Impact of urban spatial structure on carbon emissions and planning strategies

Abstract

Since the Second Industrial Revolution, rapid industrialization and urbanization have significantly increased global carbon dioxide emissions. In response, the international community has reached a consensus on the urgent need to reduce carbon emissions. As the largest developing country, China is undergoing rapid urbanization and industrialization, making it the world's largest emitter of carbon dioxide. Investigating the patterns of China's carbon emissions is therefore crucial for global climate change mitigation. Urban spatial structure, as a key element of urbanization, plays a significant role in shaping carbon emissions and provides valuable insights for low-carbon urban planning, with implications for global sustainable development. Despite its importance, research on the impact of urban spatial structure on carbon emissions in China remains limited. Most studies rely on correlation analyses and lack in-depth exploration. This thesis systematically examines the relationship between urban spatial structure and carbon emissions using remote sensing data, geographic information systems (GIS), and econometric methods. The research is framed within the thematic framework of "spatial distribution—quantitative impact—planning strategy." The study is structured into four main components: First, a literature review synthesizes existing research on urban spatial structure and related theories, establishing the focus of this study. Second, a multi-tiered indicator system is developed to analyze the impact of urban spatial structure on carbon emissions, incorporating factors such as population size, land area, land form, and green space. Third, an empirical investigation is conducted using spatial analysis, principal component analysis, and mediation effect analysis to evaluate the characteristics of urban spatial structure and its effects on carbon emissions from multiple sources. Fourth, urban planning and management strategies for carbon reduction are formulated, grounded in the empirical findings. Using prefecture-level cities in China as the study sample, this research examines the spatio-temporal distribution characteristics of carbon emissions, urban land expansion, and spatial morphology. It further explores the impact of urban spatial structure on carbon emissions and proposes carbon reduction planning strategies from the perspective of urban spatial structure. The following conclusions are drawn: First, a sub-linear relationship between city size and total carbon emissions is observed, with emissions increasing at a slower rate than city size. City innovation mediates the relationship between city size and industrial emissions, producing both increasing and decreasing effects. In less developed cities, the effect of city size on innovation increases emissions, whereas in more developed cities, the reduction effect is yet to be fully realized. Scale effects are evident in heating carbon emissions, with increasing urban population density potentially mitigating heating emissions for the same city size. Larger cities exhibit greater transportation efficiency due to developed public transit systems, although the overall effect remains limited. Second, a super-linear relationship between urban land area and carbon emissions is found, with regional disparities. The western region is most affected, followed by the northeast, central, and eastern regions in China. Urban land area has a stronger impact on transportation emissions in small- and medium-sized cities, while higher urban density significantly reduces heating-related emissions in colder regions. Third, greater complexity in urban land shape is associated with lower transportation emissions but may hinder urban development efficiency, making it a less viable strategy. Conversely, compact urban land form reduce transportation emissions, particularly in smaller cities. Polycentric urban structures lower transportation emissions but increase residential emissions. Urban green space ratios show mixed effects, positively influencing transportation emissions while negatively impacting residential emissions. Compact green space layouts mitigate transportation emissions, while balanced distributions reduce residential emissions. Finally, based on the empirical findings, spatial planning strategies for carbon emission reduction are proposed, with recommendations focused on urban population size and urban land area/form. In conclusion, this research provides a comprehensive analysis of the relationship between urban spatial structure and carbon emissions in China. The findings contribute empirical evidence and multidimensional strategies for carbon reduction, supporting China's sustainable development and global climate mitigation efforts.