New research suggests that the devastating spread of the Black Death across medieval Europe may have been triggered by a significant volcanic eruption. This historical pandemic, which decimated the population by killing between a third and half of Europeans in the mid-14th century, has long puzzled historians regarding its origins.
Scientists from Cambridge and Germany have uncovered compelling evidence linking a volcanic event to the onset of the plague. They studied sooty particles trapped in the ice sheets of Antarctica and Greenland that indicate at least one massive eruption occurred around 1345 in an unknown tropical location. This eruption would have released a vast amount of ash and sulphur into the atmosphere, creating a thick haze that affected global climate.
Corroborated by contemporary historical accounts detailing unusually cloudy skies and dark lunar eclipses, the findings are published in the journal Communications Earth & Environment. Additional analysis of tree rings from this period reveals three years of stunted tree growth, aligning with the idea that the volcanic haze led to cooler and wetter conditions—factors which likely resulted in widespread crop failures.
Dr. Martin Bauch, a historian specializing in medieval climate and epidemiology, emphasized that the resulting famine was a critical precursor to the pandemic. He noted that unusual weather patterns impacted regions from England to the Mediterranean, suggesting that the climatic effects of the eruption lasted several years.
As a result of the food shortage, cities like Venice, Genoa, and Pisa sought grain from the Mongols in 1347, which inadvertently brought infected fleas aboard ships. These fleas, carrying the bacterium Yersinia pestis, likely originated from wild gerbils in central Asia. Once in Italy, the fleas quickly transferred to rats, enabling the swift spread of the plague throughout Europe.
Dr. Bauch pointed out that these powerful Italian city-states had established extensive trade routes, allowing them to avert starvation, but ultimately contributed to a far greater disaster.
Furthermore, Professor Ulf Buentgen from Cambridge’s Department of Geography warned that the convergence of climatic, agricultural, social, and economic factors leading to the Black Death exemplifies early consequences of globalization. He noted that while such a rare combination of conditions may seem unusual, the risk of zoonotic diseases—those that jump from animals to humans—emerging under climate change is likely to rise in a globalized society, especially in light of recent experiences with pandemics like COVID-19.
This research sheds new light on the historical pandemic, connecting environmental science with the complex tapestry of history and suggesting that the events of the past continue to resonate in today’s global landscape.