With growing environmental concerns arising from greenhouse gas emissions—particularly methane (CH₄)—greater attention is being directed toward pollution reduction policies and sustainable development. Among the key factors influencing methane emissions are the circular economy, the use of green energy, globalization trends, and economic growth. In Iran, where the economy is heavily reliant on fossil fuels, evaluating the role of these variables in reducing CH₄ emissions is essential. This study employs the Autoregressive Distributed Lag (ARDL) model to examine the relationship between the circular economy, green energy, globalization, and economic growth on methane emissions in Iran during the period 2000–2020. The results indicate that the circular economy, green energy, and economic growth have a positive effect on methane emissions, while globalization has a negative impact, contributing to emission reduction. Based on these findings, it is recommended that waste management policies and the development of renewable energy be reviewed and optimized to prevent further methane emissions. Furthermore, enhancing globalization and implementing stricter environmental standards in trade and economic policies could help reduce methane emissions.