Multiscale spatial heterogeneity and interactions of digital economy development and urban-rural income inequality on energy-related carbon emissions in Chinese cities

While digital economy development and urban-rural income inequality are considered important factors affecting carbon emissions, the spatial multiscale and interactive effects of both on energy related carbon emissions remain unclear. This study employs a multiscale geographically weighted regression combined with optimal Geodetector method, based on Chinese 275 cities across 2005, 2010, 2015 and 2019 year, to analyze the spatial heterogeneity and interaction effects among digital economy development, urban-rural income inequality, and other factors influencing energy-related carbon emissions. The results identify that (1) The impact of digital economy development and urban-rural income inequality exhibits considerable spatial heterogeneity. Digital economy development demonstrates a continuously expanding spatial influence, with its bandwidth increasing from 85 to 163, whereas the impact of urban-rural income inequality remained relatively stable in its spatial scope but intensified in 2019. (2) The interaction between digital economy development and urban-rural income inequality of the northeast region shifts from a non-linear weakening to a double-factor enhancement, while in the central and western regions it continued to strengthen. In contrast, in the eastern region, the independent impact of digital economy development exhibits an inverted U-shaped trend, and its interaction with urban–rural income inequality shifts from a strong combined effect to a nonlinear diminishment, indicating a nascent synergistic effect on emission reduction. These findings indicate that achieving carbon neutrality requires leveraging digital economy development, reducing urban-rural income disparities, while formulating differentiated synergistic emission reduction strategies based on regional interaction characteristics.