Exploring the effect of human capital on carbon emissions: evidences from 125 countries

Human capital (HC) plays a crucial role in economic growth, and also has a considerable effect on environmental performance, including carbon emissions (CEs). Existing studies have drawn inconsistent conclusions on whether and how HC affects CEs, and most of them conduct case studies of a certain country or several countries with similar economic backgrounds. In order to accurately determine the effect and the influence mechanism of HC on CEs, this research conducted an empirical study by applying econometric method and the panel data of 125 countries over the period 2000-2019. The empirical results indicate that there is an inverted U-shaped nexus between HC and CEs of full sample countries, revealing that HC will increase CEs before turning point and decrease CEs after turning point. From a heterogeneity perspective, this inverted U-shaped nexus only exists in high and upper-middle income countries, while is not supported in low and lower-middle income countries. This study further disclosed that HC can affect CEs by the mediating effects of labor productivity, energy intensity, and industrial structure from a macro perspective. Specifically, HC will increase CEs by promoting labor productivity, while decrease CEs by reducing energy intensity and the proportion of secondary industry. These results can provide important references for governments of different countries to make tailored carbon reduction policies according to the mitigation effect of HC on CEs.