Global Warming

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Global Warming
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The Greenhouse Effect

• Earth is similar to a greenhouse
• Atmosphere acts like the glass in a greenhouse
• Sunlight streams through the atmosphere
• Sunlight heats the Earth
• Heat radiates up from Earths surface and some
  escapes into space
• The rest is absorbed by gases in the troposphere
  warms the air

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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

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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

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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

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The Consequences of a Warmer Earth
Global Weather Patterns
Melting Ice Rising Sea Levels
Human Health Problems
Effects on Plants Animals
Agriculture
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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

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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

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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)

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The Consequences of a Warmer Earth

• Agriculture
• Decreased crop yields
• Higher demand for irrigation ? depleting aquifers

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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)

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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.

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Reacting to Change

• Concerns/Effects
• Impact on humans
• Actions being taken
• Opposition
• Any questions?

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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.