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The year 536 CE -

Harvard historian Michael McCormick has dedicated himself to researching the year 536 in order to discover what caused the worldwide disaster described in many historical records.

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A monumental eruption -

With the help of other historians, scientists, and in particular, volcanologists, he concluded that a colossal volcanic eruption led to a global climate catastrophe. It was the biggest volcanic eruption to occur in the last 1,500 years.

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The culprit -

Scientists theorize that a volcano in Iceland was to blame, but it may also have been the infamous Krakatoa. Another expert on the subject says that the size of the eruption could be equated to 2,000 million Hiroshima-sized nuclear bombs.

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Global change at every level -

This unprecedented natural disaster plunged the world into literal darkness, causing a chain of events that would alter human history over the following century.

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Spewing ash into the atmosphere -

Volcanologists used all the available data to create a simulation of the volcanic eruption. They estimated that a massive explosion would have created a 30-mile (48-kilometer) high fountain of magma, dust, and ash.

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The spreading cloud -

The ash traveled out as far as 1,000 miles (1,600 kilometers) from the site of the eruption and began to rain down. The gushes of ash and debris were so copious that they completely blocked out the sun.

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Hanging in suspense -

The volcanic ash created by an eruption is often so fine that it is supported by even the slightest breeze. This means that it can stay suspended in the air for long periods of time.

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Traveling far and wide - A cloud of ash and sulfur dioxide from the volcano would have filled the skies across Asia, Europe, and the Middle East, casting much of the world into endless darkness. It’s estimated that this lasted for 18 months.

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Volcanic winter -

The effect was similar to that of a nuclear winter. In fact, this climate change event is referred to as the volcanic winter of 536. One Byzantine historian wrote that "the sun gave forth its light without brightness, like the moon, during the whole year."

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Drought and famine -

This blocking of the sun caused temperatures to drop. The oceans no longer evaporated under the heat of the sun, which meant the atmosphere became drier. This led to reduced rainfall, causing droughts and famines.

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Temperatures dropped -

The summer following the eruption was the coldest in 2,300 years. Temperatures in Europe dropped by 36°F (2°C) and it even snowed in China.

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The Little Ice Age -

The effects on the climate would last for more than a century, until 660 in Europe and 680 in Central Asia. This period in history has been called the Late Antique Little Ice Age.

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What happened next? -

The conditions outlined by today’s historians and scientists are terrifying, even with a full understanding of the volcanic eruption and its after-effects. But how did the people of 536 react?

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A world shrouded in darkness -

The Roman politician Cassiodorus wrote about the sudden change to the world: ”We marvel to see no shadows of our bodies at noon.” He described the sense that all the seasons had been jumbled together.

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Disastrous consequences - The knock-on effects of the darkness and subsequent climate change were catastrophic. A historian from that period wrote that, during the volcanic winter of 536, “men were free neither from war nor pestilence nor any other thing leading to death.” However, the hardship did not end when the sky eventually cleared.

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Further eruptions -

The decade that followed the first eruption was the coldest on record in 2,000 years. This caused crops to fail in Ireland, Scandinavia, Mesopotamia, and China. Unfortunately, the volcano would erupt twice more, in 540 and 547, massively prolonging the impact.

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The bubonic plague -

In 541, while Europe was already starving and struggling with crop failures and economic stagnation, the first recorded outbreak of bubonic plague occurred.

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Plague and climate change -

This might seem like bad luck, but scientists now know that outbreaks of plague are linked to changes in the climate. A drop in temperature directly affects how the plague bacterium forms and spreads.

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Countless dead -

The disease reportedly originated in Central Africa and was brought via merchant ships up the coast to Alexandria (modern-day Egypt) and to the heart of the Eastern Roman Empire. In the capital of Constantinople (modern-day Istanbul) there were 10,000 newly dead bodies to be disposed of every day. There were so many dead that they simply stopped counting. Residents fled the city and spread the disease throughout the empire. It’s not known how many millions died, but it’s estimated that 35%-55% of the population perished.

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An empire brought to its knees -

The Roman Empire under Emperor Justinian had been thriving up until this point, but was decimated by economic collapse and sickness. It was at this inopportune moment in history that they came under attack.

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Enter the Avars -

The Avars of Central Asia were a nomadic people who traveled and fought on horseback. They preceded the likes of Genghis Khan and were described by the Chinese as being barbaric, violent, and ruthless.

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Migrating west -

Within a decade of the plague's arrival, the Avars migrated from Central Asia to the fringes of the Roman Empire. Historians theorize that this sudden move was another result of the climate disaster. The survival of the Avars was based on the survival of their horses, but the reduced quality of the vegetation in Asia during this period was not sufficient to keep their horses alive. 

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Siege and blackmail -

They relocated to the west and became a major threat to the Roman Empire. Their ruthless military abilities allowed them to dominate every settlement they came across, growing closer and closer to Constantinople. They besieged the city but blackmailed their opponents into giving them gold to avoid an all-out war. They repeated this tactic over 50 years and drained an estimated US$8.3 billion worth of gold from the Roman Empire.

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Destabilization -

The plague, the economic problems that followed, and the financial drain of the Avars completely destabilized the empire.

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Troubles elsewhere -

Meanwhile, on the other side of the world, the population of the Mexican city of Teotihuacan was also suffering from the fallout of the eruption. Archaeologists have found a disproportionate number of bones of young people, particularly babies, from the mid- to late 6th century CE, suggesting that something was seriously wrong. 

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Teotihuacan -

This means that the population went into crisis almost immediately after the climatic disaster. Scientific evidence shows that there was a 30-year-long drought starting in the mid-5th century, and a massive reduction in tree growth. Historians have concluded that Teotihuacan was decimated by drought and famine as a direct consequence of the volcano eruption.

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The collapse of Teotihuacan -

There is also evidence to suggest that there was an uprising against the ruling class in Teotihuacan, quite possibly in response to the suffering of the lower classes during the period of famine, which caused the city to collapse. It would be 300 years before a new civilization established itself in Central Mexico.

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Meanwhile, in Britain... -

Around the time of the eruption, Britain was deep in the Dark Ages. The Romans had left England a century earlier, and according to legends, the great King Arthur had recently died, leaving the country in a state of disarray. The tales of King Arthur describe a period of famine in which crops wouldn’t grow and Britain was shrouded in darkness. 

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The defeat of the Celts -

What’s more, the bubonic plague reached the British Isles around 547 CE. Britain was divided into two nations at the time—the west was occupied by the Celtic Britons and the east by the Anglo-Saxons. The two halves had very little contact with each other. The Celts traded with the Roman Empire, which meant that they were the first to contract the plague and were hit much harder. This allowed the Anglo-Saxons to take over territory previously held by Celtic people who had been wiped out by the plague.

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An eruption that change human history -

These are just a few examples of how the terrible climatic change of 536 CE devastated the world through drought, famine, plague, war, and economic collapse. It’s difficult to imagine just how different human history might have been without this far-reaching natural disaster.

Sources: (Science) (History) (YouTube)

See also: What to do if a worst-case nuclear scenario actually happens

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