The city of Angkor died a slow death

Angkor Wat today, as viewed across a pond next to the 12th-century Hindu temple to Vishnu built under the rule of Suryavarman II. (credit: Bjirn Christian Tirrissen)

In the early Middle Ages, nearly one out of every thousand people in the world lived in Angkor, the sprawling capital of the Khmer Empire in present-day Cambodia. But by the 1500s, Angkor had been mostly abandoned-its temples, citadels, and complex irrigation network left to overgrowth and ruin. Recent studies have blamed a period of unstable climate in which heavy floods followed lengthy droughts, which broke down the infrastructure that moved water around the massive city.

But it turns out Angkor's waterworks may have been vulnerable to these changes because there was no one left to maintain and repair them. A new study suggests that Khmer rulers, religious officials, and city administrators had been steadily flowing out of Angkor to other cities for at least a century before the end.

A long road to ruin

University of Sydney environmental historian Dan Penny and his colleagues took sediment cores from a moat near the south gate of Angkor Thom, the citadel at the administrative and political heart of the city and the Khmer Empire. Year after year, windblown sediment and runoff from the city's drainage system settled to the bottom of the moat, storing pollen from local crops, particles of charcoal from burning, and sediment from cleared land. It makes a good measure of activity in the city: the more Angkor's administrators cleared land, built new structures, and otherwise disturbed the landscape, the more sediment washed and blew into the moat.

Read 15 remaining paragraphs | Comments