Global climate change, war, and population decline in recent human history

Abstract

Although scientists have warned of possible social perils resulting from climate change, the impacts of long-term climate change on social unrest and population collapse have not been quantitatively investigated. In this study, high-resolution paleo-climatic data have been used to explore at a macroscale the effects of climate change on the outbreak of war and population decline in the preindustrial era. We show that long-term fluctuations of war frequency and population changes followed the cycles of temperature change. Further analyses show that cooling impeded agricultural production, which brought about a series of serious social problems, including price inflation, then successively war outbreak, famine, and population decline successively. The findings suggest that worldwide and synchronistic war-peace, population, and price cycles in recent centuries have been driven mainly by long-term climate change. The findings also imply that social mechanisms that might mitigate the impact of climate change were not significantly effective during the study period. Climate change may thus have played a more important role and imposed a wider ranging effect on human civilization than has so far been suggested. Findings of this research may lend an additional dimension to the classic concepts of Malthusianism and Darwinism.agricultural production ͉ population collapse ͉ price ͉ war-peace cycles ͉ preindustrial era

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“…That environmental change can lead to social conflict has been witnessed many times during human history (Cullen et al 2000;Zhang et al 2007;Haug et al 2003;Yancheva et al 2007; Burke et al 2015). The idea behind all these observations is well-rehearsed: changes in environmental conditions-the quantity and quality of natural resources-can trigger stress and conflict between individuals and groups that depend on these resources for their livelihood, sometimes even leading to violence and war.…”

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