2015-01-27. Long dry spell doomed Mexican city 1,000 years ago.

posted Feb 3, 2015, 10:44 AM by Alan Gould
By Robert Sanders, UC Berkeley News Center. For GSS Life and Climate chapter 12. Excerpt: ...Archaeologists continue to debate the reasons for the collapse of many Central American cities and states, from Teotihuacan in Mexico to the Yucatan Maya, and climate change is considered one of the major causes. ...A UC Berkeley study sheds new light on this question, providing evidence that a prolonged period of below-average rainfall was partly responsible for the abandonment of one such city, Cantona, between A.D. 900 and A.D. 1050. At its peak, Cantona, located in a dry, volcanic basin (La Cuenca Oriental) east of today’s Mexico City, was one of the largest cities in the New World, with 90,000 inhabitants. The area was a major source of obsidian, and the city may have played a military role alongside an important trade route from the Veracruz coast into the highlands. ...UC Berkeley geographers ... found evidence of a 650-year period of frequent droughts that extended from around A.D. 500 to about A.D. 1150. This was part of a long-term drying trend in highland Mexico that started 2,200 years ago, around 200 B.C. The climate became wetter again in about A.D. 1300, just prior to the rise of the Aztec empire. “The decline of Cantona occurred during this dry interval, and we conclude that climate change probably played a role, at least towards the end of the city’s existence,” said lead author Tripti Bhattacharya, a UC Berkeley graduate student....  http://newscenter.berkeley.edu/2015/01/27/long-dry-spell-doomed-mexican-city-1000-years-ago/.