Climate Change, the Rise of the Roman Empire, and the Fall of the Ptolemies

The assassination of Julius Caesar on the Ides of March in 44 B.C.E. triggered a 17-year power struggle that ultimately ended the Roman Republic leading to the rise of the Roman Empire. To the south, Egypt, which Cleopatra was attempting to restore as a major power in the Eastern Mediterranean, was shook by Nile flood failures, famine, and disease. These events are among the best known and important political transitions in the history of western civilization. A new study reveals the role climate change played in these ancient events.

An international team of researchers, including Yale’s Joe Manning, used historical accounts and climate proxy records — natural preservers of an environment’s history (such as ice cores) — to uncover evidence that the eruption of Alaska’s Okmok volcano in 43 B.C.E. caused global climatic changes that sparked the period’s political and social unrest and ultimately changed the course of ancient history. The research was published June 22 in the journal Proceedings of the National Academy of Sciences.

The interdisciplinary team analyzed volcanic fallout records in six Arctic ice cores, and found that one of the largest volcanic eruptions of the past 2,500 years occurred in early 43 B.C.E. The researchers found that the geochemistry of tephra — rock fragments and particles ejected by a volcanic eruption — originated from the Okmok volcano in Alaska. Climate proxy records show that 43 and 42 B.C.E. were among the coldest years of the recent millennia in the Northern Hemisphere at the start of one of the coldest decades. Further research suggested that this high-latitude eruption led to pronounced changes in hydroclimate, including colder seasonal temperatures in specific Mediterranean regions during the two-year period following the eruption.

Read more at Yale University

Photo Credit: Christina Neal via Wikimedia Commons