The role of consumption of energy, fossil sources, nuclear energy, and renewable energy on environmental degradation in top-five carbon producing countries

This study examines the impact of energy consumption and usage of fossil sources (e.g., oil, gas, coal), nuclear energy, and renewable energy on carbon dioxide (CO2) emission by considering the significance of the environmental degradation for countries as well as people. In this context, the top five countries that produce more than 50% of total CO2 in the world are examined. Besides, yearly data from 1965 to 2019 is used. Moreover, multivariate adaptive regression splines is applied for empirical analysis. The results indicate that (i) coefficients of determination (R2) of the best prediction models for the countries are above 99% that provide reliable results; (ii) energy consumption, coal consumption, nuclear energy, and renewable energy usage have an effect on the CO2 emission in some of these countries whereas not effective in some others; (iii) coal, oil, and natural gas consumption are the most significant indicators for the CO2 emission generally; (iv) the effects of the variables change according to different thresholds. Therefore, following a straightforward general approach for the countries in decreasing environmental degradation cannot be helpful. The results highlight the adverse effects of fossil fuels for the CO2 emission in high carbon producing countries. Policy proposals are also discussed.