Topic 5


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Topic 5

  1. 1. GREEN HOUSE EFFECT Text 98-103 *
  2. 2. Essential Questions Definitions Learning outcomes A. How has global climate changed in the last 150 years? B. Is climate change natural or human induced? C. What is greenhouse effect and how does it work? D. What is the enhanced greenhouse effect? E. How do human activities lead to climate change? - Climate has changed in the past through entirely natural causes. - Human activities are impacting the climate system through increasing the amount of greenhouse gases in the atmosphere - Explain natural causes contributing to climate change - Explain the greenhouse effect - Explain how various human activities have led to an increase in greenhouse gases which contribute to the enhanced greenhouse effect.
  3. 3. *Increase in global temperatures over a long period of time *Decrease in global temperatures over a long period of time *
  4. 4. * - Significant increases between 0.3 C and 0.6 C. - Mean global temperatures rose faster between 1980 and 2000
  5. 5. * Natural factors Variations in solar output Volcanic eruptions Human factors (Green house effect) Burning fossil fuels Deforestation Changing land use Agriculture Industries Urbanization Because Darren Can Always Iron Uniform
  6. 6. Sun emits differing amounts of solar radiation due to changes in magnetic field High temperatures Because more sunspots found Sunspots = Higher solar activity Low temperatures Lesser sunspots found Lower solar activity * natural
  7. 7. * natural Large amount of CO2, water vapour, sulphur dioxide, dust and ash released Results in global dimming Gradual reduction of amount of sunlight reaching the earth’s surface Eg Mt Pinatubo in 1991 Lowers temperatures for 2 years Temporary effects on earth’s climate
  8. 8. *
  9. 9. •Glass panels lets in light but keeps heat from escaping. •So plants can grow with the trapped heat from the sun. *Greenhouse (Cold countries)
  10. 10. Greenhouse effect Enhanced greenhouse effect Definition Natural process to trap heat Human activities - Rapid increase in amount of greenhouse gases Effects Positive - Warm the earth’s surface Negative - Rise in global temperatures Illustration
  11. 11. Heat that reaches earth Heat that are reflected back by earth & atmosphere Heat is trapped by GH gases Heat given out from the earth Greenhouse gases in the atmosphere Solar radiation from the Sun to Earth
  12. 12. •Greenhouse gases in atmosphere = Glass panel •Traps heat naturally to keep Earth warm and livable
  13. 13. Yellow layer = Extra Greenhouse Gases / Air pollutants * Greenhouse Effect
  14. 14. *
  15. 15. *Fossil fuels = oil, coal and natural gas *Burning fossil fuels produces large amount of energy *Energy to be used for: Industries, transportation, domestic and commercial activities eg Electricity *Contributes to carbon dioxide (results in ENHANCED greenhouse effect)
  16. 16. *Loss of forests due to removal or clearance of trees *Reasons: Paper, building materials, mining, animal grazing, planting crops, infrastructure *Results in lesser trees to absorb Carbon dioxide in the atmosphere
  17. 17. A)Agriculture -Cultivate land to produce crops and raise livestock Produces: -Carbon dioxide -Nitrous Oxide -Methane
  18. 18. B) Industries -Production of goods and services eg Manufacturing - Emission of Carbon dioxide
  19. 19. C) Urbanisation -Increasing number of people living in urban areas (Cities and towns) -Fossil fuels burnt in domestic uses and transport
  20. 20. * 1.Explain natural causes contributing to climate change. [2] 2.Explain the enhanced greenhouse effect. [3] 3.Explain how various human activities have led to an increase in greenhouse gases which contribute to the enhanced greenhouse effect.[3]