Global Warming

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  • Created by: Caitlin G
  • Created on: 24-03-15 20:09
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  • Global Warming
    • Greenhouse Effect
      • Earth receives (most) energy in the form of electromagnetic radiation from the Sun
      • Solar Energy is absorbed and (some) is released back into the atmosphere as infrared raditon
        • most of this goes back into space however certain gasses in the atmosphere absorb the infrared radition
          • the energy absorbed by some of the gasses is re-emitted as energy
            • this process effectively traps a lot of heat in the lower atmosphere
      • the process in which the absorption and subsequent emission of infrared radiation by atmospheric gasses warms the lower atmosphere and the planet;'s surface
        • OCR textbook definition of global warming
      • creates an equilibrium
        • the surface of the Earth and atmospheric gasses absorb the energy at the same rate as it radiates energy
          • which is why there is a steady temperature
    • Greenhouse Gasses
      • occur naturally in the atmosphere
      • most common greenhouse gasses: Water Vapour, CH4, CO2
        • CO2 is produced via: volcanic erruptions, respiration of animals, burning or decay of organic matter
        • methane is present in smaller quantities than CO2 but it makes a greater contribution to the greenhouse effect
        • methane is: emitted during the production of coal, natural gas, oil; a product of rotting organic waste; released from certain animals as a by-product of digestion
      • clathrates
        • large quantities of methane trapped in ice-like structures below the cold northern seas
        • contain 3,000 times as much methane as tin the atmosphere
          • if released would have a huge impact on the greenhouse effect
      • absorb infrared radiation causing the molecule to vibrate
        • eventually the vibrating molecule re-emits some of it as energy in a form of radiation
          • the radiation emitted can be absorbed by other greenhouse gasses or the Earth's surface
      • Global Warming Potential (GWP
        • the ability of a trace gas to cause global warming
        • related to the lifetime of a gas in the atmosphere as well as the ability of the gas to absorb infrared radiation
        • CFCs are 25,000 times more efficient at absorbing infrared radiation than CO2
          • legislation banned large-scale use of CFCs so the effect of CFCs are diminishing
      • Reducing emissions
        • Kyoto Protocol
          • committed countries to reduce their emissions of six greenhouse gasses by 5% by 2012
            • USA (biggest emitter) refused to sign
              • in 2006 25% (8 billion tonnes) of CO2 came from the USA
        • development of non-carbon fuels
          • solar, wind, tidal, nuclear
        • EU Strategies for the Future
          • Targets
            • 20& of energy used in the EU will come from renewable sources by 202
            • 10% of fuels used in transport will be biofuels by 202
            • EU greenhouse gas emission will be reduced to 20% below 1990 levels by 2020
    • Climate Change
      • Cause: the Earth's supply f coal, natural gas, and oil is being burnt for energy
        • this releases billions of tonnes of CO2 into our atmosphere each year
      • effects
        • river overflow
        • droughts
        • failing crop yields
        • storms and hurricanes are becoming more extreme
        • sea ice is melting
        • expand water in coeans
          • sea levels rising
            • sea ice is melting
      • Climate Change Bill (2007)
        • a framework to achieve a 60% cut in the UK's Carbon emission by 2050 (compared to 1990 levels)
          • Reducing emissions
            • Kyoto Protocol
              • committed countries to reduce their emissions of six greenhouse gasses by 5% by 2012
                • USA (biggest emitter) refused to sign
                  • in 2006 25% (8 billion tonnes) of CO2 came from the USA
            • development of non-carbon fuels
              • solar, wind, tidal, nuclear
            • EU Strategies for the Future
              • Targets
                • 20& of energy used in the EU will come from renewable sources by 202
                • 10% of fuels used in transport will be biofuels by 202
                • EU greenhouse gas emission will be reduced to 20% below 1990 levels by 2020
        • UK only Bill
      • Cleaner Cars
        • Eu agreement
          • from 2012 cars must emit no more than 130g of CO2 per kilometer travelled

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