Analyzing Türkiye's ecological footprint: the impact of air transportation, renewable energy, and R&D using a non-linear ARDL approach

This study investigates the complex relationship between air transportation, research and development (R&D) expenditures, renewable energy consumption, economic growth, and the ecological footprint in T & uuml;rkiye, utilizing annual data from 1990 to 2021. Employing both linear and non-linear Autoregressive Distributed Lag (ARDL) models, the study assesses the validity of the Environmental Kuznets Curve (EKC) hypothesis and explores the short- and long-run dynamics of the ecological footprint. Both the linear and non-linear ARDL models provide support for the EKC hypothesis, suggesting that economic growth may decouple from environmental degradation in the long run. Furthermore, robustness checks corroborate these findings. In the long term, air transportation exhibits asymmetric effects; while its positive components do not have a direct impact, its negative components contribute to environmental degradation in T & uuml;rkiye. Renewable energy consumption mitigates environmental pressure, whereas the impact of R&D expenditures is not statistically significant. The findings underscore the substantial influence of air transportation on T & uuml;rkiye's ecological footprint, highlighting the necessity for sustained efforts toward sustainable practices and technological advancements within the aviation sector. Moreover, the study emphasizes the importance of investments in R&D and renewable energy for achieving environmental sustainability, while also acknowledging their complex and multifaceted impacts. The paper also discusses policy recommendations and future research directions focused on achieving a balance between economic development and environmental protection in T & uuml;rkiye.