Throughout history, medieval monks have played an integral part in recording and understanding the world around them. From writing and learning scriptures to pioneering scientific discoveries, their roles have been as varied as they have been important. One such notable example are the volcanologists of the middle ages; their observations and records providing valuable insight into this powerful and dynamic force of nature.
How did they do it? By observing the night sky. Thus they unknowingly recorded some of the largest volcanic eruptions in history. A study published in the journal ‘Nature’ talks about the medieval monk volcanologists.
The research is led by the University of Geneva (UNIGE). It was based on European and Near Eastern chronicles from the 12th and 13th centuries. They accurately dated some of the largest volcanic eruptions ever seen.
It all started by observing the Moon. It remains visible as a reddish orb because it is still bathed in sunlight that its atmosphere deflects around the Earth. What happens after a very large volcanic eruption? The eclipsed Moon almost disappears.
The monks paid special attention to the coloring of the moon. Of 64 lunar eclipses between 1100 and 1300, they faithfully documented 51. In five of these cases, they also documented the coloration of the moon. And that the moon was exceptionally dark.
Sébastien Guillet is a researcher at UNIGE. He noticed something about eclipses. “All the darkest lunar eclipses occur one year after large volcanic eruptions,” he recalls in a statement. “Large volcanic eruptions not only made the Moon disappear. They also cooled summer temperatures by limiting the sunlight reaching the Earth’s surface. This, in turn, could ruin agricultural crops,” he says.
Effects on climate
The interval from 1100 to 1300 is one of the most volcanically active periods in history. This is demonstrated by ice core cores. Fifteen eruptions were analyzed in the new study. One in the mid-1300s rivals the famous Tambora eruption of 1815, which caused “the year without a summer” of 1816. The collective effect of medieval eruptions on the Earth’s climate may have triggered the Little Ice Age. This was when winter ice fairs were held on the frozen rivers of Europe.
“We want to improve our knowledge of these otherwise mysterious eruptions. It is crucial to understand whether past volcanism affected the climate. And also society during the Middle Ages, and how it did so,” concludes the researcher. And the data from the medieval volcanologist monks, even unwittingly, help us in this goal.