The environmental Kuznets curve revisited once again

In the past decade, considerable attention has been paid to the hypothesized inverted U-shaped relationship between income level and environmental quality, known as the environmental Kuznets curve (EKC). An overview of empirical studies of this relationship finds limited evidence for an EKC. The strongest evidence is with urban SO2 concentrations. A close examination of a seminal paper in this field, which first reported the relationship between income level and SO2 concentrations, finds the relationship weak at best. Given the limited evidence for an EKC, why is it still accepted as fact? This article suggests that it both serves the interests of powerful groups in society, and it corresponds to a notion that wealthy people care more about environmental quality than do poor people.     

Environmental awareness and environmental Kuznets curve

We study the impacts of environmental awareness on environmental quality and income-pollution relationship. For our theoretical analysis, we examine a non-cooperative transboundary pollution control game between a less developed country (LDC) and a more developed country (MDC), and find that a higher level of environmental awareness by the government and citizens of the LDC has comprehensively beneficial effects on environmental policy and regional environmental quality. It also flattens the environmental Kuznets curve (EKC) and shifts it to the left. Our empirical findings confirm the theoretical projections. In the LDCs, environmental awareness plays an influential role in determining environmental expenditure; also, EKCs arrive at the peaks earlier, in countries where the public has higher environmental awareness.     

The environmental Kuznets curve in a world of irreversibility

This paper develops an overlapping generations model where consumption is the source of polluting emissions. Pollution stock accumulates with emissions but is partially assimilated by nature at each period. The assimilation capacity of nature is limited and vanishes beyond a critical level of pollution. We first show that multiple equilibria exist. More importantly, some exhibit irreversible pollution levels although an abatement activity is operative. Thus, the simple engagement of maintenance does not necessarily suffice to protect an economy against convergence toward a steady state having the properties of an ecological and economic poverty trap. In contrast with earlier related studies, the emergence of the environmental Kuznets curve is no longer the rule. Instead, we detect a sort of degenerated environmental Kuznets curve that corresponds to the equilibrium trajectory leading to the irreversible solution. I would like to thank Alain Venditti, Mabel Tidball, Alain Jean-Marie and Thierry Bréchet for their helpfull comments and suggestions. I am deeply grateful to an anonymous referee whose comments have greatly improved the paper.     

The environmental Kuznets curve when the environment exhibits hysteresis

The relevance and implications of the environmental Kuznets hypothesis are examined in the presence of stock effects and non-linearities associated with pollution generation. Stock effects lead to hysteresis and irreversibilities in environmental quality that are overlooked when emphasis is placed on the flow effects of pollutants only. It is demonstrated here that an optimal growth plan in the presence of stock effects shifts the focus away from prescribing economic growth as a panacea for environmental ills. Implications for currently industrializing economies are discussed.     

Functional sensitivity of testing the environmental Kuznets curve hypothesis

Conventional tests for the environmental Kuznets curve (EKC) hypothesis mostly apply a quadratic equation in modeling the non-linear relationship between environmental indices (such as air pollutants) and welfare measures (such as income per capita). If their inverted-U shaped pattern is empirically accepted with two significant regressors, the income per capita and its square transformation, the EKC hypothesis is supported. Using an OECD sample, this paper shows that the validity of testing the EKC hypothesis is sensitive to how we transform income non-linearly in sulfur and carbon EKC regressions. This paper carries out experiments on different powers of γ for transforming income non-linearly and concludes that only when 0 < γ < 1 and 1 < γ < 2 will the EKC regression demonstrate a testable non-linear cointegration relationship between the two air pollutants and income per capita. In the generalized EKC regressions estimated in this paper, although we find sulfur and carbon EKC patterns in the OECD sample, none of the EKC regressions using different γ is a cointegrating equation. This finding implies an inside critique to the EKC literature that failure of cointegration of the conventional EKC regression is not because of using the quadratic functional form, but because of the fundamentally spurious relationship between the trends of pollutants and income levels.     

Functional sensitivity of testing the environmental Kuznets curve hypothesis

Conventional tests for the environmental Kuznets curve (EKC) hypothesis mostly apply a quadratic equation in modeling the non-linear relationship between environmental indices (such as air pollutants) and welfare measures (such as income per capita). If their inverted-U shaped pattern is empirically accepted with two significant regressors, the income per capita and its square transformation, the EKC hypothesis is supported. Using an OECD sample, this paper shows that the validity of testing the EKC hypothesis is sensitive to how we transform income non-linearly in sulfur and carbon EKC regressions. This paper carries out experiments on different powers of γ for transforming income non-linearly and concludes that only when 0 < γ < 1 and 1 < γ < 2 will the EKC regression demonstrate a testable non-linear cointegration relationship between the two air pollutants and income per capita. In the generalized EKC regressions estimated in this paper, although we find sulfur and carbon EKC patterns in the OECD sample, none of the EKC regressions using different γ is a cointegrating equation. This finding implies an inside critique to the EKC literature that failure of cointegration of the conventional EKC regression is not because of using the quadratic functional form, but because of the fundamentally spurious relationship between the trends of pollutants and income levels.     

Economic prosperity, biodiversity conservation, and the environmental Kuznets curve

Many conservationists contend that economic growth and biodiversity conservation are incompatible goals. Some economists contest this viewpoint, arguing that wealthier countries have the luxury of investing more heavily in efforts to conserve biodiversity. Under this assumption, we expect a U-shaped relationship between per capita wealth and proportion of species conserved. We test this environmental Kuznets curve (EKC) using estimates of per capita income and deforestation rates (index of biodiversity threat) for 35 tropical countries. A prior analysis [Dietz, S., Adger, W.N., 2003. Economic growth, biodiversity loss and conservation effort. Journal of Environmental Management, 68:23-35] using conventional regression techniques failed to provide any support for the parabolic relationship predicted by the EKC hypothesis. Here, we introduce the use of quantile regression and spatial filtering to reanalyze this data, addressing issues of heteroskedasticity and spatial autocorrelation. We note that preliminary analysis using these methods provides some initial evidence for an EKC. However, a series of panel analyses with country-specific dummy variables eliminated or even reversed much of this support. A closer examination of conservation practices and environmental indicators within the countries, particularly those countries that drove our initial support, suggests that wealth is not a reliable indicator of improved conservation practice. Our findings indicate that an EKC for biodiversity is overly simplistic and further exploration is required to fully understand the mechanisms by which income affects biodiversity.     

On a clear day you might see an environmental Kuznets curve

We shed some new light on the Environmental Kuznets curve (EKC) and show how it can be viewed as a particular form of equilibrium relationship, where technology and preference parameters determine the shape of the curve. In contrast to most of the literature on the EKC, we estimate a theoretically consistent model on long-run data (Swedish sulfur emission, covering the period 1900–2002). Furthermore, we test and date structural change. The model suggests four regimes, 1900–1918, 1919–1933, 1934–1967 and 1968–2002, generating four rather different patterns for pollution over time. The policy-conclusions are consonant with Pearce’s general view about the EKC: there is no theoretical presumption that it has an inverted U shape, nor should any country try to “grow out of the environmental problems” without analyzing the benefits and costs of so doing.     

A new Cramer-Von Misses cointegration test with application to environmental Kuznets curve

This article introduces a new Cramer-Von Misses (CVM) cointegration test robust to nonlinearities. We characterize nonlinear cointegration in terms of a nonlinear moving-average filter (high pass filter) of a matrix based on permutation matrices on the discrepancy of empirical distributions. A Cramer-Von Misses (CVM) test statistic is proposed for testing the null hypothesis of two independent random walks against a broad range of cointegrating alternatives with monotonic nonlinearities and level shifts in the cointegration relationship. We derive the asymptotic distribution of this induced-order Cramer-Von Misses (CVM) cointegration test. This new non-parametric test statistic has two important properties: the invariance to monotonic transformations of the series and the robustness for the presence of several parameter shifts or structural changes. We analyse the small sample properties of this test by Monte Carlo simulations and evaluate the power of the test. Finally, this CVM test is applied to the analysis of long run environmental Kuznets curve which relates economic growth and pollution. In particular, we consider a nonlinear cointegration between gross domestic product (GDP) and CO2 emissions. Our new CVM test is able to find evidence of cointegration while classical single equation cointegration tests are not.     

The econometrics of the environmental Kuznets curve: an illustration using Australian CO2 emissions

Four econometric issues associated with the estimation and testing of the environmental Kuznets curve (EKC) are considered: (i) model specification with respect to the order of the polynomial, (ii) model specification with respect to the use of linear or log-linear specifications, (iii) integration and cointegration considerations, and (iv) missing variables and time trends. These issues are examined in reference to Australian data on four measures of CO2 emissions and three measures of per capita income. While evidence is provided for an inverted U-shaped EKC, the results cannot be generalized. It is concluded that without the use of sensitivity analysis, the results are typically fragile.     

Green technical innovation, environmental expenditure, and the environmental Kuznets curve： a dynamic s model

The relationship between the emission of pollutant and economic growth has attracted a lot of attention in the environmental debate of the recent decades. Based on some theoretical and empirical research on environmental Kuznets curve （EKC）, this paper introduces the environmental technical innovation and environmental investment into Salow growth model to discuss the relationship between GDP per capital and the emission of pollutant By the dynamic simulation and parameters analysis, the results of the model indicate： （1） when ＂green＂ technical progress and environmental investment are fixed, the relationship between GDP per capital and the emission shows the linear relationship; （2） ＂green＂ technical progress can lead to the positive growth rates with a decreasing level of emission, which is compatible with an EKC; （3） the proportion of the environmental investment can lead the different growth rates and level of emission. These results can explain that developing countries are ＂too poor to be green＂.     

Environmental resilience and economic growth: Command economy's optimization and environmental Kuznets curve

This paper constructs a two-sector environmental growth model with explicit mathematical derivation and economic intuition in a social planning economy. Through the optimal allocation of man-made capital between the production sector and the environmental sector, this paper shows that the trade-off between economic growth and environmental protection exists only when an economy deviates from its steady state. We also provide short-run transitions for both the whole economic system and individual control and state variables. In addition, technological progress in the production sector benefits economic growth rate while the improvement of technology in the environmental sector has only level effects on economic variables. This paper ends with a link between the theory and a hot empirical issue — the environmental Kuznets curve (EKC) hypothesis.     

Health benefits of tunneling through the Chinese environmental Kuznets curve (EKC)

In this paper, we first add to what is a growing literature on the existence and nature of the environmental Kuznets curve (EKC) model for developing countries, by testing for the existence of an EKC for China using a panel data set of city-specific, annual ambient levels of SO₂ pollution. We find some support for both the typical inverted-U-shaped relationship and an N-shaped, cubic configuration. More significantly, we then explore the possibility of China's “tunneling” through the EKC, by using newer, cleaner technologies, and thereby avoiding some of the environmental degradation that had often accompanied economic growth. Specifically, we estimate and economically value the health benefits realizable to Chinese cities from successful efforts to “tunnel” under the EKC over the next generation.     

Exploring the existence of Kuznets curve in countries' environmental efficiency using DEA window analysis

This paper, using data envelopment (DEA) window analysis and generalized method of moments (GMM) estimators, examines the existence of a Kuznets type relationship between countries' environmental efficiency and national income. Specifically, it measures the environmental efficiency of 17 OECD countries by constructing environmental efficiency ratios for the time period 1980-2002. The analysis with the application of dynamic panel data reveals that there isn't a Kuznets type relationship between environmental efficiency and income. Allowing for dynamic effects we find that the adjustment to the target ratio is instantaneous. We also find that increased economic activity does not always ensure environmental protection and thus the path of growth is important in addition to the growth itself.     

Environmental productivity and Kuznets curve in India

As a result of India's extremely rapid economic growth, the scale and seriousness of environmental problems are no longer in doubt. Whether pollution abatement technologies are utilized more efficiently is crucial in the analysis of environmental management because it influences the cost of alternative production and pollution abatement technologies. In this study, we use state-level industry data of sulfur dioxide, nitrogen dioxide, and suspended particular matter over the period 1991-2003. Employing recently developed productivity measurement technique, we show that overall environmental productivities decrease over time in India. Furthermore, we analyze the determinants of environmental productivities and find environmental Kuznets curve type relationship existences between environmental productivity and income. Panel analysis results show that the scale effect dominates over the technique effect. Therefore, a combined effect of income on environmental productivity is negative.     

Trading Kuznets curve: empirical analysis for China

Empirica - Due to inspiring growth over the past 20&nbsp;years, the dynamics of Chinese exports have been the focus of many researchers. In contrast to current literature, this study examines...     

中国经济增长与环境污染关系的研究——基于环境库兹涅茨曲线的实证分析

基于环境库兹涅茨曲线理论的面板数据分析模型,并考虑了人口密度、环保政策、贸易开放度、技术进步、产业结构在内的其他因素对SO2排放量的影响,选取全国30个省、自治区、直辖市2004—2011年这8年的面板数据,对我国经济增长与环境污染指标SO2排放量之间的关系进行了实证研究。研究结果表明,与倒U型的环境库兹涅茨曲线不同,我国人均GDP与人均SO2排放量存在倒N型关系。并结合控制变量对环境作用的正负效应提出了有助于降低SO2排放量、改善环境质量的针对性的政策建议。     

Refitting the Kuznets curve using a gender-specific threshold model

Previous studies have reached mixed conclusions regarding the relationship between inequality and per capita income. These studies, however, fail to consider gender differences in income inequality and how these may impact on the relationship between income inequality and per capita income. Using Australian taxation statistics, we derive three sets of Gini coefficients (i.e. female, male and total) for the period 1950–2013. We then examine the relationship between inequality and real per capita income and find that a gender-specific threshold panel regression outperforms three other conventional models. Our findings suggest that ‘one set of coefficients does not fit all’ in that the use of aggregate and constant coefficients may mask variations within, and between, gender inequality over time.     

也说腐败发展的库兹涅茨曲线

在经济发展的过程中,腐败现象存在一种倒U型的发展轨迹。制度建设的滞后,一方面导致了有害于社会发展的腐败的盛行,另一方面也使得腐败成为了改革和发展的润滑剂。而到了经济增长成熟的阶段,随着制度建设的完善,腐败会逐渐下降。     

Income inequality and economic growth—the Kuznets curve revisited

In a neoclassical growth framework with a typical political-economy mechanism, this paper reexamines the relationship between the income inequality and economic growth by introducing government spending into the production function and the utility function. It demonstrates that Kuznets’ famous inverted-U shape relationship between inequality and economic growth will hold—the growth rate will be first increasing with the income inequality before the growth rate decreases with inequality. __________ Translated from The Journal of World Economy (世界经济), 2005,(5) (in Chinese)