Researchers say a major volcanic eruption in 1345 caused climate cooling and crop failures in the Mediterranean. This event forced key port cities like Venice and Genoa to import grain via new trade routes with Central Asia's Golden Horde. These routes likely carried Yersinia pestis, the bacterium causing the Black Death, into Europe. The study, published in Communications Earth & Environment, combines historical data with ice core and tree ring analysis. Martin Bauch from the Leibniz Institute, Germany, and Ulf Büntgen from Cambridge University say that the eruption released ash and sulfur, leading to famine and new trade links. Bauch explains, "You couldn’t — from a 14th century perspective — calculate and expect this to happen — the same system which successfully saves you from starvation, will lead to their mass death if the Black Death reaches your city." The Black Death struck Europe between 1347 and 1351, caused by the bacterium Yersinia pestis. It spread through fleas on rodents, causing bubonic plague with swollen lymph nodes and fever. Pneumonic plague, an even deadlier form, spread faster through infected lungs. Previous research traced the plague's origin to the Tian Shan mountains in Central Asia. By linking climate events to historical trade records, the study shows how environmental changes helped spread the deadly disease. Paleoclimatic tools like tree rings provide key insights into ancient weather and its effects. Maria Spyrou, who identified the plague’s origin in 2022, says the study supports a mid-14th century start of the pandemic and aligns with genetic evidence. However, the exact disease path within Central Asia remains unclear. The study highlights one way plague entered Europe but acknowledges other routes may also have contributed.