**Abstract**

The Environmental Kuznets Curve (EKC) hypothesis reflects the relationship between environmental quality and GDP per capita. The environmental quality decreases in early periods of GDP growth per capita until a certain point, and after that, it begins to increase. This paper investigates the presence of the EKC curve in OECD countries over the period 1997–2015 and identifies thresholds levels of GDP per capita leading to lower emissions per capita for these countries. Also, it points out the key role of energy from renewable sources. Based on nonlinear panel data methods, findings show that CO2 emissions increase up to a certain level of income (10774\$– 44494\$ per head) and then, they decrease. Policymakers are encouraged to consider economy, technology, and environment all together and handle the legal regulations they will implement, accordingly.

**Keywords:** carbon dioxide emissions, economic growth, renewable energy consumption, renewable electricity output, trade openness, urbanization, EKC, nonlinear panel models, OECD
