I just read a very nice summary of some of the current debates over the role of droughts in the collapse of Classic Maya civilization:
Pringle, Heather (2009) A New Look at the Mayas' End. Science 324:454-456.
It looks to me like the field may be moving toward a more reasonable explanation of the Maya collapse. Nevertheless, reading the remarks from Pringle's interviews with some of the scholars involved shows that an old problem still has a major effect on the issue. That problem is when one's theoretical perspective (or preconceptions) largely determine one's understanding of a phenomenon, with only tenuous connections to the data. There have long been two polar positions on drought and the Maya collapse:
(1) Many climatologists tend to think that a serious drought will cause a society to collapse. When they identify drought conditions close in time to the Maya collapse, then the issue is resolved. The drought caused the collapse. Period. End of story. Maya society must have been sufficiently fragile to be knocked out by an environmental disater, so why waste time with special pleading. Scholars with this perspective have a rather narrow, deterministic view of causality and social change.
(2) Many archaeologists tend to think that people are creative and can find solutions to environmental and social problems. Perceptions and impacts of the environment are culturally constructed and culturally mediated. The Maya people were were creative and their society was resilient, and thus environmental problems or disasters could never cause a collapse by themselves. Scholars with this perspective often have a narrow, non-materialistic view of causality and social change.
Now almost everyone will immediately claim that the best explanation is somewhere in between these two extreme views, but just where will it lie along the continuum? Read Pringle's report and see what you think. I am not going to take sides or point fingers here (mainly because I don't have time right now; it would be fun to take an skeptical outsider's perspective on the Maya collapse). If you are interested, I list below a few of the relevant publications.
Oh, one more thing. There is now a revisionist claim that the Maya didn't really collapse (e.g., Aimers 2007). Well, what happened to the millions of people? Why were scores of cities abandoned? Why did much of elite culture disappear? To me, this is an absurd claim, analogous to the claim that Rome didn't really collapse (see Ward-Perkins 2006 for the archaeological evidence againts revisionist claims about the lack of a Roman collapse). But I guess if the Maya didn't collapse, then we don't have to worry about the cause of that non-collapse.
So, what does this have to do with archaeological publishing? Although there is some overlap, scholars promoting the two views outlined above tend to publish in different journals and volumes. They tend to write for different audiences, and they generally employ different kinds of data and distinct style of argument. Many writers seem more interested in defending a position than in an open exploration of the issues. For this reason I suspect that advances will come from new kinds of data ("Ultralocal paleoclimate indicators" in Pringle's report), and from young or outside scholars who are not yet firmly entrenched in the debates.
Aimers, James J. (2007) What Maya Collapse? Terminal Classic Variation in the Maya Lowlands. Journal of Archaeological Research 15:329-377.
Demarest, Arthur A. (2001) Climatic Change and the Classic Maya Collapse: The Return of Catastrophism (review of The Great Maya Droughts by Richardson B. Gill). Latin American Antiquity 12:105-107.
Diamond, Jared (2004) The Maya Collapses. In Collapse: How Societies Choose to Fail or Succeed, edited by Jared Diamond. Viking, New York.
Gill, Richardson B. (2000) The Great Maya Droughts: Water, Life, and Death. University of New Mexico Press, Albuquerque.
Gill, Richardson B., Paul A. Mayewski, Johan Nyberg, Gerald H. Haug and Larry C. Peterson (2007) Drought and the Maya Collapse. Ancient Mesoamerica 18:283-302.
Manahan, T. Kam (2004) The Way Things Fall Apart: Social Organization and the Classic Maya Collapse of Copan. Ancient Mesoamerica 15:107-126.
Peterson, Larry C. and Gerald H. Haug (2005) Climate and the Collapse of Maya Civilization. American Scientist 93:322-329.
Rice, Prudence M. (2007) The Classic Maya 'Collapse' and its Causes. In Gordon R. Willey and American Archaeology: Contemporary Perspectives, edited by Jeremy A. Sabloff and William L. Fash, pp. 141-186. University of Oklahoma Press, Norman.
Scarborough, Vernon L. (2007) The Rise and Fall of the Ancient Maya: A Case Study in Poliltical Ecology. In Sustainability or Collapse? An Integrated History and Future of People on Earth, edited by Robert Costanza, Lisa J. Graumlich and Will Steffen, pp. 51-60. MIT Press, Cambridge, MA.
Webster, David (2002) The Fall of the Ancient Maya: Solving the Mystery of the Maya Collapse. Thames and Hudson, New York.
Ward-Perkins, Bryan (2006) The Fall of Rome and the End of Civilization. Oxford University Press, New York.