Primal–dual approach to environmental Kuznets curve hypothesis: A demand and supply side analyses of environmental degradation

The unavoidable negative effects of global warming have been a key if not the most important issue occupying policy makers in the world at large today. The much talked about green economy nowadays seeks to achieve sustainable economic growth and development without compromising environmental quality. The relationship between environmental degradation and economic growth is largely explained by the environmental Kuznets curve (EKC) hypothesis. By employing the basic postulation of the baseline EKC framework, this study proposes and tests the existence of a dualistic approach of the EKC hypothesis. Geometry is used to illustrate the proposed dualistic model. Meanwhile, the novel dynamic common correlation effect econometric technique is employed to test the existence of the dualistic EKC within a panel of 109 countries from 1995 to 2016. The outcome from the estimated models shows that, in the global sample, the existence of the dualistic U-shaped and N-shaped EKC hypothesis is validated. When the sample is split into subsamples based on income levels, the U-shaped EKC hypothesis is validated for lower-income and high-income economies meanwhile, the N-shaped dualistic EKC is mostly associated with high-income economies.