Relationship between climate change and wars between nomadic and farming groups from the Western Han Dynasty to the Tang Dynasty period

Abstract. In ancient China, the change in regional agriculture and animal husbandry productivity caused by climate change led to either wars or peaceful relations between nomadic and farming groups. From the Western Han Dynasty to the Tang Dynasty there were 367 wars between the two groups. The nomadic people initiated 69 % of the wars, but 62.4 % were won by the farmers. On a 30 year-period timescale, warm climates corresponded to a high incidence of wars. The conflicts between the nomadic and farming groups took place in some areas which are sensitive to climate change. During the cold periods, the battlefields were mostly in the southern regions. The main causes which leading to the above results are following: (1) warm climate provided a solid material foundation for nomadic and farming groups, especially contributed to improve the productivity of nomadic group; meanwhile, the excessive desire for essential means of subsistence in nomadic group could led to wars. (2) During the cold periods, people of farming group moved to the south and construct the south, meanwhile, nomadic group occupied the central plains, thus the battlefields also changed. As the background, climate change plays an indirect role in wars between groups.