Revisiting the environmental kuznets curve hypothesis in 208 counties: The roles of trade openness, human capital, renewable energy and natural resource rent

This study aims to examine the linkages between renewable energy consumption (REC), nonrenewable energy consumption (NREC), carbon dioxide (CO 2 ) emissions, and economic growth in emerging Asian countries during the period 1975–2020 using a panel augmented mean group (AMG) estimation technique. The results of the long-run coefficient elasticity show that REC, NREC, employed labor force, and capital formation contribute significantly to long-run economic growth. The research analysis also found that NREC significantly increases long-term carbon emissions while REC significantly reduces long-term carbon emissions. Moreover, gross domestic product (GDP) and GDP 3 have a significant positive impact on environmental degradation while GDP 2 has a significant adverse impact on environmental pollution, thus validating the N-shaped Environmental Kuznets Curve (EKC) hypothesis in selected emerging Asian economies. The country-wise AMG strategy points out that India and Bangladesh have no EKC hypothesis, China and Singapore have an inverted U-shaped EKC hypothesis and Japan and South Korea have an N-shaped EKC hypothesis. Empirical evidence from Dumitrescu and Hurlin's causality test shows a two-way causality between REC and economic growth, supporting the feedback hypothesis. Strategically, this study suggests that more renewable energy is a viable strategy to address energy security and reduce carbon emissions to protect the environment and boost future economic growth in selected emerging Asian countries.

This study used the Autoregressive Distributed Lags (ARDL) model to confirm the validity of the Environmental Kuznets Curve (EKC) hypothesis on carbon dioxide (CO2) emissions in Indonesia, considering income, fossil energy consumption, renewable energy consumption, and forest moratorium and restoration policies. In the long-run, our model suggests that CO2 emissions will continue to rise simultaneously with income, implying that the EKC hypothesis is not valid for CO2 emissions in Indonesia. We found that fossil energy consumption has a positive effect on the rise of CO2 emissions, whereas renewable energy consumption, forest moratoriums, and forest restoration policies have a negative impact on CO2 emissions. This research emphasises the necessity of reducing reliance on fossil energy, increasing the use of renewable energy, and conserving Indonesia’s forests.

The dynamic impact of renewable energy consumption on CO2 emissions: A revisited Environmental Kuznets Curve approach

This study investigates the relationship between economic growth and environmental performance in selected Middle East and North Africa (MENA) countries through the lens of the Environmental Kuznets Curve (EKC) hypothesis. Due to data availability constraints, our sample includes Algeria, Egypt, Lebanon, Mauritius, Morocco, and Oman, covering the period 1990–2022. Using annual panel data, we apply panel cointegration techniques alongside Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS) estimators, complemented by Granger causality tests, to examine the interaction among GDP per capita, renewable energy consumption, and transport service exports in determining CO2 emissions per unit of GDP. The empirical findings provide only partial support for the EKC: while the DOLS results confirm an inverted U-shaped income–emissions relationship, the FMOLS estimations contradict it, suggesting a more complex and nonlinear pattern. Beyond testing the EKC, this study contributes two novel dimensions to the literature. First, it shows that renewable energy exerts a statistically significant negative effect on carbon intensity in the long run, despite weak short-run causality, highlighting the delayed but durable environmental benefits of clean energy adoption. Second, it introduces transport service exports as a proxy for structural economic transformation, capturing the role of trade-driven diversification in reducing emissions. By embedding renewable energy deployment and service-based trade dynamics into the EKC framework, the study advances a more policy-relevant and region-specific understanding of the growth–environment nexus in the selected MENA economies. The results underscore the importance of scaling renewable energy, promoting low-carbon service sectors, and aligning trade and environmental policies to ensure that economic growth supports long-term climate objectives.

India's sustainable development goals consist of higher economic growth through large investments on the one hand and ambitious carbon emission reduction plans through increased renewables on the other. It needs to be seen if the two policies related to capital formation and energy transitioning to renewables complement each other or if they have been divergent in the case of India. This paper studies the dynamic association between carbon dioxide emissions, economic growth, renewable energy (RE) consumption, and gross capital formation and tests for the existence of Environmental Kuznets Curve (EKC) hypothesis for India over the time period 1970-2018. It also tries to see if there is any possible conflict between the economic and energy goals of the country by augmenting the interaction term between renewable energy consumption and gross capital formation in the EKC framework. The empirical results not only confirm long-run relationship among the underlying variables but also indicate an "N"-shaped EKC in the long run for India which is a departure from the traditional inverted U-shaped EKC hypothesis. Renewable energy consumption is found to reduce emissions, whereas gross capital formation and the interaction term between renewable energy consumption and gross capital formation are found to raise emissions in the long run. The study concludes that India needs to align its economic policy of "Make in India" with its energy policy so that investments under the former facilitate extensive penetration, adaptation, and usage of renewable energy. A policy dichotomy between the two goals may defeat India's Intended Nationally Determined Contribution (INDC) objective of drastic reduction in carbon dioxide emissions through increased renewables by 2030.

Exploring the effects of economic growth, and renewable and non-renewable energy consumption on China’s CO2 emissions: Evidence from a regional panel analysis

Environment-economic growth nexus is one of the main concerns of the researchers in the modern era. Although there are several studies in this field, discussions are far from being reached a consensus. The main purpose of this study is to investigate the role of economic growth, renewable and non-renewable energy consumption, oil prices, and trade openness on CO2 emissions in 25 Organization for Economic Co-operation and Development (OECD) countries over the period 1990-2014. We provide a comparative panel data evidence using both the first- and second-generation estimation methods. The Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS) estimations indicate that the Environmental Kuznets Curve (EKC) hypothesis is valid in OECD countries. However, the Augmented Mean Group (AMG) estimator revealed that the EKC hypothesis is invalid. The AMG estimator is a second-generation estimator and provides robust results under cross-sectional dependence compared to the first-generation methods; therefore, the EKC hypothesis is invalid. Our additional findings show that rising renewable energy consumption and oil prices mitigate CO2 emissions while non-renewable energy consumption increases it according to all estimators. No significant relationship is found between trade openness and CO2 emissions.

Has the Environmental Kuznets Curve hypothesis become stronger? A comparative analysis for OECD countries and selected late-industrializing Asian economies.

Testing environmental Kuznets curve hypothesis: The role of renewable and non-renewable energy consumption and trade in OECD countries

Investigating the EKC hypothesis with renewable energy consumption, human capital, globalization and trade openness for China: Evidence from augmented ARDL approach with a structural break

The need to reduce carbon emissions in the face of rising climate risk and environmental degradation remains crucial to achieving environmental sustainability. This study investigates the relationship between urbanization, renewable energy, governance, and carbon emissions in West Africa, with a focus on four key questions: (1) Do renewable energy and governance reduce carbon emissions? (2) Does urbanization increase emissions? (3) Does urbanization moderate the effects of renewable energy and governance on emissions? (4) Are the Urban Environmental Transition (UET) theory and Environmental Kuznets Curve (EKC) hypothesis applicable in the West African context? Using unbalanced panel data from 16 West African countries covering the period 2002–2023, the study employs two econometric approaches — the instrumental variable fixed effects model and the Driscoll and Kraay fixed effects estimator with instrumented variables. The latter serves as the main estimator due to its robustness to cross-sectional dependence. Findings confirm both the UET theory and the EKC hypothesis in the region. Urbanization significantly increases carbon emissions, while renewable energy consumption and various governance indicators — including control of corruption, regulatory quality, and political stability — significantly reduce emissions. However, urbanization weakens the beneficial impact of renewable energy and governance on environmental quality. These findings highlight the need for integrated policy strategies that manage urban growth while strengthening renewable energy adoption and institutional quality to foster environmental sustainability in West Africa.

The Environmental Kuznets Curve (EKC) hypothesis suggests an inverted U-shaped relationship between economic growth and carbon emission. This study revisits the EKC hypothesis in Indonesia by examining the dynamic interplay among economic growth, coal production, and renewable energy consumption. Using time-series data from the World Development Bank and Our World in Data from 1991-2021, the study applies a quadratic linear regression model based on the Ordinary Least Squares (OLS) method to assess whether Indonesia exhibits the characteristic EKC pattern. Furthermore, the role of renewable energy in mitigating environmental degradation is explored. The findings confirm the existence of an EKC pattern in Indonesia, with carbon emissions initially rising alongside GDP growth but declining as income reaches higher levels. The estimated turning point occurs at an average GDP per capita of approximately USD 7,256. However, renewable energy consumption does not yet show a statistically significant effect on emissions reduction, which may be attributed to its relatively small share in the national energy mix. This study highlights the unique context of Indonesia, a major emerging economy with high fossil fuel dependency and underdeveloped renewable energy infrastructure. It offers novel insights by integrating coal production and renewable energy as core factors affecting emissions trajectories.

With the rising economic complexity of the world economy, applied research has been focusing on the economic complexity-environmental quality nexus. Many of the Middle East and North Africa (MENA) countries and Turkey show relatively low economic complexity with undiversified product spaces. The present study is thereby motivated to investigate the economic complexity-environmental quality relation for the MENA countries and Turkey. Using panel data for eighteen MENA countries and Turkey over the period 1990–2020, the fully modified ordinary least squares method of estimation is employed in two separate models, and Granger causality tests are performed. Each model includes the relation of economic complexity to carbon dioxide (CO2) emissions, one form of energy (renewable or non-renewable), population density and variables to validate the environmental Kuznets curve (EKC) hypothesis. In model (1), a negative and statistically significant renewable energy consumption has a mitigating effect on CO2 emissions, though economic complexity and its interaction with renewable energy consumption are not statistically significant. In model (2), a positive and statistically significant non-renewable energy indicates that increased fossil fuel reliance increases CO2 emissions (deteriorating environmental quality), while a negative and statistically significant economic complexity and population density reduce CO2 emissions (improving environmental quality), respectively. The EKC hypothesis is validated for the MENA countries and Turkey in both models (1) and (2), and Granger causality test results are given. Among the key policy implications are that the MENA countries and Turkey must recognize that increasing GDP and industrialization must be coupled with moving from less- to more-knowledge-based structures.

The economic complexity index, which indicates the level of knowledge and skills needed in the production of the exported goods, is a measure of economic development. Some researchers have investigated the validity of the environmental Kuznets curve (EKC) hypothesis by considering the effect of economic complexity on environmental pollution. This study, for the first time, examines the impact of economic complexity, globalization, and renewable and non-renewable energy consumption on both CO2 emissions and ecological footprint within the framework of the EKC hypothesis in the USA. To this end, the combined cointegration test and three different estimators are utilized for the period from 1980 to 2016. The main finding of the study indicates that the inverted U-shaped EKC relationship between economic complexity and environmental pollution holds for the USA. In addition to this finding, globalization and renewable energy consumption play a dominant role in reducing environmental pollution, while non-renewable energy consumption contributing factor to environmental pressure. Overall, the outcomes indicate that increasing economic complexity helps to minimize environmental degradation after a threshold, and the US government can provide a better environment by using renewable energy sources and globalization. Graphical abstract.

This study dynamically examines the impact of foreign direct investment and other explanatory variables on economic growth and carbon emissions, and tests the validity of pollution haven hypothesis (PHH) and environmental Kuznets curve (EKC) hypothesis in China, India, and Singapore from 1980 to 2020. The results of Westerlund's (Oxford Bulletin of Economics and Statistics, 69(6):709-748, 2007) panel cointegration test illustrate long-run equilibrium relationships among the proposed set of panel variables in the model. The estimated parameters of the AMG, CCEMG, and MG estimators in each of the specified models show that renewable and non-renewable energy consumption, foreign direct investment, and capital accumulation all have significant and progressive effects on economic growth. However, the labor force is insignificant and carbon emissions have a significant negative impact on economic growth. Non-renewable energy consumption significantly stimulates and renewable energy consumption significantly reduces carbon emissions. Moreover, the moderating role of non-renewable energy in the impact of foreign direct investment on carbon emissions is significantly positive, thus validating the PHH. The moderating role of renewable energy consumption in the impact of foreign direct investment on carbon emissions is significantly negative. The study's analysis also clearly validated the inverted U-shaped EKC hypothesis in China, India, and Singapore. Policymakers in emerging economies must prioritize the maturity of renewable energy, which not only increases productivity but also protects the environment from damage by reducing carbon dioxide emissions. The governments of China, India, and Singapore should initiate direct foreign inflows based on advanced and clean technologies to avoid environmental degradation and drive higher growth in these economies.