Martin Bauch and Ulf Büntgen led research indicating that a series of massive volcanic eruptions in 1345 significantly contributed to the spread of the Black Death.The researchers from Germany and the UK analyzed ice core samples from Greenland and the Arctic, and tree rings from the Pyrenees Mountains to reconstruct the climate before the pandemic.Their findings in "Communications Earth & Environment" show that cold and wet summers during 1345-1347, caused by volcanic sulfur emissions, led to major atmospheric cooling.