THE HUMAN FOOTPRINT

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THE HUMAN FOOTPRINT
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Tragedy of the Commons

• Garrett Haudin
• commonly held resource
• each individual will attempt to maximize personal
  gain
• self interests gt public interests
• degradation of resource
• cost shared by all

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Only 18 of the earths wild lands remain
The human population economy grow while the
ecosphere shrinks

• Only 18 of the earths wildlands remain

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Can we create another Earth?

• Biosphere II
• ecotechnological experiment
• different ecoregions
• 1991-1993
• 8 people
• sustainable?

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Biosphere II Results

• drop in atmospheric oxygen
• high species losses (including pollinators)
• weedy species flourished
• low crop productivity
• water quality degraded
• costs 25 mil/person

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How many earths do we need?

• E. O. Wilson estimates that we would need 3-4
  earths if all 6 billion people had the same
  standard of living as Americans

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Climate Change
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The Greenhouse Effect

• natural process
• enhanced greenhouse effect due to human
  activities

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Climate Change Through the Ages

• climatic fluctuations during Earths history
• since Industrial revolution burning of fossil
  fuels has increased levels of greenhouse gases by
  30

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Human Enhancement of Greenhouse Effect
Mauna Loa Observatory, Hawaii
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(No Transcript)
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Carbon Dioxide Trends

• before the Industrial Era (c.1750), atmospheric
  carbon dioxide (CO2) concentration was 280 10
  ppm for several thousand years
• CO2 has risen continuously since then, reaching
  367 ppm in 1999
• recent data from ice cores show current levels of
  atmospheric CO2 unprecedented in last 675,000
  years of Earths history (Siegenthaler et al.
  2005)

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Human Enhancement of Greenhouse Effect
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Carbon Dioxide Trends
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Contributions of Greenhouse Gases to Global
Warming
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Human activities that contribute to Global Warming
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Temperature Trends

• global temperature increasing currently 0.5
  degrees C annually worldwide

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Temperature trends in the lower US1901 to 1998
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Relationship between temperature and carbon
dioxide over the past 160,000 years
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Ice Melting and Glacial Retreat
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Snow, Ice Hydrological ChangesGangotri
Glacier, India
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Ice Sheets and SLR
calving front along edge of Greenland Ice Sheet

• Greenland Ice Sheet has 7 m of sea level
  equivalence
• West Antarctic Sheet has 5 m of sea level
  equivalence
• if both melt, a combined 12 m rise in sea level

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Historical Changes in Sea Level

• direct cause of sea level rise is input of
  additional water currently locked up in polar
  ice sheets
• rapid shifts in sea level in the past due to
  melting of glacial ice sheets
• sea level rose at an average rate of 10 mm/year
  between 15,000 and 6,000 years ago
• indirectly through thermal expansion of water

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Recent Sea Level Rise

• IPCC found that melting of polar ice caps
  contributed 0.2-0.4 mm/year to sea level rise in
  the 20th century
• average annual rates of increase from long-term
  tidal gauges indicate that eustatic sea level
  (overall mean global water level) rose 1-2
  mm/year in the 20th century
• SLR predicted to accelerate from the total of
  20-30 cm seen in the 20th century to 35-90 cm
  during the 21st century as a result of thermal
  ocean water expansion and loss of land ice in
  response to global warming (IPCC 2001 Michener
  et al. 1997 Leatherman 2001 Kearney, 2001
  Douglas 1992 Scavia et al. 2002)

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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Louisiana
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Sea Level Rise Scenarios - Florida