Parviz Gholami - Master student of Petroleum University of Technology (PUT) of Tehran - Iran
Mahmoud Karimi - Master student of Petroleum University of Technology (PUT) of Tehran - Iran
Saeed Tayebi - Master student of Petroleum University of Technology (PUT) of Tehran - Iran
Reza Rashidi - Master student of Petroleum University of Technology (PUT) of Tehran - Iran

This paper investigates the existence of the environmental Kuznets curve (EKC) for carbon dioxide (CO۲) emissions and its causal relationships with economic growth and openness based on econometric techniques of unit root test & co-integration and by using time series data (۳۹۷۳-۲۱۳۳) from China (an emerging market), Iran (a developing country), Korea (a newly industrialized country), Japan and United State (developed countries). The sample countries span a whole range of development stages from industrialized to newly industrialized and emerging market economies. The environmental consequences according to openness and economic growth do not show uniform results across the countries. Depending on the national characteristics, the estimated EKC show different temporal patterns. China shows an N-shaped curve while Japan has a U-shaped curve and Iran has inverted U-shaped curve. Such dissimilarities are also found in the relationship between CO۲ emissions and openness. In the case of Korea and Japan it represents an inverted U-shaped curve, while China and Iran shows a U-shaped curve. The evidence indicates that in the long-run trade liberalization has a positive significant impact on CO۲ emissions and impact of trade liberalization on emissions growth depends on the level of income. Our findings suggest that there is a quadratic relationship between relationship between real GDP and CO۲ emissions for the region as a whole except U.S.

carbon dioxide (CO۲), environmental Kuznets curve (EKC), economic growth, free trade, development