chemistry of the atmosphere

• evidence of the early atmosphere is limited because timescale is so huge.
• the atmosphere today: 78% nitrogen 21% oxygen 0.04% argon.
• increase of oxygen levels:

  • algae and plants photosynthesize
  • as plants evolved the amount of oxygen in the atmosphere increased.
  • eventually the amount of oxygen allowed animals to evolve.
• • as plants evolved carbon dioxide levels decreased
  • also in sedimentary rocks and fossil fuels.
• the earth's surface reflects lower energy, longer wavelength infrared radiation. greenhouse gases then absorb this radiation, increasing the global temperature.
• greenhouse gases:

  • carbon dioxide
  • water vapour
  • methane
• fossil fuels contain carbon that has been locked up for millions of years, burning them releases the carbon dioxide into the atmosphere.
• some climate change impacts could include:

  • rise in sea level
  • more frequent and severe storm events
  • changes in the amount and timing of rainfall
  • droughts
  • distribution of plants and animals
  • food shortages
• the carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted by a product or service.
• carbon footprint can be reduced by:

  • alternative energy supplies
  • carbon taxes
  • tree planting
  • carbon capture and storage
• problems with reducing carbon footprint:

  • disagreement between scientists
  • lack of information and knowledge
  • reluctance of people to make lifestyle changes
  • economic considerations