The Impact of Climate Change on Ancient Rome
Three pandemics in the Roman Empire coincided with abnormally cold and dry periods, suggesting that natural changes in climate may have contributed to Rome’s decline.
The Study and Its Findings
Kyle Harper at the University of Oklahoma and his colleagues reconstructed the climate of southern Italy between 200 BC and AD 600 by analysing the remains of plankton in a sediment core from the Adriatic Sea. The Roman state flourished and reached its greatest extent during the three centuries of relatively warm and wet weather beginning in 200 BC in what is now Italy. But the study found that this “Roman climate optimum” gave way around AD 130 to an era that was up to 3°C (5.4°F) colder and with more frequent droughts. Especially frigid years corresponded with the Antonine Plague in 165-180 AD, which shook the empire and possibly killed Emperor Lucius Verus. Another plunge in temperatures came during the Plague of Cyprian in 251-266, when the empire was splintering into three states ruled by warring generals and a rebel queen.
After the fall of the Western Roman Empire in 476, one of the coldest periods in the past 2000 years heralded a wave of pandemics starting with the Plague of Justinian in the 540s. This may have contributed to the loss of much of Italy, the Balkans and the Middle East from the Eastern Roman Empire. “The Roman Empire rises and falls and rises and falls,” says Harper. “There’s a series of episodes of very extreme crises in some cases. And I think the case is now overwhelmingly clear that both climate change and pandemic disease had a role in many of those episodes.”
While there are signs of these cold spells in tree rings from the northern Alps, the sediment core in this study, which was taken at the end of a current running along the entire eastern coast of Italy, offers the first clear evidence of them in the Roman heartland. Cooler, drier conditions may have disrupted harvests, weakening the immune systems of Roman citizens and encouraging the spread of disease through migration and conflict.
Volcanic Eruptions and Their Impact
Before the Plague of Justinian, which was caused by the same flea-borne bacteria as the 14th-century Black Death, three massive volcanic eruptions dimmed the sun and launched the “Late Antique Little Ice Age”. Historical accounts from this time recorded crop failures. “The sun gave forth its light without brightness, like the moon,” wrote the scholar Procopius in 536. “Men were free neither from war nor pestilence nor any other thing that brings death.”
While this new sediment record advances our understanding of Roman Italy, we don’t know enough about the rest of the empire to say climate change triggered or amplified the plagues, says Timothy Newfield of Georgetown University in Washington DC. He has argued that the effects of the Plague of Justinian have been exaggerated.
“Whether these three Roman pandemics specifically brought down Rome is in my opinion hard to argue,” he says. “No one variable or two variables can be held accountable.” But Harper says the study should raise questions about climate change in the Roman era, as well as our own: “It gives you perspective to understand that two to three degrees [Celsius] of change is absolutely enormous and puts tremendous strain on human societies.”
The plagues that shook the Roman Empire are deeply linked to the cold, dry periods that plagued the region. As the temperatures dropped and the land became parched, conditions became ripe for the spread of disease. The lack of moisture in the air and soil created an environment where germs and bacteria could flourish, leading to widespread sickness and death. Additionally, the harsh conditions put a strain on the population, making it harder for people to remain healthy and fight off illness. These cold, dry periods were a significant factor in the devastating plagues that ravaged the Roman Empire and forever altered the course of history.
During the cold, dry periods that plagued the Roman Empire, plagues swept through the population with devastating effects. The lack of moisture in the air and soil created an ideal environment for the transmission of disease, allowing germs and bacteria to spread rapidly. The harsh conditions also weakened the immune systems of the populace, making it harder for individuals to fend off illness. As a result, entire communities were decimated by sickness, and the Roman Empire was left reeling from the widespread death and destruction. The link between cold, dry periods and the plagues that shook the Roman Empire is undeniable and serves as a poignant reminder of the impact of environmental factors on human health.