Economic expansion, energy sources and environmental quality in ECOWAS sub-region: evidence from a heterogeneous panel non-linear Autoregressive Distributed Lag (PNARDL).

The level of economic growth is critical in evaluating environmental quality energy source economic growth nexus. In recent empirical works, very little attention has been given to the role of sizes of economic expansion in relation to the Environmental Kuznets Hypothesis in a panel of countries. This study, therefore, investigates the asymmetric relationships between different income groups and energy sources on the one hand with environmental quality on the other. Deviating from previous studies, this present study adopts Panel Non-Linear Autoregressive Distributed Lag (PNARDL) Model to a panel of 15 ECOWAS countries grouped into low-income and lower-middle-income countries. Results indicate that RGDP outcome for low-income nations support the EKC hypothesis when carbon footprint is used to proxy for environmental quality. Furthermore, EKC Hypothesis is also supported in lower-middle-income countries for RGDP when carbon footprint and carbon dioxide are used as proxy for environmental quality. We conclude that non-renewable energy use, harmful agricultural land practices, and unsustainable economic expansion matter so much in achieving environmental quality in the ECOWAS sub-region. Since it is considered that non-renewable energy among other energy sources influence economic activities the most, we recommend the use of renewable energy for ECOWAS sub-region in order to mitigate the damage done by fossil fuel and harmful agricultural practices in order to achieve sustainable growth and pollution-free environment.