Global Changes in the Atmosphere

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Global Changes in the Atmosphere

• Pages 139-142

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What is global warming?

• The gradual increase in the temperature of
  Earths atmosphere
• Over the last 120 years, the average temperature
  of the troposphere has increases 0.5 degrees
  Celsius

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What is the greenhouse effect?

• The process by which gases in Earths atmosphere
  trap solar energy and keep the Earth warm
• Greenhouse Gases- water vapor, carbon dioxide
  methane

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What are some causes of global warming?

• Increasing greenhouse gases (especially CO2)
• What adds CO2 to the atmosphere?
• Human activities that add greenhouse gases to the
  atmosphere may be warming Earths atmosphere
• Burning of wood, coal, oil and natural gases add
  CO2
• 1cause- motor vehicles

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Another Hypothesis?

• Natural climate variations (a natural cycle
  caused by changes in solar output)
• Remember the ice age/interglacial periods?

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Possible Effects

• Longer growing seasons in some areas and shorter
  growing seasons in others
• More evaporation drying out soil-gt dust bowls
• More storms not just hurricanes, but also winter
  storms
• Rising sea levels due to ice caps melting-gt
  flooding

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Ozone Depletion

• Chemicals produced by humans have been damaging
  the ozone layer
• Chlorofluorocarbons (CFCs)- complex chlorine
  compounds found to destroy ozone molecules
• Found in air conditioner and refrigerator
  coolants, some cleaners and spray cans

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Impacts of ozone depletion

• More UV rays reaching the surface and causing
  more eye and skin damage

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What is being done?

• In the late 1970s 196 countries joined the
  Montreal Protocol agreeing to discontinue the use
  of CFCs in spray cans.

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Figure 21
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• The Scientific Assessment of Ozone Depletion 2010
  report said a 1987 international treaty that
  phased out chlorofluorocarbons (CFC) - substances
  used in refrigerators, aerosol sprays and some
  packing foams - had been successful.

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