The heterogeneous time and income effects in Kuznets curves of municipal solid waste generation: comparing developed...

In rapidly developing countries, it is imperative to study the changes in municipal solid waste (MSW) generation for planning waste management and treatment. This study took the largest 11 economies in the world as cases, comprising half of the global population, analyzed the variations of definition of MSW among these economies. Based on the Environmental Kuznets Curve (EKC) hypothesis and using parametric model, Feasible General Least Squares (FGLS) regression, and nonparametric models, Generalized Additive Mixed Models (GAMMs), it was expected that the change features and its socioeconomic drivers of total MSW generation and per capita MSW (PCMSW) since the 1960s would be determined. Efforts were also made to find the turning/stabilizing point in the relationship between PCMSW and per capita gross domestic product (PCGDP) in each economy. It shows that population has the most important impact on total MSW, however, the economic indicators might be ignored. The United States and Germany have the highest PCMSW generation, while China and India indicate the lowest. The turning/stabilizing point in the relationship between PCMSW and PCGDP perfermed in most developed economies, Singapore and Korea reached the turning point around 1990, while for other developed economies it was 2000. Germany came to a stabilizing point in 1990, and with some arbitrary, so did the United States. The developing economies seem to be still in their early stage of the potential EKC. In developed economies, heterogeneous time effects on PCMSW seem to be more significant than heterogeneous income effects, which is contrary to developing economies.