Consider the drought that hit central Europe in AD 69. The Roman historian Tacitus remains our best source on this catastrophe. He wrote that the legions sent to deal with wayward German tribes that year were in a “bad mood” because “the Rhine [was] barely navigable due to an unprecedented drought in this climate. This explained the other grievances of the soldiers: “lack of pay and food”.
Tacitus reported that the superstitious Germans “interpreted the scarcity of water” as proof that “the very rivers, those ancient safeguards of the Empire, were abandoning us” because of “the wrath of the God of the Rhine” towards the Romans. .
And judging by what happened in Rome in AD 69, the Rhine God was indeed angry. It was the infamous “Year of the Four Emperors”, when malnourished legions joined in a civil war between the various factions vying for supremacy in Rome. Soldiers in Germania cast their spell with a portly suitor named Vitellius, who was eventually overthrown after a bloody battle. Vitellius is dead, as are tens of thousands of civilians and soldiers.
The relationship between bad weather and mutinous soldiers was not limited to this particular episode. In 2018, an economic historian compared weather data in ancient Rome with the assassination of Roman emperors. He found a strong statistical correlation between droughts in the northern border provinces and the assassinations of emperors in Rome. Beware Imperator!
Other studies of climate in ancient Rome have suggested tantalizing, if speculative, links between drought-induced famine and later epidemics, such as the Plague of Justinian. Bad weather may have sown the seeds of famine, leaving behind a population vulnerable to predators of a new pathogen.
The hypothesis that extreme weather conditions can pave the way for pandemics has also been invoked to explain the severity of the Black Death. In the 1330s, freak weather events left Europe devastated and undernourished. Different groups of researchers have argued that the resulting crop failures made the region’s population particularly vulnerable to Yersinia pestis, the bacterium that ravaged the region from 1341.
A little over a century later, another episode of extreme weather generated entirely different problems. After several years of brutal heat in the early 1470s – what a Belgian chronicler called “an unprecedented and abnormal drought [that] afflicted the whole world” – rivers dried up, crops failed and many people went mad. In Spain, political leaders blamed “conversos” – Jews who had converted to Christianity – for bad weather and burned them at the stake. It was neither the first nor the last time bad weather spawned anti-Semitism.
What was arguably the worst “mega-drought” of the last millennium happened in the following century, in the summer of 1540. Rivers, springs and wells dried up. Lake Constance, one of the deepest and largest lakes in Europe, lost so much water that people walked to the former islands.
The temperatures must have been atrocious. In France, city dwellers crowded into cellars shortly after sunrise, hoping to escape the heat. A French chronicler noted that the wine grapes were “roasted and the leaves of the vines had fallen to the ground as after a heavy frost”. A Swiss account from late July 1540 reports that it was “unbearably hot [with] everyone complains about the lack of water. Forests were burning all around.
Buildings also caught fire. Thanks to meticulous record-keeping by the Germans, we know that 1540 enjoys the dubious distinction of witnessing more fires in cities than any other peacetime year since AD 1000. Judging by anecdotal evidence in other countries, Germany was not alone.
The fires gave the sky a gruesome glow, with many observers reporting that the sun and moon were shrouded in a blood-red aura. Although many centuries have passed since the time of Tacitus, Germans and other Europeans have greeted these signs with a similar superstition, viewing them as harbingers of evil. Many people were quickly convinced that hordes of murderous arsonists – “Mordenbrunner” – were setting the fires.
A search for suspects followed. In some places, Protestants pointed the finger at Catholics, suspecting papal intrigue in deadly fires. Elsewhere, local authorities arrested more conventional scapegoats: vagrants, beggars and strangers – basically anyone who didn’t belong. In classic late medieval style, authorities tortured suspects to extract “confessions” of perfidy.
The incessant fires, blood red skies, scorching heat, crop failures and collective paranoia conspired to make the peasants terribly surly. Fortunately, such brutal conditions did not return until 1921.
Climate change has ushered in a new era. Starting in 2003, Europe suffered a number of crushing heat waves and droughts, with 2022 arguably the worst on record. Historical records tell us to be careful: extreme weather, whatever the cause, leaves chaos in its wake. It really is a very cold comfort.
More writers at Bloomberg Opinion:
• Help cities around the world prepare for extreme heat: editors
• The Summer of Our Discontent: David Fickling
• Biden’s new climate law is about to meet a fierce enemy: Eduardo Porter
(1) There were benefits. When winemakers squeezed the desiccated fruit, they ended up with a potent drink closer to sherry than regular wine. Apparently people got drunk quickly. There was a lot of rejoicing.
This column does not necessarily reflect the opinion of the Editorial Board or of Bloomberg LP and its owners.
Stephen Mihm, professor of history at the University of Georgia, is co-author of “Crisis Economics: A Crash Course in the Future of Finance”.
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