In a landmark study addressing the intersection of climate policy and social justice, researchers Song, Li, and Lee have conducted an exhaustive spatial-temporal analysis on the impact of China’s Air Pollution Prevention and Control Action Plan (APPCAP) on energy equity. The research, published in Humanities and Social Sciences Communications (2025), delves into the multifaceted effects of climate interventions beyond environmental quality, unraveling the complex dynamics that influence equity in energy distribution across Chinese cities. Utilizing advanced spatial econometric models combined with rigorous empirical data spanning nearly two decades, the study reveals how regional linkages and policy measures act in tandem to reshape energy equity landscapes with reverberating consequences over time.
Energy equity, a critical dimension for sustainable development, remains unevenly distributed among China’s urban centers, reflecting socioeconomic disparities and geographical heterogeneity. Prior investigations of APPCAP largely focused on localized environmental improvements without explicitly accounting for cross-regional spillover effects. This novel research fills that gap by incorporating endogenous spatial-temporal weight matrices, developed from a robust methodological foundation rooted in the ratio of Moran’s global index values across years, to capture the nuanced transmission pathways of policy impact between cities.
Central to the analysis is the deployment of the Dagum Gini coefficient, a sophisticated statistical measure dissecting energy equity disparities into intra-regional differences, inter-regional disparities, and super-variable density—which quantifies overlap or inequality intensity between groups. The authors extend standard Gini computations by decomposing energy equity variance across eastern, central, and western regions, providing a granular depiction of spatial heterogeneity and temporal trends from 2005 to 2022.
Over this 17-year span, China’s energy equity Gini coefficient demonstrates a sluggish but perceptible downward trajectory, from 0.361 to 0.316. This trend reflects incremental progress in ameliorating energy access imbalances among urban inhabitants. Nonetheless, the persistence of relatively high Gini values indicates deep-rooted structural inequalities. Notably, the eastern region exhibits the highest intra-regional disparities, with only a modest decrease, while the central region demonstrates the most balanced energy equity metrics. The western region’s stability in energy equity, hovering around a Gini of 0.265, suggests an entrenched status quo, necessitating targeted policy focus.
Equally telling are the inter-regional Gini coefficients, which expose significant energy equity chasms, particularly between the prosperous eastern and comparatively underdeveloped western regions. The East-West inter-regional Gini peaks at 0.391 in 2005 and remains markedly elevated, underscoring the enduring spatial inequities that challenge national cohesion in energy provision. The dominance of inter-regional differences—contributing almost 48% on average to the total energy equity variance—signals that efforts to harmonize regional development trajectories remain critical.
The study’s methodological rigor is exemplified in its construction of five diverse baseline spatial weight matrices. These matrices incorporate varying dimensions, including K-nearest neighbor relations, economic scale (GDP), intercity highway mileage reciprocals combined with economic scales, geographic distance, and threshold-based connections. By subjecting these matrices to rigorous testing using Fisher’s t-test and assessing their correspondence with observed spatial patterns, the researchers determine that a hybrid measure based on reciprocal intercity highway mileage and economic scale (denoted W3) exhibits superior effective correlation for modeling spatial spillover in energy equity.
To unpack the policy effects with temporal nuance, the research integrates these spatial weight matrices with a novel endogenous temporal weighting approach derived from the ratios of annual global Moran indices. This generates an innovative spatiotemporal weight matrix framework harnessing the Kronecker product to precisely model inter-city energy equity dynamics over time. This endogenous construction ensures that the model’s parameters are attuned to the evolving spatial structure and temporal dependencies in energy equity, overcoming limitations of exogenous spatial specifications.
The empirical heart of the study lies in deploying spatial Difference-in-Difference (DID) econometric models to estimate the causal influence of the APPCAP across cities. The authors compare traditional spatial models with their extended spatiotemporal counterparts, revealing consistent and robust positive effects of the climate policy on enhancing local energy equity levels. The spatial autoregressive coefficients remain statistically significant at the 1% level, reinforcing the presence of meaningful spatial spillover effects. In essence, policy-driven improvements in one city’s energy equity catalyze gains in interconnected regions, facilitated through geographic proximity and economic ties.
Robustness checks further validate these findings by substituting alternative spatial matrices (notably the K-nearest neighbor-based matrix W1 and its spatiotemporal analogue TW1). Results persist in confirming that APPCAP effectively elevates energy equity while underscoring how regional connectivity fosters broader systemic improvements beyond individual locales. This robust affirmation reassures policymakers of the resilience of climate initiatives in driving equitable energy transitions within complex urban networks.
The implications of this research are profound and multifaceted. By illuminating the endogenous mechanisms and spatiotemporal propagation embedded within energy equity transformations, it establishes a compelling argument for integrating spatial spillover considerations into climate policy design and evaluation. The findings suggest that localized policy efforts yield dividends not solely within direct jurisdictions but also reverberate across adjacent regions, asserting the importance of coordinated regional strategies. This insight challenges policymakers to rethink energy transition frameworks through lenses that recognize interdependence and dynamic spatial interactions.
Furthermore, the persistence of inter-regional energy disparities—particularly the stark divide between eastern and western China—signals a need for more focused investment and infrastructural development in lagging areas. Successful mitigation of these disparities could unlock broader sustainable development benefits, ensuring that energy affordability, accessibility, and environmental improvements are equitably shared. The methodological sophistication in measuring and modeling these disparities equips decision-makers with critical analytical tools for tracking progress and designing targeted interventions.
This study also marks a significant advancement in the application of spatial econometrics within environmental justice research. Its innovative coupling of endogenous spatiotemporal weighting matrices with causal inference models represents an important methodological contribution, expanding the toolkit available for analyzing complex policy impacts in systems characterized by spatial dependence and temporal evolution. Such analytical depth enhances confidence in attributing policy success and identifying effective levers to promote just and sustainable energy futures.
In summary, the research by Song, Li, and Lee offers an insightful and technical exploration of how China’s APPCAP affects not only environmental outcomes but also the crucial dimension of energy equity. By unraveling the spatiotemporal dynamics through sophisticated modeling and long-term data analysis, it uncovers both progress and persistent challenges in bridging energy disparities. The study’s policy relevance reaches beyond China, providing valuable lessons for global efforts to align climate action with social equity objectives in an increasingly interconnected world.
As energy transitions accelerate worldwide, understanding the intertwined spatial and temporal mechanisms highlighted in this research becomes imperative. The authors’ work sets a standard for future inquiry and underscores the indispensable role of spatial econometrics in revealing hidden systemic patterns. Crucially, it informs a pathway to climate policies that are not only environmentally effective but also socially just, paving the way for energy systems that serve all segments of society fairly and sustainably.
Subject of Research: The impact of China’s Air Pollution Prevention and Control Action Plan (APPCAP) on energy equity from a spatial and temporal perspective using advanced econometric models.
Article Title: The impact of climate policy on energy equity: effect, mechanism, and spatial analysis.
Article References:
Song, Y., Li, Z. & Lee, CC. The impact of climate policy on energy equity: effect, mechanism, and spatial analysis. Humanit Soc Sci Commun 12, 1752 (2025). https://doi.org/10.1057/s41599-025-06009-x
Image Credits: AI Generated
