Investigating marginal effect of economic growth on environmental quality based on six environmental indicators: does financial development have a determinative role in strengthening or weakening this effect?

Given the complexity of the correlation of economic growth with financial development, and their interactive impacts on environmental quality, this study attempted to present new insights into indecisive outcomes from the contribution of financial development in determining the impressionability of environmental indicators under economic growth conditions. Previous studies only employed a single environmental indicator for analyzing the correlation between economic factors and environmental quality. However, six environmental indicators are adopted in this study to evaluate environmental quality and to reach major goals of this research. To this end, using 2-stage system generalized technique of moment estimator, the association of economic growth, energy consumption, financial development, environmental indicators, and trade openness is determined in selected OPEC countries for years 2010 to 2019. Findings indicated that accompanied by the effects of economic growth on any EFI, ANS, PN, and EPI variables, the financial development enhances such effect. This is while, the financial development would weaken the economic growth effect on the ESI variable. Regarding EVI, no significant association was observed. Regarding to ESI, EPI, and PN, trade openness applies a significantly positive impact on environmental quality; on the other hand, it has positive role in environmental degradation based on EFI and ANS. This is while, according to the EVI variable, trade openness has not meaningful impact on environmental status. Finally, energy use has significant and positive effects on environmental degradation in each of environmental indicators. However, this variable has not shown significant impact on EPI and ANS. Alternatively, findings indicated that financial development can be considered an important and key variable in improvement of the environmental quality due to the moderating role it plays relative to the negative economic growth effect on the environmental quality. At the end of this paper, some limitations are presented, and some suggestions for further studies are provided as well.