Decoupling Urban Development and Ecological Changes: A Case Study of Shanghai-Hangzhou Bay Urban Agglomeration

With the acceleration of urbanization, there has been rapid expansion in urban areas, the associated intense human activity exerting serious impacts on urban environments. Clarifying the interaction between urbanization and the urban environment is important for promoting high-quality sustainable regional development. In this work, a decoupling model is introduced that was used to measure the interaction between (demographic, economic, spatial, and social) urbanization and the urban environment (environmental status, pressure, and response) in the Shanghai-Hangzhou Bay urban agglomeration (SHBUA) from 2003 to 2018. The results showed that: (1) the development level of the four urbanization subsystems improved to different degrees, but overall, the speed of the economic and spatial urbanization (builtup land sprawl) was faster than the social and demographic urbanization; (2) from 2015 to 2018, the relationship between urbanization and the environment in Huzhou, Jiaxing, Ningbo, and Shaoxing was strongly decoupling, indicating negative growth in the urban environment and a trend of environmental deterioration, with increased urbanization coming at the cost of environmental damage; and (3) except for Shanghai, the growth rate of the four subsystems of urbanization in the cities was higher than that of the overall environmental level. Cities with higher urbanization levels were found to be more likely to achieve harmony between urbanization and the urban environment. This study provides a basis for analyzing the relationship between urbanization and the urban environment in urban agglomerations, along with decision-making support for a more harmonious integration of man with nature in the SHBUA. China is currently undergoing a dramatic urbanization process, with populations exploding and construction land expanding in the cities. In addition, ecological cities have been proposed that would increase the area of urban ecological space, causing a negative impact on the urban environment. Despite this process taking place in China, it is unclear how urbanization affects the urban environment, which is of great significance for avoiding the wrong development mode and for realizing sustainable development. From our analysis, we found that, for cities with low levels of urbanization, such as Huzhou, Jiaxing, Ningbo, and Shaoxing, increasing urbanization accompanied a deterioration in the urban environment. Contrastingly, in the more developed cities, such as Shanghai, greater development of the economic and social environment meant more attention could be paid to the construction of the urban environment. Thus, urban environmental improvement and urbanization complement each other. By exploring the relationship between the degree of urbanization and the urban environment, it is possible to inform urban development and environmental management plans in order to mitigate the negative impact of urbanization and improve the urban environment to achieve sustainable urban development for the coming decades.