Study On The Relationship Between Urban Compactness And Urban Carbon Emissions In The Bohai Sea Rim

With the further rise in total global carbon emissions,energy saving and emission reduction has become imminent.Cities play an important role in the global carbon emission process.According to statistics,cities emit about 75% of the global total of carbon dioxide,and in coastal cities in eastern China,the proportion is close to 80%.Against the backdrop of resource constraints and emission reduction challenges,Chinese cities need to explore new ways of development.Compact city theory is an emerging planning and design concept that aims to promote sustainable urban development,which encourages cities to build denser,multi-functional and pedestrian-friendly communities.By building cities in a compact form,a more sustainable,low-carbon and liveable urban environment can be achieved.Therefore,exploring the relationship between high-quality urban construction and low-carbon economic development is crucial to achieving sustainable regional development.In this thesis,43prefecture-level cities in the Bohai Sea Rim region are studied,spanning the period2006-2020.Firstly,based on the compact city theory,the entropy value method is used to construct a comprehensive evaluation index system for city compactness,and the carbon emissions of cities at the municipal scale are calculated by the nighttime light inversion method to explore the characteristics of their spatial and temporal pattern evolution.Secondly,the relationship between urban compactness and urban carbon emissions and its driving factors are investigated using the Tapio decoupling model and geographic probes.Finally,from the perspective of compact cities,recommendations and suggestions on the high-quality and sustainable development of cities in the Bohai Rim are presented.The findings of the study are as follows.(1)The entropy method was applied to measure the compactness scores of 43prefecture-level cities in the Bohai Rim region from 2006 to 2020.Economic compactness,public transport compactness and land compactness are the main factors affecting the compactness of cities in the Bohai Rim.(2)The carbon emission data of the Bohai Rim region are measured by the inversion method of nighttime light data.From the time-series evolution characteristics,the total carbon emission,carbon emission intensity,per capita carbon emission and per capita carbon emission of cities in the Bohai Rim region show different degrees of growth trends.From the spatial evolution characteristics,the total carbon emissions in the Bohai Rim region form a pattern of two highs,one medium and one low;the carbon emission intensity generally shows a pattern of high in the west and low in the east;and the per capita and per capita carbon emissions show a spatial characteristic of "high in the southwest and low in the northeast".The spatial evolution of urban carbon emissions in the Bohai Rim is further revealed through a cold-spot analysis of the changes in urban carbon emissions in the Bohai Rim.(3)By analysing the decoupling relationships of the carbon emission indicators of 43prefecture-level cities in the Bohai Sea region,the decoupling relationship between urban compactness and carbon emission intensity in the Bohai Sea region varies significantly,showing a general trend of "declining decoupling-strong decoupling-strong negative decoupling-weak decoupling".The geodetectors show that economic compactness,land compactness,ecological compactness and transport compactness have a greater influence on the decoupling relationship.The results of the geodetector interaction show that the main factors influencing the evolution of the decoupling relationship between urban compactness and carbon emission intensity in the Bohai Rim are output intensity per unit area,density of tertiary industry output,GDP per capita and road network area per capita.