Climate, Kuwae, and the Fall of Constantinople in 1453: What do Tree Rings tell us

1
Climate, Kuwae, and the Fall of Constantinoplein
1453 What do Tree Rings tell us?
Edward R. Cook1, Richard Seager1, Mark
Cane1 Ramzi Touchan2, Carol Griggs3, Sturt
Manning3 1Tree-Ring Lab, Lamont-Doherty
Earth Observatory 2Laboratory of Tree-Ring
Research, University of Arizona 3Malcolm
and Carolyn Wiener Laboratory for Aegean and
Near Eastern Dendrochronology, Cornell University

• Talk presented at
• Climate Extremes During Recent Millennia And
  Their
• Impact On Mediterranean Societies
• National and Kapodistrian University of Athens
• Athens, Greece
• September 14-16, 2008

2
The Ottoman Turks lead by Sultan Mehmed II
successfully conquered Constantinople on May 29
(Julian) or June 7 (Gregorian), 1453 (later
renamed Istanbul), thus bringing to an end the
Byzantine Empire that had lasted for over 1,000
years.
3
Leading up to the final conquest onMay 29,
several Cassandra-like portents of doom
frightened the inhabitants

• Unseasonable thunderstorms and hail
• A lunar eclipse on May 22
• The city enveloped in fog on May 26
• Intensely red twilight that looked like flames
  engulfing the dome of Hagia Sophia

4
From Eye Witnesses at the Time of the Siege
At the first hour of the night, there appeared a
wonderful sign in the sky, which was to tell
Constantine the worthy, emperor of
Constantinople, that his proud empire was to come
to an end ... The moon rose, being at this time
at the full ... but it rose as if it were no more
than a three-day moon, with only a little of it
showing ... The moon stayed in this form for
about four hours. -- Venetian surgeon, Nicolo
Barbaro. Such was the unheard-of and
unprecedented violence of that storm and hail
that it certainly foreshadowed the imminent
loss of all, wrote the Greek chronicler
Kritovoulos of Imbros, and ... like a torrent of
fiercest waters, it would carry away and
annihilate everything.
5
So, what about the Kuwae volcanic eruption?
Constantinople
Kuwae in Vanuatu
6
(A.D. 1455.9-1459.9)
2001 Journal of Geophysical Research
7
Figure 6.14
Northern Hemisphere Temperature Response to
Natural and Anthropogenic Forcings - From IPCC
AR4WG1 Chapter 6
8
Kuwae -- 4th coolest NH summer since AD 1400
(-0.50C cooling)
9
Kuwae -- 4th coolest NH summer since AD 1400
(-0.50C cooling)
So could the Kuwae eruption have lead to The
Fall Of Constantinople?
10
Kuwae probably produced a red volcanic twilight
as seen here, but what about direct climate
effects?
From Volcanic Eruptions and Climate Alan Robock
2000 Reviews of Geophysics
11
1453
Five of the largest cooling events due
to volcanic eruptions extend over the
eastern Mediterranean region near
Constantinople. This includes Kuwae in 1453.
12
Cold in 1453
13
1995 Nature
Cold in 1453
14
2006 Journal of Climate
Cool in 1453
15
2008 Climate Dynamics
Cool in 1453
16
European Temperature Response To Kuwae In 1453
Cold North
Büntgen European Alps
Cool South
Büntgen Pyrenees
17
2007 Geophysical Research Letters
Wet in 1453
18
2008 Geophysical Research Letters
Slightly Dry in 1453
19
Wetter in 1453
20
2003 International Journal of Climatology
Normal in 1453
21
2005 Climatic Change
Normal in 1453
22
New March-May scPDSI Reconstruction Centered On
Constantinople (Tree-ring data courtesy of Ramzi
Touchan, Carrol Griggs, and Sturt Manning scPDSI
data courtesy of Gerard van der Schrier)
Wet in 1453
23
Mediterranean Moisture Conditions In Response To
Kuwae In 1453 Mostly Normal To Above-Normal
Esper Morocco PDSI
Anything else?
24
North Atlantic Oscillation and the Arctic
Oscillation
Positive Phase Negative Phase
NAO
AO
25
Bo Christiansen 2008 Journal of Climate
Positive phase in year t1
Positive phase in year t1
2006 Journal of Geophysical Research
The IPCC models tend to simulate a positive
phase of the Arctic Oscillation in response to
volcanic forcing similar to that typically
observed.
26
2002 Journal of Climate
Slightly below average in 1453, but a rebound
towards more positive as observations and models
predict.
27
So what do the tree rings say overall about Kuwae
and the Fall of Constantinople?

• Conditions around Constantinople were probably a
  bit cooler and wetter in 1453 leading up to its
  conquest.

28
So what do the tree rings say overall about Kuwae
and the Fall of Constantinople?

• Conditions around Constantinople were probably a
  bit cooler and wetter in 1453 leading up to its
  conquest.
• The NAO index was probably in a weak negative
  phase in 1453, consistent with the reconstructed
  cooler and wetter conditions, but possibly moved
  towards a more positive phase by the volcanic
  eruption.

29
So what do the tree rings say overall about Kuwae
and the Fall of Constantinople?

• Conditions around Constantinople were probably a
  bit cooler and wetter in 1453 leading up to its
  conquest.
• The NAO index was probably in a weak negative
  phase in 1453, consistent with the reconstructed
  cooler and wetter conditions, but possibly moved
  towards a more positive phase by the volcanic
  eruption.
• Equal or larger temperature, precipitation,
  drought, and NAO anomalies generally occurred one
  or more years prior to 1453 and the eruption of
  Kuwae.

30
So what do the tree rings say overall about Kuwae
and the Fall of Constantinople?

• Conditions around Constantinople were probably a
  bit cooler and wetter in 1453 leading up to its
  conquest.
• The NAO index was probably in a weak negative
  phase in 1453, consistent with the reconstructed
  cooler and wetter conditions, but possibly moved
  towards a more positive phase by the volcanic
  eruption.
• Equal or larger temperature, precipitation,
  drought, and NAO anomalies generally occurred one
  or more years prior to 1453 and the eruption of
  Kuwae.
• This suggests that cooler-wetter climate
  conditions were already in place around
  Constantinople before the eruption of Kuwae.

31
So what do the tree rings say overall about Kuwae
and the Fall of Constantinople?

• So while Kuwae may have contributed to the
  overall anomalous atmospheric and weather
  conditions around Constantinople noted by eye
  witnesses and viewed as portents of doom by some
  (unseasonable fog, hail, intense red twilight),
  the massive eruption probably did not produce
  climatic conditions sufficient to materially
  affect the conquest of Constantinople by the
  Ottoman Turks.

32
So what do the tree rings say overall about Kuwae
and the Fall of Constantinople?

• So while Kuwae may have contributed to the
  overall anomalous atmospheric and weather
  conditions around Constantinople noted by eye
  witnesses and viewed as portents of doom by some
  (unseasonable fog, hail, intense red twilight),
  the massive eruption probably did not produce
  climatic conditions sufficient to materially
  affect the conquest of Constantinople by the
  Ottoman Turks.
• Rather, the last days of Constantinople, as told
  in the book 1453 by Roger Crowley, may simply
  have come down to the Kerkoporta gate being left
  unlocked during the height of battle.

33
The Rest is History!