Abstract:

Although it is widely acknowledged that urban expansion is one of the most important processes affecting global sustainable development, an increasing number of cities are shrinking across the world. There is growing interest in urban shrinkage because it has reached a global scale, decisively affecting the fate of many cities over the past half-century. In recent years, urban shrinkage has become a big challenge for China's new-type urbanization construction and sustainable development due to slower economic growth, rapid aging, and massive migration. Although research on urban shrinkage has rapidly increased in recent years, many theoretical and methodological issues must be further discussed, such as the identification of shrinking cities from multiple dimensions and the dynamic process of urban shrinkage. Therefore, this paper proposes a new, multi-dimensional analysis framework from the following aspects of urban shrinkage: types of shrinking dimensions, number of shrinking dimensions, and temporal evolution. Subsequently, this framework was employed to explore the spatial-temporal evolution characteristics of shrinking cities in China by means of GIS spatial analysis and grey relational analysis. The results indicate the following: 1) this new framework presents satisfactory flexibility and higher adaptability, and it helps to enhance the comparability of shrinking city studies. Furthermore, it has considerable potential in promoting the construction of a multi-dimensional typology for shrinking cities and analyzing the possible temporal evolution paths of urban shrinkage. 2) In the four periods of 1995-2000, 2000-2005, 2005-2010 and 2010-2015, the proportion of population shrinking cities accounted for 9.55%, 20.34%, 15.34% and 19.72% of the total cities in China respectively; while the proportion of economic shrinking cities were 5.32%, 4.85%, 0.47% and 8.29%, and the proportion of space shrinking cities were 7.04%, 3.44%, 3.76% and 1.72% respectively. Population shrinkage is the main characteristic of urban shrinkage in China. From the perspective of spatial distribution, population shrinkage is a national phenomenon because such cities are distributed in various regions in China. As for temporal evolution, the proportion of population-shrinking cities in Western and Northeast China, with relatively lagging economic development, increased significantly. 3) The extent of urban shrinkage in China is not very serious because the population shrinkage rates of the majority of shrinking cities were less than 3%, and only two continuous population-shrinking cities have been identified: Yakeshi (Inner Mongolia) and Qidong (Jiangsu Province). Furthermore, no continuous economic- or space-shrinking city exists in China. 4) Three interesting paradoxes were revealed regarding urban shrinkage in China: the built-up areas in 93.03% population-shrinking cities were expanded, the gross domestic product (GDP) of 92.37% population-shrinking cities were increased, and the built-up areas of 94.57% economic-shrinking cities were expanded. The emergence of the above paradox has a strong relationship with China's factor-dependent economic growth model and local governments' land financing model.

Key words: urban shrinkage, analysis framework, new-type urbanization, population loss, China