Economic Growth Does Not Mitigate Its Decoupling Relationship with Urban Greenness in China

Accompanied by China's rapid economic growth, significant urban greening has occurred in Chinese cities, in particular in the urban core areas. In contrast, rapid urbanization and economic growth also led to a high probability of vegetation degradation in urban fringe regions. However, these significant spatial differences in urban greenness associated with economic growth in Chinese cities are not well understood. This study explored the spatiotemporal characteristics of the nighttime light (NTL) and annual maximum enhanced vegetation index (EVImax) in urban areas from 2001 to 2020. A strong decoupling status between economic growth and urban greenness on the national scale was found. Overall, 49.15% of urban areas showed a decoupling status. Spatially, this percentage of urban areas with a decoupling status would significantly decrease when the long-term average NTL surpasses 51. Moreover, this significant threshold of decoupling status was found in 189 cities out of 344 (54.65%) in China. This threshold in each city showed significant spatial heterogeneity but can mostly be attributed to the gradient in the long-term average precipitation (P-mean) of each city during the period of 2001-2020. Specifically, a spatial increase in P-mean of 100 mm responded to a decrease in the threshold of 0.4 DN (p < 0.01). In contrast, there was no significant correlation between the threshold and the economic growth status of each city. Our results provide valuable insights for coordinating the development of urban greening and economic growth.

Automated summary

With China's rapid economic growth, urban greening in Chinese cities, particularly in urban core areas, has significantly improved. However, rapid urbanization and economic growth have also led to a high likelihood of vegetation degradation in urban fringe regions. This study examined the spatiotemporal characteristics of nighttime light and enhanced vegetation index in urban areas from 2001 to 2020, and found a strong decoupling between economic growth and urban greenness on a national scale, with 49.15% of urban areas showing a decoupling status.