Posted by: Johan Normark | February 23, 2012

One more mega-drought study

It sure looks like we are being “flooded” by various palaeoclimatological studies that supposedly confirm the mega-drought model for the Maya collapse. Most of these studies, but not all, are made by palaeoclimatologists with little to no consideration of the archaeological record near the sources themselves. We often see climate data retrieved from Lake Chichancanab being used to explain changes at Tikal, hundreds of km away in a quite different environment. It would help these studies if they took a look at the archaeological record from the nearby Cochuah region instead, only 7-35 km away (the data I use for my study).  

In a new study, made by Martin Medina-Elizalde and Eelco Rohling, data from Lake Chichancanab, Tecoh cave and Punta Laguna are being analyzed. They have calculated that during two of the severe droughts (around AD 830 and 928), the water level of Lake Chichancanab dropped by 30% and the annual precipitation in Yucatan decreased by 40%. This they point out is not as severe as in previous estimates.

I have not yet read the whole article yet as I cannot access Science at my home, but if this is the main conclusion I only feel stronger support for my own model (I really need to send the article to a journal). Lake Chichancanab is a shallow lake. Changes in the water levels of the dozens of Prehispanic wells we have encountered in the Cochuah region would not have been at great risk as one could always extend the depth of the well (they range between 15 and 35 m depth in the region). Tainter also points out that precipitation can decrease by 90% and it is still within the range of some maize varieties.

Yes, there were severe droughts but the archaeological record from the Cochuah region indicates that there were settlement strategies to cope with these changes. Population became more mobile than before. But that is another story which I should finish once and for all…

Lake Chichancanab

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