Is there an Environmental Kuznets Curve in the Carbon Dioxide Emissions?

The environmental Kuznets curve (EKC) is a relationship across countries between the level of environmental pollution and per capita GDP. This paper investigates the strength of empirical evidence in favour of the existence for an EKC in carbon dioxide emissions, accounting for the model uncertainty created by the numerous candidate regressors proposed in the literature. Using model averaging methods, I find strong evidence in favour of the existence of EKC in carbon dioxide emissions. In contrast, evidence in favour of the significance of many of the additional regressors disappears once model uncertainty is accounted for and robustness is examined. The conclusion reached is that social policy may influence environmental degradation, for which an eventual deterioration is signalled.