperature to rise (global warming)
• This process is called the enhanced greenhouse effect
• Diagram showing how the greenhouse effect occurs:
  

Consequences of Global Warming

Global warming leads to various detrimental effects:

• Climate Change: The Earth's temperature rises, causing widespread climate fluctuations.
• Rising Water Levels: Melting glaciers elevate water levels, resulting in floods in low-lying regions.
• Species Extinction: Destruction of habitats leads to the extinction of various species.
• Species Migration: Animals shift to more hospitable areas to escape adverse conditions.
• Spread of Diseases: Warmer climates facilitate the spread of diseases.
• Habitat Loss: Changing climates threaten habitats of various species.