A Climate and Social-Ecological Analysis of Locust Infestation Since the Mid-17th Century in the Chinese Dynasty

Since ancient time, locusts have been regarded as a devastating pest, posing serious threats to human societies and agricultural production. Numerous studies have shown that the drivers of locust infestation are closely related to climate and environmental conditions, but the mechanism has been under studied. The Chinese dynasties possess a rich and extensive quantity of historical documents, ranging from official historical books to local chronicles, particularly during the Qing Dynasty (1644-1911). These documents provide detailed accounts of various natural disasters, including locust infestations and their impacts on agrarian societies, as well as the social phenomena triggered by these events. The purpose of this study is to investigate the drivers of locust infestations by integrating perspectives from both climate and social systems, and to analyze the contributing factors and interactions influencing these infestations.

We collected locust data and climate indices from the REACHES database in the Qing dynasty (Wang et al., 2018), along with relevant social data such as population, governmental efficacy, crop harvest and conflict from the SIER (Societal Impact Events Records) database (White et al., 2024). To capture both frequency and severity of locust infestations, we constructed a locust infestation index and conducted sensitivity tests to ensure the stability of this index. Then we converted all data into 1° X 1° latitude/longitude resolution for conducting regression and correlation analyses, to identify the determinant factors in each cell and to categorize the spatial features. We aim to clarify the associations between locust infestations and their climatic and societal driving factors from the long-term data in the historical perspective.