Title: The Fate of Rome: Climate, Disease & the End of an Empire
Author: Kyle Harper
Scope: 3 stars
Readability: 4 stars
My personal rating: 5 stars
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Topic of Book

A new theory explaining the fall of the Western Roman empire.

If you would like to learn more about history, read my book From Poverty to Progress: How Humans Invented Progress, and How We Can Keep It Going.

Key Take-aways

• Roman empire expanded and consolidated power during a period of warm, wet weather called the Roman Climate Optimum.
• This climate made agriculture much more productive. This agricultural productivity created wealth that enabled the Roman empire to expand.
• As Rome expanded geographically and expanded cities into wet lowlands, Romans came into contact with new diseases, such as malaria and the plague.
• Increased trade and migration enabled those diseases to spread. This created pandemics, perhaps for the first time in world history.
• After 450 the climate began to cool, lower agricultural productivity and wealth. This is sometimes called the Little Ice Age.
• The combination of cooler climate and pandemics left it harder for the empire to defend itself against invasion by German tribes.
• The Huns, climate refugees from the Central Asian steppe, provided the final knock-out blow because they forced Germanic tribes to move west and south into Roman territory.

Important Quotes from Book

Few empires in history have achieved either the geographical size or the integrative capacities of the Roman commonwealth.None have combined scale and unity like the Romans— not tomention longevity. No empire could peer back over so many centuries ofunbroken greatness, advertised everywhere the eye wandered in the forum.

The Romans built a giant, Mediterranean empire at a particular moment in the history of the climate epoch known as the Holocene— a moment suspended on the edge of tremendous natural climate change. Even more consequentially, the Romans built an interconnected, urbanized empire on the fringes of the tropics, with tendrils creeping across the known world. In an unintended conspiracy with nature, the Romans created a disease ecology that unleashed the latent power of pathogen evolution. The Romans were soon engulfed by the overwhelming force of what we would today call emerging infectious diseases. The end of Rome’s empire, then, is a story in which humanity and the environment cannot be separated.

Rome’s rise coincided with a period of geopolitical disorder in the wider Mediterranean in the last centuries before Christ. Republican institutions and militaristic values allowed the Romans to concentrate unprecedented state violence, at an opportune moment of history. The legions destroyed their rivals one by one. The building of the empire was bloody business. The war machine whetted its own appetite. Soldiers were settled in rectilinear Roman colonies, imposed by brute force all over the Mediterranean.

The grand and decisive imperial bargain, which defined the imperial regime in the first two centuries, was the implicit accord between the empire and “the cities.” The Romans ruled through cities and their noble families. The Romans coaxed the civic aristocracies of the Mediterranean world into their imperial project. By leaving tax collection in the hands of the local gentry, and bestowing citizenship liberally, the Romans co- opted elites across three continents into the governing class and thereby managed to command a vast empire with only a few hundred high- ranking Roman officials. In retrospect, it is surprising how quickly the empire ceased to be a mechanism of naked extraction, and became a sort of commonwealth.

Time was their ally; the process we now call secondary state formation saw Rome’s adversaries become more complex and formidable over the centuries. These threats relentlessly drained the resources of frontier zones and heartland alike. In tandem with dynastic strife, they were fatal to the fortunes of empire.

The discovery of rapid climate change in the Holocene is a revelation. We are learning that the Romans were, in planetary perspective, lucky. The empire reached its maximal extent and prosperity in the folds of a late Holocene climate period called the Roman Climate Optimum (RCO). The RCO reveals itself as a phase of warm, wet, and stable climate across much of the Mediterranean heartland of empire. It was an inviting moment to make an agrarian empire out of a pyramid of political and economic bargains.

From the middle of the second century, the Romans’ luck ran into short supply. The centuries that form the object of our inquiry witnessed one of the most dramatic sequences of climate change in the entire Holocene. First, a period of climate disorganization covering three centuries (AD 150– 450) set in, which we will propose to call the Roman Transitional Period. At crucial junctures, climate instability pressed on the empire’s reserves of strength and intervened dramatically in the course of events. Then, from the later fifth century, we sense the stirrings of a decisive reorganization that culminated in the Late Antique Little Ice Age. A spasm of volcanic activity in the AD 530s and 540s brought on the most frigid spell in the entire Late Holocene. Concurrently, the level of energy arriving from the sun slipped to its lowest point in several millennia. As we will see, the deterioration of the physical climate coincided with unprecedented biological catastrophe to overwhelm what was left of the Roman state.

This book will argue that the influence of the climate on Roman history was by turns subtle and overwhelming, alternatingly constructive and destructive. But climate change was always an exogenous factor, a true wild card transcending all the other rules of the game. From without, it reshaped the demographic and agrarian foundations of life, upon which the more elaborate structures of society and state depended.

In the Roman Empire, the revenge exacted by nature was grim. The prime agent of reprisal was malaria.

The Roman disease environment was also formed by the connectivity of the empire. The empire created an internal zone of trade and migration as had never existed. The roads and sea lanes of the empire moved not only peoples, ideas, goods— they moved germs.

Starting in the second century, the combination of Roman imperial ecology and pathogen evolution created a new kind of storm, the pandemic.

The centuries of later Roman history might be considered the age of pandemic disease. Three times the empire was rocked by mortality events with stunning geographical reach. In AD 165 an event known as the Antonine Plague, probably caused by smallpox, erupted. In AD 249, an uncertain pathogen swept the territories under Roman rule. And in AD 541, the first great pandemic of Yersinia pestis, the agent that causes bubonic plague, arrived and lingered for over two hundred years. The magnitude of these biological catastrophes is almost incomprehensible. The least of the three pandemics, by casualty count, was probably the mortality known as the Antonine Plague. We will argue that it carried off perhaps seven million victims.

It is worth declaring at the outset a few of the main contours of the narrative. It is a story with four decisive turns, when the pace of events gathered momentum and disruptive change trailed close behind. At each of the points of transformation in the transit between the high empire and the early middle ages, we will try to seek out the specific and intricate lines of connection between natural and human systems.

(1) The first was a multifaceted crisis during the age of Marcus Aurelius, triggered by a pandemic disease, that interrupted the economic and demographic expansion..

(2) Then, in the middle of the third century, a concatenation of drought, pestilence, and political challenge led to the sudden disintegration of the empire. In what has been called the “first fall” of the Roman Empire, the bare survival of an integrated imperial system was an act of willful reconstitution, and a close- run thing. The empire was rebuilt, but in a new guise— with a new kind of emperor, a new kind of government, a new kind of money, and, soon to follow, a new kind of religious faith.

(3) This new empire then roared back. But in a decisive and dramatic period of two generations spanning the end of the fourth and beginning of the fifth centuries, the coherence of the empire was conclusively broken.

(4) In the east, a resurgent Roman Empire enjoyed renewed power, prosperity, and population increase. This renaissance was violently halted by one of the worst environmental catastrophes in recorded history— the double blow of bubonic plague and a little ice age.

Related Books

• “Escape from Rome: The Failure of Empire and the Road to Prosperity” by Walter Scheidel
• “Rome and China: Comparative Perspectives on Ancient World Empires” by Walter Scheidel
• “The Dynamics of Ancient Empires” by Morris and Scheidel
• “Geopolitics in Late Antiquity” by Hyun Jin Kim

If you would like to learn more about history, read my book From Poverty to Progress: How Humans Invented Progress, and How We Can Keep It Going.