Evaluating Urban Carbon Neutrality Pathways and Co-benefits through an Integrated Downscaling Framework: A Case Study of the Beijing–Tianjin–Hebei Region, China

To address the dual challenges of climate change and air pollution, an urban-scale decision-making framework is required in China to quantify energy-environment-health co-benefits, thereby addressing the limitations of existing macro-level research. This study proposes a novel analytical framework integrating scenario prediction, dynamic downscaling, pathway optimization, and benefit evaluation. The framework combines the provincial-level Global Change Analysis Model (GCAM-China) with a municipal-level dynamic downscaling model, a high-resolution emission inventory (Gridemis), the Scenario Model Intercomparison Project (ScenarioMIP), and an air quality and health assessment model. This approach effectively translates national climate goals into heterogeneous, sector-specific, municipal-scale emission pathways. It quantifies energy structure transitions, pollutant mitigation, and health co-benefits under various policy mixes while also considering future climate-related risks. Applied to the Beijing-Tianjin-Hebei region, the results show that synergistic efforts for carbon neutrality and stringent air quality policies will drive the regional energy system from coal dominance to a diversified, cleaner structure. By 2060, this optimized pathway could reduce major air pollutant emissions by 30-88%, promote a more equitable distribution of environmental and health benefits, and significantly lower premature mortality risks. This study provides a practical tool for energy and environmental policy, offering broad applicability for other regions.