1. The Toba Catastrophe and the Bottleneck Effect
Time frame: 75,000–67,000 BCE
The Toba catastrophe was an eruption of the supervolcano of the same name that occurred between 77,000 and 69,000 years ago in modern-day Indonesia. Although the exact date is unknown, studies of geological data and DNA of modern humans suggest that this event led to the death of most of the human population at that time.
Due to ash ejected by Toba, volcanic winter lasted about 10 years, leading to planetary cooling of approximately 3–5°C. It’s impossible to estimate the number of victims, but quite feasible to count the survivors. Africa’s inhabitants largely avoided the dangers, while residents of Europe and Asia bore the full brunt of the eruption’s consequences. Analysis of genetic data shows that the planet’s population declined to just 2,000–10,000 individuals.
Humanity essentially found itself on the brink of extinction—this is called the “bottleneck effect.” And we are all descendants of those few who managed to survive the Toba catastrophe. Most likely, this was the most dangerous period in human history, when our entire species literally looked death in the face.
2. The Bronze Age Collapse
Time frame: 1205–1150 BCE
The Bronze Age catastrophe was a series of significant social, economic, and political upheavals that occurred in various regions of Eurasia and the Mediterranean.
According to records from that period, certain barbaric “Sea Peoples” invaded the Mycenaean kingdoms, the Hittite kingdom in Anatolia and Syria, as well as the Egyptian Empire in Syria and Canaan. As a result, many civilizations and cultures collapsed. Trade connections were disrupted, the economy suffered, and an era of resource shortages and declining literacy began.
Many developed states either disintegrated or descended into barbarism. Mycenaean and Luwian scripts disappeared entirely. Cities from Troy to Gaza were almost completely destroyed by wars, marauders, and civil unrest. Many of them were never resettled.
Cambridge historian Robert Drews describes the Bronze Age Collapse as “perhaps the worst disaster in ancient history, even more catastrophic than the fall of the Western Roman Empire.” Shipbuilding, architecture, metalworking, water supply, textile arts, and painting rolled back many years and were revived only approximately 500 years later—during the late archaic period.
But every cloud has a silver lining: at least, thanks to this catastrophe, most peoples of Europe and Asia transitioned from bronze to iron.
3. Volcanic Winter and the Plague of Justinian
Time frame: 536–549 CE
Choosing the worst year in history is a difficult task because humanity has experienced many terrible periods throughout its existence. But according to Michael McCormick, a Harvard historian specializing in the Middle Ages, the year 536 fits best.
That’s when the first of three powerful volcanic eruptions occurred in Iceland, leading to the onset of the Late Antique Little Ice Age. Europe, the Middle East, and part of Asia plunged into darkness for a full 18 months. Procopius of Caesarea wrote: “The sun gave forth its light without brightness, like the moon, throughout this whole year, and it seemed exceedingly like the sun in eclipse.”
Due to eternal twilight, temperatures on the planet dropped by 1.5–2.5°C in the summer of 536, marking the beginning of the coldest decade in the last 2,300 years. Droughts and poor harvests occurred worldwide, and in China, snow fell in summer, leading to famine. Irish chronicles noted bread crop failures from 536 to 539.
And as if that weren’t enough, in 541, the first pandemic of bubonic plague struck the largest empires of the time—the Sasanian and Byzantine. The Byzantine emperor Justinian I became infected but managed to survive, which is why the disease received his name.
The plague swept across the entire Mediterranean, becoming one of the deadliest in history—it claimed the lives of more than 100 million people. Byzantium, for instance, lost half its population. Disease and bad weather led to political chaos and prolonged stagnation in Europe, continuing until 640. This period received the telling name “The Dark Ages.”
4. The Great Famine and the Black Death
Time frame: 1315–1353 CE
Life in medieval Europe was difficult in itself and full of various troubles. But in 1315, a special disaster occurred. Rain fell all spring and summer, and temperatures remained low, leading to massive crop failures. Straw and hay spoiled from moisture, so there wasn’t enough feed for livestock. In Lorraine, for example, wheat prices rose by 320%, making bread an unaffordable luxury not only for peasants but also for nobility. The Great Famine began.
The scale of the disaster was such that even King Edward II of England had to go hungry. According to Bristol city chronicles, in 1315, “the great famine was so terrible that the living barely sufficed to bury the dead. Horse and dog meat were considered delicacies.” In addition, wet weather adversely affected people’s health, and many suffered from pneumonia, bronchitis, and tuberculosis. The famine lasted, by some estimates, until 1322.
However, life in the Middle Ages became even harsher with the arrival of Khan Janibeg in 1346. His army brought with them other uninvited guests—plague bacteria. During the siege of the city of Caffa, the cunning khan devised a plan to catapult the corpses of his own soldiers who had died from plague over the fortress walls. An epidemic began in the city, and in panic, Genoese merchants who sailed away on their ships spread the infection throughout Europe.
Thus began the second plague pandemic in history after the Justinianic Plague. Its peak fell between 1346 and 1353, but isolated outbreaks of the disease continued to flare up until the 19th century. Called the “Black Death,” the disease became one of the most devastating events in human history. People became covered with ulcers and purulent abscesses the size of apples, all accompanied by terrible fever and vomiting, leading to inevitable and agonizing death.
The pandemic claimed the lives of about 200 million people in Europe and Asia and reduced the world’s population by 22%. It took more than 300 years to restore the previous population size.
5. The Little Ice Age and the Thirty Years’ War
Time frame: 1600–1648 CE
The year 1600 marked the beginning of one of the most unfavorable periods in history. On February 19, 1600, a powerful eruption of the Huaynaputina volcano in Peru occurred, which became the strongest in South America throughout the entire time of human presence on the continent. This event led to the beginning of the so-called Little Ice Age.
Global cooling caused serious consequences in many parts of the world. For example, summer temperatures in China significantly decreased, leading to crop failures and epidemics. As a result of such unfavorable conditions, the Ming Dynasty was overthrown in 1644, and the country found itself in a state of social and political crisis. And in Korea, drought in 1670 led to the death of 20% of the population.
Europe also experienced extremely cold summer periods, covering practically the entire century. Global temperatures there dropped by 1–2°C.
Greenland became covered with glaciers, and Norwegian settlements disappeared from the island. Even southern seas froze, allowing people to ride sleighs on the Thames and Danube. Between 1621 and 1669, the Bosphorus Strait froze over. And the Moscow River became a reliable platform for holding fairs.
Cold weather led to reduced crop yields, food shortages, hunger riots, and unrest. For example, in Ireland, civil war and famine claimed the lives of more than 500,000 people during the decade of the 1650s. Epidemics of infectious diseases began, aggravated by malnutrition and poor hygienic conditions.
And from 1618 to 1648, the Thirty Years’ War broke out in Europe, which was one of the most brutal religious conflicts in history. The struggle between Catholic and Protestant forces was accompanied by numerous battles, sieges, massacres, and devastation. It encompassed much of Europe, including present-day Germany, Austria, Czech Republic, Netherlands, and Denmark.
Climate catastrophe, famine, and wars, according to some estimates, led to the death of almost a third of the Earth’s population at that time.
6. Two World Wars and the Spanish Flu Pandemic
Time frame: 1914–1945 CE
The first half of the 20th century became an extremely bad time. In 1914, World War I began. Before it, the world had not seen such large-scale conflicts that would employ so many advanced military technologies. For the first time, armies on the battlefield began using artillery, aviation, tanks, poison gases, and other weapons of mass slaughter. New tactics and strategies were developed that led to enormous losses and destruction.
After the war, four empires disappeared: the German, Austro-Hungarian, Ottoman, and Russian. At least 9 million people died in combat, and more than 5 million civilians were killed.
And immediately after the war ended in 1918, the world was gripped by the Spanish flu pandemic. The exact number of deaths is unknown—estimates range from 17.4 to 100 million people, that is, from 0.9 to 5.3% of Earth’s population. The Spanish flu was characterized by unusually high mortality, especially among young people. Malnutrition, overcrowded medical camps and hospitals, and poor hygiene excessively increased the disease’s lethality.
In the 1930s, the world economy faced the Great Depression. This economic crisis engulfed practically all countries and led to a sharp decline in production, unemployment, and worsening living conditions for millions of people. It brought massive bankruptcies, loss of savings, and hunger.
Finally, World War II, which broke out in 1939, became the most destructive conflict in history. It led to the deaths of 60 to 70 million people, including civilians. It was characterized by massive air raids, tank battles, and submarine warfare. The atomic bomb was also used.
The war was accompanied by genocide and mass killings. Over six years of fierce fighting, it turned much of Europe into ruins, and it took decades for humanity to recover from all this nightmare.