11 Natural Disasters That Led to Wars

1. Eruption of Thera, c. 1600 BCE

Some of the most important events of ancient history -- and Greek mythology -- resulted from one of the more spectacular disasters to ever strike the eastern Mediterranean: the eruption of the volcanic island of Thera, today known as Santorini, sometime around 1600 BCE.

This massive explosion sent an incredible 24 cubic miles of earth and rock into the air and sea and (perhaps in conjunction with an earthquake) triggered a tsunami that swept the Aegean Sea. The ancient Minoan civilization on the island of Crete was probably fatally weakened by the multi-pronged natural disaster. Not long afterwards the Minoans were conquered by the Mycenaeans, warlike raiders from mainland Greece who descended on the defenseless Cretans and a host of other civilizations around the eastern Mediterranean.

Indeed, contemporary records from Egypt tell of chaotic conditions in the natural and human world around this time, followed in the 14th century BCE by the first mentions of the “Sea Peoples” -- seaborne raiders who almost succeeded in conquering Egypt before they were finally repelled in the 13th and 12th centuries BCE. Although the identity of Sea Peoples remains mysterious, some of them were probably Mycenaean Greeks, who (according to legend) also attacked the city of Troy in Asia Minor around 1200 BCE. It’s pure literary speculation, but the sea monster Cetus, sent by Poseidon to attack Troy, might be a symbolic representation of the Aegean tsunami.

2. Earthquake at Sparta, 464 BCE

In addition to living in a geological hotspot, the ancient and classical Greeks faced numerous ethnic and social divisions -- and natural disasters could provide the catalyst for open warfare. This was especially true in Sparta, where a relatively small population of Spartan “equals” (full citizens) ruled over a vast population of indentured laborers known as “helots,” who had no rights and worked in conditions resembling slavery.

The Spartans always feared a helot rebellion, and with good reason. After a massive earthquake leveled the city of Sparta and killed many Spartan warriors in 464 BCE, the helots seized their chance and staged what became the most serious uprising in Sparta’s history. The situation was so dire, in fact, that the Spartans called on their Athenian rivals for help in putting down the rebellion -- but then changed their mind out of fear the democratic Athenians might be more sympathetic to the oppressed helots. The Athenians were furious about Sparta’s humiliating dismissal of the Athenian contingent, setting the stage for the Peloponnesian War (so that’s two conflicts resulting from one disaster!).

3. Central Asian drought, c. 350-450 CE

As nomadic pastoralists who relied on herd animals for food and clothing, the Huns of Central Asia were as vulnerable to drought as any settled farming population. So when a prolonged dry period hit their homeland and surrounding areas beginning around 350 CE, the Huns picked up and moved to more welcoming climes in Eastern and Southern Europe. There were some minor obstacles, of course, including the Germanic tribes and the Roman Empire, but the Huns never let this sort of thing get in their way. Armies of horse-mounted warriors swirling out of Central Asia subjugated various barbarian tribes, who became vassals of the Huns or sought protection from them across the border in the Roman Empire. However the Western Roman Empire couldn’t protect its own population, let alone the Germanic tribes. By 395 CE the Huns were raiding the Eastern Roman Empire and the Persian Empire, and during the reign of Attila (434-453 CE) they devastated Europe from the gates of Constantinople to the modern French city of Orleans. As noted the Huns’ depredations also triggered Germanic migrations, which ultimately resulted in the fall of Rome.

4. A "climatic event," 535-536 CE

While the Huns disappeared from the pages of history shortly after Attila’s death, the Germanic tribes invading the Roman Empire stuck around a bit longer -- and weird climatic events continued to result in violent conflict.

Although no one knows exactly what happened, the Byzantine historian Procopius recorded extreme weather events in 535-536 CE that indicate drastic cooling: “During this year a most dread portent took place. For the sun gave forth its light without brightness... and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear. And from the time when this thing happened men were free neither from war nor pestilence nor any other thing leading to death.” Irish chronicles covering the same period recount failed harvests, and evidence of cooling, drought, and crop failures has also been found in places as diverse as China and Peru.

In North Africa, as Procopius noted, the effects included another round of strife, as defeated Vandals, Moors and mutinous Roman soldiers rebelled and began plundering the countryside after their demands for land were rebuffed. Although the rebellion spread across North Africa, the Byzantines eventually defeated the rebels, who according to Procopius were “battling hunger” while also fighting the Romans. Contemporary scholars speculate that the events of 535-536 CE were caused by atmospheric dust from a huge volcanic explosion or a comet or meteorite hitting the earth.

5. Fiery dragons (?), 8th century CE

While it’s once again hard to know exactly what was happening (the early medieval period was not known for accurate meteorology), the first Viking raids apparently resulted from a similar sequence of unusual climatic events leading to bad harvests and, finally, desperate violence. The unfortunate victims of these raids lived in England, where the Anglo-Saxons had ruled since the end of the Roman Empire. In 792 CE, the inhabitants of Northumbria were terrified by “excessive whirlwinds and lightning storms” (along with “fiery dragons” – see previous parentheses). Meanwhile, archaeological evidence suggests that across the North Sea in Norway harvests failed in 792-793 CE. So it’s probably not a coincidence that one of the first Viking raids, the plundering of the famous Lindisfarne monastery, came in January 793. And this was just the beginning, as droughts blanketed Western Europe again in 794 and 797.

One possible explanation: contemporary scholars speculate those “fiery dragons” may have been meteor showers, which kicked up atmospheric dust, resulting in another bout of cooling; Chinese chronicles recount repeated meteor showers in this period.

6. Central American drought, 9th-10th centuries

Severe climate changes were also probably to blame for much of the warfare that apparently accompanied the collapse of Classic Mayan civilization beginning c. 800 CE. Although the Mayans lived in the midst of lush rain forests, there were actually very few sources of freshwater that were available year-round: the Mayan city-states relied on advanced techniques for collecting and storing rainwater for both agriculture and human consumption, making them especially vulnerable to repeated droughts. And that’s exactly what happened at 50-year intervals in 760, 810, 860, and 910, according to scientists who studied sediment core samples from the Caribbean Sea to determine the amount of rainfall during this period.

These four droughts correspond to distinct phases in the decline and eventual collapse of the Mayan civilization. However drought was far from the only culprit, with adverse environmental conditions triggering other negative trends in a cascading or “snowball” effect. This included intensifying warfare, as rival city-states battled each other for diminishing resources, city-states dissolved in civil war, and populations migrated in search of food. Mayan written records and archaeological evidence both point to escalating conflict during this period, as war was waged more often, with a larger proportion of the population participating, and by more brutal methods. Archaeological evidence includes fortifications built around even small villages, skeletal trauma resulting from combat, and the sudden appearance of foreign objects, suggesting invasion by outsiders.

7. Central Asian drought, 1212-1213 CE

Central Asian droughts are just bad for civilization. The same basic phenomenon that drove the Huns to invade Europe also played a role in the devastating Mongol invasion of China led by Genghis Khan in 1212-1213 CE. Archaeological evidence points to a long period of severe climate change in Mongolia and other parts of northern Asia lasting from 1175-1300 CE, with a drastic drop in temperatures resulting in less forage for herd animals as well as fewer wild animals for hunting. Luckily for the conquered population of northern China, a Chinese administrator was able to convince the Mongols to drop their plan to turn wheat fields into pastures for Mongol horses -- a move that would have resulted in the deaths of millions of Chinese from starvation.

Interestingly, Genghis Khan decreed a number of environmental protections in the Mongol homeland (but not necessarily in conquered areas) including forbidding the cutting down of trees and hunting wild animals during their breeding season. It’s also worth noting that half a century after the first Mongol invasions of China, Karakorum -- the new imperial capital in Mongolia -- was entirely dependent on food shipments from China, giving Kublai Khan leverage over rival Mongol princes.

8. Southern Africa drought, c. 1800 CE

The rise of Shaka Zulu, one of Africa’s greatest warriors, was tied to a period of devastating drought in southern Africa. After the discovery of the New World, the introduction of corn to southern Africa by European colonists triggered a population explosion, even as -- unbeknownst to native farmers -- corn cultivation was also leaching minerals from the soil. When a prolonged drought hit around 1800, the food supply collapsed, leading to fierce competition for resources among native tribes.

Gradually rising from a lowly position to leadership of the Zulus, Shaka’s innovations with new weapons and fighting techniques allowed him to unite rival tribes through diplomacy and conquest. But he also became notorious for his paranoia and brutality. Indeed the Zulu expansion resulted in a huge upheaval -- the Mfecane, or “scattering,” which saw huge numbers of deaths and massive movements by refugee populations across southern Africa from 1815-1840. While the precise death toll will probably never be known, some scholars estimate that as many as two million people perished during the Mfecane.

9. Haiphong typhoon, 1881 CE

One of the deadliest typhoons on record also facilitated European imperialism in southeast Asia, leading to the French conquest of Vietnam. On October 8, 1881, a massive Pacific typhoon hit the northern Vietnamese city of Haiphong, which serves as the main port for the country’s capital, Hanoi. Although its name means “coastal defense,” the city was completely unprepared for the huge storm, as sustained winds of 115 miles per hour generated a 20-foot storm surge that totally swamped the low-lying city; according to one contemporary account, “there were six feet of water in the houses three and four miles distant from the sea shore.” Over 300,000 people died in this catastrophe.

Adding insult to injury, the typhoon weakened the native government and provided a convenient pretext for the French conquest of northern Vietnam, as the French argued that the Vietnamese emperor was incompetent and unable to protect his own people. In 1882-1883 French forces marched into Haiphong, Hanoi, and the central Vietnamese city of Hue, completing their takeover of the country. However they still had to fight off Chinese mercenaries, while native resistance continued in rural areas, with guerrilla tactics foreshadowing the later Vietnam War.

10. East Pakistan cyclone, 1970

What is today the independent nation of Bangladesh used to be part of Pakistan: these predominantly Muslim areas were originally a single country, which split from Hindu-majority India following independence in 1947. But a terrible natural disaster in the form of a huge cyclone helped precipitate a civil war, leading to the independence of “East Pakistan.”

By 1970 tensions were already simmering between East and West Pakistan, as East Pakistan complained of oppression by West Pakistan; the populations of the two sections came from different ethnic backgrounds and spoke different languages, and the Bengali people of East Pakistan felt they were discriminated against by the government. Then on November 12, 1970, the huge Bhola cyclone hit East Pakistan with sustained winds of 115 miles per hour and a storm surge 34.8 feet high, coinciding with high tide. Up to 500,000 people were killed by the storm and flooding, leading to intense anger at the government and military, which were criticized for failing to heed warnings about the storm and bungling relief efforts in its aftermath.

Popular anger reached new heights when the government said it would go ahead with elections scheduled for December, even though most parts of East Pakistan were in no condition to participate. Civil war broke out in March 1971, and quickly widened into a regional conflict when India intervened on the side of Bengali rebels in East Pakistan. The war finally concluded with a resounding defeat for West Pakistan, and independence for the new nation of Bangladesh, in December 1971.

11. Darfur drought, 1983-present

Although it only came to the attention of the Western world in the first years of the 21st century, the brutal conflict in Darfur traces its roots back to the early 1980s, when drought conditions first triggered competition among tribal groups for scarce resources. These conflicts were intensified by shifting geography, as desertification increasingly pushed nomadic and settled groups into each other’s territory, along with the breakdown of traditional forms of conflict resolution (tribal councils) due to government interference. The mounting tension finally erupted into all-out civil war and genocide in 2002, when settled “African” tribesmen formed the rebel Sudan Liberation Army to protect themselves against the “Arab”-dominated central government (actual ethnic identities are more fluid than these terms might suggest). The central government responded by encouraging the nomadic “Arab” janjaweed to form militias, and the situation soon escalated from combat to mass murder. To date the United Nations estimates that 300,000 people have been killed in Darfur, although the true death toll may be higher.