The Black Death — one of the deadliest pandemics in human history, estimated to have killed up to half of Europe’s population — might have been set in motion by a volcanic eruption, a new study suggests.By looking at tree rings from across Europe to better understand 14th century climate, checking data against ice core samples from Antarctica and Greenland, and analyzing historical documents, researchers have constructed a “perfect storm” scenario that could explain the origin of the historic tragedy. They reported their findings Thursday in the journal Communications Earth & Environment.The study authors believe an eruption occurred around 1345, about two years before the start of the pandemic, from either a single volcano or a cluster of volcanoes of unknown location, likely in the tropics. The resulting haze from volcanic ash would have partially blocked sunlight across the Mediterranean region over multiple years, causing temperatures to drop and crops to fail.AdvertisementAdvertisementAdvertisementAdvertisementAn ensuing grain shortage threatened to spark a famine or civil unrest, so Italian city-states, such as Venice and Genoa, resorted to emergency imports from the Black Sea region, which helped keep the population fed.However, ships that carried the grain were loaded with a deadly bacterium: Yersinia pestis. The pathogen, originating from wild rodent populations in Central Asia, went on to cause the plague that devastated Europe.“The plague bacterium infects rat fleas, which seek out their preferred hosts — rats and other rodents. Once these hosts have died from the disease, the fleas turn to alternative mammals, including humans,” said study coauthor Martin Bauch, a historian of medieval climate and epidemiology from the Leibniz Institute for the History and Culture of Eastern Europe in Germany.The bubonic plague was the most common type of plague during the Black Death, and it manifested with buboes, or swollen lymph nodes. – Pictures from History/Universal Images Group/Getty Images“Rat fleas are drawn to grain stores and can survive for months on grain dust as an emergency food source, enabling them to endure the long voyage from the Black Sea to Italy,” Bauch added. “After arriv …
