Overview
- Ice cores from Greenland and Antarctica record a pronounced sulfate spike around 1345, ranked among the largest of the past 2,000 years and indicative of a tropical source.
- Tree-ring evidence, including rare consecutive 'blue rings' in the Spanish Pyrenees, shows unusually cold, wet summers from 1345 to 1347, echoed by reports of hazy skies and dark lunar eclipses.
- The cooling coincided with failed harvests and surging grain prices across the Mediterranean, prompting Venice, Genoa and Pisa in 1347 to import grain from the Golden Horde around the Black Sea.
- Researchers contend Black Sea grain cargoes likely carried Yersinia pestis–infected fleas that seeded initial European outbreaks in ports such as Messina, Genoa, Venice, Pisa and Palma.
- Published in Communications Earth & Environment, the study does not pinpoint the volcano and warns that climate shocks interacting with global trade can elevate zoonotic pandemic risks today.