The Janus-Faced Role of Renewable Energy Development in Global Carbon Reduction Under Renewable Energy Policies

The global-scale empirical analysis of how renewable energy policies (REPs) affect carbon emissions and the mediating role of renewable energy development (RED) in this mechanism remains underexplored. To fill this research gap, we extracted and organized REPs data from IEA's databases for 135 countries until 2018 and conducted empirical analyses of these issues. We find that: (a) REPs significantly reduce global carbon emissions, especially through regulatory, economic, and R&D policies. (b) REPs' effectiveness in mitigating carbon emissions is enhanced by robust energy infrastructure, strong control of corruption, and adherence to the rule of law. Besides, the balance of REPs types does not influence their efficiency, but REPs prioritizing certain renewable energy (RE) types aligns better with carbon reduction goals. (c) RED displays a Janus-faced influence on REPs' carbon reduction effect—renewable energy consumption (REC) positively mediates it, whereas renewable energy share (RES) exerts a negative mediation. Specifically, REC consistently reduces carbon emissions, while RES initially increases and then decreases carbon emissions, exhibiting an inverted U-shape. (d) The initial rise in carbon emissions with RES is due to the low substitution of RE for fossil energy and the country-specific heterogeneity in organizational, geographic, industrial, economic, demographic, and temporal factors.