The industry–energy–population triple transformation and its pathways to environmental sustainability

Abstract

With global climate action lagging behind and record-breaking heat waves occurring with increasing frequency, China’s role in achieving the temperature control targets of the Paris Agreement has become increasingly critical. As the world’s largest carbon emitter, the pace, trajectory, and regional variations of China’s structural transformation will profoundly influence the global process of deep decarbonization. Based on provincial panel data from 2000 to 2021, this study integrates industrial upgrading (ISU), energy decarbonization (EDI), and population aging (PAG) into a unified analytical framework to systematically examine the joint mechanisms through which these three structural transformations affect environmental sustainability (CI). Different from existing studies that mainly explain carbon emission reduction performance from a single transformation dimension, this paper combines spatial convergence models and panel threshold regression models to further identify the spatial convergence characteristics, dynamic impact mechanisms, and nonlinear interaction effects of carbon intensity evolution. This provides empirical evidence for understanding the regional differences and phased patterns of China’s low-carbon transformation. The results reveal that CI exhibits a pronounced spatial gradient, increasing progressively from northwest to southeast, reflecting significant regional heterogeneity in decarbonization pathways. Overall, the triple structural transformation significantly promotes the decline in carbon intensity, with EDI playing the dominant role, followed by PAG and ISU. Moreover, economic growth strengthens the mitigating effect of PAG on CI. Both EDI and ISU exhibit stage-dependent effects, with their emission-reduction impacts intensifying as economic development surpasses critical threshold levels. Notably, ISU demonstrates a self-reinforcing decarbonization effect once the threshold is crossed. The impact of structural transformation on environmental sustainability is highly dependent on thresholds and context. PAG significantly cuts CI in all regions (strongest in the central, weakest in the eastern); EDI achieves significant emission reduction in the eastern and central regions. ISU lowers CI markedly in the eastern and western regions, yet this effect has not been observed in the central region. This study provides a mechanism-based explanation for regional heterogeneity in China’s low-carbon transition, and offers policy implications for designing differentiated climate strategies and optimizing the implementation of nationally determined contributions (NDCs).