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Climate Change (Managements (Alternative Energy Supply (Burning fossil…

- - - - Milankovitch cycles - three distinct cycles of the Earth's orbit believed to affect climate change (scientists believe that these cycles affect the Earth's climate and seasons)
        
        Eccentricity cycle - path of the Earth as it orbits the Sun. This sin't fixed, it switches between being circular and elliptical. Complete circuit occurs every 100,000 years or so, and coincides closely with alternating cold and warm periods (glacial and inter-glacial) in the Quaternary period.
        
        Axial Tilt - Earth spinning on axis, causing night and day (currently 23.5 degrees). Over a period of 41,000 years, it moves back and forth between two extremes, 21.5 and 24.5
        
        Precession - A natural 'wobble' of the Earth - complete one takes 26,000 years. This accounts for the very long days and nights in certain regions like Northern Norway
    - - Cyclical changes in solar energy output appears to be related to sunspots. This is a dark patch on the surface of the sun, the frequency of which go from minimum, to maximum, to minimum, over a period of 11 years - called the sunspot cycle.
      - At maximum sunspot activity, the sun gives off more heat. Large explosions occur on the surface of the sun, resulting in solar flares.
      - At minimum sunspot activity, solar output is reduced, which can lead to lower temperatures on Earth.
      - Very few sunspots were observed between 1645 and 1715, coinciding with the coldest period in the 'Little Ice Age' where Europe experienced a very cold climate and extreme winters.
    - - Volcanic activity can be very violent, producing large quantities of gas, ash and liquids into the atmosphere. Short term this can block the sun, leading to cooler temperatures on the Earth. The droplets formed when sulpher dioxide turns to sulfuric acid reflect the sun's radiation, a long term affect that can affect the climate for years. Cooling of the lower atmosphere and reduction of surface temperatures in called volcanic winter.
  - - - Accounts for about 20% of the enhanced greenhouse effect, due to it's ability to absorb heat well.It comes from farm livestock (mainly cows), rice farming, burning biomass for energy and decaying organic matter in landfill sites and compost tips.
    - - Accounts for approximately 60% of the enhanced greenhouse effect. Global concentration of CO2 has increased by 30% since 1850. It is mainly due to the deforestation and burning of wood, car exhausts, and burning fossil fuels (oil, gas and coal) in industry and power stations to generate electricity.
    - - There are very small concentrations in the atmosphere and are ~300 times more effective at capturing heat than carbon dioxide. Nitrous Oxides are released from agricultural fertilizers, sewage treatment, power stations that produce electricity and car exhausts.
- - - - According to the intergovernmental Panel on Climate Change (IPCC), the average global sea level has risen between 10 and 20cm in the past 100 years. There are two reasons why sea levels has risen: When temperatures rise and freshwater ice melts, more water flows to the seas from glaciers and ice caps. When ocean water warms it expands in volume - this is called thermal expansion.
    - - Glaciers throughout the wold are shrinking and retreating. It is estimated that some may disappear completely by 2035. Arctic sea ice has thinned by 65 per cent since 1975 and in 2014 its extent was at an all-time low.
    - - The Milankovitch cycles are believed to be the cause of the Earth's seasons, causing cold periods in the winter and warm periods during the summer (see below - natural causes of Earth's orbit)