The Little Ice Age and European Civilization

Historian Geoffrey Parker has an essay in the Times today urging us to prepare for climate change, and citing the fate of Europe in the 17th century as an example of what might happen if we don't:

During the 17th century, longer winters and cooler summers disrupted growing seasons and destroyed harvests across Europe. It was the coldest century in a period of glacial expansion that lasted from the early 14th century until the mid-19th century. The summer of 1641 was the third-coldest recorded over the past six centuries in Europe; the winter of 1641-42 was the coldest ever recorded in Scandinavia. The unusual cold that lasted from the 1620s until the 1690s included ice on both the Bosporus and the Baltic so thick that people could walk from one side to the other. The deep cold in Europe and extreme weather events elsewhere resulted in a series of droughts, floods and harvest failures that led to forced migrations, wars and revolutions. The fatal synergy between human and natural disasters eradicated perhaps one-third of the human population. . . .

Western Europe experienced the worst harvest of the century in 1648. Rioting broke out in Sicily, Stockholm and elsewhere when bread prices spiked. In the Alps, poor growing seasons became the norm in the 1640s, and records document the disappearance of fields, farmsteads and even whole villages as glaciers advanced to the farthest extent since the last Ice Age. One consequence of crop failures and food shortages stands out in French military records: Soldiers born in the second half of the 1600s were, on average, an inch shorter than those born after 1700, and those born in the famine years were noticeably shorter than the rest.

Like many historians and archaeologists, I have lately been thinking hard about climate and its effects on human civilization. The archaeological record is full of what look like population booms and busts, and shifts in the climate are often suggested as the cause. As you can see from the wikipedia chart above, which overlays ten different reconstructions of the climate over the past 2000 years, there have indeed been broad shifts in the climate, and the Little Ice Age stands out as one of the most dramatic. On the other hand you can also see that various reconstructions differ greatly in detail, both in terms of the timing and the severity of these fluctuations. Quite likely this is because the effects of these cycles varied greatly from place to place.

This variability is one problem with Parker's reconstruction of a Europe-wide catastrophe. If a year was colder and wetter than normal, that might be catastrophic in parts of northern Europe; but why would it be catastrophic in the south, where crops were more often threatened by drought? A list of famines and riots proves nothing, since crops failed somewhere in Europe every year.

The 17th century was indeed a time of great turmoil across Europe. But how much of that was due to climate change? This, I submit, is a hard question. The great disturbances of the age were not acts of random violence, but expressions of profound political and intellectual changes. The causes (perhaps) of these conflicts included the re-establishment of strong national governments after a millennium of weak central power; rivalry between these nations for pre-eminence in Europe; conflicts inspired by the attempts of these newly strong states to control the church within their borders; and conflicts over what form that church would take. It was a time of great ideological ferment, giving us both radical democratic agitation and the most fantastic assertions of "absolute" royal power.

Was all of that, as a Marxist might say, mere superstructure over a deep roiling of the continent caused by crop failures, famine, and hordes of wandering beggars? Or, if we don't want to go that far, could we say that people are more prone to embrace radical ideas when the existing systems are obviously not working? There were, it is worth pointing out, two very cold periods within the long span of the Little Ice Age -- in Northern Europe anyway -- and the second was precisely the revolutionary epoch of 1775 to 1825.

Against this we might argue that the overall structure of European population was governed by the iron scissors of Thomas Malthus. In good times, population rose until it reached a sort of limit set by the overall productive capacity of the civilization. Thus in the Middle Ages technical advances, increased order, and better weather led to a long span of population growth that lasted from about 1000 to 1250 or 1300. By 1300, the continent was full, and there was bound to be increased conflict over resources whether the weather changed or not. The bad weather of 1315-1317 led to famine across the north because the system was already strained to the limits, and it remained strained to the limits until the Black Death came along and swept a third of the continent away. The 16th century was another era of growth, caused (it seems) by a decrease in the virulence of the plague. (Evolution of biological defenses? Better quarantines and other measures? Changes in the disease organism itself? Nobody knows.) By 1600 the population was once again pressing against those Malthusian limits.

Another important caveat can best be explained by the events of the 20th century. Europe went through another revolutionary epoch between 1914 and 1968 or so that had nothing to do with bad weather. This was a crisis entirely caused by the internal development of European civilization and the world economy. Could such things happen only in the modern, industrial era, or might past civilizations have generated their own crises?

One final point: is a crisis necessarily a bad thing? No doubt the Little Ice Age was bad for people who starved, went hungry or were killed in riots, but if the atmosphere of crisis helped inspire the era's radical political and scientific thinking, then much of our modern world traces back to a cold spell. Whatever else happened in 17th-century Europe, it was an era of extraordinary accomplishment in art, mathematics, science -- especially physics, physiology, and economics -- exploration, global trade, technology, and more. I know I have said this before, but it bears repeating that the droughts some people think led to the collapse of Mayan civilization were no more severe than the Little Ice Age, which had rather the opposite effect on Europe.

I am not entirely sure what I think about all of this, but "climate change is bad for us" strikes me as far too simple.