The Maya are often thought of as one of the most advanced civilizations in the Americas. Their breakthroughs in astronomy enabled them to predict where the moon and planets would be years into the future and they left behind impressive architecture and artwork. A new study may have solidified a cause for their decline.
Researchers have determined that drought was indeed a factor in the demise of the Mayan empire, which occupied what is now southern Mexico and northern Central America, from about 250 A.D. to 950 A.D.
But how much of a factor is still up in the air.
A study published in the February 24 issue of Science shows research over the last 10 years of climate proxy records. According to ScienceMag.org, that means looking at lake and coastal sediments to detect rainfall levels.
Professor Martín Medina-Elizalde, of the Yucatan Center for Scientific Research in Mexico, led the study and told Science Daily that researchers have been saying for more than a century that drought was related to the civilization’s demise.
"Our results show rather modest rainfall reductions between times when the Classic Maya civilization flourished and its collapse between 800 to 950," researcher Eelco Rohling, a paleoclimatologist at the University of Southampton in England, told LiveScience. "These reductions amount to only 25 to 40 percent in annual rainfall, but they were large enough for evaporation to become dominant over rainfall, and open water availability was rapidly reduced. The data suggest that the main cause was a decrease in summer storm activity."
Having dry spells in the summer was the worst timing for the Mayans.
"Summer was the main season for cultivation and replenishment of Maya freshwater storage systems and there are no rivers in the Yucatan lowlands," Rohling told LiveScience.
He explained that the ancient Maya had become dependent on the normal levels of rainfall. "Then, even a rather subtle climatic change was enough to create serious problems," he told LiveScience. "Societal disruptions and abandonment of cities are likely consequences of critical water shortages, especially because there seems to have been a rapid repetition of multiyear droughts."
Gerald Haug, a climate geologist of the Swiss Federal Institute of Technology in Zurich, Switzerland, told ScienceMag.org that this study is a good addition to the evidence that climate change contributed to the decline of the Mayan civilization, but he says researchers should not ignore other factors like social and political developments.
The authors of this study also noted that the droughts that helped bring down the ancient Mayans are coming to the same region again, as predicted by the Intergovernmental Panel on Climate Change.
"There are differences too, but the warning is clear—what seems like a minor reduction in water availability may lead to important, long-lasting problems," Medina-Elizalde told LiveScience. "This problem is not unique to the Yucatan Peninsula, but applies to all regions in similar settings where evaporation is high. Today, we have the benefit of awareness, and we should act accordingly."