Warfare, Shmittah – and Volcanic Forcing: a New Perspective on the Causes of Famine in Judea during the Maccabean Revolt
Abstract: The importance to Jewish history and identity of the events of the 160s BCE cannot be overstated: the Maccabean Revolt against Seleucid rule laid the political groundwork for the emergence of the independent kingdom of Judea and set its ideological direction. Among the critical episodes of that decade mentioned in narrative sources are two famines said to have been so severe that they altered the course of the rebellion. These have been little examined heretofore; however, recently improved dating of atmospheric aerosol records derived from polar ice cores and geoscientific studies of the impacts of volcanic eruptions on climatic and social conditions provide a new lens through which the consecutive famines can be understood, supporting the contention that volcanic forcing of the environment was a significant contributory factor for both occurrences. In addition, this fresh perspective enables a reassessment of the textual sources concerning these seminal episodes of Judean history.
Author: Selga Medenieks
Citation: 'Warfare, Shmittah – and Volcanic Forcing: a New Perspective on the Causes of Famine in Judea during the Maccabean Revolt.' (2025) JAJ 16.2, pp. 243-272.
CNH-L: Volcanism, Hydrology and Social Conflict: Lessons from Hellenistic and Roman-Era Egypt and Mesopotamia
Abstract: This project examines the link between explosive volcanic eruptions and the annual Nile river summer flooding in antiquity. Large volcanic eruptions can reduce average global temperatures and suppress average global precipitation. This is known to have had dramatic effects on annual rainfall on the Nile watershed in historic times. The human response to this annual flooding, and to its variability over the years, was the major driver of Egyptian history up to the completion of the high dam at Aswan in 1970. This project, a collaboration among historians, scientists, hydrologists, and statisticians, seeks to understand the coupling between the hydrological cycle and human society in Egypt during the Hellenistic era (305 BCE - 30 BCE), a well-documented period of economic, technological and social change with often violent rivalries between major regional powers. The results will also inform our understanding of best-practice responses to the changing climate in the modern world. The project will inform the broad public about human and natural systems and the complex interactions between them at diverse scales, through a traveling exhibition program developed at the Yale Peabody Museum of Natural History.
This project will capitalize upon a rare confluence of natural and human archives for Ancient Egypt and the Near East. By comparing rich historical records (papyrus documents and inscriptions) with environmental data and regional climate and hydrologic simulations for repeated abrupt climate events, the research will determine whether and how social dynamics are climate-driven, and whether and how human water management affects regional climate and hydrology. Volcanic eruptions provide tests of human and natural system sensitivity to abrupt shocks because their repeated occurrence allows the identification of systematic relationships in the presence of random variability. The project will make three important contributions: (1) integrate historical data from a wealth of different archives to analyze the connections between climate variability, social unrest, and institutional change during the Hellenistic era; (2) improve knowledge of hydrological responses to volcanic eruptions; (3) document the extent of human impacts on Mediterranean hydrology. Simulations will be used to evaluate the climatic impact of large and sustained volcanism and intensive regional water management. This historical analysis will delineate the mechanisms through which environmental stress influenced state-level behaviors, community responses (such as changes in land and water management), and interstate conflict during the Hellenistic period, and how in return human activities interactively affected soils, land cover, hydrology, and regional climate.
Author: Francis Ludlow
Investigating hydroclimatic impacts of the 168–158 BCE volcanic quartet and their relevance to the Nile River basin and Egyptian history
Abstract: The Ptolemaic era (305–30 BCE) is an important period of Ancient Egyptian history known for its material and scientific advances, but also intermittent political and social unrest in the form of (sometimes widespread) revolts against the Ptolemaic elites. While the role of environmental pressures has long been overlooked in this period of Egyptian history, ice-core-based volcanic histories have identified the period as experiencing multiple notable eruptions, and a repeated temporal association between explosive volcanism and revolt has recently been noted. Here we analyze the global and regional (Nile River basin) hydroclimatic response to a unique historical sequence of four large and closely timed volcanic eruptions (first a tropical one, followed by three extratropical northern hemispheric events) between 168 and 158 BCE, a particularly troubled period in Ptolemaic history for which we now provide a more detailed hydroclimatic context. The NASA (National Aeronautics and Space Administration) GISS (Goddard Institute for Space Studies) ModelE2.1 Earth system model simulates a strong radiative response with a radiative forcing (top of atmosphere) of −7.5 W m−2 (following the first eruption) and −2.5 W m−2 (after each of the three remaining eruptions) at a global scale. Associated with this, we observe a global surface cooling of the order of 1.5 ∘C following the first (tropical) eruption, with the following three extratropical eruptions extending the cooling period for more than 15 years. Consequently, this series of eruptions is observed to constrain the northward migration of the inter-tropical convergence zone (ITCZ) during the Northern Hemisphere summer monsoon season, and major monsoon zones (African, South Asian, and East Asian) were seen to experience a suppression of rainfall of >1 mm d−1 during the monsoon (JJAS) season averaged for 2 years after each eruption. A substantial suppression of the Indian and North African summer monsoon (over the Nile River headwater region) was seen to strongly affect the modeled river flow in the catchment and discharge at river mouth. River mass flow over the basin was observed to decrease by 29 % and 38 % relative to an unperturbed (non-volcanic) annual mean flow in the first and second year, respectively, after the first (i.e., tropical) eruption. A moderate decrease ranging between 5 % and 18 % was observed after the third and fourth (extratropical) eruptions. These results indicate, in sum, that the first eruption likely produced a strong hydroclimate response, with the following extratropical eruptions prolonging this. These results also support the recently hypothesized association between ice-core-based signals of explosive volcanism and hydroclimatic variability during the Ptolemaic era, including the suppression of the agriculturally critical Nile summer flooding.
Citation: Singh, R., Tsigaridis, K., LeGrande, A. N., Ludlow, F., and Manning, J. G.: Investigating hydroclimatic impacts of the 168–158 BCE volcanic quartet and their relevance to the Nile River basin and Egyptian history, Clim. Past, 19, 249–275, https://doi.org/10.5194/cp-19-249-2023, 2023.
Extreme climate after massive eruption of Alaska’s Okmok volcano in 43 BCE and effects on the late Roman Republic and Ptolemaic Kingdom
Abstract: 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.
Authors: Joseph R. McConnell, Michael Sigl, Gill Plunkett, Andrea Burke, Woon Mi Kim, Christoph C. Raible, Andrew I. Wilson, Joseph G. Manning, Francis Ludlow, Nathan J. Chellman, Helen M. Innes, Zhen Yang, Jessica F. Larsen, Janet R. Schaefer, Sepp Kipfstuhl, Seyedhamidreza Mojtabavi, Frank Wilhelms, Thomas Opel, Hanno Meyer, and Jørgen Peder Steffensen
Reply to Strunz and Braeckel: Agricultural failures logically link historical events to extreme climate following the 43 BCE Okmok eruption
Authors: Joseph R. McConnell, Michael Sigl, Gill Plunkett, Andrew I. Wilson, Joseph G. Manning, Francis Ludlow, and Nathan J. Chellman
Commentary: The Sun of Rome is set! volcanic dust veils and their political fallout
Author: Clive Oppenheimer
Volcanic suppression of Nile summer flooding triggers revolt and constrains interstate conflict in ancient Egypt
Abstract: Volcanic eruptions provide tests of human and natural system sensitivity to abrupt shocks because their repeated occurrence allows the identification of systematic relationships in the presence of random variability. Here we show a suppression of Nile summer flooding via the radiative and dynamical impacts of explosive volcanism on the African monsoon, using climate model output, ice-core-based volcanic forcing data, Nilometer measurements, and ancient Egyptian writings. We then examine the response of Ptolemaic Egypt (305–30 BCE), one of the best-documented ancient superpowers, to volcanically induced Nile suppression. Eruptions are associated with revolt onset against elite rule, and the cessation of Ptolemaic state warfare with their great rival, the Seleukid Empire. Eruptions are also followed by socioeconomic stress with increased hereditary land sales, and the issuance of priestly decrees to reinforce elite authority. Ptolemaic vulnerability to volcanic eruptions offers a caution for all monsoon-dependent agricultural regions, presently including 70% of world population.
Authors: Joseph G. Manning, Francis Ludlow, Alexander R. Stine, William R. Boos, Michael Sigl, and Jennifer R. Marlon
Revolts under the Ptolemies: A Paleoclimatological Perspective
Abstract: Our goal in this chapter is to outline the main explanations offered to date for the causes of unrest in the Ptolemaic period, before proceeding to contribute a new perspective that implicates volcanically-induced shocks to the agriculturally-critical annual Nile flood as potential triggers in many revolts. To date, while the causes of unrest have been debated, they are understood by most scholars as springing from nationalism, economic problems or some combination of these and other factors.
Authors: Francis Ludlow and Joseph G. Manning