Study suggests that a volcanic eruption may have triggered the arrival of the plague in Europe

The Black Death, which struck Europe in 1347, decimated more than half of the continents population, disrupting societies and halting ongoing conflicts. Recent research indicates that volcanic eruptions, unknown to Europeans at the time, could have played a crucial role in accelerating the arrival of the plague.

The study, published in Communications Earth & Environment, proposes that the eruptions created environmental conditions favorable for the spread of plague-carrying fleas. The eruptions caused a temporary drop in global temperatures, leading to crop failures across Europe. Facing the threat of famine, some Italian city-states, including Florence and Venice, imported grain from distant regions, unintentionally bringing plague-infected fleas with it.

City leaders successfully averted mass starvation by feeding both their citizens and thousands of migrants, but this effort inadvertently introduced the pandemic. They could not have imagined the hidden danger, said Martin Bauch, a medieval historian involved in the study.

The research highlights the complex ways climate change can affect human societies and animal populations. While the origins and spread of the Black Death have been debated for decades, this study is the first to clearly link a volcanic eruption to the pandemics onset. Previous studies noted climate influences but often lacked specificity, explained Henry Fell, a postdoctoral researcher in England.

Volcanic eruptions can lower global temperatures by releasing sulfur into the stratosphere, which reduces sunlight reaching the Earth. Evidence for eruptions around 1345 comes from tree rings, ice cores, and historical records, all indicating a period of cooling and famine in the Mediterranean region that coincided with the plagues arrival. Ice core analysis showed an exceptionally strong sulfur signal, surpassing the Mount Pinatubo eruption of 1991, while tree rings displayed rare blue rings signaling extreme stress. Written accounts from China, Japan, Germany, France, and Italy described diminished sunshine and increased cloudiness.

Although the exact volcano responsible remains unknown, researchers deduced it was likely tropical, based on similar sulfate levels in both polar ice cores. Historical documents report widespread crop failures and soaring wheat prices, with severe famine across Spain, southern France, Italy, Egypt, and the eastern Mediterranean.

Italian city-states, with established grain reserves and trade networks, eventually imported grain from the Black Sea. Unaware of the plagues presence, they unintentionally facilitated its introduction to Europe. Bauch noted that while the Black Death might have reached Europe eventually, the eruptions likely accelerated its arrival.

Between 1347 and 1353, up to 60% of Europes population perished, making it one of the deadliest periods in human history. Previous research traced plague origins using written accounts, archaeology, and DNA evidence. In 2022, scientists identified Yersinia pestis, the bacterium causing plague, in bodies from modern-day Kyrgyzstan dating to 13381339. Marmots in the Tian Shan mountains carry a related strain, suggesting a possible initial emergence of the Black Death in that region.

Fell commented that the study convincingly links volcanic activity to the plague, providing insight into how environmental factors reshaped human history. The Black Death reappeared in Europe for centuries, leaving an enduring impact on society.

Author: Ava Mitchell