Climate change, state capacity and nomad–agriculturalist conflicts in Chinese history

The nomad–agriculturalist conflicts under the influence of climate change are investigated with the case of China in 965–1805 CE (mid-to-late Imperial China). Quantitative approach has been adopted with the supplement of qualitative method to re-interpret the conflicts at the long-term national scale under the paradigm of environmental humanities. Our results show that in a deteriorating climate, the state capacity of both nomads and agriculturalist polities were dampened. Nomads initiated southerly migration and invasion towards agriculturalist polities in response to climate-induced subsistence pressure. In turn, agriculturalists defended their territories against the nomadic invasions. When drought and cooling occurred concurrently, nomads were more likely to break the agriculturalist polities' defense. This is the first-ever study focusing on the military actions of agriculturalist polities towards nomadic polities, which helps to give a more holistic picture about geopolitics in environmentally vulnerable regions. The findings may help supplement current "war–peace" theories by illustrating the responses of different types of polities in a deteriorating climate and reveal the peaceful culture of agriculturalists. This analysis of historical China may have global implications and contribute to the understanding of social dynamics under climate change in coming decades. Copyright © 2018 Elsevier Ltd and INQUA. All rights reserved.