Overview
- Peer‑reviewed research published Dec. 4, 2025 in Communications Earth & Environment by Ulf Büntgen (University of Cambridge) and Martin Bauch (Leibniz Institute/GWZO) outlines the proposed climate–trade pathway.
- Polar ice cores from Greenland and Antarctica show a pronounced sulfate spike around 1345, ranked the 18th largest in two millennia, consistent with a major tropical eruption.
- Tree‑ring records, including distinctive ‘blue rings,’ indicate unusually cold, wet summers from 1345 to 1347 across southern Europe, matching contemporary reports of hazy skies and failed harvests.
- Facing famine, Italian maritime republics including Venice, Genoa and Pisa imported Black Sea grain in 1347, with early plague outbreaks documented in ports such as Messina, Genoa, Venice, Pisa and Palma.
- The specific volcano is not identified and causation is inferred from converging proxies and records, but the study underscores how climate shocks can heighten zoonotic risk via trade networks.