The evident connection between human evolu- tion and climatic changes has been concurred by scientists. Although many people are trying to forecast the impacts of climatic changes on our future society, there are not any studies to quantitatively scrutinize the interrelation between climatic changes and social developments by using historical data. In line with this knowledge gap, this study adopted a scientific approach to compare the paleoclimatic records with the historical data of wars, social unrests, and dynastic transitions in China spanned from the late Tang to Qing Dy- nasties. Results showed that war frequency in cold phases was much higher than that in mild phases. Besides, 70%— 80% of war peaks and most of the dynastic transitions and nationwide social unrests in China took place in cold phases. This phenomenon could be attributed to the diminishing thermal energy input in cold phases resulting in the fall of land-productivity and hence, the deficiency of livelihood re- sources across society. Accompanied with certain social cir- cumstances, this kind of ecological stress was transformed into wars and social unrests, followed by dynastic transitions in most of the cases. By closer examination, it was even found that war frequency was negatively correlated with tempera- ture anomaly series. As land carrying capacities vary from one climatic zone to another, the magnitude of war-tempera- ture association also differed among different geographic regions. It is suggested that climatic change was one of the most important factors in determining the dynastic cycle and alternation of war and peace in ancient China.