climate change

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  • Created by: Devika_C
  • Created on: 03-11-19 14:39
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  • CLIMATE CHANGE
    • evidence
      • then
        • fossil records
        • looks at oxygen trapped in layers of ocean sediments
      • now
        • shrinking glaciers & melting ice
          • melting = more water = expanded oceans = higher risk of flooding
        • rising sea levels
          • melting = more water = expanded oceans = higher risk of flooding
        • seasonal changes
          • tree flowering and bird migration
      • all shows global warming is true
    • causes
      • natural
        • orbital changes
          • milankovitch cycle
            • eccentricity - 100,000 years = change from circular to oval
              • this constantly changes the earth's distance from the sun
            • axial tilt - 41,000 = change in tilt - 21.5-24.5
              • this constantly changes the earth's distance from the sun
            • precession - 26,000 years = axis wobbles
          • solar activity
            • sun spots - dark patches on the surface of the sun which show reduced surface temperature
              • high energy solar flares which has an increasing output of heat
          • volcanic activity
            • volcanic ash
              • blocks the sun
            • sulphur dioxide
              • converted into droplets of acid and acts like mirrors which reflect the solar radiation back into space
        • human
          • greenhouse gas effect
            • naturally keeps the earth warm enough to support life
            • greenhouse gases traps heat that would escape to space
            • allows short-wave radiation(light) from the sun to the earth
            • traps long wave radiation (heat) that would escape to the atmosphere
          • human impact on greenhouse gases
            • 60% of the warming greenhouse gases = CO2
              • most carbon dioxide comes from burning fossil fuels
            • deforestation of tropical rainforests are also a major source
            • methane is growing faster due to rice farming, sewage treatment, farm livestock etc
      • managing the impacts of climate change
        • alternative energy sources
          • burning fossil fuels = 87% of all CO2 emissions
          • use : hydro electricity, nuclear power, solar, wind and tides
            • provides sustainable, low carbon alternatives
        • carbon capture
          • uses tech to capture CO2 produced from burning fossil fuels, then its used for long-term storage in geological reservoirs eg; gas wells
        • planting trees
          • trees act as carbon sinks, removing CO2 by photosyn.
        • international agreements
          • governments are negotiating towards a more sustainable future
            • paris agreement : 2015: first legally binding global climate deal
              • aim: limit temp increase to 1.5 degrees above pre-industrial levels
      • global impacts
        • more heat-related diseases and illnesses
        • reduced crop yields and water supplies
        • low-lying coastal areas are more likely to flood
        • more extreme weather
      • adapting to climate change
        • agricultural adaptation
          • farmers will need to
            • cope with extreme weather
            • manage water supply
            • plant trees to shade seedlings
            • change crops to suit the new climate
        • risks from rising sea levels
          • threaten important agricultural land
          • increase rates of coastal erosion
          • contaminated freshwater supplies with salt water
          • reducing risks
            • construction of sea walls
            • construction of artificial islands
            • restoration of coastal forests
            • building houses on stilts - 3m high

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