Connecting volcanic climate impacts to famine in China using the REACHES database

Abstract. Volcanic eruptions have been linked to historical famines in many parts of the world. In China, reduced temperatures following major eruptions can destabilise the hydroclimate and agricultural production, contributing to subsistence crises and even the downfall of dynasties. This study provides the first long term analysis of the specific connection between volcanic activity and famine in eastern China from 1440 to 1900 CE. Using the REACHES historical climate database, it reconstructs indices measuring temperature, drought, flooding, crop failure and famine. Superposed epoch analysis of these indices reveals a recurring, though regionally distinct, association between eruptions and famine. Famine peaks occur in northern China in the year of an eruption, in central China one to three years later – coinciding with delayed drought and crop failure – and in southern China in the first post-eruption year. Correlation analysis indicates statistically significant relationships between volcanic forcing, hydroclimatic extremes, crop failure and famine. Case studies – including a new assessment of the impacts of the 1809 “unknown” eruption – demonstrate how other factors, such as the El Niño Southern Oscillation, non-volcanic climate processes, price volatility, disease and state relief mediate volcanic impacts. Many of these factors form feedback loop than can delay, amplify or counteract volcanic effects. We conclude that while eruptions may not be the primary drivers of famine in China, they significantly increase the risk of drought, flood, harvest failure and subsequent subsistence crises. The findings demonstrate the capacity of major volcanic events to destabilise food systems through coupled climatic and societal pathways.