Greenhouse effect

• Greenhouse effect


  The process by which greenhouse gases in the Earth's atmosphere absorb and re-emit infrared radiation, warming the Earth's surface
• Main greenhouse gases and their sources


  • Carbon dioxide (CO₂) - produced by burning fossil fuels in factories, also released when trees are burned
  • Methane (CH₄) - produced by cattle, also caused when waste in landfill decays
  • Chlorofluorocarbons (CFCs) - found in chemicals in fridges
  • Nitrous oxide (NOx) - released in car fumes, catalytic converters can reduce this
  • Water vapour (H₂O) - human activity has not really changed this level much
• Solar radiation passes through the Earth's atmosphere


  Most of this radiation is absorbed by the Earth's surface and warms it
• Infrared radiation is emitted from the Earth's surface


  Some of this infrared radiation passes through the Earth's atmosphere, but some is absorbed and re-emitted by the greenhouse gases (methane, carbon dioxide, water vapour), warming the Earth
• Some of the solar radiation is reflected by the Earth's atmosphere


  This contributes to the greenhouse effect
• As the Earth's temperature increases


  Glaciers will melt, causing polar bears to lose their habitat
• As the Earth's temperature increases


  Mosquitoes can survive in more areas, leading to the spread of diseases
• As the Earth's temperature increases


  Mass extinction of animals, insects and plants will occur as they cannot adapt fast enough
• Acid rain formation


  1. Sulfur dioxide from burned fossil fuels goes into the atmosphere

  2. Gets dissolved in water

  3. Forms acid rain with pH less than 5.5
• Acid rain


  • Damages the waxy layer of leaves, making it difficult for trees to grow
  • Can make water bodies too acidic for aquatic life
• Carbon monoxide (CO)


  • Colourless, odourless gas formed when petrol and diesel are burned in combustion engines
  • Binds to haemoglobin in red blood cells, causing suffocation