Population Booms and Busts in the European Neolithic

A major study of 7,944 radiocarbon dates from the European neolithic, led by British archaeologist Stephen Shennan, suggests that populations rose and fell dramatically between 8,000 and 4,000 years ago. The initial spread of farming across the continent, between 8,000 and 6,000 years ago, led to huge population growth, followed a few centuries later by a crash in which the population fell by at least 30 percent, and perhaps as much as 60 percent. After that event populations seem to have been fairly stable in some areas, but other saw further booms and busts.

Studies like this obviously depend on what sites archaeologists have chosen to investigate, and these are not really a random sample of the past. But in Europe there has been so much archaeology over the past 70 years, much of it driven by development pressure rather than the whims of excavators, that I think the record we have built up has real meaning. The evidence from Ireland is particularly clear; in Ireland the initial neolithic boom was followed by centuries in which it is hard to find any evidence of habitation in some areas. You can click on the figure above for a better view.

I don't know why this would be surprising. After all, the two thousand years of Europe's recorded history has seen two major population crashes. The first took place as the Roman Empire was falling in the fourth to seventh centuries, driven by the collapse of order, the decline in trade, and the spread of disease. Populations slowly rebounded, and around 1000 CE they entered a period of rapid growth that lasted about 250 years. Growth then faltered, and in 1348 the Black Death caused a second great crash. The population stayed low for a century or so before entering into another growth period. So why shouldn't the neolithic period have experienced population booms and crashes?

These rises and falls do not correlate very well with changes in the climate. Shennan et al. suggest that environmental factors may have been involved; for example, the initial neolithic settlers depended heavily on wild foods, which their rising population may have driven near to extinction. But I think we should not rule out epidemic disease as a potential cause.