**1. Introduction**

China has become one of the world's major consumers of energy and emitters of carbon dioxide. The Chinese government has therefore set a goal to reach peak carbon emissions by 2030 and carbon neutrality by 2060 [1,2]. Cities, as highly concentrated places of population and industry, typically produce about 80% of total carbon emissions; in Chinese cities, the proportion is as high as 85% [3]. Therefore, controlling urban carbon emissions is crucial for achieving emission-reduction targets [4,5]. In China, with rapid urbanization and enormous imbalances in regional development, some cities are growing, while others are shrinking [6,7]. The populations and economies of growing and shrinking cities are varied, resulting in divergent effects on carbon emissions. Accordingly, CO2 emission-mitigation policies need to be adjusted according to the characteristics of different cities [5]. It is necessary, therefore, to explore the characteristics and driving factors of carbon emissions in growing and shrinking cities to more effectively achieve emission targets.
