Allometric evolution between economic growth and carbon emissions and its driving factors in the Yangtze River Delta region

Balancing economic growth and carbon emissions reduction is crucial for achieving integrated development in the Yangtze River Delta (YRD) region and meeting green initiatives. This study utilized the allometric growth model to analyze the decoupling relationship between economic growth (EG) and carbon emissions (CE) in the YRD city cluster from 2000 to 2017. In addition, the geographically weighted quantile regression model (GWQR) was used to identify factors influencing this relationship. The main findings are as follows: (1) from 2000 to 2017, a V-shaped positive correlation trend was observed between EG and CE. Meanwhile, the spatial correlation level declined, with strong incidence values concentrated in the central and northern parts of the delta region. Conversely, areas with low incidence intensity were scattered across certain counties in the Anhui Province and the northwest region of Zhejiang Province. (2) From 2000 to 2017, the region witnessed a dominant I-type negative allometric growth pattern with weak economic expansion between EG and CE. In addition, most counties underwent a shift from positive allometry to negative allometry, particularly types I and II. (3) The influence of various factors on allometric growth pattern varied across counties and quantiles. Population density (POP) consistently had negative impacts at the 0.1 and 0.9 quantiles for all counties, while showing both positive and negative effects at the 0.3, 0.5, and 0.7 quantiles. Urbanization rate (URB) generally had a negative impact, except at the 0.7 quantile. The ratio of the tertiary industries to GDP (TER) had a negative effect only at the 0.1 quantile but had mixed positive and negative effects at other quantiles. Carbon sequestration of terrestrial vegetation (CSE) exhibited both positive and negative impacts at higher quantiles but consistently had a positive impact at the 0.1, 0.3, and 0.5 quantiles. These findings provide valuable insights into the complex relationship between these factors and allometric growth in different regions and quantiles, informing policy-making and sustainable development strategies.