Climate and Civilization

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Climate and Civilization
The Thames in Ice - James Abbott McNeill
Whistler (1834-1903)
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Climate and Civilization

• Climate has facilitated migration
• Early settlers of N. America
• Land bridge during ice age
• Greenland settlement
• in medieval warm period
• Climate has played a pivotal role in military
  history
• 1588 Spanish Armada
• 1812 Napoleons retreat from Moscow

3
Defeat of the Spanish Armada, 1588-08-08 by
Philippe-Jacques de Loutherbourg, depicts the
battle of Gravelines - painted in 1797
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The Retreat by Vereschagin
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In 1812 - Priashnikov
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The night halt of the Great Army by Vereschagin
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Theory of Climate and Civilization

• Other factors are involved in these pivotal
  events
• E.g. Spanish Armada destruction also involved
  excellent British seamanship
• Disease and famine contributed to Napoleons
  losses.

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Climate and Evolution

• Humans have endured 8 glacial episodes in the
  last 730 k y.
• 20 abrupt climate changes during the last 120,000
  years
• In the context of adapting to abrupt climate
  shifts Natural selection favored those who
  developed the most effective hunting strategies,
  and the necessity of coordinated hunting behavior
  led to an increased intelligence and a bigger
  brain.
• Ice age population bottlenecks (Calvin, 1990)
  promoted brain development.
• The throwing theory explains in a simple and
  plausible way why the brain of our ancestors made
  such astonishing progress (Calvin, 1990).

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Precambrian (4.6 0.57 Ga)

• Faint Young Sun paradox
• Solar output ¼ less that today, yet why so warm?
  A number of feedbacks are required to keep the
  surface as warm as evidence suggests
• 30-300 x elevated CO2 (Garrels and Perry, 1974
  Polack and Yung, 1980)
• Presence of simple life at 3.8 Ga implies
  temperatures lt 58 C, casting doubt that the
  Greenhouse effect was strong enough to explain
  no-glaciation