Some historians say AD 536 was the worst year to live in Europe. An extreme winter, famine, the first outbreak of the plague, wars and mass migration. All these crises may have had a common cause: two gigantic volcanic eruptions that sent Europe and Asia into a small ice age.
Sanne de Jong (Radboud University Nijmegen) conducted research into the consequences of climate change on ancient Mediterranean society on the basis of 6th-century texts and geological data. For that research, De Jong won de Volkskrant-IISH thesis prize, an annual prize for theses of master’s students in history.
Why an investigation into extreme disaster?
‘It may sound crazy, but natural disasters have always fascinated me, especially volcanic eruptions. The inspiration for this particular topic came from an influential scientific paper about a volcanic eruption in AD 536 that had been so massive that the ash cloud blocked the sun, causing extreme cold and starvation in Europe. That combination of volcanic eruption and history was exactly what I was looking for. The historical knowledge already existed, as did the geological data, but they were not yet connected. By doing that, I wanted to get a more complete picture of that period.’
How can volcanic eruptions lead to famine and war, and on such a large scale?
‘The principle is simple: during a volcanic eruption, ash particles are released into the air, where they sometimes do not easily escape. There they form a kind of screen that blocks the sunlight, causing the earth’s surface to cool down. The more intense the eruption, the more intense and longer lasting this effect.
The high amount of ash particles found in glacial ice that formed in the 6th century shows that the eruptions of 536 and 540 may have been the largest ever. As a result, the cold lasted a long time. Intense frost, crop failure, and famine followed.
‘In my research I also looked at the long-term consequences of the ash cloud. First, the immune systems of the peoples beneath the ash cloud may have been compromised by famine and lack of sunlight. That may have contributed to the outbreak of the first plague epidemic. Furthermore, we can also link the origin of the wars in those decades to cold, hunger and migration caused by the ash cloud.
‘I immediately recognize the speculative aspect of my research. I’m certainly not saying that war and disease were caused by the ash cloud, but I think the sources do indicate that the ash cloud played a role in catalyzing those events.”
What exactly do those sources say?
‘My research is built on the connection of geological data and historical sources. The geological data, for example, came from previously mentioned glacier samples, which record a past climate in the ice. In addition, the analysis of tree rings also speaks volumes about the temperature in the 6th century. For example, a tree ring, corresponding to the year 537, is deformed because the tree sap froze due to the cold weather.
‘In addition to geological material, I have collected many texts from the Mediterranean region in the 530s, which repeatedly describe cold, hunger, disease and war. For example, a certain Procopius wrote about 537 that ‘the rays of the sun lacked any brightness’. They “shone like the moon for a whole year, as in an eclipse, and from that moment on man was besieged with war, plague, and everything else that brings death.”
‘I have read many of these passages, specific to that place and period, to get an idea of the frequency with which people of that time wrote about extreme cold and hunger. Those numbers peaked after 536 and 540, providing direct evidence of the severity of climate change at that time due to the volcanic eruptions.’
An epidemic, war, climate change, it won’t get much more topical than that. Was that a reason for you to pick up this topic?
‘Hell yes. More and more attention is being paid to the influence of climate on the course of history. Without that dimension, it seems as if man has all the power in his hands, but in reality, of course, that is not the case. This research is about how fragile humans are, and how strong nature is. I think we can use history to see that we need to be prepared for the next disaster.”
