Towards Sustainable Environment in OECD Nations: The Moderator Role of Renewable Energy in Uncovering the Hidden Link Between Military Expenditure and Ecological Footprint

This study examines the relationships among military spending, renewable energy (RNW), globalisation, economic growth, and ecological footprint in 35 OECD member countries, using data covering 1990–2022. Specifically, this study contributes to this discussion by presenting empirical evidence on the link between military expenditure and ecological footprint, while accounting for the moderating role of RNW in OECD countries. The analysis utilised Kao, Pedroni, and Westerlund cointegration tests, Driscoll-Kraay robust standard error tests, Dumitrescu-Hurlin causality tests, and FMOLS and DOLS techniques for robustness verification. Empirical results show that military spending in OECD countries increases the ecological footprint, leading to environmental degradation. Furthermore, the combined effect of military expenditure and RNW reduces the ecological footprint and contributes to environmental sustainability. The results contribute to the existing literature by underlining the role RNW plays in reducing the ecological footprint of military expenditures and by offering policy recommendations for environmental sustainability. From a managerial and policy perspective, the findings suggest that defense-related institutions and policymakers should integrate environmental sustainability criteria into military planning and procurement strategies. Increasing the use of renewable energy in military infrastructure, logistics, and defense technologies may significantly reduce the ecological footprint associated with military expenditure. Therefore, the transition toward renewable energy supported defense systems can serve as a strategic tool for aligning national security objectives with sustainable development goals.