Role of energy in estimating turning point of Environmental Kuznets Curve: an econometric analysis of the existing studies

The objective of the present study is to examine the role of energy-related variables while estimating the turning points of the assessed inverted U-shape relationship between economic growth and environmental quality, popularly known as Environmental Kuznets Curve (EKC). We conduct a systematic review the of existing studies concerning EKC hypothesis and apply Tobit model for 235 observations to examine the role of energy on turning points reported in the existing studies after controlling other study-specific characteristics. Our analysis shows that studies where energy variable is included to estimate EKC, the turning point is recorded higher as compared to the studies where it is not. Among other study-specific features, income level of the sample countries, econometric specification, type of data set and environmental indicator used are found to have a significant impact on the turning points. However, there is no significant impact of trade-related variables and population on the estimated turning points.