Spatio-temporal patterns and spillover effects of synergy on carbon dioxide emission and pollution reductions in the Yangtze River Delta region in China

The synergy of pollution and carbon dioxide (CO2) emission reductions has been perceived as a crucial mechanism and central target for fulfilling green economic and social development in China. With the combination of the coupled coordination degree model (CCDM) and spatial autocorrelation analysis, we explored the spatio-temporal trends of coupling coordination degree (CCD) between pollution and carbon reductions in the Yangtze River Delta (YRD) between 2011 and 2019, and the spatial Durbin model (SDM) was used to study the driving mechanisms behind CCD. The results demonstrate the coupling coordination degree demonstrated a staged upward trend with a heterogeneity of spatial distribution trend of "High-East, Low-West". Furthermore, the prominent spatial autocorrelation has led to the emergence of radiation effect of synergistic management in some central cities. The SDM indicated that the CCD are greatly influenced by multifarious social-economic factors such as opening-up level, population size, energy intensity, economic development, and technological advancement to varying degree. However, there was substantial discrepancy among the spatial spillover effects of contributory factors on CCD amongst cities of various synergistic categories. Based on regional disparities in synergy levels, this study proposes corresponding policy implications, including fostering cooperative governance, enhancing policy innovation, and promoting technological progress.