Investigating the environmental Kuznets curve modified with HDI: evidence from a panel of eco-innovative countries

Considering the increase in polluting emissions, the importance of determining the relationship between economic development and environmental quality is a crucial issue in achieving sustainable development goals. This study explores and empirically tests the validity of the Environmental Kuznets Curve (EKC) hypothesis in a panel data of 39 countries is assembled over the period 1993–2018. For this purpose, the Human Development Index is used as a measure of development, contrary to classical studies in which GDP growth was determined as an indicator of economic growth. Also using by two different measures of pollutant emissions, such as methane ( \({{\text{CH}}}_{4}\) ${\text{CH}}_4$ ) and carbon ( \({{\text{CO}}}_{2}\) ${\text{CO}}_2$ ) emissions, examining to the validity of the EKC hypothesis. The analysis method consists of the fixed effect and robustness estimation of the panel data model, and employed the U-test approach in the study. Empirical findings in this study show that strong evidence to support an inverted U-shaped relationship between CO₂ emissions and human development, although the U-test results point at mixed results for CH₄ emissions. In addition, it is detected that negative relationship between environmental related technological innovation and pollutants emission such as \({{\text{CH}}}_{4}\) ${\text{CH}}_4$ and \({{\text{CO}}}_{2}\) ${\text{CO}}_2$ , which highlights the importance of promoting innovative technologies in struggle global warming.