CNH-L: Volcanism, Hydrology and Social Conflict: Lessons from Hellenistic and Roman-Era Egypt and Mesopotamia

Lead PI: Dr. Kostas Tsigaridis

Unit Affiliation: Center for Climate Systems Research (CCSR)

August 2018 - January 2023
Africa ; Nile, Egypt
Project Type: Research

DESCRIPTION: 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.


Yale University


National Science Foundation