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Chapter 21 Global Climate Change

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Title: Chapter 21 Global Climate Change


1
Chapter 21Global Climate Change
2
Overview of Chapter 21
  • Introduction to Climate Change
  • Causes of Global Climate Change
  • Effects of Climate Change
  • Melting Ice and Rising Sea Level
  • Changes in Precipitation Patterns
  • Effects on Organisms
  • Effects on Human Health
  • Effects on Agriculture
  • Dealing with Global Climate Change

3
Introduction to Climate Change-Mean Annual
Global Temperature 1960-2005
4
Climate Change Terminology
  • Greenhouse Gas
  • Gas that absorbs infrared radiation
  • Ex Carbon dioxide, methane, nitrous oxide,
    chlorofluorocarbons and tropospheric ozone
  • Positive Feedback
  • Change in some condition triggers a response that
    intensifies the changed condition
  • Infrared Radiation
  • Radiation that has a wavelength that is longer
    than that of visible light, but shorter than that
    of radio waves
  • Greenhouse Effect
  • Increase of heat in a system where energy enters
    (often as light), is absorbed as heat, and
    released sometime later

5
Introduction to Climate Change
  • Evidence for Climate Change
  • 11 of the 12 years between 1995 and 2006 were
    among the twelve warmest years since the
    mid-1800s
  • Phenological spring in N. hemisphere now comes 6
    days earlier
  • Warming is not due to natural causes (are we
    sure?)
  • Human produced greenhouse gases are most
    plausible explanation

6
Causes of Climate Change
  • Greenhouse gas concentrations increasing

7
Causes of Climate Change
  • Increased concentration of CO2 (right)
  • Burning fossil fuels in cars, industry and homes
  • Deforestation
  • Burning of forests

8
Greenhouse Effect
9
Other Pollutants Cool the Atmosphere
  • Atmospheric Aerosols tend to cool the atmosphere
  • Both human and natural sources
  • Tiny particles that remain in troposphere for
    weeks or months
  • Contain many chemicals, but often contain sulfur
  • Complicates models of climate change

10
Climate Models
  • Climate affected by
  • winds, clouds, ocean currents, and albedo
  • Used to explore past climate events
  • Advanced models can project future warming events
  • Models are only as good as the data and law used
    to program them
  • They have limitations

11
Climate Models
12
Effects of Global Climate Change
  • Ocean as CO2 sink - excess CO2 is starting to
    harm ocean life

13
Effects of Global Climate Change- Melting Ice and
Rising Sea Levels
  • Sea level rise caused in 2 ways
  • Thermal Expansion
  • Water expands as it warms
  • Melting of land ice
  • Retreat of glacier and thinning of ice at the
    poles
  • Melting has positive feedback
  • Increased melting decreases ice, which decreases
    albedo leading to further warming

14
Melting Ice and Rising Sea Levels
1957
1998
15
Case-In-Point Impacts in Fragile Areas
  • Eskimo Inuit live traditional life dictated by
    freezing climate
  • Climate change is altering their existence
  • Wildlife are smaller or displaced
  • Reduced snow cover and shorter river ice seasons
  • Thawing of permafrost (right)

16
Effects of Global Climate Change- Changing
Precipitation Patterns
  • Some areas will get more water, some areas will
    have greater droughts
  • Ex Hurricanes will likely get stronger

17
Effects of Global Climate Change- Effects on
Organisms
  • Zooplankton in parts of California Current have
    decreased by 80 since 1951
  • Effecting entire food chain
  • Decline in krill around Antarctica
  • Caused decrease in penguin populations
  • Species have shifted their geographic range
  • Migrating birds are returning to summer homes
    earlier
  • Food is not available at this time

18
Effects on Organisms - Coral Reefs
  • Coral reefs can be bleached (right) due to
    increase in water temperature
  • Affects coral symbiotes and makes them more
    susceptible to diseases to which they would
    otherwise be immune

19
Effect on Organisms - VegetationBeech Tree Range
20
Effects on Human Health
  • Increased number of heat-related illnesses and
    deaths

21
Effects on Agriculture
  • Difficult to anticipate
  • Productivity will increase in some areas and
    decrease in others
  • Rise in sea level will inundate flood plains and
    river valleys (lush farmland)
  • Effect on pests is unknown
  • Warmer temperatures will decrease soil moisture-
    requiring more irrigation
  • Location (i.e. elevation and altitude) where
    certain crops can be grown may have to change

22
International Implicationsof Climate Change
  • Developed vs. Developing countries
  • Differing self-interests
  • Differing ability to meet the challenges of
    climate change

23
Dealing with Global Climate Change
  • To avoid the worst of climate change, CO2 levels
    must be stabilized at 550ppm
  • 50 higher than current levels
  • Two ways to attempt to manage climate change
  • Mitigation
  • Focuses on limiting greenhouse gas emissions to
    moderate global climate change
  • Adaptation
  • Focuses on learning to live with to the
    environmental changes and societal consequences
    brought about by global climate change

24
Dealing with Global Climate Change- Relationship
Between Mitigation and Adaptation
25
Dealing with Global Climate Change- Mitigation
  • Locate/invent alternative fuels to fossil fuels
  • Increase efficiency of cars and trucks
  • Sequestering carbon before it is emitted
  • Plant and maintain trees to naturally sequester
    carbon

26
Dealing with Global Climate Change- Adaptation
  • Rising sea levels and coastal populations
  • Move inland
  • Construct dikes and levees
  • Adapt to shifting agricultural zones
  • NYC sewer line

27
International Efforts to Reduce Greenhouse Gas
Emission
  • Kyoto Protocol
  • Legally binding
  • Provides operational rules on reducing greenhouse
    gases
  • US and Australia have not signed it- it will be
    difficult to implement without US backing
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