TY - JOUR

T1 - Extreme climate after massive eruption of Alaska's Okmok volcano in 43 bce and effects on the late roman republic and ptolemaic kingdom

AU - McConnell, Joseph R.

AU - Sigl, Michael

AU - Plunkett, Gill

AU - Burke, Andrea

AU - Kim, Woon Mi

AU - Raible, Christoph C.

AU - Wilson, Andrew I.

AU - Manning, Joseph G.

AU - Ludlow, Francis

AU - Chellman, Nathan J.

AU - Innes, Helen M.

AU - Yang, Zhen

AU - Larsen, Jessica F.

AU - Schaefer, Janet R.

AU - Kipfstuhl, Sepp

AU - Mojtabavi, Seyedhamidreza

AU - Wilhelms, Frank

AU - Opel, Thomas

AU - Meyer, Hanno

AU - Steffensen, Jørgen Peder

PY - 2020/7/7

Y1 - 2020/7/7

N2 - 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 eruption led to pronounced changes in hydroclimate, including seasonal temperatures in specific Mediterranean regions as much as 7 °C below normal during the 2 y period following the eruption and unusually wet conditions. While it is difficult to establish direct causal linkages to thinly documented historical events, the wet and very cold conditions from this massive eruption on the opposite side of Earth probably resulted in crop failures, famine, and disease, exacerbating social unrest and contributing to political realignments throughout the Mediterranean region at this critical juncture of Western civilization.

AB - 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 eruption led to pronounced changes in hydroclimate, including seasonal temperatures in specific Mediterranean regions as much as 7 °C below normal during the 2 y period following the eruption and unusually wet conditions. While it is difficult to establish direct causal linkages to thinly documented historical events, the wet and very cold conditions from this massive eruption on the opposite side of Earth probably resulted in crop failures, famine, and disease, exacerbating social unrest and contributing to political realignments throughout the Mediterranean region at this critical juncture of Western civilization.

KW - Climate forcing

KW - Ice core

KW - Okmok

KW - Rome

KW - Volcano

U2 - 10.1073/pnas.2002722117

DO - 10.1073/pnas.2002722117

M3 - Journal article

C2 - 32571905

AN - SCOPUS:85088101484

VL - 117

SP - 15443

EP - 15449

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 27

ER -