Moon pyramid view from Sun pyramid at Teotithuacan.

Rise and fall of agrarian states influenced by climate volatility

Climate variability is one of the major forces in the rise and fall of agrarian states in Mexico and Peru, according to a team of researchers looking at both climate and archaeological records.

"We are arguing that the climate information in both areas is good enough to establish that climate is playing some role in the rise and fall of these city states," said Douglas Kennett, professor of environmental archaeology at Penn State. "Now we need to further refine the archaeological data."