Thirty years of 3-D urbanization in the Yangtze River Delta, China

• Published in: The Science of the total environment 2024-11, Vol.949, p.174909, Article 174909
• Main Authors: Yin, Chenglong, Chen, Ruishan, Xiao, Xiangming, Van de Voorde, Tim, Qin, Yuanwei, Guo, Xiaona, Meng, Fei, Pan, Li, Yao, Yuan, Li, Yinshuai
• Format: Article
• Language: English
• Subjects: 3-D urban expansion; Couple analysis; Dominant type; Sustainable development; Urban land resources; Yangtze River Delta
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.174909

Accurately capturing the urbanization process is essential for planning sustainable cities and realizing the United Nations Sustainable Development Goal 11. However, until recently, most of the studies on urban expansion in the world have focused on area growth but have little knowledge of height dynamics. This study mapped the spatial distribution of urban built-up areas (UBA) in the Yangtze River Delta (YRD), one of the most urbanized regions in China, to investigate the spatio-temporal evolution in both the horizontal and vertical directions from 1990 to 2020. We coupled and analyzed the horizontal and vertical urban expansion from the 3-D perspective and identified the dominant types. The results showed that 30 cities (73.17 % of the total number of cities) were increasing in the 3-D combined expansion intensity. The decreasing cities were mainly located in Anhui Province. Despite the increasing number of skyscrapers, horizontal growth has dominated urban expansion over the past three decades. The UBA area of the YRD has grown from 4,855.30 km2 to 44,447.15 km2, while the average building height has slowly decreased by 1.26 m. Significant unevenness and differences existed in horizontal and vertical expansions of varying provinces and cities. Our study can accurately grasp the 3-D urban expansion process in the YRD and could promote the efficient development and sustainable utilization of urban land resources in China and beyond. [Display omitted] •This study analyzed the 3-D urban expansion process in the YRD of China.•Promoted the efficient development and sustainable utilization of urban land resources•The average building height of the YRD and most cities showed a downward trend.•There was significant unevenness in urban expansion across the YRD.•This study typically represented China's 3-D urban development process.