Improving the environmental Kuznets curve for evaluating the relationships between carbon dioxide emissions and economic development

In this study we used an improved approach to test the EKC hypothesis for carbon dioxide emissions by taking the first-order derivative of the traditional quadratic EKC equation. We found the long-term historical carbon dioxide emissions rarely supported the EKC theory at various scales (country to globe), but the short-term (especially the most recent decades) carbon dioxide emissions widely supported the EKC hypothesis. We concluded that though the overall development of a country or region might not follow an EKC pattern, but the EKC hypothesis might still be justified during different periods of the economic growth.