Douglas Kennett/Penn State
The ancient Maya civilization may have risen ? and then fallen ? in response to climate change, scientists report after creating precise climate records going back 2,000 years.
The researchers, whose findings appear in the current issue of the journal Science, reconstructed rainfall patterns using cross-sections of stalagmites from a cave near the ancient city of Uxbenka, in what is now southern Belize. First, they dated the samples with the technique called uranium-thorium dating; then, to generate a climate record, they measured oxygen isotopes, which are sensitive to rainfall.
The early classic Maya period ? about A.D. 450 to 660 ? ?was remarkably wet,? said an author of the study, Douglas Kennett, a geo-archaeologist at Penn State. ?There was a proliferation of population, an increase in agriculture and a rise in divine kings that became prominent leaders.?
But then things dried up. The researchers compared the climate record with an existing ?war index? ? a log of hostile events based on how often certain keywords occurred in Maya inscriptions on stone monuments ? and found a strong correlation between drought and warfare between cities.
?About A.D. 660, you get indications of some social stress that goes up in tandem with this drying period,? Dr. Kennett said.
Maya cities were linked, but each operated with its own autonomous political structure. When resources were strained, the groups may have turned against one another.
Over several hundred years, ?the social fabric was eventually destabilized,? Dr. Kennett said. Most Maya cities collapsed between A.D. 800 and 900.