A view from caves

Climate Change Effects on the Rise and Fall of the Chinese dynasties

WANG XianfengEarth Observatory of Singapore, NTU

Sixth ICRM Symposium, 23-24 April 2015

Warnings from history, and today …

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JJA 850hPa streamline field based on the NCAR/NCEP atmospheric reanalysis data (Kalnay et al., 1996)

Almost half of the world’s population depends on Asian monsoon rainfall for their livelihood.

Wanxiang Cave

1. Rain

2. Soil: high pCO2

3. Dissolve CaCO3

5. Precipitate CaCO3

4. Degas CO2

Limestone

Soil

Cave

Limestone

��18O

speleothemcarbonate cave

1cm

Climate Proxy:Speleothem 18O/16O (or �18O), a rain gauge in the tropics. Simply speaking, the lower the ratio, the higher rainfall is.

Ca2+ + 2HCO3- �� CaCO3 + H2O + CO2

Carbonate precipitation in caves

Dissolution / karstification

H2O

H2O

CaCO3

�18O

�18O6th

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Oxygen isotopic ratio (��18O or 18O/16O) of precipitation shifts to low values during the summer rainy season

Hig

h su

mm

er ra

infa

ll

WET

Dating Methods:

238U 234U 230Th 206Pb

Half-life4.468 0.005

x109 years(Jaffey et al. 1971)

245,620 75,580260 years 110 years

(Cheng et al. 2000, 2013)

230Th dating (U/Th dating or 238U-234U-230Th dating): applied to carbonates from as young as 1 year to over 700 kyr

Ultra-clean chemistry room MC-ICP-MSMicro-sampling

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the 1,800-yr long monsoon record from Wanxiang Cave(Zhang et al., 2008, Science)

WET

the monsoon record from Wanxiang Cave vs. the drought/flood index reconstructed from local historical literatures (Tan et al., 2011, Climate of the Past)

Drought

WET

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(Berkelhammer et al., 2010, EPSL)

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the monsoon record from Wanxiang Cave, China vs. the record from Dandak Cave, India

Chinese Culture History& the Asian Monsoon

The Wanxiang Cave record

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(1)

(the Northern Qi, AD 550-577)

By the side of the rill, at the foot of the hill,The grassland stretches beneath the firmament tranquil.

The boundless grassland lies beneath the boundless skies.When the winds blow and grass bends low,My sheep and cattle will emerge before your eyes.

A Shepherd’s Song

(1)

(epiage.com)

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2009

(1)A Shepherd’s Song?

(2)

Late Tang weak monsoon period

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In 875 AD:

History as a Mirror

Locusts swarmed over the land

(2)

( 875)

( )

Huang, Chao

The Huang Chao Uprising (870s and 880s) fueled by the drought, led to the end of the Tang Dynasty.

(2)

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(3)

Northern Song strong monsoon period

During the Northern Song strong monsoon period (~AD 960 to 1020), the Chinese population more than doubled and reached 100 millions.

Along the River During ChingMing Festival, by Zhang, Zeduan

(3)

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Rice became the staple of the Chinese diet, and rice cultivation expanded northwards substantially (~doubled from AD 975 to AD 1021).

(3)

(4)

Late Yuan weak monsoon period

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At the end of the Yuan Dynasty, there were a series of droughts and peasant uprisings. In 1368 Zhu, Yuanzhang, who led the uprising, took Beijing.

His parents and older brother all died during the the droughts at the end of the Yuan Dynasty.

Zhu, YuanZhang1st Emperor Ming Dynasty

(4)

the Ming Dynasty (1368-1644 AD)(5)

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(5)

Late Ming weak monsoon period

Known as one of the most severe droughts in Chinese history

Affected more than 20 provinces in both northern and southern China.

The Chongzhen Drought (1637 to 1643)at the end of the Ming Dynasty

(5)

Last Ming Emperor: Chongzhen (ruled 1628-1644)

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Li, ZiCheng

( )

5

The widespread drought helped the rebel leader, Li Zhicheng overthrow Chongzhen in 1644.

(5)

--- ·

Boyangfu(ancient Chinese philosopher)

Dynasty would collapse, if people were poor without harvest from water and land. In the past, the Xia Dynasty collapsed when Yi and Luo Rivers dried-up, and the Shang Dynasty collapsed when the Yellow River dried-up.

-- Boyangfu (~800 BC)

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Whereas other factors would certainly have affected these chapters of Chinese cultural history, climate indeed played a significant role.

“ … climate change is a ‘threat multiplier’ that will impact national security.”

--- US. Department of Defense, 2014

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China: Hai Cheng, Pingzhong Zhang, Yongjing Wang, Xinggong Kong, Ming Tan, Yanjun Cai

USA: Larry Edwards, Wally Broecker, Sidney HemmingBrazil: Augusto Auler, Francisco CruzSingapore: colleagues at EOS

With Thanks:

Funding support:National Research Foundation of SingaporeNational Science FoundationGary Comer Science & Education Foundation... ...

GRUPO BAMBUÍ DE PESQUISAS ESPELEOLÓGICAS

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