Climatic and Societal Impacts of Volcanic Eruptions in the Western Han Dynasty (206 BCE–8 CE): A Comparative Study

Abstract. The Western Han dynasty (206 BCE–8 CE) experienced periods of extreme climate, accompanied by the evolving concept of the “mandate of heaven” that shaped societal response to disasters. While recent studies suggest that certain climate anomalies during the Han era are related to the atmospheric impacts of explosive volcanic eruptions, this paper employs both quantitative and qualitative methods to establish these associations more systematically. It categorizes and quantifies climatic stressors and selected societal events and applies superposed epoch analysis to examine the timing and statistical significance of their potential associations with ice-core-based dates of explosive eruptions. The paper then selects two historical periods, 180–150 BCE and 60–30 BCE, and offers a comparative analysis of recorded climatic and societal stresses, atmospheric optical anomalies, and societal responses to consecutive natural disasters. These periods are chosen because of the occurrence of massive volcanic eruptions known from polar ice-cores. For instance, in 43 BCE, when the Okmok volcano in Alaska erupted, a pale-blue sun and extreme summer cold are documented. Similarly, ice-cores identify a cluster of substantial eruptions in 168 BCE, 164 BCE, 161 BCE and 158 BCE that may have heavily impacted societies such as Egypt. Comparing the responses to the disasters of these periods also allow us to incorporate historical materials not suitable for quantification and to evaluate the effectiveness of Han dynasty disaster prevention and mitigation measures, thereby identifying factors that may contribute to better resilience to sudden and drastic environmental changes.