Measuring the Effectiveness of American Crop Adoption in Reducing Famines and Wars During Climate Extremes in Late Imperial China

Existing large-N quantitative research on historical human–environment interactions has predominantly focused on the detrimental impacts of climate variability on social stability, economic performance, and the collapse of civilizations. In contrast, this study shifts the analytical lens toward the resilience strategies that human societies historically employed to adapt to environmental stressors. Specifically, we examine the role of agricultural innovation, namely, the introduction of high-yield American crops, as a key mechanism of social resilience during periods of climatic extremes.

 

Focusing on the Ming and Qing Dynasties in China, we investigate how the diffusion of four American crops—maize, peanuts, sweet potatoes, and potatoes—shaped the relationship between hydroclimatic extremes (floods and droughts) and Malthusian catastrophes, including famines and wars. Drawing on data from 3,071 local gazetteers across 236 prefectures, we employ a spatial Durbin model to assess both the direct and spatial spillover effects of crop adoption on societal outcomes during periods of environmental stress.

 

Our results reveal that the introduction of American crops significantly mitigated the incidence of Malthusian crises, although the effects varied by crop type and climatic condition. Maize and peanuts were particularly effective in reducing the occurrence of wars during flood years, while peanuts, sweet potatoes, and potatoes were associated with reduced famine incidence during droughts. Regional analysis further indicates that the mitigating effects were especially pronounced in the southwestern mountainous regions and that spillover effects were strongest in the central-eastern rice cultivation zone.

 

These findings highlight the critical role of agricultural diversification in enhancing societal resilience to climate shocks. By uncovering the regionally differentiated impacts of specific crops, this study contributes to a more nuanced and context-sensitive understanding of the historical human–environment nexus and the adaptive capacities of agrarian societies in the face of climatic extremes.