Anthropologist: "When you have cold temperatures, rainfall is much lower, causing drought, causing dramatic depopulation."

Droughts caused Maya culture demise, anthropologist says

He also indicated that 13 volcanic eruptions during Spanish colonization of the region (1450-1850) led to conditions that created drought and famine.

Temperature changes, particularly cold, cause dry conditions.

"My theory is that cold weather is associated with lower rainfall in the Maya lowlands," he said. "When you have cold temperatures, rainfall is much lower, causing drought, causing dramatic depopulation."