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NOAA/IPRC Workshop onClimatic 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
Source: van de Plassche et al. (2003 [Geology]Solar irradiance (14C) and sea-level change at Farm River Marsh, NE USA
Climatic Influences on Environments:an empirical study from the Pacific
Source: Razjigaeva et al., 2004 [Palaeo3]Kurile Islands, Northwest Pacific Ocean
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
Source: William R. DickinsonClimate influence on society through environmental filter
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
China
Japan
Russia
Philippines
Indonesia
Papua NewGuinea
Australia
NewZealand
Kiribati
MarshallIslands
CookIslands
Alaska
Hawaii
FrenchPolynesia
EasterIsland
GalapagosIslands
Canada
United States
EastAntarctica
WestAntarctica
Chile
Peru
Panama
IndianOcean
AtlanticOcean
TasmanRise
DrakePassage
180°
0°
Volcanic Pacific Islands
Limestone Pacific Islands
Pacific Island paleoclimate
archives
History of human settlement of the Pacific Islands
EQUATOR New Guinea
Solomon Islands
Marshall Islands
Vanuatu
NewCaledonia
FijiTonga
Tuvalu
?
?
Samoa CookIslands
Marquesas
Easter Islandcolonization AD 690
limit of colonization before 750 BC (2700 BP)
limit of pre-Lapita settlement
limit of colonization before AD 500 (1450 BP)
NewZealand - colonization ~AD 1275?
Panamacolonization byPacific Islanderspre-AD 1513?
Hawaiian Islandscolonization AD 650
FrenchPolynesia
?
Taiwan
Philippines
Japan
China
Australiahuman arrival 40.000 BC?
RussiaCanada
United States
human arrival 40,000 BC?
human arrival 30,000 BC?
human arrival 15,000 BC?
Monte Verdehuman arrival 33,000 BC?
Pikimachayhuman arrival 25,000 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.
-20
-19
-18
-17
-16
-17
-18
-19
-20
-21
-18
-15
-12
1000 1200 1400 1600 1800 2000
Time (Years AD)
Huascarán
Quelccaya
Sajama
Little Ice AgeMedieval Warm Period AD 1300Event
Recentwarming
warmer
cooler
δ
O (
‰)
18
δ
O (
‰)
18
δ
O (
‰)
18
Ice coring – tropical Andes
Thompson et al., 2003 [Climatic Change]
Medieval Warm Period – comparative warmth
Little Ice Age – comparative coolness
Recent Warming - increasing warmth
(transition) AD 1300 Event – cooling
Medieval Warm Period Little Ice AgeAD 1300Event
Recentwarming
900 1100 1300 1500 1700 1900
Time (Years AD)
? ?Steller Lobe, Alaska
Prince William Sound, Alaska
Llewellyn Glacier, Alaska
??Colonel Foster Glacier, Vancouver Island
southern Canadian Rockies (general)
Cordillera Blanca, Peru
Cordillera Central, Chile
Soler Glacier, Patagonia
Kiwa Glacier, Canadian Rockies
Robson Glacier, Canadian Rockies
Cathedral, Pagoda and Siva glaciers, Canada
Sredniaya Avacha, Kamchatka
??Glaciar Lengua, southernmost Andes
Glaciar Frias, Patagonia
Compilation from Nunn (2007) book
22
20
18
16
Pre
cip
itatio
n (
cm)
1 500 1000 1500 2000
Time (Years AD)
extreme low standof Mono Lake
extreme low standof Mono Lake
Owens Lakelow stand
extreme low standof Lake Tenaya
low standof Lake Tenaya
Medieval Warm Period Little Ice Age
AD 1300Event
wetter
drier
RecentWarming
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)
1833 lithograph by Louis Auguste de Sainson
Ravenga Tombolo
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
Korokune hillfort
Dates for the establishment of hillforts and fortified caves in the Sigatoka Valley, Viti Levu 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 (98-year 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.
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