This colder and wetter weather resulted in many crop failures. People were more vulnerable and insecure. People began to suspect that something evil was at play, and as reports spread, fear was often in the air.

All of this coincided with the climate event known as the Little Ice Age, peaking between 1560 and 1630 during a time known as the Grindelwald Fluctuation. Glaciers in Switzerland were expanding significantly. This period saw some of the lowest temperatures recorded in our current geological era.

The three witches in Shakespeare's 1606 play Macbeth show us an obvious example of the superstitions going around of women gathering to create weather disasters. "When shall we three meet again?" one of the witches asks. "In lighting, thunder, or in rain?"

Because of the widespread reporting of weather, people were suddenly aware of what weather was like over a longer period of time, which gave them a sense of a natural order. A big storm was therefore seen as "unnatural," and a witch was often to blame.

It's important to remember that magic very much existed for people in early modern Europe. But there was good and bad magic. Both altered the natural world and reordered it. Black magic involved things like the creation of storms or calamities, while tolerated magic warned about or stopped them.

In total, there were some 60,000 executions in Europe, and double that count for court prosecutions. The victims were accused of renouncing God and making a deal with the Devil. Stereotypes of them included destroying crops, killing infants, riding on brooms, all popularized by printing.

During this same period, there was a rise in persecutions of people who were accused of practicing witchcraft. This had been happening in Germany and Switzerland from the late 13th century, but now it was spreading outward from central Europe into places like Poland, England, and Scotland.

One of the most popular genres in the new age of printing was weather reporting, including almanacs and calendars. Johannes Kepler wrote in 1610 that no book sold as many copies as weather books.

To fully get this story, you have to first understand the monumental contribution of the printing press for the spread of ideas. Before, a single copy of a book would take years to produce, and so audiences were rather limited. Now, an author's work could be produced over and over again.

Tomorrow is #Halloween 🎃, which means it's the "Season of the Witch!" Here is a little bit about the relationship between environment and witchcraft in early modern Europe, because it tells us something really interesting about how we humans have thought about weather, climate, and disasters. 🧵