What have we learned from Environmental Kuznets Curve hypothesis? A citation-based systematic literature review and content analysis

This study provide a bibliometric-based systematic literature review of academic research on the Environmental Kuznets Curve (EKC). The main aim is to identify the leading sources of knowledge in terms of the most influential journals, articles, and authors. Furthermore, a thorough content analysis of the 100 most influential papers is provided for identifying the important research attributes, such as the characteristics of data, methodologies, and major findings. The study identifies 1654 articles on EKC from Scopus-Indexed journals. Ecological Economics is the leading journal based on total citations (15,452), h_index (59), and the g_index (94). The most cited article in terms of total citations belongs to Stern, D. I. entitled “The rise and fall of the EKC curve”, published in World Development in 2004. From the content analysis of 100 papers, we find that 66% used panel data. Fully Modified Ordinary Least Square (FMOLS) and Autoregressive Distributed Lag (ARDL) models are the most popular methodologies used in EKC studies so far. CO2 emission is a widely used variable to measure environmental degradation. The majority of the studies have confirmed inverted U-shaped EKC for both panel and time-series studies. The Granger causality results show that income Granger causes environmental degradation. For future direction, it would be interesting to investigate EKC hypotheses against a wider nature-economy nexus that could better explain the sources and causes of change in the type of such nexus. Additionally, adequate and appropriate exogenous variables that could explain external shocks into the nature-economy nexus.