Indirect Urbanization Impacts Shape Vegetation Growth and Carbon Sink Dynamics: Synergies and Trade-Offs across China

Urbanization significantly influences vegetation dynamics with both direct and indirect effects. Direct impacts involve the conversion of natural or vegetated land into impervious surfaces, whereas indirect impacts result from urbanization-induced changes in the climate, environmental conditions, and human activities. This study quantifies these direct and indirect effects across 360 Chinese cities using spatial statistical analyses and a random forest model along urban-rural gradients. Our findings show that indirect urbanization fosters vegetation growth (36.2%) and enhances carbon sinks (24.2%), with stronger effects in urban centers that decrease toward rural areas. Furthermore, 52.5% of the study grids demonstrated positive synergies between vegetation growth and carbon sinks, primarily driven by indirect urbanization factors, with significant influences from climatic and anthropogenic variables. Notably, indirect urbanization offsets approximately 38.5% of the carbon losses caused by impervious surface conversion. These results underscore the complex interplay between vegetation dynamics and urbanization, offering valuable insights for sustainable urban planning.