China's urbanization SD modelling and simulation based on land use

Abstract

China is still experiencing the process of rapid urbanization. How will cultivated land and ecological land, such as woodland, grassland, and water body change? Will construction land continue to grow rapidly? These are not only the concerns of national macro-policy makers, but also the specific problems faced by scholars and ordinary people. This paper attempts to make a multi- scenario analysis of the above issues by constructing a system dynamics (SD) model of China's urbanization based on land use. This SD model integrates the relationship between land use and multi-factors in the urbanization process, including economy and population, and highlights the dominant role of land resources in the urbanization process. The conclusions can be drawn as follows: First, according to the results of stock- flow validation and sensitivity analysis, the China's urbanization SD model based on land use is effective with great reliability and stability. Therefore, the model can be used to predict and simulate the future trend of urbanization process and land resource use in China. Second, in order to meet the requirement of the "National Land Planning Outline (2016- 2030)" that the amount of cultivated land should be maintained at 12166.67 × 104 hm2, there will be a need to supplement 83.17 × 104- 412.67 × 104 hm2 of cultivated land from other types of land by 2050. This is because the cultivated land will show a decreasing trend in the China's urbanization in the future. In the low scenario, medium and high- speed economic growth, the amount of cultivated land by 2050 will be reduced to 12366.60 × 104, 12083.50 × 104, and 11754.00 × 104 hm2, respectively. Third, with the improvement of urbanization levels, the total amount of construction land will increase accordingly. Specifically, if China's urbanization level reaches 78% by 2050, the total construction land will increase to 4283.89×104-4464.90×104 hm2, with a net increase of 155.87 × 104- 342.88 × 104 hm2 compared with 2020. Fourth, the overall trend of ecological land in 2020-2050 is to increase first and then decrease. By 2050, the woodland will significantly increase to 29406.60 × 104- 30733.80 × 104 hm2, the grassland will decrease to 25784.50 × 104- 27809.90 × 104 hm2, and the water body will not decrease and even increase slightly, the area of which would be 4283.89 × 104- 4464.90 × 104 hm2. The research results can provide scientific supports for the multi- scenario simulation, evaluation, and decision- making of territorial spatial planning.