Overview
- Polar ice cores record a major sulfur spike in 1345 — the 18th strongest in two millennia — indicating a large tropical eruption that likely cooled the climate for several years.
- Tree‑ring analyses, including rare consecutive ‘blue rings,’ and contemporary accounts of dim skies and dark lunar eclipses point to unusually cold, wet summers from 1345 to 1347 and widespread crop failures.
- Facing shortages, Venice, Genoa and Pisa imported grain from the Golden Horde in 1347, and the study links those shipments to the earliest plague outbreaks in ports such as Messina, Genoa, Venice, Pisa and beyond.
- The research, published Dec. 4 in Communications Earth & Environment by teams at the University of Cambridge and GWZO, outlines a testable climate‑famine‑trade pathway but does not identify a specific volcano or prove direct causation.
- The hypothesis complements prior genetic evidence of a Central Asian origin for Yersinia pestis and underscores how climate shocks interacting with global trade can heighten zoonotic pandemic risks.