A significant volcanic eruption may have played a crucial role in the spread of the Black Death across Europe in the 1340s. Researchers have presented compelling evidence suggesting that a climate crisis induced by volcanic activity contributed to the conditions that facilitated the transmission of plague pathogens at a critical moment in history.
The Black Death, which peaked in the mid-14th century, is one of history’s most catastrophic events, resulting in the deaths of tens of millions globally. Caused by the bacterium Yersinia pestis and spread by fleas, the disease could lead to death within a day in its most severe forms. While much about its origins and spread remains uncertain, recent analysis supports the theory that the second plague pandemic re-emerged from outside Europe, specifically from regions such as Kyrgyzstan along established trade routes.
In a study conducted by historian Martin Bauch from the Leibniz Institute for the History and Culture of Eastern Europe and paleontologist Ulf Büntgen from the University of Cambridge, researchers examined various sources, including ice cores from Antarctica and Greenland, tree ring data from eight European regions, and historical weather accounts from the 14th century. Their findings indicate that a volcanic eruption occurred around 1345 CE, leading to significant climatic changes.
Ice core samples from that period revealed a substantial increase in sulfur levels, marking one of the 18th largest spikes in the past 2,000 years. This spike aligns with evidence of a major volcanic eruption, contributing to a dramatic cooling of the climate. The researchers also noted that tree ring data from 1345 to 1347 indicated unusually cold summers, particularly around the Mediterranean, further corroborating the volcanic influence.
Accounts from Europe and Asia during this time describe weather anomalies consistent with volcanic activity, including cold, wet summers and subsequent crop failures. An unidentified tropical volcano likely erupted in 1345, triggering a chain of events that led to famine in regions such as Spain, southern France, and northern Italy, where grain prices surged.
The Black Death reached Italy in 1347, coinciding with Venice’s decision to lift its trade embargo on the Golden Horde. This allowed grain shipments from the Black Sea to flow into Italian ports, including Messina, Genoa, and Pisa, which became the first European locations to report outbreaks of plague. The research indicates that fleas carrying Yersinia pestis could have thrived on these grain vessels, facilitating the spread of the disease throughout Europe.
Maps illustrating the dispersal of the plague indicate its movement from Mediterranean grain ports northward into the English Channel and the North Sea, eventually reaching the coasts of England and Norway via established maritime routes.
The comprehensive nature of this research highlights how climate proxy data and historical documentation can piece together a clearer understanding of the events that led to one of the largest mortality crises in pre-modern history.
The study concludes that the volcanic eruption, or a series of eruptions around 1345 CE, contributed to the cold and wet climate conditions experienced across southern Europe between 1345 and 1347. These climatic disruptions forced Italian maritime republics to seek alternative grain sources, which inadvertently facilitated the spread of the plague. As the researchers state, “This unusual change in long-distance maritime grain trade prevented large parts of Italy from starvation and distributed the plague bacterium Yersinia pestis via infected fleas in grain cargo across much of the Mediterranean basin.”
The findings of this research have been published in the journal Communications Earth & Environment, marking a significant advancement in our understanding of how environmental factors can influence historical events and human health.
