Tuesday, August 25, 2009


I have been reading Collapse, Jared Diamond's account of the collapses of several past civilizations - Easter Island, the Maya, the Anasazi, and the Greenland Norse settlement prominent among them - and discussions of environmental stresses and sustainability issues in modern societies. Included is some original research of his with a coauthor on the factors affecting success or failure in the Pacific Islands. He also discusses a few cultures which adapted and moved back from the brink, including Tokugawa Japan, the New Guinea Highlands, Tikopia and medieval Iceland. In the case of Tikopia success involved the wiping out of two of the clans by the one surviving clans while in Iceland severe desertification occurred in the uplands before things stabilized. So success is relative.

My preconception was that he would be overly deterministic about the role of environmental degradation in these stories. But that isn't the case. In fact, for an economist things seem a bit too open ended. He tries to explain these examples by a five factor theory but I can summarize in fewer points, I think.

Societies tend to overshoot their carrying capacity when either they experience long periods of favorable climate (e.g. Greenland) or move into new areas where they misperceive the carrying capacity even in the short-run (e.g. Iceland). In the latter case environmental degradation results causing a fall in carrying capacity. In the former a change in climate for the worse is the cause in fall in carrying capacity. What happens next depends on the fragility of the environment and the rigidity of institutions. A more fragile environment (e.g. Easter Island vs sustainable example) or more rigid institutions increases the likelihood of collapse. For example, the Greenlanders seem to have eaten no fish for inexplicable reasons and otherwise seem to have tried to maintain European style agriculture rather than adopt ideas from the native Americans (they did hunt seals but not all types). Rulers need to show their people that they can provide for them to legitimate their rule as well as compete with rival rulers. It might make more sense to try to maintain the current system at continuing environmental cost until it finally collapses rather than admit that it has failed. At the same time temples (Maya) or statues (Easter Island) tend to get bigger and bigger.

We can certainly see the same symptoms in our world today. Rulers seek legitimacy by maintaining economic growth. There is a fear of accepting even small reductions in GDP in order to protect the climate. And conservative attitudes in institutions prevail. The Greenlanders didn't want to be like the Inuit, while conservative Americans don't want to be like the French or Swedish today. As institutional economists long-ago noted technology changes faster than institutions do.

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