Climate Change Causes and Effects

• Nitrous oxide is emitted from soils and oceans
• Causes of Natural Climate Change

  • Milankovitch Cycles
  • Volcanic eruptions
  • Sunspot activity
  • Atmospheric dust
• Milankovitch Cycles


  Long term changes to the Earth's orbit and position, which changes how much solar radiation the Earth receives
• Milankovitch Cycles


  1. The Earth's orbit changes every 100,000 years - a more circular orbit leads to cooler periods and an elliptical orbit leads to warmer periods

  2. The Earth's tilt varies every 40,000 years - the greater the tilt the hotter summers are and colder the winters are

  3. Every 24,000 years the Earth wobbles on its axis and this can affect the seasonal temperatures
• Volcanic eruptions


  Large scale eruptions lead to vast quantities of ash being ejected into the atmosphere, blocking solar radiation and leading to a decrease in temperatures
• Sunspot activity


  Increased sunspot activity is linked to higher average temperatures
• Atmospheric dust


  Asteroids and meteors entering the Earth's atmosphere may increase the amount of dust which decreases temperatures
• The Greenhouse Effect and The Enhanced Greenhouse Effect
• Human Sources of Greenhouse Gases

  • Carbon Dioxide (CO2)
  • Methane (CH4)
  • Nitrous Oxide (N2O)
  • Chlorofluorocarbons (CFCs)
• Carbon Dioxide (CO2)


  Sources from human activity: Burning of fossil fuels - power stations, vehicles; Burning of wood; Deforestation - trees utilise CO2 in photosynthesis, the fewer trees the less CO2 is removed from the atmosphere
• Methane (CH4)


  Sources from human activity: Decay of organic matter - manure, waste in landfill, crops; Released by cattle and during rice cultivation
• Nitrous Oxide (N2O)


  Sources from human activity: Artificial fertilisers; Burning fossil fuels
• Chlorofluorocarbons (CFCs)


  Sources from human activity: Aerosols; Refrigeration units; Air conditioning
• Fossil fuels account for almost 50% of global greenhouse gas emissions
• Uses of Fossil Fuels


  • Transportation
  • Construction
  • Heating
  • Manufacturing
  • Energy production
• Agriculture


  Deforestation to clear land for grazing and crops leads to less CO2 being absorbed during photosynthesis; The production of fertilisers and pesticides uses fossil fuels; Increased raising of dairy and beef cattle as well as rice cultivation increases methane emissions; Artificial fertilisers also increase the amount of nitrogen oxide released into the atmosphere
• Construction


  The manufacture of cement releases CO2 - it is made from limestone which contains carbon
• Transport


  The increasing global population has led to increased numbers of cars, lorries and planes; Most transport uses petrol/diesel which comes from oil as fuel this releases CO2
• Explain how the increasing use of fossil fuels and changes in agriculture may have contributed to global changes in temperature

  1. Fossil fuels account for over 50% of global greenhouse gas emissions

  2. Burning these releases carbon dioxide into the atmosphere

  3. Fossil fuels are used in transportation, building, heating homes, manufacturing industry, and generating electricity

  4. Producing food uses fossil fuels in the production of fertiliser and pesticides, and in transporting

  5. Changing forest cover to farmland also releases greenhouses gases

  6. Increases in meat, dairy and rice production create more methane
• Social effects of Climate Change

  • Health impacts
  • Employment impacts
  • Impacts on homes
• Economic effects of Climate Change

  • Impacts on agriculture
  • Impacts on employment
  • Impacts on settlements
• Environmental effects of Climate Change

  • Sea level rise
  • Natural hazards
  • Ecosystem change