Can urban land maturation and efficiency enhancement meet future economic growth demands in China’s coastal cities

While research on land use efficiency (LUE) - defined as the added value of secondary and tertiary industries per unit of urban land - has advanced considerably, systematic understanding of its temporal dynamics during urban land maturation and its growth potential remains limited. This study develops a novel analytical framework for urban land maturation and efficiency enhancement (ULMEE), conceptualizing it as a dynamic process of functional transition from singular to multiplex configurations with concomitant LUE improvements over time. Using multi-source data fusion and LitPop method to identify the spatiotemporal patterns in pixel-scale LUE among Chinese coastal cities, this study reveals that: the average LUE of urban land at the ages of 5, 15, and 25 years is 323 million, 695 million, and 922 million yuan/km2, respectively, validating the ULMEE process. Because as much as 69% of urban land is under 15 years old, there remains plenty of potential for ULMEE. This study applies the shared socioeconomic pathways (SSPs) method to reveal that, except for scenario SSP3 (regional rivalry pathway in SSPs), cities of all scales will rely on ULMEE to meet the demands of a 5% economic growth rate before 2035. However, after 2040, cities of all scales will need to add new urban land to meet the demands of economic growth. This study provides a theoretical foundation for restricting the scale of newly added urban land in China’s coastal cities and selecting potential pathways for ULMEE. These findings provide a theoretical basis for sustainable urban expansion strategies with global implications for developing economies.