Possible Connection Found Between Black Death and Unexplained Volcanic Activity

The devastating Black Death, which wiped out up to half of Europes population within a few years, could have been intensified by a previously unknown volcanic eruption. This theory was presented in a study published on December 4 in Communications Earth & Environment, suggesting the eruption caused several years of unstable climate and crop shortages.

The resulting agricultural crisis pushed several Italian states to source grain from regions around the Black Sea. Researchers propose that fleas carrying Yersinia pestis, the bacterium responsible for the plague, traveled along with these imported grains, introducing the disease to Europe.

Martin Bauch, a historian specializing in medieval and environmental studies at Germanys Leibniz Institute for the History and Culture of Eastern Europe, noticed a severe crop failure in northwestern Italy starting in late 1345 after heavy rains. Within two years, the Black Death emerged, prompting him to investigate a potential link.

Records of grain trade indicate that some Italian cities had depleted local food reserves, forcing them to import grain from the Black Sea area. While this ensured food supply, it may have inadvertently carried the plague, Bauch and his co-author suggest.

The team examined European tree-ring data to track temperature fluctuations in the century before the Black Death, corroborating historic reports of abnormal rainfall. They also analyzed polar ice core studies for volcanic sulfur deposits, which can affect global climate and rainfall patterns. A notable eruption in 1345 stood out, though its location and origin remain unknown. The researchers suspect it occurred near the equator, as its traces appear in ice cores from both poles, but identifying the volcano will require further research.

Previously, historians believed the plague reached Italy via sailors fleeing conflicts in the east, but this theory has lost credibility. Evidence now shows the disease circulated in Asia decades before reaching Europe, setting the stage for the pandemic. According to Monica Green, a historian of medicine, these conditions depended on multiple prior events.

Even without pinpointing the exact eruption, the study presents a compelling link between climate disruption and the spread of plague. Henry Fell, a disease ecologist at the University of Nottingham and University of York, notes that while climates role in the Black Death is often discussed, the exact mechanisms connecting it to the plague are complex due to interactions among humans, fleas, bacteria, and rodents.

The research emphasizes that understanding the Black Death remains incomplete. Its relevance persists today, as plague still exists in some regions and the COVID-19 pandemic has highlighted the global consequences of infectious outbreaks. Green underscores the importance of studying pandemics to better prepare for future health crises.

Author: Zoe Harrison