NOAA/IPRC Workshop on
Climatic Changes in the Last 1500 Years:
Their Impacts on Pacific Islands,
East-West Center, 13th November 2007
A Shock to the System:
Climatic Disruption of Pacific Island
Societies around AD 1300
Patrick D. Nunn
Professor of Oceanic Geoscience
The University of the South Pacific
Climate, Environment and Society
• Climatic change
produces
environmental
change.
Channelled scablands, NW USA
Climate, Environment and Society
• Climatic change
produces
environmental
change.
• Both climatic and
environmental
changes can
profoundly affect
human societies.
Fiji floods, 2004 [courtesy Fiji Times]
Climatic Influences on Environments:
insights from high-resolution data series
Solar irradiance (14C) and sea-level
change at Farm River Marsh, NE USA
Source: van de Plassche et al. (2003 [Geology]
Climatic Influences on Environments:
an empirical study from the Pacific
Kurile Islands, Northwest Pacific Ocean
Source: Razjigaeva et al., 2004 [Palaeo3]
Climatic Influences on Human Society:
general considerations
• Environmental
determinism versus
cultural determinism.
• Emerging acceptance
of the potential of
climatic change to
“force” changes in
pre-modern human
societies.
• Watershed studies
Climatic Influences on Human Society:
watershed studies from the Pacific
Direct influence of climate on society
Source: Titanium (precipitation proxy), Cariaco Basin, Venezuela, and its effects on Maya civilization in
central America (Haug et al., 2001 [Science])
Climatic Influences on Human Society:
watershed studies from the Pacific
Climate influence on society through environmental filter
Source: William R. Dickinson
Island societies are good case studies because
their societies often register an amplified
response to climate forcing.
•
•
•
•
Why?
Relative smallness.
Relative isolation.
Relative homogeneity
of environments and
societies.
Necker Island, Hawaii Islands
The Pacific Basin
Russia
Alaska
Canada
China
United States
Atlantic
Ocean
Japan
Marshall
Islands
Hawaii
Philippines
Papua New
Guinea
Kiribati
Panama
0°
Indonesia
Cook
Islands
Australia
Indian
Ocean
French
Polynesia
Peru
Easter
Island
New
Zealand
Tasman
Rise
Galapagos
Islands
Chile
180°
East
Antarctica
West
Antarctica
Drake
Passage
Volcanic
Pacific
Islands
Limestone
Pacific Islands
Pacific Island
paleoclimate
archives
History of human settlement of the
Pacific Islands
Russia
human arrival
30,000 BC?
Canada
human arrival
15,000 BC?
United States
Japan
China
human arrival
40,000 BC?
Taiwan
Philippines
limit of pre-Lapita
settlement limit of colonization
before 750 BC (2700 BP)
limit of colonization
before AD 500 (1450 BP)
Marshall
Islands
New
Guinea
Hawaiian Islands
colonization AD 650
Solomon
Islands
EQUATOR
?
Tuvalu
Marquesas
Samoa
Vanuatu
Australia
human arrival 40.000 BC?
New
Caledonia
Fiji
Panama
colonization by
Pacific Islanders
pre-AD 1513?
Cook
Islands
Pikimachay
human arrival
25,000 BC?
French
Polynesia
Tonga
?
New
Zealand - colonization ~AD 1275?
Easter Island
colonization AD 690?
Monte Verde
human arrival
33,000 BC?
Organization of this talk
1. Last-millennium climate change in the Pacific
2. Environmental changes on tropical Pacific
Islands during the last millennium
3. Societal changes on tropical Pacific Islands
during the last millennium
4. Possible climate forcing of last-millennium
environmental and societal change in the
tropical Pacific Islands: the AD 1300 Event
Part 1
Last-millennium climate change in
the Pacific
Last-millennium climate changes
in the Pacific: summary
• Medieval Warm Period (ca. AD 750-1250),
comparatively warm dry climate with high sea level.
• AD 1300 Event (ca. AD 1250-1350), rapid cooling,
increased precipitation, falling sea level.
• Little Ice Age (ca. AD 1350-1800), comparatively
cool climate, higher climate variability (increased El
Niño frequency), low sea level.
• Recent Warming (ca. AD 1800-present), warming,
reduced climate variability, rising sea level.
Ice coring – tropical Andes
-17
Thompson et al., 2003 [Climatic Change]
δ18O (‰)
Huascarán
-18
-19
-20
Medieval Warm Period –
comparative warmth
Medieval Warm Period
AD 1300
Event
Little Ice Age
Recent
warming
-16
warmer
cooler
-19
-12
Sajama
-15
Little Ice Age –
comparative coolness
18
δ O (‰)
-20
18
-18
δ O (‰)
-17
Quelccaya
(transition)
AD 1300 Event –
cooling
-18
Recent Warming increasing warmth
-21
1000
1200
1400
1600
Time (Years AD)
1800
2000
AD 1300
Event
Medieval Warm Period
Recent
warming
Little Ice Age
Sredniaya Avacha, Kamchatka
Steller Lobe, Alaska
?
?
Prince William Sound, Alaska
Llewellyn Glacier, Alaska
Kiwa Glacier, Canadian Rockies
Robson Glacier, Canadian Rockies
Cathedral, Pagoda and Siva glaciers, Canada
Colonel Foster Glacier, Vancouver Island ?
?
southern Canadian Rockies (general)
Cordillera Blanca, Peru
Cordillera Central, Chile
Soler Glacier, Patagonia
Glaciar Frias, Patagonia
Glaciar Lengua, southernmost Andes?
900
1100
?
1300
1500
Time (Years AD)
1700
1900
Compilation from Nunn (2007) book
AD 1300
Event
Medieval Warm Period
Little Ice Age
Recent
Warming
Precipitation (cm)
22
wetter
20
18
drier
16
extreme low stand
of Mono Lake
Owens Lake
low stand
extreme low stand
of Mono Lake
extreme low stand
of Lake Tenaya
1
500
1000
low stand
of Lake Tenaya
1500
2000
Time (Years AD)
Medieval Warm Period – comparatively dry
Little Ice Age – comparatively wet
Westernmost USA, Nevada
dendrochronology (Hughes and
Graumlich, 1996 book chapter)
and lake-level data
Stalagmite, Buddha Cave, east China (Paulsen et al., 2003 [Quaternary Science Reviews].
El Niño
frequency
change
A. Laguna
Pallcacocha,
Ecuador
B. Laguna
Aculeo,
Chile
C. Sacramento
River, USA
D. Historical
records
Compilation from
Nunn (2007) book
Pacific Islands compilation
Compilation from Nunn (2007) book
Last-millennium climate changes
in the Pacific: the AD 1300 Event
• Too much emphasis
hitherto on discrete
periods rather than
transitions as the causes
of environmental and
societal change.
• The AD 1300 Event was
the most rapid period of
climatic change within the
past few thousand years.
Source: Dahl-Jensen et al., 1998 [Science]
Part 2
Environmental changes on tropical
Pacific Islands during the last
millennium
Qaranilaca (Sail Cave),
Vanuabalavu Island,
Fiji
Anthropogenic cave fill
Storm-wave deposit
-No sign of cave occupation during Medieval Warm
Period (cave flooded?)
-Fill begins accumulating about AD 1400 (sea level
has fallen?)
-Transient cave occupation begins about AD 1450
during Little Ice Age (sea level low)
-Cave fill now being eroded (sea level rising)
Kawai Nui wetland, O’ahu Island, Hawaii
-During Medieval Warm
Period, Kawai Nui was an
ocean bay (sea level high)
-During Little Ice Age, Kawai
Nui became a brackish-water
swamp (sea level low)
Tikopia Island,
eastern outer
Solomon Islands
Original research:
Kirch and Yen (1982)
Ravenga Tombolo
1833 lithograph by Louis Auguste de Sainson
Part 3
Societal changes on tropical Pacific
Islands during the last millennium
(a) settlement-pattern change and the emergence of conflict
(b) end of cross-ocean interaction
Easter Island (Rapanui)
-Colonized about AD 690 (maybe AD 1200)
-AD 1300, conflict begins, statue-making
frenzy
mata’a – obsidian spearheads
Tatuba
Cave
Dates for the
establishment of
hillforts and fortified
caves in the Sigatoka
Valley, Viti Levu Korokune
hillfort
Island, Fiji (courtesy
of Dr Julie Field)
Tatuba
Cave
Korokune
hillfort
Changing settlement pattern, Kaua’I Island, Hawaii during the
last millennium
New Zealand (not tropical!)
Beginning
around AD
1300,
coastal
settlements
were
abandoned
in favor of
fortified
hilltop
settlements
named pa.
Conflict
ensued.
The pa at Tolaga about 1780 (Herman Spöring)
Palau
Islands,
western
tropical
Pacific
Babeldaob Island
Rock Islands
End of cross-ocean interaction
Part 4
Climatic forcing of last-millennium
environmental and societal change
in the tropical Pacific Islands
Model of the
“AD 1300 Event”
-Climate change
drives environmental
change
-Environmental
change drives
societal change
-Climate change also
directly drives
societal change
One example of societal response to climate forcing is
settlement-pattern change
Warm, moist
climate: sea
level rising
Warm, dry
climate: sea
level high
Cool, variable
climate: sea
level low
Solar forcing (sunspot numbers) and Pacific climate change
Summer temperatures,
Canadian Rockies
Precipitation and
temperature,
eastern China (98year lag)
Solar forcing and sea-level change in the Pacific
Solar irradiance (∆14C) and sea-level change, Pacific Islands composite
(90-year lag) from Nunn (2007) book.
Conclusion
• Climate change, both
directly and through
environmental filters,
caused profound
societal changes in
the tropical Pacific
Islands during the last
millennium.
Nunn, P.D. 2007. Climate, Environment and
Society in the Pacific during the Last
Millennium. Amsterdam: Elsevier, 316 p.
Nunn, P.D. 2007. The AD 1300 Event in the
Pacific Basin: overview and teleconnections.
The Geographical Review, 97, 1-23.
Nunn, P.D. 2007. Holocene sea-level
change and human response in Pacific
Islands. Earth and Environmental Science,
98, 117-125.
Nunn, P.D., Hunter-Anderson, R., Carson,
M.T., Thomas, F., Ulm, S. and Rowland, M.
2007. Times of plenty, times of less:
chronologies of last-millennium societal
disruption in the Pacific Basin. Human
Ecology: An Interdisciplinary Journal, 35,
385-402.
Thank you for your attention.