http://www.earth.columbia.edu/articles/view/2661 Did Climate Influence Angkor’s Collapse?
Evidence Suggests Changing Environment Can Bring Down a Civilization
posted: 2010-03-29
Decades of drought, interspersed with intense monsoon rains, may have helped bring about the fall of Cambodia’s ancient Khmer civilization at Angkor nearly 600 years ago, according to an analysis of tree rings, archeological remains and other evidence. The study, published this week in the journal Proceedings of the National Academy of Sciences, may also shed light on what drives—and disrupts—the rainy season across much of Asia, which waters crops for nearly half the world’s population.
Historians have offered various explanations for the fall of an empire that stretched across much of Southeast Asia between the 9th and 14th centuries, from deforestation to conflict with rival kingdoms. But the new study offers the strongest evidence yet that two severe droughts, punctuated by bouts of heavy monsoon rain, may have weakened the empire by shrinking water supplies for drinking and agriculture, and damaging Angkor’s vast irrigation system, which was central to its economy. The kingdom is thought to have collapsed in 1431 after a raid by the Siamese from present-day Thailand. The carved stone temples of its religious center, Angkor Wat, are today a major tourist destination, but much of the rest of the civilization has sunk back into the landscape.
“Angkor at that time faced a number of problems—social, political and cultural. Environmental change pushed the ancient Khmers to the limit and they weren’t able to adapt,” said the study’s lead author, Brendan Buckley, a climate scientist and tree-ring specialist at Columbia University’s Lamont-Doherty Earth Observatory. “I wouldn’t say climate caused the collapse, but a 30-year drought had to have had an impact.”
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"Both human society and the earth's climate system are complex systems capable of unexpected behavior. Through the long-term perspective offered by climate and archaeological records, we can start to identify and understand the myriad ways they may interact,” said study coauthor Kevin Anchukaitis, a tree ring scientist at Lamont. “The evidence from monsoon Asia should remind us that complex civilizations are still quite vulnerable to climate variability and change."