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c. 1300s-1400s CEPeer-reviewed · 2 sourcesDebated

Tree-Ring Evidence Shows Decades of Drought Strained Angkor's Water System

Climate scientists find a 30-year drought followed by a punishing wet spell in the century before collapse

On the timeline · around c. 1300s-1400s CE · Decline, the Fall of Angkor, and the Long TwilightCrisis and the Reign of Jayavarman VIIDecline, the Fall of Angkor, and the Long TwilightTree-Ring Evidence Shows Decades of Drought Strained Angkor's Water System125013001350140014501500

Quick facts

Researchers
Brendan Buckley, Roland Fletcher, Edward Cook
Method
Tree-ring (dendrochronology) reconstruction
First drought
c. 30 years, mid-1300s
Driest single year on record
1403

What happened

Climate scientists Brendan Buckley, Roland Fletcher, and Edward Cook published research in the Proceedings of the National Academy of Sciences showing that Angkor experienced two long, severe droughts in the century before its final collapse, reconstructed from a seven-and-a-half-century tree-ring record from tropical southern Vietnam. The first drought, in the mid-1300s, lasted roughly 30 years and was the most sustained dry period the region had seen in eight centuries; the second, shorter drought around the turn of the 15th century included the single driest year in the entire tree-ring record, 1403. Between and after these droughts came unusually intense monsoon seasons capable of causing severe flooding. The National Library of Australia's synthesis of this research notes that when rains did return after prolonged drought, sediment no longer held in place by cleared forest washed into the barays and canals, clogging them with silt.

Why it matters

This gives the empire's collapse a physical mechanism beyond politics and war: a water-management system built for a stable monsoon cycle could not absorb decades-long drought followed by violent flooding, and once the reservoirs and canals silted up, the labor and organization needed to dredge them out again may no longer have been available.

How we know

The drought chronology comes from dendrochronology, dating and cross-matching annual growth rings in long-lived Vietnamese cypress trees to reconstruct centuries of monsoon variability, a method independent of any Khmer written record.

Sources

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Part of a timelineThe Khmer Empire28 events · How a trading kingdom on the Mekong became a temple-building empire that vanished into the jungleView all →
Tree-Ring Evidence Shows Decades of Drought Strained Angkor's Water System · The Khmer Empire · SourcedStory