Transcript Medieval Climate Anomoly

Medieval Climate Anomaly
Climate in Medieval Time
Bradley, R. et al
Cultural Responses to Climate Change During the
Late Holocene
deMenocal, P.
Medieval Warm Epoch → Medieval Climatic Anomaly
Bradley’s hypothesis
Prolonged droughts in some areas and exceptional
rains in others suggest that changes in frequency
or persistence of circulation regimes may account
for the climate in this period.
“Persistent positive North Atlantic Oscillation mode
dominated the medieval climate anomaly”, Science
Trouet, 2009
Cultural Responses to Climate Change
James Hutton, 1785: The present is the key to understanding the past.
Peter deMenocal, 2001: The past must be used to understand the present.
Hypothesis: Water availability, rather than temperature, is the key
climatic determinant for life in semiarid expanses across the planet.
Relevance: Further study of past cultural adaptations to
persistent climate change may provide valuable perspective on
possible responses of modern societies to future climate change.
4 Case studies
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Akkadian collapse (4200 years ago)
Mayan collapse (1200 years ago)
Mochica collapse (1500 years ago)
Tiwanaku collapse (1000 years ago)
Archeological and paleoclimate histories that
illustrate past cultural responses to late
Holocene climate change.
Akkadian empire (4300 to 4200 B.P.)
Roy, 2003
Cullen, 2000
Gulf of Oman sediment core M5-422: A detailed record
of variations in regional dust export based on
mineralogical and geochemical tracers of wind-borne
sediments from Mesopotamian sources (Fig. 4)
Excavated residence from Tell Leilan
Esther
Fig. 4
Classic Maya empire (1200 to 1000 B.P.)
Fishleigh, 2012
Sediment cores from Lake Punta Laguna and Lake Chichancanab
document an abrupt onset of more arid conditions spanning ~200 years
between 1200 and 1000 years B.P.
Fig. 6 Sediment data from the lakes
Moche IV-V Transformation (1400 B.P.) and
Tiwanaku collapse (900 to 300 B.P.)
Fig. 7 Quelccaya, Peru
deMenocal’s Take Home message
Further study of past cultural adaptations to
persistent climate change may provide valuable
perspective on possible responses of modern
societies to future climate change.
Tuesday: Little Ice Age (1350 – 1850 A.D.)
Formerly the earth produced all sorts
of fruit, plants and roots.
But now almost nothing grows…
Then the floods, the lakes and the blue waves
brought abundant fish.
But now hardly one can be seen.
The misery increases more.
The same applies to other goods…
Frost and cold torment people
The good years are rare.
If everything should be put in a verse
Only a few take care of the miserables…
Olafur Einarson (1573-1659)
Icelandic priest