MEXICO CITY, Feb. 24 (UPI) -- Relatively mild drought may have caused the collapse of the classic Maya civilization in what is now southern Mexico and Guatemala, researchers say.
It had long been believed that prolonged severe drought caused the collapse of the civilization in around 950 A.D, but Mexican and British researchers now think seasonal water supplies in the region could have been exhausted by a small but sustained drop in rainfall.
Researchers from Britain's University of Southampton collaborated in the research with the Yucatan Center for Scientific Research in southern Mexico.
Analyzing estimates of rainfall and evaporation rates between 800 and 950 A.D., when the Maya civilization went into sharp decline, they found a relatively modest decline in rainfall was enough to deplete freshwater storage systems in the Yucatan lowlands, where there are no rivers, the BBC reported Friday.
"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 was rapidly reduced," Professor Eelco Rohling of Southampton University said.
"Societal disruptions and abandonment of cities are likely consequences of critical water shortages, especially because there seems to have been a rapid repetition of multi-year droughts," he said.
Archaeologists have long argued over the collapse of the classic Maya civilization, with other studies blaming social unrest, disease and deforestation for its demise.