Drought Doubt

Although the drought theory may be a popular explanation for the Classic Maya collapse, it assumes that the Maya were not able to adapt to such climate changes.  Many archaeologists believe that it fails to explain the complexity of the “collapse” and rightly so. Although there are a multitude of sites showing the occurrence of devastating droughts, many sites do not actually show this (see map below), in particular Laminai and other sites along the eastern Caribbean strip in Belize (Aimers, 2011).

Map showing sites with (in pink) and without (in blue) evidence of drought.
Source: Metcalfe (unpublished), provided by Dr. Elizabeth Graham, an archaeologist at UCL

It is therefore important to note that the palaeoclimate data that has been presented needs to be interpreted with care, keeping in mind that they are not always unambiguous. The location, chronology and the proxy used for past rainfall are all important when evaluating various records. For instance, the greater the distance from the area of interest (the Maya region), the less representative the archive will be – pretty self explanatory. So in the case of the Venezuelan marine sediment core record, does it actually inform us of what the climate was like some 2,700 kilometres away in the Maya lowlands? Figure 2 shows us how far away it really is.

Archaeological evidence from the sites marked in blue imply different rates of abandonment at different places. For example, in the Petexbatun region collapse occured in the 8th century, for Chichen Itza in the 11th century and for Mopan Valley possibly as late as the 13th century. Other sites like Laminai were not abandoned until the 1600s (after the Spanish invasion).
The sites marked in red have provided drought evidence, each with different (although still fairly similar) timings of occurrence. This contributes to the doubt surrounding the drought theory. 

Another important point to consider is how well the record is dated. Of course it will never be 100% accurate or precise, as there are numerous problems attached with all types of dating, but there are still some proxies that are far more accurate than others, especially tree rings. Other problems arise from calibrating a proxy and rainfall; we cannot always rely on it to be correct.

While there is enough robust evidence showing that a series of drought did occur, much remains to be understood. The difficulty in comparing palaeoclimate and archaeological records does not help matters and will require mutual cooperation from both fields in order to fill in the large gaps in our knowledge (Hodell, 2011).