20th Century's Deadliest Disasters
20th Century’s Deadliest Disasters

20th Century’s Deadliest Disasters

Khalid Elhassan - October 26, 2020

20th Century’s Deadliest Disasters
A marmot. CBS News

6. The Black Death’s Ebb and Flow Was Greatly Impacted by the Weather

Weather fluctuations in the fourteenth century played a key role in the Black Death’s recurrences. Yersinia pestis, thrives on fleas that are usually hosted by ground rodents such as marmots – which don’t mingle with humans. However, bouts of bad weather in the 1300s struck those rodents’ habitats and decimated their populations. So their plague-infected fleas fled to alternate hosts such as rats – which do thrive amidst human populations.

20th Century’s Deadliest Disasters
Bubonic plague victims. History

A tragic cycle developed, driven by weather fluctuations. Bad weather kills off the usual rodents – which don’t live amongst humans – that host the fleas that host Yersinia pestis. So the fleas flee to rodents like rats that live among humans. Then a Black Death outbreak ensues. While killing humans, the infected fleas also wipe out their rat hosts, extinguishing the plague. Ten or fifteen years later, bad weather again decimates the usual rodents that typically host the plague-infected fleas. The fleas flee to rats, whose populations by then have recovered. The rats reintroduce the flea plagues to humans, and another Black Death outbreak occurs, lasting until the rats die off.

20th Century’s Deadliest Disasters
Illustration from the medieval Liber Chronicarum, depicting skeletons rising from the grave for the dance of death. Live Science

5. People Eventually Adapted to the Tragic Consequences of History’s Greatest Plague

Take the experience of the world’s reaction to Covid-19, and multiply it many times over, to get an idea of how contemporaries felt about and reacted to the Black Death. The shock of a plague that wiped out up to two-thirds of the population – which is what the Black Death did – was great, to say the least. The economy contracted sharply, as trade came to a standstill, and wars came to a halt. However, people are adaptable, and adapt to the tragic just as they adapt to everything else.

Medieval people soon adjusted to the Black Death, grew accustomed to the plague, and took its frequent recurrences in stride. The immediate reaction to the first and deadliest wave was only temporary: the dead died, but life went on for the survivors. Within a few years, trade had resumed, the economy picked up, and the survivors went back to waging wars and settling their disputes and differences by killing each other.

20th Century’s Deadliest Disasters
Plague victims. Vox

4. The Tragic Events of the Black Death Shaped the World

The Black Death’s longer-term consequences revolved around the sudden impact of a significantly reduced population. In many parts of Europe, the land under cultivation shrank because many serfs and laborers had died. However, that often led to an increase in productivity in the land that was cultivated. With more land available than could be cultivated, people focused on cultivating the best agricultural lands, abandoning more marginal lands or turning them into pastures.

The shortage of labor was great new for surviving laborers. Faced with a labor scarcity, landowners and employers had to compete for workers by offering them better wages and working conditions. Those changes brought new fluidity to a stratified society. The land economy survived, but was weakened, as a new money economy – which ultimately replaced it – emerged. Psychologically, the shock of the Black Death caused more people to ask more questions to which the Catholic Church had few answers. That served to speed up and fuel the budding Renaissance. The world would never be the same.

20th Century’s Deadliest Disasters
Justinian. Ringling Museum

3. Before the Black Death, There Was Justinian’s Plague

The Black Death was history’s deadliest plague. Tragic and lethal as it was, Justinian’s Plague, 541 – 542 AD, gives it a run for its money in deadliness and long-lasting consequences. It was named after the Byzantine Emperor Justinian I, during whose reign it occurred – and who came down with it, but survived. Justinian’s Plague is history’s first known recorded pandemic, because it swept across three continents, Europe, Asia, and Africa.

Like the Black Death, Justinian’s Plague was caused by the Yersinia pestis bacterium. Also like the Black Death, Justinian’s Plague struck with a devastating initial outbreak, followed by several recurrences in succeeding years. By the time the last recurrence ended, Justinian’s Plague had killed an estimated 25 million to 100 million people.

20th Century’s Deadliest Disasters
The Silk Road helped spread Justinian’s Plague. YouTube

2. Black Rats Carried the Plague Across the World of Late Antiquity

The strain of Yersinia pestis bacterium responsible for Justinian’s Plague originated near Central Asia, near the border between modern China and Kyrgyzstan. Like the Black Death, Justinian’s Plague was mainly bubonic, felling its victims with all the bubonic plague’s tragic horrors. It first struck China and northern India, made its way via trade routes to the Great Lakes region of Africa, then down the Nile to Egypt.

20th Century’s Deadliest Disasters
A ship rat. Jaya Pest Control

Like the Black Death, Justinian’s Plague was transmitted by infected fleas carried by black rats. Egypt was the Byzantine Empire’s granary, and from its seaports, ships laden with grain – and also rats hosting infected fleas – sailed across the Mediterranean. From Egypt, the plague rapidly spread to the rest of the Middle East, the Eastern Mediterranean, and Constantinople, which served as both capital and commercial center for the Byzantine Empire. From Constantinople, the plague swiftly spread through the rest of Europe.

20th Century’s Deadliest Disasters
Plague victims. Brooklyn College Library

1. Justinian’s Plague Ended the Classical Age, and Kick Started the Feudal Era

Justinian’s Plague hit Europe hard: an estimated 40% to 50% of the continent’s population perished during the pandemic’s tragic course and aftermath. However, not all parts of Europe were equally hard-hit. The plague followed the established trade routes, so ports and cities got the worst of it. By contrast, the countryside and the parts of Europe of the established trade routes got off relatively lightly.

20th Century’s Deadliest Disasters
Justinian’s Plague. Art Station

That uneven death toll, heavy in the cities and relatively light in the countryside, transitioned Europe out of what was left of the Classical Age, and ushered in the Feudal Era. The Classical Age had been marked by a significant urban culture. Justinian’s Plague – on top of Justinian’s many wars – put paid to that, devastating the cities and an economy built around sustaining urban life. The center of power shifted from the cities to the countryside, and rural strongmen emerged as the founders of feudalism. One era and way of life ended, and another one began.


Where Did We Find This Stuff? Some Sources and Further Reading

Cantor, Norman F. – In the Wake of the Plague: The Black Death and the World it Made (2002)

Cracked – 6 Historical Tragedies That Were Way Worse Than You Thought

Crawford, Dorothy – Deadly Companions: How Microbes Shaped Our History (2018)

History Collection – Historic Disasters That Were Way Worse Than People Think

Devastating Disasters – Yellow River Flood, China, 1887 AD

Disaster History – Central China Flood, 1931

Encyclopedia Britannica – Huang He Floods

Encyclopedia Britannica – Tangshan Earthquake of 1976

History Collection – Unusual Historic Crises and Calamities

Facts and Details – Yellow River

Flood List – Central China Flood, 1931

Hurricane Science – 1839 Coringa Cyclone

Live Science – Mount Vesuvius & Pompeii: Facts & History

Live Science – What Was the Black Death?

History Collection – 16 Dreadful Details about the Black Plague

McNeil, William H. – Plagues and People (1976)

National Geographic, September, 2007 – Vesuvius, Asleep for Now

New York Times, September 15th, 1996 – China’s Endless Task to Stem Centuries of Floods

Rosen, William – Justinian’s Flea: Plague, Empire, and the Birth of Europe (2007)

History Collection – Seven Deadliest Plagues in History

Sigurosson, Haraldur, and Carey, Steven – The Eruption of Vesuvius in AD 79 (2002)

Time Magazine, October 15th, 1956 – Science: Man of Pompeii

Wikipedia – 1976 Tangshan Earthquake