Bisset Tazeb
Department of Economics, Dire Dawa University, Dire Dawa, Ethiopia.
Environ Sci Pollut Res Int. 2023 Jan;30(2):3321-3334. doi: 10.1007/s11356-022-22394-1. Epub 2022 Aug 10.
The environment has been delivering ecological balance through mitigation and ultraviolet ray protection. Nevertheless, human interactions have been creating unfavorable changes on environmental quality. Accordingly, based on a panel data (1996-2018), this study inspected evidence for N-shaped EKC across 41 SSA countries classified under three income categories. By extending the EKC hypothesis and using the three-stage simultaneous equation modeling, the study also estimated the direct and indirect effects of the three governance indices on environmental quality in the region. Consequently, the study confirmed N-shaped EKC only in the upper middle-income SSA countries. Furthermore, in the lower-income SSA countries, while the institutional governance index has a direct negative effect on environmental degradation, government effectiveness has an indirect negative effect on GHG emissions through renewable energy consumption. In the lower-middle-income SSA countries, while economic governance has a direct positive effect, political and institutional governances have a direct negative effect on environmental degradation. Here, also, political stability and the absence of violence have an indirect negative effect on GHG emission through income. In the upper middle-income SSA countries, control of corruption and the regulatory quality of the government has an indirect negative effect on environmental quality through income and renewable energy consumption, respectively. The inconclusive effects of the three governance indices on environmental quality might be the result of income heterogeneity across the region. Thus, policy prescriptions based on understanding the heterogeneous effects of governance indices within the three income groups might help to prove environmental quality in the region.
环境一直通过缓解和紫外线防护来维持生态平衡。然而，人类活动却一直在给环境质量带来不利变化。因此，基于面板数据（1996 - 2018年），本研究考察了41个撒哈拉以南非洲国家（分为三个收入类别）的N型环境库兹涅茨曲线的证据。通过扩展环境库兹涅茨曲线假说并使用三阶段联立方程模型，该研究还估计了三个治理指数对该地区环境质量的直接和间接影响。结果，该研究仅在撒哈拉以南非洲的中高收入国家证实了N型环境库兹涅茨曲线。此外，在撒哈拉以南非洲的低收入国家，虽然制度治理指数对环境退化有直接负面影响，但政府效能通过可再生能源消费对温室气体排放有间接负面影响。在撒哈拉以南非洲的中低收入国家，经济治理有直接正面影响，而政治和制度治理对环境退化有直接负面影响。同样，政治稳定和没有暴力通过收入对温室气体排放有间接负面影响。在撒哈拉以南非洲的中高收入国家，控制腐败和政府的监管质量分别通过收入和可再生能源消费对环境质量有间接负面影响。这三个治理指数对环境质量的影响尚无定论，可能是该地区收入异质性的结果。因此，基于理解三个收入组内治理指数的异质效应的政策建议可能有助于改善该地区的环境质量。
