Driving mechanism of the allometric relationship between economic development and carbon emissions in the Yangtze River Delta urban agglomeration, China

Exploring the allometric characteristics and driving mechanisms of economic development (ED) and carbon emissions (CE) is significant for promoting regional sustainable development. This study applied the panel grey relational model and the Driscoll–Kraay estimation method to investigate the internal mechanism of economic development and carbon emissions, to analyse their spatiotemporal correlation and allometric characteristics, and finally to characterize the impact mechanism of their allometric growth of the Yangtze River Delta urban agglomeration (YRDUA). The results show that (1) the spatiotemporal distribution patterns of economic development and carbon emissions are coincident and positively correlated, with the strength of the time-series correlation between them being less than the average value of 0.757 from 2016 onward. (2) The economic development-carbon emissions vertical allometric growth coefficient showed a trend of increasing and then decreasing and was always in a negative allometric growth state. The relative growth rate of carbon emissions was lower than that of economic development, and the per unit GDP carbon emissions decreased slightly. The horizontal allometric growth coefficient showed that more than 90% of the cities are in the negative allometric growth state, and that the negative allometric II and III levels are the main ones. (3) Per capita GDP, industrial structure, and energy structure are the boosting factors of the allometric growth coefficient, while population density and environmental regulation play a restraining role. Trade openness showed a restraining effect in 2010–2015 and turned into a promoting effect in 2016–2020. In both stages, the energy structure is one of the most crucial driving factors. The findings reported in this study can provide support for urban agglomerations to achieve low-carbon city development goals.