Beyond the environmental Kuznets curve: Do combined impacts of air transport and rail transport matter for environmental sustainability amidst energy use in E7 economies?

This study is motivated by the United Nations Sustainable Development Goals (UN-SDG-7,8,11,12 and 13) on the need for clean and responsible energy consumption in view of anticipated actions for environmental sustainability. The world has been plagued with various consequences of environmental degradation including the attendant risks of climate change which has been exacerbated by rising greenhouse gas (GHGs) emissions over the years. To this end, we explore the combined effect of rail, air transportation, and urbanization in an EKC framework for the case of the E7 economies between 1995 and 2016. This study distinguishes itself from the extant ones by extending the EKC framework to explore the nexus between air transport, rail transport, urbanization, and the environment. The empirical evidence obtained from the study is based on second-generation panel econometric methods that are robust to heterogeneity and cross-sectional issues. Firstly, the findings lend support to the EKC phenomenon for E7 economies, thereby, implying that emphasis is placed on higher-income status in the bloc relative to environmental sustainability. Secondly, conventional energy from fossil fuel and air transport significantly dampen environmental quality among the E7 economies. Thirdly, rail transport and urban population, on the contrary, strongly aid the improvement of environmental quality among the E7 countries thus underscoring the significance of green urban mass (rail) transportation to the environmental sustainability agenda. Hence, in view of the economic growth trajectory among the E7 economies, useful policy blueprints were highlighted in the concluding section of the study.