Washington, March 30 (ANI): In a new study, researchers have come across evidence which suggests that climate change may have helped bring about the fall of Cambodia's ancient Khmer civilization at Angkor nearly 600 years ago.
Historians have offered various explanations for the fall of the 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.
"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," he added.
Scientists, led by Buckley, were able to reconstruct 759 years of past climate in the region surrounding Angkor by studying the annual growth rings of a cypress tree, Fokienia hodginsii, growing in the highlands of Vietnam's Bidoup Nui Ba National Park, about 700 kilometers away.
By hiking high into the mountain cloud forests, the researchers were able to find rare specimens over 1,000 years old that had not been touched by loggers.
After extracting tiny cores of wood showing the trees' annual growth rings, researchers reconstructed year-to-year moisture levels in this part of Southeast Asia from 1250 to 2008.
The tree rings revealed evidence of a mega-drought lasting three decades - from the 1330s to 1360s - followed by a more severe but shorter drought from the 1400s to 1420s.
The droughts may have been devastating for a civilization dependent on farming and an irrigation system of reservoirs, canals and embankments sprawling across more than a thousand square kilometers.
"The droughts could have led to crop failure and a rise in infectious disease, and both problems would have been exacerbated by the density of the population," Buckley said.
The study also finds that the droughts were punctuated by several extraordinarily intense rainy seasons that may have damaged Angkor's hydraulic system.
The study suggested that during a normal monsoon season, Angkor's hydraulic network could have handled heavy downpours, but after extended droughts, the system may have been vulnerable to massive siltation and clogging. (ANI)