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2022 Study: Volcanic Eruptions Triggering the Black Death

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2022 Study: Volcanic Eruptions Triggering the Black Death

Clip title: How Volcanoes Caused The Black Death Author / channel: SciShow URL: https://www.youtube.com/watch?v=g8Chxr0xbFA

Summary

The video explores a compelling new theory suggesting that volcanic eruptions may have played a significant role in triggering the Black Death, a pandemic that devastated medieval Europe. While volcanoes are typically associated with direct destruction like lava flows and ashfall, scientists now propose that a series of volcanic events set off a domino effect leading to the widespread plague. The Black Death, caused by the bacterium Yersinia pestis, swept across Europe starting in 1347, killing an estimated 50 million people, or half the continent’s population. Although the bacterium was definitively identified in the 19th century and its strain traced to Kyrgyzstan, spreading via Asian trade routes to the Black Sea by the 1340s, the exact mechanisms behind its rapid and deadly spread into Western Europe remained unclear until recently.

A 2022 study, using a multidisciplinary approach combining climate data from tree rings and ice cores with historical written records, has provided a potential answer. Ice core records from Greenland and Antarctica revealed significant spikes in atmospheric sulfur dioxide, a key indicator of volcanic activity, in the years leading up to the pandemic. Specifically, a massive eruption in 1345, two years before the Black Death took hold in Europe, released an estimated 14 million tons of sulfur into the atmosphere—more than twice the amount ejected by the 1991 Mount Pinatubo eruption. This equatorial volcanic outburst would have caused a “volcanic winter,” scattering sunlight and significantly cooling the planet.

This volcanic cooling led to a period of exceptionally cold and wet summers across Europe between 1345 and 1347. Evidence from tree rings showed lower density wood and “blue rings” (indicating abnormal growth conditions due to cold), confirming these unfavorable growing seasons. The resulting poor harvests and widespread crop failures caused severe famine, particularly in heavily urbanized Italian city-states like Venice, Genoa, and Pisa, which relied on food imports. To stave off starvation, these cities were compelled to reopen crucial trade routes with Central Asia, specifically with the Mongols who controlled access to distant grain-producing regions.

Ironically, these very trade routes, reopened out of necessity, carried not only much-needed grain but also infected fleas (Yersinia pestis) from plague-ridden regions. Unbeknownst to the Europeans, who lacked understanding of disease transmission at the time, these fleas infested the grain shipments. Once unloaded in Italian ports, the infected fleas spread from rodents and domestic animals to the human population. The timing and locations of the first Black Death outbreaks in Europe closely mirrored the arrival of these grain ships. Thus, the catastrophic Black Death pandemic emerged from a “perfect storm” of natural climatic events, leading to socioeconomic disruptions and ultimately facilitating the rapid spread of the infectious bacterium through global trade networks. This historical event serves as a stark reminder of how interconnected global systems can lead to both progress and unforeseen calamities.

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Description

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Volcanoes have caused many devastating disasters over the years, but they’re not usually blamed for pandemics. Except that a team of researchers say a volcanic eruption may have caused the Black Death. Here’s how.

Hosted by: Hank Green (he/him)

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Sources: https://docs.google.com/document/d/e/2PACX-1vRS3JGVwcwdZvsSd6sWB9T9UKBg0DB13ZfiWrVg3QxED5TvhnMkj_S6-F09aDed343aYQa4yQPgAcXG/pub

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SciShow, science, Hank, Green, education, learn, complexly, hank green, How Volcanoes Caused The Black Death, black death, plague, bubonic plague, the bubonic plague explained, plague documentary, disease

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