Did the Maya Cause Their Own Droughts?

Interesting work presented at AGU by a University of Alabama/NASA/etc. group suggesting the the possibility that Mayan deforestation may have brought on the drought conditions that some blame for the collapse of classic Maya culture.

I have thought that the Maya might make a good case study for a society done in by drought, expanding in wet times and therefore losing the resilience necessary to cope with drought. Smart archaeologists disagree on the drought hypothesis, with some arguing that “collapse” was not synchronous across the Maya region and therefore drought is not a reasonable explanation. But it’s at the very least an idea worth entertaining.

This new work suggests an intriguing wild card. What if cutting down the rainforest reduced the amount of atmsopheric moisture available via evapotranspiration, thereby reducing rainfall? The group’s modelling run suggests it’s a possibility:

Domain averaged dry season rainfall in the Maya lowlands decreases to 128.9mm for the deforested scenario, a decrease in 9.7 percet over current conditions…. Continued deforestation that would be representative of those prior to the collapse of the Maya civilization in the region can be expected to lead to additional decreases in dry season precipitation throughout the entire region by about 10mm to 100mm. Improper land use management in this region could lead to futures catastrophes for the modern humans.

(Hat tip Roger Pielke Sr., who is one of the coauthors and who pointed this out to me.)