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Chapter 20 Global Climate Change


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Title: Chapter 20 Global Climate Change

Chapter 20Global Climate Change
Overview of Chapter 20
  • 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

Introduction to Climate Change-Mean Annual
Global Temperature 1960-2005
Climate Change Terminology
  • Greenhouse Gas
  • Gas that absorbs infrared radiation
  • Ex Carbon dioxide, methane, nitrous oxide (N2O),
    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 wavesthink heat
  • Greenhouse Effect
  • Increase of heat in a system

Introduction to Climate Change
  • Some evidence for Climate Change
  • Temperature increase of 1.4 degrees F since 1880
  • Extreme northern latitudes 7.4 increase (40 of
    N. polar ice cap melt)
  • 9 of the 10 warmest years between 2000-2009
  • Ice core sampling measures greenhouse gases up to
    500,000 years ago. (CO2 and temp. correlate)
  • Human produced greenhouse gases are most
    plausible explanation

Causes of Climate Change
  • Greenhouse gas concentrations increasing

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

Greenhouse Effect
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 (but
    accounted for)

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

Climate Models
Effects of Global Climate Change
Increase CO2 in Ocean
  • Ocean as CO2 sink - excess CO2 is starting to
    harm ocean life (acidification ? decline of coral

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
  • Melting has positive feedback
  • Increased melting decreases ice, which decreases
    albedo leading to further warming
  • Threatens small islands and coasts flooding
    erosion and intense storms

Melting Ice and Rising Sea Levels
Case-In-Point Impacts in Fragile Areas
  • Melting permafrost
  • Support structure for Tundra plants, houses,
  • Release CO2 and methane from decomposing material
    (remember bacteria decompose more/faster at
    warmer temperatures.)
  • See article

Near Fairbanks, Alaska
Changing Precipitation Patterns
  • Some areas will get more water, some areas will
    have greater droughts
  • Ex Hurricanes will likely get stronger due to
    warmer water
  • Exaggerate El Nino effects

Effects on Organisms
  • Zooplankton in parts of California Current have
    decreased by 80 since 1951
  • Effecting entire food chain
  • Polar ice cap melting too far for Polar bear to
    swim to hunt seals
  • Polar bear ?seal (seal carcass to Arctic fox)
  • Decline in krill around Antarctica
  • Caused decrease in penguin populations
  • Species have shifted their geographic range
  • Migrating birds are returning to summer homes
  • Food is not available at this time

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

Effect on Organisms - VegetationBeech Tree Range
Effects on Human Health
  • Increased number of heat-related illnesses and
    deaths malaria, schistosomiasis, leishmaniasis

Effects on Agriculture
  • Rise in sea level will inundate/destroy flood
    plains and river valleys (lush farmland)
  • 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
  • Difficult to anticipate
  • Productivity will increase in some areas and
    decrease in others

Effects summarized
  • Rising sea levels
  • Change in precipitation patterns
  • Sensitive organisms decline decrease of
    organisms at bottom of food chain
  • Increase range of disease causing organisms
  • Decrease ability to grow crops in certain areas

International Efforts to Reduce Greenhouse Gas
  • Kyoto Protocol
  • Provides rules on reducing greenhouse gases
  • US and Australia have not signed it- difficult to
    implement without US backing
  • US concern LDC not have same expectations to

Dealing with Global Climate Change
  • Two ways to attempt to manage climate change
  • Mitigation/Reduction
  • 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

Dealing with Global Climate Change- Mitigation
  • Locate/invent alternative fuels to fossil fuels
  • Increase efficiency of cars and trucks
  • Drive less bike lanes, carpool, wide sidewalks
  • Sequestering carbon before it is emitted
  • Plant and maintain trees to naturally sequester

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