• Energy Research

Abstract Concern has risen that current global warming and more frequent extreme events such as droughts and floods will increase conflict around the world. This concern has spurred both social science research on contemporary climate, peace, and conflict as well as research in the historical sciences on past climate, weather, warfare, and violence. This perspectives article compares these two fields of scholarship and examines how each may benefit the other. It finds significant convergences in methods and insights across contemporary and historical research as well as persistent patterns in causal pathways between climate and conflict. Contemporary climate, peace, and conflict (CPC) research may sharpen methods and causal models for historical researchers. Historical studies, particularly those informed by contemporary research, may elucidate deep origins and long-term effects of climate-related conflicts. For policymakers and the public, history offers comprehensible ways to make sense of complex and contingent linkages and to construct cogent narratives of the past as well as storylines for the future.

Humans possess limited knowledge on what generated cultural dynamics to strengthen human resilience to overcome climate-induced stresses. Although the highly developed mental ability of humans could have enabled significant human resilience in history, no study has empirically explained or has even scientifically confirmed how and when such dynamics arose. To fill the current research gap, this study therefore explores the associations among climatic conditions, the evolutional dynamics of human thinkers and their thoughts, and human ecological-socioeconomic conditions in the past 2500 years in Europe. Results from quantitative modellings and causal analyses confirm that climatic-ecological stresses led to human ecological-socioeconomic crises, and thereby dramatically increased twice of the thinkers' number and their thoughts' impact across different philosophies in truth, knowledge, and ethics for adaptation at multi-decadal to centennial temporal scales, especially in spirituality oriented mentality. The process of the stress-generated cultural dynamics displays some similarities with the stress-induced mutagenesis in organism evolution. Ultimately, climatic-ecological stresses prompt the escalation in the number of thinkers and impacts of their thoughts and flourishing of philosophy. Such stress-regenerated cultural dynamics imply that the current climate change threat may stimulate another thriving phase of cultural selection and lift humans to the next homeostatic plateau of civilization. Findings also extend the cognate scope of psychological, sociological, and civilization studies.

This study seeks to provide further insight regarding the relationship of climate-epidemics in Chinese history through a multi-scalar analysis. Based on 5961 epidemic incidents in China during 1370-1909 CE we applied Ordinary Least Square regression and panel data regression to verify the climate-epidemic nexus over a range of spatial scales (country, macro region, and province). Results show that epidemic outbreaks were negatively correlated with the temperature in historical China at various geographic levels, while a stark reduction in the correlational strength was observed at lower geographic levels. Furthermore, cooling drove up epidemic outbreaks in northern and central China, where population pressure reached a clear threshold for amplifying the vulnerability of epidemic outbreaks to climate change. Our findings help to illustrate the modifiable areal unit and the uncertain geographic context problems in climate-epidemics research. Researchers need to consider the scale effect in the course of statistical analyses, which are currently predominantly conducted on a national/single scale; and also the importance of how the study area is delineated, an issue which is rarely discussed in the climate-epidemics literature. Future research may leverage our results and provide a cross-analysis with those derived from spatial analysis.

We investigated the relationship between a 2000-year history of nomadic migration and climate change in historical China. By using updated data and statistical methods, the study solved several unanswered questions from past research about the relationship between climate change and the nomadic migration, especially over the long term and on a large spatial scale. The study used correlation analysis, multiple regression analysis, and Granger causality analysis to quantitatively verify the following causal pathway: climate change â' nomadic migration â' conflicts between pastoralists and agriculturalists. In the long term, precipitation was a statistically more influential factor on nomadic migration than temperature in historical China. How climate change affects the migration of nomadic minorities in the long term is theoretically explained based on the Push-Pull model as well as statistical evidence.

Recent studies have shown strong temporal correlations between past climate changes and societal crises. However, the specific causal mechanisms underlying this relation have not been addressed. We explored quantitative responses of 14 fine-grained agro-ecological, socioeconomic, and demographic variables to climate fluctuations from A.D. 1500–1800 in Europe. Results show that cooling from A.D. 1560–1660 caused successive agro-ecological, socioeconomic, and demographic catastrophes, leading to the General Crisis of the Seventeenth Century. We identified a set of causal linkages between climate change and human crisis. Using temperature data and climate-driven economic variables, we simulated the alternation of defined “golden” and “dark” ages in Europe and the Northern Hemisphere during the past millennium. Our findings indicate that climate change was the ultimate cause, and climate-driven economic downturn was the direct cause, of large-scale human crises in preindustrial Europe and the Northern Hemisphere.

Climate change has been statistically proven to substantially influence the economy of early modern Europe, particularly in the long term. However, a detailed analysis of climate change and the economy of historical China remains lacking, particularly from a large-scale and quantitative perspective. This study quantitatively analyzes the relationship between climate change and the economy in late imperial China (AD 1600–1840) at the national level. This study also compares the findings on the relationship between climate change and the economy in late imperial China with those in early modern Europe. Results of multivariate regression and Granger causality analyses indicate that (1) climate change induces economic fluctuations in late imperial China, particularly in the long term; (2) given that the economic center is located in South China during the study period, temperature has a greater influence on the economy than precipitation; (3) the population of China is statistically proven to primarily act as consumers in the long term; and (4) given the long-term role of the Chinese population, the economic vulnerability in late imperial China under climate change is further increased and is higher than that in early modern Europe, whose population mainly acts as producers in the long term. In conclusion, the late imperial Chinese society has a high economic vulnerability to climate change. These findings revisit Malthusian theory and 'Great Divergence' theory by including the perspective of economic vulnerability under climate change during the study period. The role of the population must be investigated further to address the socioeconomic vulnerabilities under climate change.

We investigated the mechanism of epidemics with the impacts of climate change and socio-economic fluctuations in the Ming and Qing Dynasties in China (AD 1368-1901). Using long-term and high-quality datasets, this study is the first quantitative research that verifies the 'climate change → economy → epidemics' mechanism in historical China by statistical methods that include correlation analysis, Granger causality analysis, ARX, and Poisson-ARX modeling. The analysis provides the evidences that climate change could only fundamentally lead to the epidemics spread and occurrence, but the depressed economic well-being is the direct trigger of epidemics spread and occurrence at the national and long term scale in historical China. Moreover, statistical modeling shows that economic well-being is more important than population pressure in the mechanism of epidemics. However, population pressure remains a key element in determining the social vulnerability of the epidemics occurrence under climate change. Notably, the findings not only support adaptation theories but also enhance our confidence to address climatic shocks if economic buffering capacity can be promoted steadily. The findings can be a basis for scientists and policymakers in addressing global and regional environmental changes.