650-Year-Old Drought Led to Abandonment of Ancient City
A drought that lasted a staggering 650 years led to the abandonment of an ancient city in Mexico, prompting the once-thriving civilization to literally seek greener pastures, new research says.
The findings are published in the journal Proceedings of the National Academy of Sciences.
At the height of its existence, Cantona - a once-fortified city located just east of modern-day Mexico City - boasted some 90,000 inhabitants. But between 900 AD and 1050 AD its people fled for reasons that still remain a mystery to scientists.
In order to learn more about Cantona's collapse, researchers took a closer look at the climate before and after its abandonment - a factor that until now has been understudied.
Based on sediment samples of the nearby lake Aljojuca, researchers could use oxygen isotopes to determine how much precipitation and evaporation occurred at the site back during Cantona's heyday. What they found was that while the region did have wet summers and dry winters, its monsoon season was regularly interrupted by long-term droughts lasting hundreds of years.
Consequentially, these long dry spells affected the area's crops and water supply.
"The decline of Cantona occurred during this dry interval, and we conclude that climate change probably played a role, at least towards the end of the city's existence," lead researcher Tripti Bhattacharya, a graduate student of geography at the University of California, Berkeley, said in a statement.
Interestingly, at the beginning of this dry period some 1,000 years ago, Cantona's population actually grew. Scientists suspect that political turmoil and droughts elsewhere drove more people to the fortified city, but it wouldn't be able to sustain so many people for long.
"In a sense the area became important because of the increased frequency of drought," noted researcher Roger Byrne. "But when the droughts continued on such a scale, the subsistence base for the whole area changed and people just had to leave. The city was abandoned."
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