The aim of this paper is to augment the existing literature on convergence of CO2 emissions, by adding carbon footprint per capita and ecological footprint per capita to the convergence debate. We use the residual augmented least squares regression to examine the stochastic convergence of the environmental indices in 27 OECD countries. Furthermore, in contrast to the previous studies which mainly used the conventional beta-convergence approach to examine conditional convergence, we use a beta-convergence method that is capable of identifying the actual number of countries that contribute to conditional convergence. The sigma-convergence of the environmental indices is also examined. The results suggest that conditional convergence exists in 12 countries for CO2 emissions per capita, 15 countries for carbon footprint per capita and also 13 countries for ecological footprint per capita. There is evidence for sigma-convergence for all the three indicators. The policy implications of the results are discussed in the body of the paper.
Obesity is a worldwide concern as it leads to adverse effects on human health. This study uses a panel of 165 countries and annual data from 2000 to 2014 to examine the obesity Kuznets curve (OKC) hypothesis. By using tests and estimators that are robust to cross-section dependence (CSD), our results support the OKC hypothesis. This indicates that obesity increases at the initial stage of economic development and eventually would decrease once the threshold is reached. In addition, we find that the role of global warming on obesity is not significant. Food production is found to be a contributing factor to obesity. Besides, one-way and two-way causalities are identified between the variables. This study provides important insights particularly about the relationship between (i) economic growth and obesity and (ii) environmental degradation and obesity. Implication of the results and policy recommendations are also provided to policymakers and health personnel in finding solutions to the obesity epidemic around the world.
This study examines the impact of economic growth, corruption, health, and poverty on environmental degradation for three countries from ASEAN, namely Indonesia, Malaysia, and Thailand using annual data over the period of 1994-2014. The relationship between environmental degradation (pollution) by carbon dioxide (CO2) emissions and economic growth is examined along with some other variables, namely health expenditure, poverty, agriculture value added growth, industrial value added growth, and corruption. The ordinary least squares (OLS) method is applied as an analytical technique for parameter estimation. The empirical results reveal that almost all variables are statistically significant at the 5% level of significance, whereby test rejects the null hypotheses of non-cointegration, indicating that all variables play an important role in affecting the environment across countries. Empirical results also indicate that economic growth has significant positive impact, while health expenditures show significantly negative impact on the environment. Corruption has significant positive effect on environment in the case of Malaysia; while in the case of Indonesia and Thailand, it has insignificant results. However, for the individual analysis across countries, the regression estimate suggests that economic growth has a significant positive relationship with environment for Indonesia, while it is found insignificantly negative and positive in the case of Malaysia and Thailand, respectively, during the period under the study. Empirical findings of the study suggest that policy-makers require to make technological-friendly environment sequentially to surmount unregulated pollution, steady population transfers from rural areas to urban areas are also important, and poverty alleviation and better health provision can also help to improve the environment.
Recent research has shown a huge impact of non-renewable energy (NRE) production on environmental health. In this context, this work analyzes the effects of GDP growth and long- and short-term consumption of renewable and non-renewable energy (RE and NRE, respectively) on carbon emission in BRICS and OECD economies. The quantile autoregressive distributed lag (QARDL) model was employed on the panel data from 1980 to 2016. Findings suggest a negative GDP-carbon emission correlation and a positive NRE-carbon emission correlation in the considered economies. Furthermore, carbon emission decreases with increase in gross capital formation, whereas trade openness does not have any significant effect on carbon emission. It has been determined that the application of the error correction method (ECM) has less effect on energy consumption as compared to the past levels and changes in energy consumption. In the long-term, a positive correlation of carbon emission and energy consumption is observed, whereas limited short-term effects of energy consumption on carbon emission are observed. Therefore, an RE-based energy production approach is recommended in the selected region for the future projects.
This study highlights the importance of mineralogical composition for potential carbon dioxide (CO2) capture and storage of mine waste materials. In particular, this study attempts to evaluate the role of mineral carbonation of sedimentary mine waste and their potential reutilization as supplementary cementitious material (SCM). Limestone and gold mine wastes were recovered from mine processing sites for their use as SCM in brick-making and for evaluation of potential carbon sequestration. Dominant minerals in the limestone mine waste were calcite and akermanite (calcium silicate) while the gold mine waste was dominated by illite (iron silicate) and chlorite-serpentine (magnesium silicate). Calcium oxide, CaO and silica, SiO2, were the highest composition in the limestone and gold mine waste, respectively, with maximum CO2 storage of between 7.17 and 61.37%. Greater potential for CO2 capture was observed for limestone mine waste as due to higher CaO content alongside magnesium oxide. Mineral carbonation of the limestone mine waste was accelerated at smaller particle size of carbonation efficiency. Reutilization of limestone mine waste as SCM in brick-making exhibited greater compressive strength and lower water absorption compared to the bricks made of gold mine waste. The gold mine waste is characterized as having high pozzolanic behaviour, resulting in lower carbonation potential. Therefore, it has been noticeable that limestone mine waste is a suitable feedstock for mineral carbonation process and could be reutilized as supplementary cementitious material for cement-based product. This would be beneficial in light of environmental conservation of mine waste materials and in support of sustainable use of resources for engineering construction purposes.
For the purpose of this study, the role of technological innovation is examined. Few studies have examined empirically and theoretically the relationship between technological innovation and ecological footprint in conjunction with other factors, such as the human capital index and renewable energy sources, such as biofuels and nuclear power. This study examines the impact of technological innovation on G-7 countries' ecological footprints from 1990 to 2020. A cross-sectionally augmented autoregressive distributed lag (CS-ARDL) model is used in the study. The results of the study show that technological innovation minimizes the ecological footprint. A lower ecological footprint is also associated with increased usage of human capital and renewable energy. Depletion of the natural environment is a short-term and long-term consequence of increased GDP growth. Our results confirm that ecologically sustainable technology enhances the quality of the environment. Consistent panel causality results were achieved. In the context of the G-7 countries, our study's results could support the idea that there are new policy ideas that could help achieve the Sustainable Development Goals (SDG 3, 4, 7, 8, 9, and 13).
OECD countries have encountered the challenges of improving the environmental sustainability while maintaining economic growth by not impairing employment. This study attempts to reexamine the environmental Kuznets curve (EKC) hypothesis by using ecological footprint as an indicator of environmental degradation. Besides, our study aims to test the validity of environmental Phillips curve (EPC) and role of clean energy on ecological footprint. Our data cover a panel of 36 OECD countries from 1995 to 2015. We adopt the second-generation panel unit root and cointegration test to account for the presence of cross-section dependence (CSD). Moreover, the long-run relationship is estimated using Common Correlated Effect Mean Group (CCEMG) and Augmented Mean Group (AMG) that are robust to CSD. Our findings reveal that the EKC hypothesis is not valid while EPC is confirmed in OECD countries. Though there is a trade-off between unemployment and environmental degradation in OECD countries, the development of new technologies, especially in the clean energy sector, could be a key factor contributing to sustainable growth and better environmental quality. Thus, it is recommended that OECD countries should focus on the development of innovative green technologies and strengthen the initiatives that promote renewable energy consumption.
Under the new development model, the digital economy has become a new engine to promote the green development of the economy and achieve the goal of "double carbon." Based on panel data from 30 Chinese provinces and cities from 2011 to 2021, the impact of the digital economy on carbon emissions was empirically studied by constructing a panel model and a mediation model. The results show that firstly, the effect of the digital economy on carbon emissions is a non-linear inverted "U" shaped relationship, and this conclusion still holds after a series of robustness tests; secondly, the results of the benchmark regression show that economic agglomeration is an essential mechanism through which the digital economy affects carbon emissions and that the digital economy can indirectly suppress carbon emissions through economic agglomeration. Finally, the results of the heterogeneity analysis show that the impact of the digital economy on carbon emissions varies according to the level of regional development, and its effect on carbon emissions is mainly in the eastern region, while its impact on the central and western regions is weaker, indicating that the impact effect is primarily in developed regions. Therefore, the government should accelerate the construction of new digital infrastructure and implement the development strategy of the digital economy according to local conditions to promote a more significant carbon emission reduction effect of the digital economy.
A modified outdoor large-scale nutrient recycling system was developed to compost organic sludge and aimed to recover clean nitrogen for the cultivation of high-value-added microalgae. This study investigated the effect of calcium hydroxide addition on enhancing NH3 recovery in a pilot-scale reactor self-heated by metabolic heat of microorganisms during thermophilic composting of dewatered cow dung. 350 kg-ww of compost was prepared at the ratio of 5: 14: 1 (dewatered cowdung: rice husk: compost-seed) in a 4 m3 cylindrical rotary drum composting reactor for 14 days of aerated composting. High compost temperature up to 67 °C was observed from day 1 of composting, proving that thermophilic composting was achieved through the self-heating process. The temperature of compost increases as microbial activity increases and temperature decreases as organic matter decreases. The high CO2 evolution rate on day 0-2 (0.02-0.08 mol/min) indicated that microorganisms are most active in degrading organic matter. The increasing conversion of carbon demonstrated that organic carbon was degraded by microbial activity and emitted as CO2. The nitrogen mass balance revealed that adding calcium hydroxide to the compost and increasing the aeration rate on day 3 volatilized 9.83 % of the remaining ammonium ions in the compost, thereby improving the ammonia recovery. Moreover, Geobacillus was found to be the most dominant bacteria under elevated temperature that functions in the hydrolysis of non-dissolved nitrogen for better NH3 recovery. The presented results show that by thermophilic composting 1 ton-ds of dewatered cowdung for NH3 recovery, up to 11.54 kg-ds of microalgae can be produced.
In this study, we explore the dynamics between innovation, institutional quality, and foreign-aid flows in middle-income countries. Using an appropriate econometric model, we investigate the links between these variables in 79 middle-income countries (MICs) over 2005-2020. The results from our study show that foreign aid, institutional quality, and innovation have strong endogenous relationships. The short-run outcomes show that innovation Granger-causes institutional quality; foreign aid Granger-causes innovation; and quality of institutions Granger-causes foreign aid. The long-run outcomes indicate that institutional quality and innovation significantly affect the flow of foreign aid to the MICs. These results indicate that policy-makers in both foreign aid donor and recipient countries should pursue appropriate policies on foreign aid, quality of institutions, and innovation. For instance, in the short run, planners and evaluators in donor countries can direct their aid to MICs that have persistent challenges in improving their institutions and enhancing their innovative capabilities. In the long run, recipient countries ought to recognize that their institutional quality and innovation have a considerable impact on the inflows of foreign aid to their countries.
This study investigates the energy security and income roles in testing environmental Kuznets curve (EKC) for developing countries from 1990 to 2019. The panel quantile regression approaches are employed to examine the relationship between the variables, considering that income and energy security effects on carbon emissions may vary across distributions. Findings revealed that the EKC hypothesis was inconsistent at low and high quantiles when estimating energy availability, affordability, and acceptability. The validity of inverted U-shaped EKC is supported at high quantiles for energy affordability and accessibility in developing countries. However, given the energy accessibility and acceptability, the EKC hypothesis becomes invalid in developing countries. Notably, developing countries have yet to progress toward achieving energy security as a switch component to low carbon emissions. This study contributes to the literature by revealing the effect of availability, accessibility, affordability, and acceptability of energy security on carbon dioxide emissions (CO2). Thus, it suggests implications for improving environmental quality in developing countries by enhancing energy security. Diversifying energy sources with nuclear, renewable, and developing technologies reduces dependence risks on a single source while improving efficiency through technology and demand management lowers carbon emissions and strengthens energy security. Beyond energy security, this study emphasises sustainable urban planning to promote compact development, effective transportation, and green infrastructure to reduce energy use and improve environmental sustainability, ultimately reducing carbon emissions.
Climate change repercussions such as temperature shifts and more severe weather occurrences are felt globally. It contributes to larger-scale challenges, such as climate change and biodiversity loss in food production. As a result, the purpose of this research is to develop strategies to grow the economy without harming the environment. Therefore, we revisit the environmental Kuznets curve (EKC) hypothesis, considering the impact of climate policy uncertainty along with other control variables. We investigated yearly panel data from 47 Belt and Road Initiative (BRI) nations from 1998 to 2021. Pooled regression, fixed effect, and the generalized method of moment (GMM) findings all confirmed the presence of inverted U-shaped EKC in BRI counties. Findings from this paper provide policymakers with actionable ideas, outlining a framework for bringing trade and climate agendas into harmony in BRI countries. The best way to promote economic growth and reduce carbon dioxide emissions is to push for trade and climate policies to be coordinated. Moreover, improving institutional quality is essential for strong environmental governance, as it facilitates the adoption of environmentally friendly industrialization techniques and the efficient administration of climate policy uncertainties.
Trace (microgram liter) quantities of either toluene or benzene injected into an amino-acid-limited continuous culture of Pseudomonas sp. strain T2 were utilized immediately with affinities of 2.6 and 6.8 liters g of cells h, respectively, and yielded large amounts of organic products, carbon dioxide, and cells. The immediate utilization of hydrocarbons by hydrocarbon-deprived organisms helps to establish the nutritional value of nonpolar substrates in the environment. The observation of small Michaelis constants for toluene transport led to tests of metabolic competition between hydrocarbons; however, competitive inhibition of toluene metabolism was not found for benzene, naphthalene, xylene, dodecane, or amino acids. Benzene and terpenes were inhibitory at milligram liter concentrations. Toluene was metabolized by a strongly inducible system when compared with benzene. The capacity of toluene to effect larger affinity values increased with exposure time and concentration. The kinetics of induction suggested saturation phenomena, resulting in an induction constant, K(ind), of 96 mug of toluene liter. Maximal induction of amino-acid-grown cells required about 80 h, with the affinity reaching 317 liters g of cells h.
We aimed to assess the efficacy of Centella asiatica for improvement of the signs and symptoms of chronic venous insufficiency (CVI). We searched 13 electronic databases including the Cochrane Central Register of Controlled Trials for randomised controlled trials assessing the efficacy of Centella asiatica for CVI. Two review authors independently selected studies, assessed the risks of bias of included studies and extracted data. The treatment effects of similar studies were pooled whenever appropriate. Eight studies met the inclusion criteria. The pooling of data of similar studies showed that Centella asiatica significantly improved microcirculatory parameters such as transcutaneous partial pressure of CO2 and O2, rate of ankle swelling and venoarteriolar response. Three out of the eight studies did not provide quantitative data. However, these studies reported that patients treated with Centella asiatica showed significant improvement in CVI signs such as leg heaviness, pain and oedema. Our results show that Centella asiatica may be beneficial for improving signs and symptoms of CVI but this conclusion needs to be interpreted with caution as most of the studies were characterised by inadequate reporting and thus had unclear risks of bias, which may threaten the validity of the conclusions.
The recent progress report of Sustainable Development Goals (SDG) 2023 highlighted the extreme reactions of environmental degradation. This report also shows that the current efforts for achieving environmental sustainability (SDG 13) are inadequate and a comprehensive policy agenda is needed. However, the present literature has highlighted several determinants of environmental degradation but the influence of geopolitical risk on environmental quality (EQ) is relatively ignored. To fill this research gap and propose a inclusive policy structure for achieving the sustainable development goals. This study is the earliest attempt that delve into the effects o of geopolitical risk (GPR), financial development (FD), and renewable energy consumption (REC) on load capacity factor (LCF) under the framework of load capacity curve (LCC) hypothesis for selected Asian countries during 1990-2020. In this regard, we use several preliminary sensitivity tests to check the features and reliability of the dataset. Similarly, we use panel quantile regression for investigating long-run relationships. The factual results affirm the existence of the LCC hypothesis in selected Asian countries. Our findings also show that geopolitical risk reduces environmental quality whereas financial development and REC increase environmental quality. Drawing from the empirical findings, this study suggests a holistic policy approach for achieving the targets of SDG 13 (climate change).
The global demand for palm oil has grown rapidly over the past several decades. Much of the output expansion has occurred in carbon- and biodiversity-rich forest lands of Malaysia and Indonesia (M&I), contributing to record levels of terrestrial carbon emissions and biodiversity loss. This has led to a variety of voluntary and mandatory regulatory actions, as well as calls for limits on palm oil imports from M&I. This paper offers a comprehensive, global assessment of the economic and environmental consequences of alternative policies aimed at limiting deforestation from oil palm expansion in M&I. It highlights the challenges of limiting forest and biodiversity loss in the presence of market-mediated spillovers into related oilseed and agricultural commodity and factor markets, both in M&I and overseas. Indeed, limiting palm oil production or consumption is unlikely to halt deforestation in M&I in the absence of active forest conservation incentives. Policies aimed at restricting palm oil production in M&I also have broader consequences for the economy, including significant impacts on consumer prices, real wages, and welfare, that vary among different global regions. A crucial distinction is whether the initiative is undertaken domestically, in which case the M&I region could benefit, or by major palm oil importers, in which case M&I loses income. Nonetheless, all policies considered here pass the social welfare test of global carbon dioxide mitigation benefits exceeding their costs.
Carbon emissions are primarily the result of human activity in urban areas. Inadequate sanitary facilities, contaminated drinking water, nonrenewable energy, and high traffic congestion have all impacted the natural ecosystem. Using data from 1975 to 2019, the study assessed the impact of the aforementioned variables on Pakistan's carbon emissions in light of this crucial fact. The ARDL cointegration method was used to estimate the short- and long-run parameter estimates. Urban sanitation challenges and energy consumption increase carbon emissions, which affects the natural environment by raising a country's carbon intensity. Economic expansion confirmed the inverted U-shaped relationship between carbon emissions and economic growth to verify the Environmental Kuznets Curve (EKC) hypothesis in the long run. In contrast, the monotonically rising function of carbon emissions provides evidence of the nation's economic development in the short run. Access to clean drinking water improves population health and encourages the purchase of eco-friendly products. The government must improve sanitation services and use renewable energy sources to enhance air quality.
The unceasing rise of greenhouse gas emission has led to global warming and climate change. Global concern on this phenomenon has put forward the microalgal-based CO2 sequestration aiming to sequester carbon back to the biosphere, ultimately reducing greenhouse effects. Microalgae have recently gained enormous attention worldwide, to be the valuable feedstock for renewable energy production, due to their high growth rates, high lipid productivities and the ability to sequester carbon. The photosynthetic process of microalgae uses atmospheric CO2 and CO2 from flue gases, to synthesize nutrients for their growth. In this review article, we will primarily discuss the efficiency of CO2 biosequestration by microalgae species, factors influencing microalgal biomass productions, microalgal cultivation systems, the potential and limitations of using flue gas for microalgal cultivation as well as the bio-refinery approach of microalgal biomass.
Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO2) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO2 sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO2-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO2 exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.
Phytosterols provide important health benefits: in particular, the lowering of cholesterol. From environmental and commercial points of view, the most appropriate technique has been searched for extracting phytosterols from plant matrices. As a green technology, supercritical fluid extraction (SFE) using carbon dioxide (CO2) is widely used to extract bioactive compounds from different plant matrices. Several studies have been performed to extract phytosterols using supercritical CO2 (SC-CO2) and this technology has clearly offered potential advantages over conventional extraction methods. However, the efficiency of SFE technology fully relies on the processing parameters, chemistry of interest compounds, nature of the plant matrices and expertise of handling. This review covers SFE technology with particular reference to phytosterol extraction using SC-CO2. Moreover, the chemistry of phytosterols, properties of supercritical fluids (SFs) and the applied experimental designs have been discussed for better understanding of phytosterol solubility in SC-CO2.