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Global Warming

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Global Warming The Greenhouse Effect Earth is similar to a greenhouse Atmosphere acts like the glass in a greenhouse Sunlight streams through the atmosphere & heats ... – PowerPoint PPT presentation

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Title: Global Warming


1
Global Warming
2
The Greenhouse Effect
  • Earth is similar to a greenhouse
  • Atmosphere acts like the glass in a greenhouse
  • Sunlight streams through the atmosphere heats
    the Earth
  • As this heat radiates up from the Earths
    surface, some of it escapes back into space
  • The rest is absorbed by gases in the troposphere
    warms the air

3
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4
Greenhouse Gases
  • Gases that absorb radiate heat
  • Carbon dioxide (CO2) burning fossil fuels
    deforestation
  • Chlorofluorocarbons (CFCs) refrigerants,
    aerosols, propellants
  • Methane (CH4) animal waste, biomass burning,
    fossil fuels, landfills, livestock, sewage
  • Nitrous oxide (N2O) biomass burning,
    deforestation, burning fossil fuels, microbial
    activity
  • Water vapor (H2O) evaporation, plant respiration

5
Measuring CO2 Levels
  • Varies with seasons
  • Summer ? growing plants use CO2 (levels decrease)
  • Winter ? grass leaves decay release carbon
    (levels rise)
  • CO2 levels have increased by over 20 in less
    than 50 years
  • Burning of fossil fuels (power plants, cars)
  • Millions of trees are burned in rainforests to
    clear the land

6
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7
Global Warming
  • A gradual increase in the average global
    temperature
  • Link between the increase in greenhouse gases in
    the atmosphere and the increase in temperature

8
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9
The Consequences of a Warmer Earth
Global Weather Patterns
Melting Ice Rising Sea Levels
Human Health Problems
Effects on Plants Animals
Agriculture
10
The Consequences of a Warmer Earth
  • Melting Ice Rising Sea Levels
  • Coastal wetlands other low-lying areas could be
    flooded
  • Beaches could be extremely eroded
  • Salinity of bays estuaries might increase,
    adversely affecting marine fisheries

11
The Consequences of a Warmer Earth
  • Global Weather Patterns
  • Hurricanes typhoons may be more common
  • Cause a change in ocean current patterns (like
    shutting off the Gulf Stream) which could
    significantly affect the worlds weather
  • Severe flooding drought

12
The Consequences of a Warmer Earth
  • Human Health Problems
  • Greater numbers of heat-related deaths
  • Allergies (trees flowers flowering earlier
    longer)
  • Mosquitoes could establish themselves in areas
    that are too cold for them now (spread diseases)

13
The Consequences of a Warmer Earth
  • Agriculture
  • Decreased crop yields
  • Higher demand for irrigation ? depleting aquifers

14
The Consequences of a Warmer Earth
  • Effects of Plants Animals
  • Alter range of species composition of plant
    communities
  • Reduction of zooplankton (food source for many
    marine animals) due to warming of surface waters
  • Might kill algae that nourishes corals (killing
    coral reefs)

15
Reducing the Risk
  • Kyoto Protocol
  • Requires developed countries to decrease
    emissions of carbon dioxide other greenhouse
    gases by an average of 5 below their 1990 levels
    by 2012
  • Developed in 1997 by reps from 160 countries
  • In March 2001, the U.S. decided not to ratify the
    Kyoto Protocol
  • Attempt to slow global warming is made difficult
    by the economic, political social factors faced
    by different countries.

16
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17
Assignment
Imagine you are employed by the EPA to design a
public-service advertising campaign to encourage
the reduction of carbon dioxide. Be persuasive,
creative, factual, and informational.
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