[Aztlan] global warming and the Incas

[Michael Smith]

It is always fun to juxtapose paleoclimatic data and cultural
developments, as in the notice on global warming the the rise of the
Inca. For the Maya, droughts and the collapse remain a major topic of
debate (with no resolution in sight, it seems). For central Mexico,
consider that the period from 500-1100 AD was a time of lowered
rainfall, according to British limnologists (see citations in my The
Aztecs, 2nd edition, 2003, chapter 1 I think). Wow, that drought must
have caused the fall of Teotihuacan and the rise of the Aztecs! Well,
these are two research questions we can now cross out as solved!

Oops, sorry about the sarcasm. My point here is that it is easy to
juxtapose two kinds of chronological phenomena, but much more difficult
(or even impossible, it sometimes seems) to establish a causal
relationship. Just how can we go about establishing empirically that
climatic events or processes in the past influenced (or even "caused")
cultural transformations as documented by archaeologists? I am unaware
of rigorous methods and standards for doing this.

To some people, the simple co-occurrence of such events provides
sufficient justification. "There were droughts around the time of the
Maya collapse? Well, now we have solved that mystery." To others, such
natural phenomena can never provide sufficient explanation for human
cultural change. "Use of the environment, and environmental effects, are
culturally mediated, so environmental variables alone can never generate
cultural change." I have blogged about this at:

http://publishingarchaeology.blogspot.com/2009/05/maya-collapse-when-the
oretical.html

Environmental data on climate and rainfall and such are great, but until
someone comes up with rigorous methods for evaluating their influence on
cultural processes, I remain very skeptical about most interpretations.
(My own hunch is that the central Mexican droughts WERE important in the
fall of Teo and the rise of the Azttecs, but this remains a hunch).

Mike (in Mazatlan, photographing the very nice collection of Sinaloa
pottery in the INAH museum, and enjoying the shabby colonial atmosphere
in the old city)

Michael E. Smith, Professor
School of Human Evolution & Social Change
Arizona State University
www.public.asu.edu/~mesmith9
http://publishingarchaeology.blogspot.com
http://calixtlahuaca.blogspot.com