Volcano eruption may have led to the Black Death coming to Europe

The Black Death, an outbreak of bubonic plague that killed up to 60 percent of the population of medieval Europe, may have been caused by volcanic activity around 1345.

Plague bacteria Yersinia pestisspread by fleas feeding on rodents and then transmitted to people bitten by infected fleas. It is unclear what led to the outbreak in Europe in the 14th century, but historical sources suggest that the transport of grain from the Black Sea to Italy may have played a role.

“The Black Death was a central event of the Middle Ages, and I wanted to understand why such an extraordinary amount of grain had to be brought to Italy in 1347,” says Martin Belli at the Institute of History and Culture of Eastern Europe. Leibniz in Germany.

To investigate, Bauch and his colleague Ulf Büntgen at the University of Cambridge analyzed climate data derived from tree ring data, ice cores and written records.

Observers in Japan, China, Germany, France, and Italy independently reported decreased sunshine and increased cloud cover between 1345 and 1349. It was likely the result of a sulfur-rich volcano erupting—or multiple eruptions—in an unknown tropical location, Bauch and Büntgen suggest.

Ice cores from Greenland and Antarctica, as well as thousands of tree-ring samples collected from eight different European regions, also suggest that a dramatic climate event may have occurred.

Moreover, researchers discovered official records showing that, faced with famine caused by cold weather and crop failure, Italian authorities implemented an emergency plan to import grain from the Mongols of the Golden Horde around the Sea of ​​Azov in 1347.

“They acted in a highly professional, rational and efficient manner and achieved their goal of mitigating high prices and impending famine by importing grain before starvation could occur,” Bauch says. “It was because these societies were excellent at preventing famine that the plague bacterium entered Italy as a stowaway carried along with the grain.”

At the time, the cause of the plague was not known, and the outbreak was blamed on things like “astral constellations and toxic fumes released into the atmosphere by earthquakes,” he says.

While the plague may have eventually reached Europe, the population loss may have been lower if the emergency had not occurred, Bauch says. “My argument is not against preparedness, but rather for recognizing that effective precautions in one area can create problems in unexpected areas.”

Aparna Lal from the Australian National University in Canberra say it is likely that a “perfect storm of factors” led to the Black Death reaching Europe. “Rising food prices, documented widespread hunger, and cold and wet weather may have reduced immunity due to poor nutrition and caused behavioral changes, such as spending more time indoors around other people for long periods of time,” she says.

However, she said more work will be needed to untangle causation and correlation. “Short-term disturbances caused by the eruptions appear to have had a significant impact on local weather patterns, as has been documented, but whether they were responsible for the entry of the Black Death into Europe, as claimed, requires further evidence,” says Lal.

Renaissance Science: Italy

Meet the great scientific minds and discoveries of the Renaissance that helped cement Italy's role at the forefront of scientific activity – from Brunelleschi and Botticelli to polymaths such as Leonardo da Vinci and Galileo Galilei.