A Human-Land System Dynamics Model of Ancient China: A Case Study in the Downfall of the Western Han Dynasty

The reason for the downfall of ancient dynasties in China is one of the most controversial topics in the academic circle. The scarcity of important reference data such as ancient cultivated area, population, and food supply per capita led to the insufficient comprehensive and systematic basis for the research results. For these defects, this paper, taking the Western Han Dynasty as an example, reconstructed the dynamic changes of key variables such as population, cultivated area and food supply per capita by establishing the human-land system dynamics model, and designed different scenarios so as to systematically analyze and attribute the fundamental reason for the downfall of the dynasty. The human-land system dynamics model can accurately reproduce the dynamic changes of key variables such as population, cultivated area, food production and food supply per capita in the Western Han Dynasty, and it is affected by factors such as climatic disasters and government efficiency (officials-people ratio). Conclusion: Through the simulation results in different scenarios, national food supply per capita, even at the end of the Western Han Dynasty, was above the famine critical value, and the national famine of the whole country never happened. At the end of the Western Han Dynasty, there was an increase in the ratio of officials to people, and decline in the food transportation relying on the government efficiency, resulting in the food supply per capita in some regions below the critical value of famine, which triggered the peasant uprising. If the government efficiency was increased by 1.3 times, downfall of the Western Han Dynasty would not happen. Therefore, government efficiency is the most crucial factor for the downfall of the Western Han Dynasty.