Chapter 10 Climate Change

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Chapter 10Climate Change

• Geosystems 6e
• An Introduction to Physical Geography

Robert W. Christopherson Charles E. Thomsen
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Causes of Climate Change

• Variations in the Earths orbital characteristics
• Atmospheric carbon dioxide variations
• Volcanic eruptions
• Variations in solar output
• Humans

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Greenhouse Gases

• Human activities are enhancing the Earths
  natural greenhouse effect
• Carbon dioxide, methane, nitrous oxide, CFCs, and
  water vapor
• Greenhouse gases are transparent to sunlight but
  opaque to longwave radiation

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Carbon Dioxide

• Atmospheric CO2 levels began rising during the
  Industrial Revolution
• Tremendous fossil fuel burning and heavy
  deforestation increased CO2 levels this trend
  continues
• CO2 is responsible for 64 of global warming

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Carbon Dioxide Sources
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What are the Fossil Fuels?
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Carbon Dioxide Sources
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Methane

• Methane currently increasing faster than CO2 in
  the atmosphere
• 19 of total atmospheric warming attributed to
  methane
• Methane generated by rotting vegetation,
  digestion in cattle and termites, burning of
  vegetation, and melting permafrost

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Methane (CH4)
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Volcanic Eruptions

• Sulfur dioxide reacts with water vapor causing
  haze
• Combined with ejected particulate matter
• One of the coldest years in the last two
  centuries was 1816, the Year Without a Summer
• Caused by eruption of Tambora in 1815
• Temperatures can decrease after eruptions for up
  to 3 years

Mount St. Helens
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Variations in Solar Output

• Climate models predict that a change in solar
  output of only 1 percent per century alters the
  Earths average temperature by 0.5 -1.0 C
• Sunspots
• Huge magnetic storms
• Seen as dark (cooler) areas
• on the sun's surface.
• Cycle every 11, 90, and
• 180 years

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GCM Predictions

• Crop patterns and natural plant/animal habitats
  will shift to maintain preferred temperatures
• During this century, climate regions could shift
  90-350 miles poleward
• Soil moisture projected to decrease in
  midlatitudes

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GCM Predictions

• Forest cover will undergo major species
  disturbances
• Expansion of zones affected by tropical diseases
• Alpine glaciers

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Global Temperatures
1.4C 2.5F
Figure 10.28
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Temperature Anomalies for 2003
Figure 10.28
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Sea Level Issues
During this century, global warming will cause
sea levels to rise at least 1.5 meters (about 4.5
feet).
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Sea Level Rise

• During the 20th century, sea level rose 4-8
  inches
• Could rise 3.5-34.7 inches this century
• Thermal expansion of water will increase sea
  level rise
• Higher sea levels destruction of small island
  nations, river deltas, lowland coastal farming,
  barrier islands

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July 2029 Temperature Forecast
Figure 10.31
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Disintegration of Ice Shelves

• In 2002, Larsen-B ice shelve collapsed in 35 days
  after existing for 11,000 years
• Warmer ocean and air temperatures are melting
  shelves on both sides
• Clear evidence of changes in Earths energy
  balance

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Antarctic Ice Disintegration
Figure 10.32
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Arctic Climates

• Changes in ocean temperatures could alter global
  temperatures
• Arctic region warmed 9F since 1987
• This has led to a freshening of northern oceans
• Greenland ice melting at 1m/year
• Permafrost is melting
• Increased precipitation in Arctic/Antarctic areas

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End of Chapter 10Climate Change

• Geosystems 6e
• An Introduction to Physical Geography

Robert W. Christopherson Charlie Thomsen
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Chapter 19 Ecosystem Essentials

• Geosystems 6e
• An Introduction to Physical Geography

Robert W. Christopherson Charles E. Thomsen
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Ecology

• Study of relationships between organisms and
  their abiotic environment
• Can be studies at several levels
• Population
• Community
• Ecosystem
• Biosphere

Fig 1.8
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Communities
Fig. 19.3
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Community Terms

• Habitat
• Type of environment where an organism resides
• Niche
• Function of a life form within a community
• In stable community, no niche is left unfilled
• Competitive Exclusion Principle applies
• No two species occupy same niche at same time

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Interactions in communities

• Competition
• Negative for both species (/)
• Symbiotic/Mutualistic (/)
• Both species benefit
• lichen (fungi and algae)
• Predation and Parasitic (/)
• One benefits, one loses