The relationship between environmental degradation, energy use and economic growth in Nigeria: new evidence from non-linear ARDL

Abstract

Purpose: The purpose of this paper is to study the relationship among environmental degradation, energy use and economic growth, thus lending a voice to testing the relevance, or otherwise, of the environmental Kuznets curve (EKC) hypothesis in Nigeria. Design/methodology/approach: The authors rely on the secondary data obtained from World Bank’s World Development Indicators for Nigeria, between 1981 and 2014. The non-linear autoregressive distributed lag (ARDL) technique is used after examining the unit root properties – using the augmented Dickey–Fuller and Phillips–Perron methods – and the long-run relationship – using the ARDL bounds approach to estimate the asymmetries in the effects of economic growth on the environment. Findings: The findings of this study uphold the relevance of the EKC hypothesis in Nigeria, as the growth of GDP first reduces the environmental quality but raises it over time. Furthermore, the use of energy is found to deteriorate environmental quality, given that CO2 rises by 0.002% for a unit increase in the consumption of energy in Nigeria. Research limitations/implications: A limitation to this research is the data coverage, which is just between 1981 and 2014, based on availability. One other limitation is the use of electric power consumption as a proxy for energy use (because of the difficulty in obtaining accurate data on energy consumption in Nigeria). Future research should, therefore, test different other proxies, to either agree with the findings or justify any deviation therefrom. Also, the use of up-to-date data is recommended as an improvement to this study, while a non-linear technique should be used on studies involving the panel of countries. Originality/value: Many studies have examined this relationship by simply taking the square of GDP as a measure of its non-linear effect on the environment. The authors are one of the first who consider the asymmetric effect of economic growth on the environment through the non-linear ARDL technique. With this, the partial sums of positive and negative changes in economic growth on the environment are easily established