The Apocalyptic Library

The Fate of Rome: Climate, Disease, and the End of an Empire by Kyle Harper

Desolation by Thomas Cole

Spoiler alerts ahead! After more than 1,000 years of ironclad rule, the Roman Empire fell on its own sword. A government that once circled the Mediterranean Sea and stretched from northern Britain to eastern Syria, the Roman Empire quickly collapsed. The decline of the Romans has been the object of great fascination. Historians have argued its cause to be alternately at the hands of invading armies, factional infighting, political incompetence, economic downturn, civic unrest, and decadence (to name a few theories), but a new research adds another couple of nails to the coffin of Rome.

A proper description of the arguments in Kyle Harper’s The Fate of Rome: Climate, Disease, and the End of an Empire could be book-length itself. Let’s try to keep it short. Drawing on the fields of paleoclimatology and advanced genomic sequencing—plus a classicist’s love of comparative literature—Harper describes the Roman collapse as a far more natural affair than previously supposed. More specifically, he finds compelling evidence that slow and subtle change in the climate covering the Empire’s footprint added stress to the intricate systems of the imperial economy, trade, politics, and civil defense. These changes may have also created salubrious conditions for insalubrious malefactors, namely the germs that cause diseases like smallpox, malaria, and Bubonic plague.

What Harper reveals is a model for a civilizational collapse that has much less to do with human ambition or folly than originally imagined.


Huns, Germs, and Sleet

While there were assuredly missteps in the deployment of this legion or that phalanx, centuries-long global shifts may be to blame for the entire imperial machine stalling out. With the clockwork breaking down, Rome was more vulnerable to threats from within and without.

As noted, the particularities of the history of Rome’s collapse have long been debated and prioritized. What Harper brings to the conversation in The Fate of Rome are a few complicating possibilities which provide new uncertainty to the ranking. What emerges is the vision of a “perfect storm,” which is itself an apt metaphor for a situation blurred in part by climate change.

An important period of context is the 2nd Century AD. The late 100s marked the end of a climatological grace period around the Mediterranean called the Roman Climate Optimum. This delightfully named weather pattern was in part responsible for the happy growth of empire. It provided long years of statistically significant sunlight, fair weather, and warm temperatures to the whole region. The Empire built and reinforced its networks of trade and agriculture during this time, providing the security to feed millions of people under its rule. A unified civilization of this size had no unprecedented at this point in history.

Then the storm clouds rolled over the horizon. Throughout a period of about 250 years, the temperature around the Mediterranean dropped, the Nile River went dry, and floods rotted grain in the fields of central Europe. Despite the best efforts of bureaucrats, an enduring food crisis starved the empire and threw its currency into spiraling turmoil. This climate period is called the Late Antiquity Little Ice Age.

As it happens, different diseases spread more or less well depending on the climate. During the downturn of the temperature and increase in flooding, an outbreak of malaria wreaked havoc. During a separate part of the long cold snap, the geographic range of the black rat shifted from the Asian steppes to the Mediterranean basin. With the mammal’s relocation came a fellow traveler: the Bubonic Plague.

The “success” of these diseases was, ironically, increased by the redundant engineering of the Roman trade network. The efficient transportation of goods and people between the major cities, regional hubs, and far-flung outposts quickened the spread of these deadly diseases. A major outbreak of smallpox, thus, was able to move quickly from the Ethiopian uplands to the Capitol city, and the darkening of bodies from the world’s first Black Plague pandemic was able to touch every last corner of the Empire, perhaps infecting as much as 60% of its inhabitants.

With a weakened populace, it was comically easy for the Huns, a civilization of nomadic and war-like people from central Asia, to invade the Empire. (As it happens, the central Asian steppes were suffering their own profound environmental changes; the nomadic tribes that lived there naturally decided to pack up and move.) Attila famously pillaged all the way to northern Italy before deciding to turn around for home. Whether by luck or prescience, the warlord left southern Europe before the outbreak of yet another plague. Ultimately, the Romans would never recover from these shocks.


Pope Gregory I and the Ascent of Apocalyptic Christianity

Pope Gregory I

Christianity’s ascent from an off-shoot cult of Judaism to the state-sponsored religion of the Roman Empire is an astounding story for another day. It is fair to say that eventually the two entities were indistinguishable. After the comingling of the Empire and the Church, it’s fair to assume that what happens to the Empire happens to Christianity. The Church, too, would be affected deeply by the climatological uncertainty of the Late Antique Little Ice Age. And the Christian mouthpiece of that uncertainty of most interest was Pope Gregory I. Gregory the Great, as he was called, was the world’s leading eschatologist of the sixth century.

“Gregory [the Great]’s eschatology is the thread that holds together the entire fabric of his thought and career,” writes Harper.

If we wish to understand his view of the world, we must appreciate his certainty that it was in its last hours. This sensibility was a direct response to his experience of the natural environment. Nature itself was writhing in anticipation of the end. Gregory’s papacy had been born in a moment of dire natural emergency. Late in AD 589, torrential rains inundated Italy. The Adige flooded. The Tiber spilled its banks and crept higher than Rome’s walls.

In addition to the Old Testament worthy downpour from the Alps, Gregory presided over a faith community best by global plague, invading armies, and other natural phenomena such as solar eclipses and earthquakes. His papacy during these events and the reign of the emperor Justinian is largely responsible for the adoption of the Book of Revelation into the New Testament canon. A violent, supernatural understanding and expectation of an impending apocalypse would become a hallmark of Christian thinking—even to this day.

Gregory’s turbulent era in human civilization can be recognized in ripples across the world of antiquity. The Fate of Rome continues:

The natural catastrophes of the sixth century induced one of the greatest mood swings in human history. The occlusion of the sun, the rattling of the earth, and the advent of worldwide plague stoked the fires of eschatological expectation, across the Christian world and beyond. Signs of profound collective distress have been detected in places so far removed as Norse myth and Chinese Buddhism.


What is perhaps most instructive about Harper’s work—and what lands a history book on front page of The Oblivious—is how a multitude of blind, benign factors can influence a relatively swift collapse of a social structure. The primary disruptions of Late Antiquity are breakdowns in trade; in our world, these networks are even more interconnected. This makes the way we get our food, the speed by which we can travel the globe, and our capacity to wage war and peace both more redundant and secure—as well as a greater liability.

The Romans didn’t have access to malaria medicines, but they also didn’t have to worry about air travel and a 48-hour spread of communicable disease. Additionally, the crux of the Roman supply problem was cold weather, but warming temperatures will devastate crop production with drought as well. Migration will be its own challenge. It is foolish to think that we can engineer ourselves out of the global system.

Noting the fractious politics during the time of Emperor Justinian, Harper leaves us with a commonsensical warning at the end of The Fate of Rome:

Justinian’s opponents erred in believing that the natural order is full of predictable harmony and regularity. Justinian’s belief that nature is full of violent and ceaseless flux was closer to the truth. But the emperor’s intellectual victory did little to steel his empire against the overwhelming


Guns, Germs, and Steel: The Fate of Human Societies by Jared Diamond

The History of the Decline and Fall of the Roman Empire by Edward Gibbon