Can economic growth and urban greenness achieve positive synergies during rapid urbanization in China?

Abstract

Rapid urban expansion reflects the increasing economic growth in China. As an original conceive for urban sustainability, economic growth contributes to vegetation changes. However, the spatiotemporal heterogeneity of the relationships between these two factors remains unclear in China. After analyzing the spatiotemporal characteristics of the urban expansion in different cities in China from 2002 to 2020, we found a rapid and continuous urban expansion in China, with the mean annual expansion of 1710.96 km2 year−1 (p < 0.01). However, based on the trends of annual maximum enhanced vegetation index (EVImax) and the nighttime light (NTL), a strong incoordination status (areas with significant increasing NTL (p < 0.05) but significantly decreasing EVImax) between urban greenness and economic growthwas found during this rapid urban expansion period. Spatially, >60% of cities showed incoordination status and 38.08% of cities showed strongly incoordination status. At pixels levels, these strong incoordination status in urban areas can be fully explained by long-term average NTL digital Number (DN) gradient.Based on a piecewise linear regression model, the proportion of areas with the strong incoordination status was significantly increased by the 1.07% DN−1 (p < 0.01) when multi-year average NTL value is <50, but decreased strongly afterward, with the slope of −2.96% DN−1 (p < 0.01). The strong incoordination between urban greenness and economy can be rapidly mitigated with the rapid economic growth. This threshold can be a critical indicator for decision-makers in identifying and analyzing the status of ecological civilization in various regions of China.