Environmental Hazards

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  • Environmental Hazards
    • Causes and effects of global warming
      • First emerged as a concern in the 1980s
        • As a result of rising global temperaturess
          • Believed to be from human activity
            • Burning fossil fuels
            • Destruction of forests (deforestation)
      • There is a debate as to whether global warming exists
        • It could be another example of changes in temperature the world has seen over millions of years
      • It is important to distinguish global warming from the greenhouse effect
        • The greenhouse effect
          • it is a naturally occurring phenomena, which without it human life would not exist on Earth.
      • Causes of global warming
        • Many greenhouse gases exist naturally  and it is human actions that are increasing their concentrations within the lower atmosphere.
          • It is believed that as the amount of greenhouse gases in the atmosphere increases, the of infra-red radiation in the lower atmosphere also increases, thus rising temperatures
          • Major sources of greenhouse gases
            • Water vapour
              • Source - Oceans, lakes, rivers, reservoirs. Humans have little impact upon levels
              • Use - Absorbs limited outgoing radiation
              • Way it increases global warming - Water vapor and clouds are responsible for 98% of the natural greenhouse effect.
            • Carbon dioxide
              • Source - Burning of fossil fuels, and forests, breaking animals, less produced by the southern hemisphere (less land)
              • Use - Absorption of long wave radiation (infra -red)
              • Way it increases global warming - Approximately 50%
            • Methane
              • Source - Much from break down of organic matter by bacteria (rice paddy fields) cows, swamp marshes
              • Use - Same as Carbon dioxide
              • Way it increases global warming - Approximately 17%
            • Ozone
              • source - Naturally from some oxygen atoms. Ozone in the troposphere is due to chemical reactions between sunlight and agents of pollution
              • Use -  Filters short wave UV radiation
              • Way it increases global warming - Difficult to estimate
            • CFC's
              • Source - Fridges and aerosols
              • Way it increases global warming - 25%, but increasing due to ability to survive within the atmosphere for 100 years
            • Nitrous oxide
              • Source - Nitrate fertilizers  transport and power stations (combustion)
              • Use - Absorption of long wave radiation
              • Way it increases global warming - Approximately 6%
      • Positive and negative effects
        • Health
          • Effect - Malaria and cholera increase due to temperature increase
          • (-) - More money needed to fight disease, strain on medical services, rise in death rate
        • Vegetation
          • Effect - Shifting flora and fauna to different areas. Extinction of some species
          • (-) - Spread of pests and disease, alteration in crop yields, may increase food shortages
          • (+) - Canadian Prairies could become major wheat growing belt. Areas able to grow different crops, for example, citrus fruits in the UK
        • Weather
          • Effect - More extreme climates in inland locations. More frequent and devastating hurricanes.
          • Both (-) and (+) is currently unknown at present
        • Ocean
          • Effect - Sea temperatures increase, sea levels rise, shift in ocean currents
          • (-) - Change s in the number of fish stocks and their location will impact the fish industry
          • (+) - Increase in fish stocks in certain areas
        • Landscape
          • Reduced snow cover in some areas. Glaciers melt in Antarctica.
          • (-) - Rise in sea levels
          • (+) - Extended summer season in some landscapes due to higher temperatures, increasing revenue
        • Hydrology
          • Effects  - Reduction of wetland area, as precipitation is reduced. In some places river flooding may increase
          • (-) - Great pressure on water supplies. Problems for HEP schemes and irrigation
          • (+) - Increased awareness of water conservation measures, less water wastage
        • Population
          • Effect - Reduction of areas suitable for human habitation, for example, lowland Bangladesh
          • (-) - Better forecasting needed to warn people of approaching storms. Insurance premiums will increase.
          • (+) - More accurate weather forecasting developed
        • Climate
          • Source - Location of Jet stream may alter. Depressions may shitft south, causing them to be more intense
          • (-) - Better forecasting need to warn people of approaching storms. Insurance premiums will increase.
          • (+) - More accurate weather forecasting.
    • Solutions to globl warming
      • way of reducing Greenhouse gas emissions
        • Switch from use of fossil fuels to 'greener' sources of energy.
          • Wind power, nuclear power, HEP
        • Increase tariffs on industry for emitting greenhouse gases, or price fuel so that their costs reflect the impacts that they have on the environment
        • increasing double-glazing and insulation in buildings to increase energy efficiency
        • Limit the amount and rate of deforestation by provision of relevant management stategies
        • Replant trees
        • make greater use o gas rather than coal and oil due to is greater energy eficiency
        • invest more money into public transport and increasing fuel efficiency of cars
      • Advantages of the approches
        • Can work well i advice is given in conjunction with indigenous populations
        • In the UK government legislation already exists, and new buildings no have a minimum of 20%increase in their energy efficiency
        • In the UK the aim is to keep carbon dioxide emissions at 1990 levels and this depends on substitution of gas for coal and oil.
        • Difficult to enforce effectivley. Fines oten mean little to large industries
        • Fossil fuels would be the most expensive fossil fuels would be the most expensive fuel, therefor reducing their use. Car companies are already investigating more energy efficient fuels and energy sources
        • Changing to nuclear power is one of the fastest ways of reducing carbon dioxide output.
        • Would reduce soil erosion, and absorb carbon dioxide
      • Disadvantages of the approaches
        • Implementation is difficult, especially when the destruction is widespread as in Amazonia
        • Difficult to oversee ona  large scale
        • Tree growth is very slow and it would take many decades to replace the trees lost through deforestation
        • Encourages a more mindful approach to the environment
        • There would be a need to construct many more power stations
        • Much concern exists over the safety of nuclear power, especially after Chernobyl  Disposal of nuclear waste is problematic and the construction of new power stations is highly expensive
        • Encouraging people to use public transport is highly problematic, especially for those livng in rural areas

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