Extreme climate after massive eruption of Alaska’s Okmok volcano in 43 BCE and effects on the late Roman Republic and Ptolemaic Kingdom ...

• Main Authors: McConnell, Joseph R., Sigl, Michael, Plunkett, Gill, Burke, Andrea, Kim, Woon Mi, Raible, Christoph C., Wilson, Andrew I., Manning, Joseph G., Ludlow, Francis, Chellman, Nathan J., Innes, Helen M., Yang, Zhen, Larsen, Jessica F., Schaefer, Janet R., Kipfstuhl, Sepp, Mojtabavi, Seyedhamidreza, Wilhelms, Frank, Opel, Thomas, Meyer, Hanno, Steffensen, Jørgen Peder
• Format: Text
• Language: English
• Published: National Academy of Sciences NAS 2020
• Subjects: 550 Earth sciences & geology; 530 Physics; Arctic; Alaska
• Online Access: https://dx.doi.org/10.7892/boris.145066; https://boris.unibe.ch/145066/

The assassination of Julius Caesar in 44 BCE triggered a power struggle that ultimately ended the Roman Republic and, eventually, the Ptolemaic Kingdom, leading to the rise of the Roman Empire. Climate proxies and written documents indicate that this struggle occurred during a period of unusually inclement weather, famine, and disease in the Mediterranean region; historians have previously speculated that a large volcanic eruption of unknown origin was the most likely cause. Here we show using well-dated volcanic fallout records in six Arctic ice cores that one of the largest volcanic eruptions of the past 2,500 y occurred in early 43 BCE, with distinct geochemistry of tephra deposited during the event identifying the Okmok volcano in Alaska as the source. Climate proxy records show that 43 and 42 BCE were among the coldest years of recent millennia in the Northern Hemisphere at the start of one of the coldest decades. Earth system modeling suggests that radiative forcing from this massive, high-latitude ...