“Civilization exists by geological consent, subject to change without notice.” – Will Durant
The last centuries of ancient Egypt were tumultuous times. Coastal towns were abandoned, famine fueled social unrest, and after a series of disastrous defeats of the Egyptians by the Roman army, the last pharaoh, the famously beautiful Cleopatra, committed suicide in 30 BCE. The cause may have been a series of major volcanic eruptions, possibly on the other side of the world, that triggered a severe drought in Egypt.
Archaeologists have been excavating the city of Berenice on Egypt’s Red Sea coast since 1994. Berenice was a kind of combination of city and military base and of strategic importance. Founded between 275 and 260 BCE, the town was abandoned just a few decades later.
In the desert environment, Berenice depended on wells for water. Archaeologists discovered a well still containing water today, even if it tastes a bit salty. However, the well dried up between 220 and 200 BCE, as a layer of sand containing two bronze coins dating from the decades before 199 BCE suggests. As no other items dating to this time period were found in the ruins, the town was likely abandoned and buried by sand, including the well.
There must have been a drought lasting several years to cause the well to dry up, so the archaeologists in a study published in the journal Antiquity, and the most likely cause of the drought is a volcanic eruption.
There are no active volcanoes to be found today in Egypt, but volcanic gases and sulfate aerosols released by a powerful volcanic eruption into Earth’s atmosphere can have widespread effects.
The Monsoon, driven by global wind patterns, brings every year rain from the Indian Ocean to the coastal areas of eastern Africa. Because temperature differences, mostly between the cold sea and the hot continent, are a main driving force behind wind patterns, changing temperatures will also change wind patterns. Volcanic ash and gases (like sulfur-dioxide) absorb sunlight, cooling Earth’s surface, weakening the Monsoon. This caused the summer rains over Egypt to fail. The lack of rain could explain the well drying out, which perhaps helped encourage inhabitants to abandon Berenice.
A 2017 study analyzing chemical traces preserved in ice cores found that in 209 BCE a volcanic eruption released lots of sulfate aerosols into Earth’s atmosphere. It is unclear which volcano would have been responsible, but comparing the chemical traces with the chemical composition of lava-rocks of known origin, geologists pinpointed four possible culprits: Popocatéptl in Mexico, Pelée on the island of Martinique in the Lesser Antilles, Tsurumi or Hakusan, both of which are in Japan.
The same study identified two other sulfate spikes in the ice record, dating to 46 and 44 BCE. A study published in 2020 identified the possible source as Alaska’s Okmok volcano in the Aleutian Islands. Based on the size of the caldera and estimated volume of erupted material, the Okmok eruption was the biggest volcanic eruption in the last 2,500 years. The mega-eruption of Okmok in 43 BCE likely influenced the climate on a global scale. Documents report widespread famine, diseases, and land abandonment happening simultaneously, contributing to a religious and political crisis in Egypt. It was this hungry and demoralized society that in the end was defeated by a new, emerging power, the future Roman Empire.