Some of the main crises that affected the Roman Empire, including major epidemics, invasions and prolonged phases of political instability, are linked to periods of unfavorable weather in Italy, the heart of imperial territory. The conclusion comes from a new analysis of seabed sediments, which made it possible to create a detailed portrait of the climatic variations present during the rise and decline of Rome.
O work has just been published in the specialized journal Science Advances and adds to a series of indications that climate changes and their association with ancient pandemics may have played an important role in the processes that ended up leading to the decline of the Roman Empire.
The new data, which were analyzed by European and American experts, are an important contribution to the debate because they bring the first climate records considered to have high temporal resolution – in this case, with a margin of error of just three years – for the Roman imperial era. in most of Italy.
“Every paleoclimatic record [ou seja, do clima do passado] It’s a piece of the puzzle,” one of the study’s authors, historian Kyle Harper, from the University of Oklahoma and the Santa Fé Institute (both in the USA), told Folha. “There is some correlation [dos dados italianos] with other regions of the empire, but we certainly encourage other researchers to consider our records in light of those obtained elsewhere.”
In the work, which was coordinated by Karin Zonneveld, from the Center for Marine Environmental Sciences at the University of Bremen (Germany), the team obtained sediments from the bed of the Mediterranean Sea in the region of Taranto (southern region of Italy, in what would be the upper part of the “boot” formed by the country’s map).
The key to the method used by the team are dinoflagellates, single-celled algae that can be compared to biological thermometers. They are extremely sensitive to variations in temperature and nutrient composition of the water, so the species of dinoflagellates in the environment changes as these conditions change, generally on a year-to-year scale.
This means that it is possible to use changes in the types of dinoflagellates in deep-sea sediments to put together a timeline of climate change, as long as it is possible to precisely date these comings and goings.
That’s what the researchers did, with intriguing results. First, they found that the period from Rome’s transformation into a Mediterranean superpower (around 200 BC) until the end of the second dynasty of emperors (100 AD) is marked by relatively high and stable temperatures, with abundant rainfall.
This matches the hypothesis that these centuries would correspond to what some scholars call the Roman Climatic Optimum Point or Roman Warm Period, with excellent conditions for agriculture in Italy.
Things, however, changed after 100 AD, with several phases of cold and relative aridity until 275 AD, in addition to much more variability between one year and another. After that, things seemed to improve a little, until they went completely wrong after 537 AD, with abrupt and intense drops in temperature and humidity (of the order of 3 degrees Celsius, on average) until the end of the century.
There are some interesting coincidences in this list. The strongest are with three major pandemics that devastated the Roman world. The Antonine Plague occurred during a cold pulse between the years 160 AD and 180 AD, after several decades of a tendency towards cold and aridity.
The Plague of Cyprian, which began in the year 251, coincides with a second phase of intense cooling after a period of warming. Finally, the Plague of Justinian begins in the year 541 of the Christian Era, again when temperatures plummet. In this case, the Western Roman Empire no longer existed, but the Eastern Roman Empire still existed, based in Constantinople (present-day Istanbul).
Only in the case of the Plague of Justinian is the cause of the pandemic (the bubonic plague bacteria) known with certainty. The researchers emphasize that it is not possible to directly attribute the origin of deadly diseases to climate change. But it makes sense to imagine that the inclement climate had effects such as worsening harvests and the spread of hunger for the majority of the population of the Roman Empire, making pandemics, when they arrived, more devastating.
Furthermore, even without diseases, the scenario had the potential to intensify conflicts and rebellions, such as the so-called Crisis of the Third Century (the 3rd century AD), when dozens of emperors ascended the throne and were overthrown over the course of a few decades.