Nothing lasts for ever, not least human civilizations. There are many reasons why societies stand or fall, and these lessons from the past require investigation at various places and on various timescales.
Archaeology, it seems, really is a matter of life and death — this was the theme to emerge from a meetingFootnote 1 convened to address the question of what makes societies more likely to collapse or to achieve long-term sustainability. Just as we do today, our ancestors faced problems of resource depletion, environmental degradation, political instability, demographic pressure and social upheaval. And, as today, success in dealing with these challenges was never assured.
Consider the following contrasts. The islands of eastern Polynesia were all settled within a few centuries of one another by people sharing the same ancestral culture. Yet whereas some islands, such as Tahiti, have sustained human populations for centuries, others, such as Easter Island (Rapa Nui), supported populous and complex societies for only a short time before experiencing profound demographic and social disruption.
Completely isolated since its initial colonization, variously dated between about AD 750 and 12001,2, this scrap of land came to the notice of the world with the visit of the Dutch explorer Jacob Roggeveen on Easter Sunday, 1722. Roggeveen marvelled not only at the more than 200 massive stone statues, the Moai, which ring the coast, but also at the barrenness of the landscape and the destitution of its small population. The rich soils of Easter Island, oddly enough, supported a depauperate vegetation virtually devoid of woody plants.
That Easter Island had once supported a much larger population with a complex political structure was clear from the archaeological record. But it took a combination of archaeological and palaeoenvironmental data (pollen, microscopic charcoal and faunal analysis) to reveal the extent to which the island's degraded landscape was a product of human action. Once covered by subtropical forests dominated by a now-extinct species of large palm3,4, the island environment was ravaged by intensive human exploitation. With the destruction of plants for canoe-building, offshore food resources such as the marine mammals exploited early in the island's human history receded from reach, as did any chance of mobility as an option for addressing the mismatch between resources and needs.
Although ecological constraints certainly played a role in the variable success of human populations on Pacific islands (B. Rolett, Univ. Hawaii), cultural practices were clearly also crucial. Longer-term sustainability involved agricultural systems and levels of resource extraction compatible with local conditions.
Not all anthropogenic environmental change has led to cultural collapse, as both the contrasts between Pacific islands and the evidence from more complex continental contexts shows. One such comparison is between the long-term occupation of the Basin of Mexico and the well-studied collapse of the Classic-period Maya (Fig. 1). The Maya, a complex urban society organized into a series of competitive city states, abruptly ceased building monumental structures around the ninth century AD. Large parts of the Maya homeland were depopulated, although others continued to thrive. Many factors — including environmental degradation, population expansion, warfare and a decline in the ideology of kingship — seem to have been at issue in the collapse (D. Webster, Penn. State Univ.). Not far away, however, in central Mexico, the city of Teotihuacan managed to maintain a large population, perhaps as many as 100,000 people, for more than 400 years (G. Cowgill, Arizona State Univ.). The area has continued to support a large population to this day.
The experiences of past societies may be thought of as social and ecological ‘experiments’ (C. Redman, Arizona State Univ.). In each case, past conditions, responses to change (real or perceived) and outcomes of behaviour constitute data for broader comparisons. Defining cases requires more precise definitions, drawing distinctions between restorations of continuity, societal transformations, failures or ‘mini-collapses’ such as dynastic transitions, and collapse proper (Redman). Considerations of spatial and temporal scale are essential, not least in defining sustainability. The historical record represents the cumulative outcome of multiple processes (S. van der Leeuw, Arizona State Univ.), so explanations must integrate processes and contingent events operating at different scales.
Several factors seem to have determined whether societies failed, collapsed, or experienced either episodic change or ‘radical continuity’. On the one hand, environmental changes, natural or self-inflicted, caused or assisted many cases of collapse and failure (J. Betancourt, Univ. Arizona). Other factors include rates of demographic change (Webster), the degree to which élites were isolated (and insulated) from social problems, the strength of communication across hierarchies (S. Schroeder, Univ. Wisconsin), levels of investment in infrastructure, and the ability to balance commitment to cultural values with the flexibility required to manage uncertainty (J. Diamond, UCLA; M. Nelson, K. Spielmann, Arizona State Univ.).
In the past, many societies with fewer vulnerabilities than today's Western societies have failed, whereas others with more vulnerabilities have succeeded (B. Nelson, Arizona State Univ.). The long archaeological record of human history constitutes the best and, for most of our history, the only source of data about the long-term consequences of human choices. One of the values of archaeological research is that it offers a rich source of data on human actions and their consequences — data that may someday play the same kind of role in understanding present challenges that palaeoecology now does in climate modelling. By identifying the differences, as well as the similarities, between past and present societies, archaeology can publicize environmental and social risks and vulnerabilities while underscoring an increasingly wide range of technical and cultural solutions (Betancourt).
What lessons does current archaeological research have for policy-makers? For one, it is clear that large-scale environmental degradation is almost always a factor in social collapse. Awareness of ecological inflexion points, beyond which recovery is no longer possible, may make the difference between success and failure. Total collapse of a civilization may be rare, but cultural transformations are not only common but perhaps also necessary. For example, the long-term occupation of parts of south Asia may have been made possible by a willingness to experiment with new social forms and technological strategies, including radical changes in agriculture and cuisine. In today's globally connected world, failures tend to have ramifications well beyond local contexts, making the lessons of the past perhaps even more relevant.
*How Societies Chose to Fail or Succeed, Global Institute of Sustainability Workshop, Arizona State University, Tempe, Arizona, USA, 31 January to 2 February 2006.
Green, R. C. & Weisler, M. I. Asian Perspect. 41, 213–241 (2002).
Hunt, T. L. & Lipo, C. P. Science 311, 1603–1606 (2006).
Flenley, J. R. & King, S. M. Nature 307, 47–50 (1984).
Dransfield, J. et al. Nature 312, 750–752 (1984).
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