Earth System Impacts on Humans Flashcards

1
Q

Earth system impacts on human societies

A
  • 8200 BP event
  • The ‘browning’ of the Sahara
  • Medieval warm period
  • Little Ice Age
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2
Q

The 8200 BP event

A

The Lake Agassiz megaflood 8200 BP caused sea levels to rise 1.4 m -enough to displace
European coastal communities?
Kick-starting European agriculture?

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3
Q

The browning of the Sahara

A

A small change in Earth’s orbit

  • leads to a small change in the distribution of solar radiation
  • nudges the Earth System across a threshold
  • As vegetation reduces the microclimate in the soil changes
  • Leads to less vegetation and even drier conditions
  • Amplification of initial climate signal caused by positive feedback
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4
Q

Medieval Warm Period

AD 950-1250

A

Evidence for impacts not so easy to find in Europe
Expansion of vineyards northwards in Europe
In Europe few records of famines etc - benign
times?

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5
Q

Little Ice Age in Europe

A

• Cooling 1150-1460 very cold 1560-1850
• Impacted all aspects of life
• Growing season perhaps 15-20% reduced
• Poor grain and wine harvests - 1816 the year ‘without
summer’
• Bad harvest in France 1788 led to bread riots, ‘let them
eat cake’, and the French Revolution?
• Malnutrition - influenza, malaria (ague), bubonic plague
• Abandonment of uplands
• Greater severity of storms
• Widespread Northern hemisphere phenomenon

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