Reported in August’s Human Ecololgy, scientific researchers David D. Zhang, Jane Zhang, Harry F. Lee and Yuan-qing He, have analysed historical Chinese warfare records and paleo-climatological reconstructions. Results show that warfare frequency in eastern China (its southern portion in particular) significantly correlated with the Northern Hemisphere temperature oscillations. Almost all peaks of warfare frequency and dynastic changes occurred in cooling phases.The authors further suggest that in historic China, the reduction of thermal energy during cooling phases significantly shrank agricultural production. Such ecological stress interacted with population pressure and China’s unique historic and geographic setting to bring about the high frequencies of warfare over the last millennium.