Abstract
This paper discusses the history of agricultural and pastoral development on the Loess Plateau by the Qin-Han Empire in ancient China and its relationship with global climate change. Section 1 examines the pastoralization of the Loess Plateau through the establishment and transformation of the Han Dynasty’s ranch-stable pastoral system, which was originally completed under the Qin during the Warring States period. Section 2 explores the expansion of agricultural land on the Loess Plateau during the reign of Emperor Wu of the Western Han, focusing on the New Frontier (Xin Qinzhong) projects and their failure in the Hetao Plain. This failure triggered by flooding in the lower reaches of the Yellow River, ultimately led to a shift toward oasis development in the Hexi Corridor. Section 3 examines the development of agricultural lands on the Qinghai Plateau during the Eastern Han period, the pastoralization of the northern Loess Plateau because Qiang and Xiongnu migration, and the expansion of agricultural lands in the Wuding River basin. This indicates that the proximity of agricultural and pastoral settlements was one of the factors in 2nd century AD rebellions and conflicts. Section 5 presents a model of the relationship between the development of the Loess Plateau and climatic change in the following four phases: 1) The hypsithermal interval (5000 BC–3000 BC) and the 4.2 ka climate event (2400 BC–1800 BC); 2) a drying climate and the social changes from the Spring and Autumn period to the Warring States period and the establishment of the Qin Empire (BC 5C–BC 3C); 3) a warm and humid climate and the expansion of the Han Empire (BC 2C–AD 1C); and finally, 4) cold weather and the fall of the Han Empire (AD 2C–).
https://ror.org/02std5y37 
