topic c9- chemistry of the atmosphere

• how many phases are there in the evolution of the atmosphere

  3
• phase 1

  volcanoes gave out gas

  
• phase 1

  • atmosphere made up of mostly carbon dioxide
  • volcanoes also released nitrogen, water vapour, methane and ammonia
• phase 2

  oceans, algae and green plants absorbed CO2
• phase 2

  • water vapour condensed and formed oceans
  • carbon dioxide dissolved by oceans
  • early plant form underwent photosynthesis, removing more carbon dioxide
• phase 3

  green plants and algae produce oxygen

  
• phase 3

  • plants removed oxygen during photosynthesis
  • algae evolved first, then other plants
  • now, atmosphere is 80% nitrogen and approx 20% oxygen, with small amounts of other gases too- CO2 and water vapour- 1%
• greenhouse gases- cause the greenhouse effect

  
• greenhouse gases

  • greenhouse gases include gases such as carbon dioxide, methane and water vapour
  • greenhouse gases act like an insulating layer in the Earth's atmosphere
  • they reflect the radiation from the sun back towards the Earth
  • this is called the greenhouse effect
• climate change

  
• climate change

  • due to human activity, greenhouse gases are increasing faster than expected
  • too many greenhouse gases accelerates the rising temperatures of the Earth
  • this means polar ice caps are melting faster, changes in rainfall patterns and higher frequency of extreme weathers
• human activities that increase greenhouse gases

  • deforestation
  • burning fossil fuels
  • agriculture
  • creating waste
• deforestation

  • trees are cut down for housing and land
  • less CO2 is absorbed from the atmosphere
• burning fossil fuels

  carbon that was locked up in fossil fuels is released
• agriculture

  more farm animals produce more methane
• creating waste

  • landfill sites store waste in large quantities
  • decomposition causes CO2 and methane to be released
• carbon footprints

  • a measure of the amount of carbon dioxide and other greenhouse gases released over the full cycle of something
  • this could be
  • production of a product
  • a service
  • an event
• carbon footprints

  • measuring a footprint can be very hard, even impossible
  • there are many factors to consider, especially in a complex process
• how to reduce a carbon footprint

  • renewable or nuclear energy
  • using efficient processes
  • reduce waste
  • more fuel-efficient transport
  • educating people on why it is important, to raise awareness