Volcanic eruption may have catalyzed the plague's arrival in Europe: study

A study suggests that a volcanic eruption around 1345 cooled the climate, leading to crop failures. On the ships that carried grain to fill the gap came plague-carrying fleas.

When the Black Death swept through Europe beginning in 1347, the plague wiped out more than half of the continent’s population, upending societies and interrupting wars.

New research suggests that a volcanic eruption or multiple eruptions, unknown to Europe’s inhabitants, most likely catalyzed the pandemic’s arrival on the continent’s shores.

The theory, described in a study published Thursday in the journal Communications Earth & Environment, suggests the eruptions set off a series of events that enabled the fleas that spread the plague to proliferate in Europe.

The eruptions dimmed global temperatures for a few years, causing a sudden climate shift that affected harvests in Europe. With crops failing and fears of starvation rising, some wealthy Italian city-states like Florence and Venice imported grain from elsewhere in the world. And on those ships most likely came plague-infected fleas.

The actions of Florence’s leaders prevented mass starvation — tens of thousands of famine refugees migrated there, and the city was able to feed them in addition to its own citizens. But the imports unwittingly ushered in a pandemic.