Study On System Simulation And Relationship Between Coordinated Development Of Urbanization And Carbon Emissions In The Yangtze River Delta

As one of the regions with the highest urbanization level in China,the Yangtze River Delta plays an important role in the process of urbanization.On the other hand,high-speed urbanization has led to a series of problems about unbalanced development and internal imbalance,and inevitably aggravated the consumption of fossil energy,resulting in a significant increase in carbon emissions.Therefore,it is of significance to carry out study on system simulation and relationship between coordinated development of urbanization and carbon emissions for exploring the comprehensive path of high-quality urbanization and low-carbon city construction.Taking the Yangtze River Delta as the research object,this thesis analyzed the spatio-temporal evolution of urbanization coordinated development and carbon emissions,explored the relationship between them from three aspects: causality,corerelation mechanism and co-evolution.Finally,an integrated system of coordinated development of urbanization and carbon emissions was constructed to simulate the evolution trend under multiple scenarios.The main conclusions are as follows:(1)Based on coordinated development model and carbon emission model,the spatio-temporal evolution of coordinated development of urbanization and carbon emissions in the Yangtze River Delta was revealed.The coordinated development level of urbanization had been continuously improved,experienced three stages of unbalanced recession,transition and coordinated development and realized the transformation from mild imbalance to good coordination.The areas with higher coordination development level had formed a Z-shaped coupling and coordinated development zone of "Nanjing-Shanghai-Hangzhou-Ningbo".The total carbon emissions during 2000-2018 increased continuously,but the growth rate slowed down gradually.And there was a significant spatial difference in total carbon emissions,with the distribution pattern of "high in the middle,low in the north and south".(2)The inner relationship between coordinated development of urbanization and carbon emissions was explored by the panel Granger test,panel threshold model and co-evolution curve.The coordinated development level of urbanization was the Granger cause of carbon emissions,and vice versa.The effects of urbanization subsystems on carbon emissions were different.The impact of the coordinated development of urbanization on carbon emissions presented an inverted U-shaped curve that promoted first and then suppressed,showed a significant double threshold effect.Economic development and population growth were the leading factors for carbon emission growth,while the decrease of energy intensity can effectively curb carbon emissions.The synergistic evolution process between coordinated development of urbanization and carbon emissions presented an obvious three-stage disciplinarian,and the development characteristics of each stages were obviously different.(3)Combined with system dynamics model and coordinated development model,a comprehensive system of coordinated development of urbanization and carbon emissions was constructed,on this basis,the baseline scenario,low carbon scenario,intensified low carbon scenario,coordinated development scenario and intensified coordinated development scenario were setted,and the collaborative evolution trend under different scenarios during 2019-2035 was simulated.Under the baseline scenario,urbanization had not yet reached superior coordination due to the lagging development of economic,social and ecological urbanization.The total carbon emissions continued to increase and failed to peak carbon emissions.The other four scenarios can all reduce carbon emissions to different degrees,but the evolution trend of coordinated development of urbanization was different.In summary,intensified coordinated development scenario can not only conducive to carbon emission reduction,but also can promoted urbanization to superior coordination,which was an effective way to achieve high-quality urbanization and low-carbon city construction.