Tree-ring studies show cycles of extreme drought and flooding
SUMMIT COUNTY — New scientific evidence suggests that extreme cycles of drought and intense monsoon rains may have contributed to the fall of Cambodia’s ancient Khmer civilization at Angkor nearly 600 years ago.
A study of tree rings, archeological remains and other evidence suggests that climate impacts were severe enough to disrupt the civilization that built the mighty Angkor Wat temples. 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. Written records corroborate the latter drought, which may have been felt as far away as Sri Lanka and central China.
Similar studies suggest that abrupt environmental changes may have pushed other ancient civilizations over the edge, including the Anasazi people of the southwestern United States; the Maya people of Central America, and the Akkadian people of Mesopotamia. There is some evidence that other once-powerful kingdoms in what is now Vietnam and Myanmar may have fallen during the late 1700s, following extreme dry and wet periods.
The authors of the current study and other researchers suggest that El Niño, possibly abetted by longer, decades-long cycles across the Pacific basin, may have played an important role in shutting down the monsoon rains in this region, creating withering droughts in the past. Some scientists suspect that warming of the global climate may intensify these cycles in the future, raising the possibility of alternating Angkor-like droughts and destructive floods that could affect billions of people. Continue reading