Climate change

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  • Climate change
    • Causes
      • Natural
        • Astronomical forcing
          • Milankovitch cycles (every 100,000 yrs- due to the tilt of the earth's axis
          • Earth's axis shifts from 21.5° to 24.5°
          • +_0.5°C
        • Solar output
          • Sunspots- dark spots on the sun caused by intense magnetic storms
          • 11  year cycles
            • Maunder Minimuum- 1645-1715, little sunspots- same time as the Little Ice Age
          • Varying solar radiation by 0.1%
        • Volcanic and cosmic
          • Eject material (ash, SO2, CO2, H2O) into the stratosphere where the winds distribute it across the world
          • Tambora, Indonesia (1815), 200m. tns of SO2, decrease in global temp. 0.4-0.7°C
      • Human
        • Increase in greenhouse gases
          • 2 factories open a week in China
          • 14% agriculture, 14% transport, 14% industry, 17% deforestation, 24% electricity & heat, 5% waste,
          • fossil fuels have increased CO2 by 25%
          • Industrialisation
          • US=1st, China= 2nd
          • Deforestation
            • 90% of forest cover cleared from Ethiopian highlands
    • Evidence
      • Long term
        • Ice cores
          • Trapped air bubbles in the ice
            • CO2 concentrations
              • Holocene (now), Hoxnian (250ppm)= high conc.
              • Wolstonian (200ppm)= low conc.
            • Oxygen isotopes
              • glacier- O16 evaporated more easily
        • Oceans
          • CO2 sinks- absorbing
        • Pollen
          • May lag behind climate change
          • Different species of plants (e.g. tundra in UK)
      • Medium term
        • Qualitative evidence (paintings, poems, diaries, journals)
        • Tree rings
          • Changes in thickness- thick= good conditions
          • Bristlecone Pines (US)
        • Retreating glaciers
          • Position of rocks
        • Examples
          • Medieval Warm Period (1400-1800)
          • Little Ice Age (800-1400) -0.5°C. Thames froze
      • Short term
        • Met Office
        • More frost free days
        • European growing season is longer by 11 days- spring 6 days earlier
          • Plants start growing at 5°C
        • Butterflies moving further north
        • IPCC
          • 2°C 50% plants destroyed
    • The Greenhouse Effect
      • Incoming short-wave (UV) radiation
        • Absorbed by the land and ocean and reflected as long wave (IR) radiation
          • Most IR is radiated back into space
            • Some is returned due to the presence of greenhouse gases
              • CO2- 280ppm
          • More is trapped by the greenhouse gases
            • CO2- 430ppm
      • Without= -18°C
      • Average =15°C
    • Greenhouse Gases
      • CO2- transport, energy, etc.
      • CH4- rice production, burning vegetation, coal mining, livestock, permafrost melting
        • increased 4 times more quickly than CO2
      • NO2-Agricultural fertilisers, fossil fuels, synthetic chemicals
        • Destroys ozone
      • CFCs- propellants in spray cans, foam plastics, refidgeration
        • Now banned by Montreal protocol
        • Destroys ozone
      • H2O- evaporation of water- more cloud cover and condensation
      • CO2, CH4, NO2 increased exponentially
    • Strategies
      • Adaptation
        • Geo-engineering
          • Orbiting solar shields, ocean iron seeding
            • "one off" change, avoid lifestyle changes, costly, untried technology, unknown side effects
        • Agricultural technology
          • Drought tolerant crops
            • Quickly adopted, costly for developing world
        • Land-use planning
          • No development on floodplains and coasts
            • Reduces vulnerability, costly, opposed by residents and businesses
        • Changing our lifestyles to cope with a new environment rather than trying to stop climate change
      • Mitigation
        • Carbon neutral development
          • Afforestation, renewable energy
            • Land-use and lifestyle changes
        • Carbon capture
          • Power stations, industry
            • High costs, encourages usage of finite resources
        • Sustainable development
          • Reduced resource consumption, recycling, locally sourced
            • Slow, lifestyle changes opposed
        • Reducing the output of greenhouse gases and increasing the size of greenhouse gas sinnks
      • Sustainable Development
        • Development that meets the needs of the present without compromising the ability of future generations to meet their owns needs
    • Impacts
      • Increased food, water, farming costs
      • Migration
      • Increased health costs
      • Increased aid
      • Coastal and flood defences (>$10bn)
      • Poverty bomb
    • Players
      • Businesses
        • Shell, BP, Ford, etc. funded the Global Climate Coalition opposing action against climate change
          • Now leaving due to public pressure, fears about energy supply, demands from investors, government, new technologies and markets
      • UK
        • Reduce CO2 emissions by 60% by 2050
        • 20% renewable sources 2020
        • Taxing cars- B=£35, G=£400
        • London climate change strategy
          • Green Homes Programme and new building standards
          • Small scale renweables
          • Recycling
          • Concerting all 8000 buses to diesel and charging £25 for heavily polluting vehicles
      • USA
        • 18% reduction by 2012
      • China
        • Reduce CO2 emissions by 1.5bn tns
      • EU
        • Carbon trading scheme (EU ETS) and Certified Emission Reduction credits
      • Contraction and convergence- come countries increase, others decrease
      • Climate crusaders- famous people advertising climate change
        • WWF, Al Gore, Arnold Schwarzenegger
      • Montreal Protocol
      • Kyoto Protocol
        • 55 countries for it to become enforced- 2005 when Russia signed it
        • EU=8%, USA=6%, Iceland=10%, Russia=0%
        • 2001, USA bwithdrew- damage economy
    • Key terms
      • Weather
        • The day to day state of the atmosphere
      • Climate
        • The average of weather (long term)
      • Adaptive capacity
        • The extent to which a system can cope with climate change (resources)
      • Climate vulnerability
        • The degree to which a natural or human system lacks the ability to cope with climate change
        • Vulnerability= magnitude of change, speed of change, sensitivity of system, adaptive capacity
    • Barriers
      • Uncertainty
        • Inertia of system- gases already in atmosphere
        • Positive feedback- e.g. permafrost and albedo
        • Uncertainty of how it might change
      • Political inertia- losing votes
      • Costs- damage economic growth
      • Lack of international agreements
  • Earth's axis shifts from 21.5° to 24.5°

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