Popular Manias

There is an interesting article by Tim Harford in Slate Magazine:

In the early medieval period, the Catholic Church dismissed the idea that witches had supernatural powers, and some church documents argued that it was heresy to believe in witchcraft. Without church support, it's easy to see why witch trials were not popular.

Yet when the trial and execution of suspected witches surged in the mid-16^th century and throughout the 17^th, it was a cross-cultural phenomenon. Trials took place in many countries and were conducted by both Protestants and Catholics, and in both secular and religious courts. Perhaps a million women were killed across Europe after being accused of witchcraft, and most of them died during this period. Why?

Historian Wolfgang Behringer has one possible explanation: Temperatures dropped sharply around the time that the trials gained in popularity. The "little ice age," in which average temperatures fell by about 1 degree Celsius, was enough to freeze the Thames River on many occasions.

Emily Oster, an economist at the University of Chicago, has tried to gather systematic data on the link between witch trials and the weather. The results look striking: Between 1520 and 1770, colder decades go hand-in-hand with more trials. The link may be simply that witches were often blamed for bad weather. Or there may be a less direct link: People tend to lash out in tough times. There is some evidence, for instance, that lynching was more common in the American South when land prices and cotton prices were depressed.

I tend to be cynical and facetious, so I'm sitting here puzzling about just which meteorological phenomenon is responsible for the American financial meltdown. Could it be La Niña causing the current financial turmoil? Since I'm a climate warming agnostic, I'm not willing to believe that we are throwing banking corporations onto the pyre because the last few summers have been hot in places (actually, 2007 and 2008 have been cooler than the blistering years of the late 1990s). Oh well, I guess I'll just continue to puzzle over this.