Human Population Growth

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Human Population GrowthHabitat Destruction
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US population growth

• 1 b every........................... 8 seconds
• 1 d every......................... 12 seconds
• 1 i (net) every.................. 26 seconds
• Net gain of 1 every......... 13 seconds

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zero pop change April, 2240
45,000 675,000
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• Growth trend is not unique to US
• 2004 estimates (CIA website)
• India (1.07B)
• 2.85 children/woman
• 22.8 births/1,000 population
• 8.38 deaths/1,000 population
• ? 1.44
• Sudan (39.1M)
• 4.97 children/woman
• 35.79 births/1,000 population
• 9.37 deaths/1,000 population
• ? 2.64
• Greenland (58k)
• 2.42 children/woman
• 15.96 births/1,000 population
• 7.7 deaths/1,000 population

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• http//www.census.gov/population/www/popclockus.ht
  ml

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5 min population growth ? 9503 8815 698
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• 2.33 persons/sec

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Question 1

• Human population growth is sometimes blamed for
  the loss of biological diversity. Is this valid?
• Is human population growth a concern for our
  environment?

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Habitat Destruction

• Almost all modern environmental problems are
  linked to human population growth habitat
  destruction.
• HD - Destruction of wildlife habitats by
  increasing pressure for land by fast-growing
  human populations, pollution and
  over-exploitation (EPA definition)
• Examples
• Habitat conversion and fragmentation.
• Reductions in habitat quality, overexploitation
  (harvesting, pet trading), (pollution, inc.
  global temps, soil erosion, introduced
  competitors/predators, etc.)

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Tree harvesting
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• Komi clearcuts

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Habitat Conversion

• Wisconsin forest fragmentation

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50 Million acres every year
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Tropical Rainforests
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Habitat Conversion
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Mauna Loa, Hawaii
After the conversion
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Overgrazing
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Over harvesting

• Rotenone abuse

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Results from digs of Paleolithic, archaeological
remains
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Introduced (Exotic) species
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Pollution
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Manila Bay Pollution
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Mexico City
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Gasses trapped in ice pack
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• Coal/oil fired pollutants

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Extinctions (real and ecological)
Group Number of species Number threatened 1994 Number threatened 1999 percent

Fishes 24000 452 752 3
Amphibians 3000 59 146 5
Reptiles 6000 167 296 5
Boidae 17 9 53
Birds 9500 1029 1183 12
Mammals 4500 505 1130 25
Cervidae 14 11 79
Gymnosperms 758 242 - 32
Angiosperms 240000 21895 - 1
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Question 2

• How do we value the diversity of life or natural
  items?
• How should we value them?

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Why is biodiversity valuable?

• Direct values ? , meat, fibers
• Indirect values ?
• Aesthetics
• Religious
• Optional ? (e.g. rosy periwinkle)
• See next slides
• Intrinsic value

Vincristine - leukemia
Vinblastine Hodgkins disease
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Question 3

• What choices do you make on a daily basis that
  are good for the environment?
• What choices do you make on a daily basis that
  are bad for the environment?

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Question 4

• Is the protection of the diversity of life a
  moral decision?

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Question 5 6

• Should we slow human population growth?
• How?