Chapter 21 Global Climate Change

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Chapter 21Global Climate Change
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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

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Introduction to Climate Change-Mean Annual
Global Temperature 1960-2005
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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

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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
• Rate of sea level rise has increased
• Retreating glaciers and extreme weather
• Warming is not due to natural causes
• Human produced greenhouse gases are most
  plausible explanation

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Causes of Climate Change

• Greenhouse gas concentrations increasing

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Causes of Climate Change

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

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Greenhouse Effect
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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

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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

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Effects of Global Climate Change

• Ocean as CO2 sink - excess CO2 is starting to
  harm ocean life

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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

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Melting Ice and Rising Sea Levels
1957
1998
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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)

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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

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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

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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

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Effect on Organisms - VegetationBeech Tree Range
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Effects on Human Health

• Increased number of heat-related illnesses and
  deaths

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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

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International Implicationsof Climate Change

• Developed vs. Developing countries
• Differing self-interests
• Differing ability to meet the challenges of
  climate change

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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

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Dealing with Global Climate Change- Relationship
Between Mitigation and Adaptation
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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

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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

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International Efforts to Reduce Greenhouse Gas
Emission

• Kyoto Protocol
• Legally binding
• Provides operational rules on reducing greenhouse
  gases
• US and Australia have not sign it- it will be
  difficult to implement without US backing