Research On Evaluation Of Comprehensive Land Carrying Capacity Of Beijing-Tianjin-Hebei Region Based On System Dynamics

With rapid economy and society development,the resource and environmental issues in Beijing-Tianjin-Hebei region have become more and more prominent.Under this background,how to improve the comprehensive land carrying capacity has become the key to achieve sustainable development.Therefore,the evaluation of comprehensive land carrying capacity in Beijing-Tianjin-Hebei region are of great significance.This thesis mainly studies the following contents: first,constructing a system dynamics model of comprehensive land carrying capacity,and dividing the system into four subsystems: resource,environment,society and economy.Based on historical data,the model equations are constructed,the parameters are determined,and the model is tested.Second,carrying out the historical evaluation of the comprehensive land carrying capacity.This study uses the mean square error method to determine index weights in the multi-index evaluation system.By using historical data and simulation data respectively,the land carrying capacity of resource,environment,society and economy is calculated,as well as the comprehensive land carrying capacity.Third,using the established system dynamics model to simulate and predict the four different development modes of Beijing-Tianjin-Hebei region,which are expansion,intensive,environmental-friendly and coordination modes.The land carrying capacities of resource,environment,society,economy and comprehensive land carrying capacity under the four modes are evaluated accordingly.The main findings are: first,the comprehensive land carrying capacity of Beijing-Tianjin-Hebei region in 2000-2017 shows an increasing trend,with only a slight decline in some years.The land resource carrying capacity first decreases and then continues to rise.The land environmental carrying capacity fluctuates within a small range.The land social and economic carrying capacities continue to rise.Second,the situation is different from Beijing,Tianjin and Hebei region.Specifically,the land resource carrying capacity of Hebei is much higher than that of Beijing and Tianjin,and Beijing's land social and economic carrying capacity are much higher than those of Hebei.After calculation combined with corresponding weights,Hebei's comprehensive land carrying capacity is the highest,Beijing is slightly lower than Hebei,and Tianjin has a certain gap with the former two.Third,simulation analysis of different development modes in Beijing-Tianjin-Hebei region shows that the overall performance of the coordinated development mode is the best,with the comprehensive land carrying capacity of the early stage improving fast and exceeding the other three modes in a short period of time.It is followed by the environmentally-friendly development mode,which can continue to grow but at a low rate.The next is the intensive development mode,with similar early change trend to the coordinated development mode.However,due to the large decline in the later period,there is a certain gap with the former two.The expansion development mode is the most unacceptable,its early comprehensive land carrying capacity improves the fastest,but then it falls sharply,resulting in the final comprehensive land carrying capacity below the initial level.Based on the conclusions above,the thesis puts forward the following suggestions:(1)Adhere to the Beijing-Tianjin-Hebei integrated development strategy,and complement each other's advantages.(2)The economic development mode should insist on intensive use of resources and refuse to exchange high land input for growth.(3)Insist on the coordinated development of environmental protection and economic development.