Hydrodynamic and geochemical controls on soil carbon mineralization upon entry into aquatic systems

Erosion is the most widespread form of soil degradation and an important pathway of carbon transfer from land into aquatic systems, with significant impact on water quality and carbon cycle. However, it remains debatable whether erosion induces a carbon source or sink, and the fate of eroded soil carbon in aquatic systems remains poorly constrained. Here, we collect 41 representative soils from seven erosion-influenced basins and conduct microcosm simulation experiments to examine the fate of soil carbon under three different scenarios. We showed that soil carbon mineralization was generally promoted (by up to 10 times) in water under turbulence relative to in soils, but suppressed under static conditions upon entering into aquatic systems. Moreover, the enhancement of mineralization in turbulent systems is primarily related to soil aggregate content, while suppression in static systems positively relates to macromolecule abundance, indicating that soil geochemistry affects the magnitude of hydrodynamic effects on carbon mineralization. Random forest model further predicts that erosion may induce significant carbon sources in basins dominated by turbulent waters and aggregate-rich soils. Our findings demonstrate hydrodynamic and geochemical controls on soil carbon mineralization upon delivery into aquatic systems, which is a non-negligible part of the boundless carbon cycle and must be considered when making region-specific conservation strategies to reduce CO₂ emissions from inland waters.

Oil palm (Elaeis guineensis) plantation on tropical peatland in South East Asia: Photosynthetic response to soil drainage level for mitigation of soil carbon emissions

While existing moratoria in Indonesia and Malaysia should preclude continued large-scale expansion of palm oil production into new areas of South-East Asian tropical peatland, existing plantations in the region remain a globally significant source of atmospheric carbon due to drainage driven decomposition of peatland soils. Previous studies have made clear the direct link between drainage depth and peat carbon decomposition and significant reductions in the emission rate of CO₂ can be made by raising water tables nearer to the soil surface. However, the impact of such changes on palm fruit yield is not well understood and will be a critical consideration for plantation managers. Here we take advantage of very high frequency, long-term monitoring of canopy-scale carbon exchange at a mature oil palm plantation in Malaysian Borneo to investigate the relationship between drainage level and photosynthetic uptake and consider the confounding effects of light quality and atmospheric vapour pressure deficit. Canopy modelling from our dataset demonstrated that palms were exerting significantly greater stomatal control at deeper water table depths (WTD) and the optimum WTD for photosynthesis was found to be between 0.3 and 0.4 m below the soil surface. Raising WTD to this level, from the industry typical drainage level of 0.6 m, could increase photosynthetic uptake by 3.6 % and reduce soil surface emission of CO₂ by 11 %. Our study site further showed that despite being poorly drained compared to other planting blocks at the same plantation, monthly fruit bunch yield was, on average, 14 % greater. While these results are encouraging, and at least suggest that raising WTD closer to the soil surface to reduce emissions is unlikely to produce significant yield penalties, our results are limited to a single study site and more work is urgently needed to confirm these results at other plantations.

Performance and mechanism of modified biological nutrient removal process in treating low carbon-to-nitrogen ratio wastewater

For solving the challenge of difficult nutrient removal, high running cost and CO₂ emission at low carbon-to-nitrogen (C:N) ratio, Bi-Bio-Selector for nitrogen and phosphorus removal (BBSNP) process was developed. Under parallel operation conditions, full-scale BBSNP was less influence by low C:N ratio (3.5-2) than Anaerobic-anoxic-aerobic (AAO) and achieved better nitrogen removal performance. The mechanism of performance advantage in BBSNP was analyzed by mass balance and high throughout sequencing. It demonstrated BBSNP developed unique microbial community at C:N ratio of 2. Higher abundance of Saccharibacteria, Ferruginibacter, Ottowia, Dokdonella, Candidatus_Nitrotoga and Nitrospira in BBSNP was responsible for better chemical oxygen demand (COD) utilization efficiency, denitrification, denitrifying phosphorus removal and nitrification. Meanwhile, under low C:N ratio, BBSNP could save 10% organic carbon and 15% oxygen requirement, reduce 53% running cost and 21% CO₂ emission, which had practical value in relieving energy crisis and carbon emission of wastewater treatment plants (WWTPs).

Evaluating the dynamic effects of mitigation instruments on CO2 emissions in China's nonferrous metal industry: A vector autoregression analysis

Reducing carbon dioxide (CO₂) emissions in China's nonferrous metal industry is important for reaching China's ambitious goals for carbon peaking and neutrality. Prior research identified several carbon abatement instruments for the industry. However, the dynamic influence of different mechanisms on CO₂ emissions in the industry remains unclear, and few studies have researched CO₂ emission reductions in two nonferrous metal related industrial subsectors: nonferrous metal ore mining and nonferrous metal smelting. This research evaluated the dynamic effect of abatement instruments on the CO₂ emissions in these two subsectors. The research discovered the factors that are highly linked with CO₂ emissions by using an enhanced Stochastic Impacts by Regression on Population, Affluence, and Technology model. The dynamic influence of these factors on CO₂ emissions in the two subsectors was investigated using a vector autoregressive model. Findings show that in the two subsectors, labour productivity and industrial value-added are the most important factors explaining CO₂ changes. The two variables have a negative long-term effect on CO₂ emissions in the nonferrous metal ores mining, and increase CO₂ emissions in the smelting of nonferrous metals. Improving energy efficiency in the nonferrous metal smelting industry decreases the CO₂ emissions only in the short term. In all sectors, lowering the electrical carbon emission factors and changing the energy structure using different techniques are expected to help reduce long-term CO₂ emissions. These results are critical for the Chinese government in creating long- and short-term energy plans for the nonferrous metal sector.

Carbon stock stability in drained peatland after simulated plant carbon addition: Strong dependence on deeper soil

Peatlands are vital soil carbon sinks, yet this function is jeopardized by plant carbon which could change the decomposition rate of soil organic carbon, knowing as "priming effect". How the priming effect depends on depth is a critical question in drained peatland given the heterogeneity of soil layers defined by the water table, which include the surface acrotelm, inter-mesotelm and deep catotelm. Here, through incubation, we quantified the response of these three soil layers to addition of ¹³C-labeled oxalate, glucose, cellulose, or cinnamic acid under anoxic or oxic conditions on the Zoige Plateau in Tibet. Soil carbon in the inter-mesotelm showed the greatest decomposition, with the highest humification index and lowest microbial biomass carbon, while the soil carbon at the surface acrotelm was least decomposed. Under anoxic conditions, exogenous carbon addition reduced CO₂ emission by 12.2% at the surface acrotelm but increased by 59.8% in the inter-mesotelm and 23.5% in the deep catotelm. In the inter-mesotelm, oxalate addition significantly increased CO₂ emission by 63.9%, while cinnamic acid significantly increased it by 92.9%. In the deep catotelm, cinnamic acid significantly increased CO₂ emission by 55.3%. These results suggested that deeper soil organic carbon was more sensitive to plant carbon, particularly complex or recalcitrant carbon, than surface acrotelm soil. Under oxic conditions, carbon addition increased surface soil CO₂ emission by 18.9%, and triggered even greater increase at inter-mesotelm and deep catotelm soil, with proportions of 48.3% and 32.0%, respectively. Under both conditions, peat profile CO₂ release increased by 17.2-31.4% after exogenous carbon addition, and more than 77.8% of the increase came from the deeper two layers. These findings highlighted the need to take full account of priming effect of deeper soil in order to assess and predict the stability of carbon stocks in drained peatland.

Dynamics and internal links of dissolved carbon in a karst river system: Implications for composition, origin and fate

Dissolved carbon (DC) deciphers biotic and abiotic processes in aquatic ecosystems, representing a critical component of global carbon cycling. However, underlying drivers of riverine DC dynamics and internal links have yet to be studied. Here, we investigated fluvial physicochemical characteristics, dissolved inorganic carbon (DIC) species, carbon dioxide (CO₂) exchange, dissolved organic carbon (DOC) compositions and properties in a karst river system Qijiang, Southwest China. Carbonate dissolution combined with photosynthetic uptake could explain dynamics of DIC species. Carbon sequestration caused low-magnitude of partial pressure of aqueous CO₂ (pCO₂, 620.3 ± 1028.7 μatm) and water-air CO₂ flux (F, 154.3 ± 772.6 mmol/m²/d), yielding an annual CO₂ emission of 0.079 Tg CO₂/y. Relatively high biological index (BIX, 0.77-0.96 on average) but low humification index (HIX, 0.67-0.78 on average) indicated notable autochthonous processes. Humic-like component was the predominant DOC, accounting for 39.0%-75.2% with a mean of 57.2% ± 6.17%. Meanwhile, tryptophan-like component (5.84% ± 2.31%) was also identified as collective DOC by parallel factor analysis (PARAFAC) across samples. Biological metabolism established internal linkages between DIC and DOC in the karst river system. Our findings highlighted biological process as a determinant for DC cycling in karst aquatic ecosystems.

Coordinated effects of energy transition on air pollution mitigation and CO2 emission control in China

China has made progress in energy transition to improve air quality, but still confronts challenges including further ambient PM_2.5 reduction, O₃ pollution mitigation, and CO₂ emission control. To explore the coordinated effects of energy transition on air quality and carbon emission in the near term in China, we designed 4 scenarios in 2025 based on different projections of energy transition progress with varying end-of-pipe control level, in each of which we calculated emissions of major air pollutants and CO₂, and simulated ambient PM_2.5 and O₃ concentrations. Results show that energy transition has disparate effects on emission reduction of different air pollutants and sectors, which largely depends on their current end-of-pipe control levels. The different effects on emission reduction may result in opposite variation tendencies of ambient PM_2.5 and O₃ concentration in a future scenario with aggressive energy transition policies and end-of-pipe control level in 2018. With the end-of-pipe control level strengthened in 2025, PM_2.5 and O₃ concentration could both reduce on the national scale, but the reduction of ambient O₃ lags behind PM_2.5, indicating the difficulty of O₃ pollution control. As to CO₂, national emission would go up in 2025 either implementing current or aggressive energy transition policies due to growing needs of electricity and on-road transportation, but emissions in most provinces could decline to below the 2018 level with aggressive energy transition policies because of substitution of clean energy in industrial, residential and off-road transportation sectors. The study results suggest strictly implementing restrictive end-of-pipe control measures along with energy transition to simultaneously reduce ambient PM_2.5 and O₃ concentration, and accelerating substitution of renewable energy in power sectors where electricity generation grows rapidly to synergistically control air pollution and CO₂ emissions. Furthermore, the projection of CO₂ emissions could provide references for short-term emission control targets from the perspective of air quality improvement.

A systematic assessment of city-level climate change mitigation and air quality improvement in China

China is facing dual challenges of air pollution and climate change. By using city-level data, we comprehensively assessed air quality and CO₂ emission changes from 2015 to 2019 for 335 Chinese cities. We selected important regions for air pollution control and categorized all cities into different classes according to their development levels. Our novel approach revealed new insights on different patterns of changes of PM_2.5, O₃, and CO₂ by region and city class. We found that PM_2.5 concentrations decreased remarkably due to mandatory city-level reduction targets, especially in the Beijing-Tianjin-Hebei (-27%) region. Nonetheless, O₃ concentrations and CO₂ emissions increased in 91% and 69% of Chinese cities, respectively. Observed CO₂ emission reductions in more developed cities were mainly due to prominent energy intensity reduction and energy structure improvement. Our study indicates a lack of synergy in air pollution control and CO₂ mitigation under current policies in China. To address both challenges holistically, we suggest setting mandatory city-level CO₂ emission reduction targets and reinforcing clean energy and energy efficiency measures.

The integrated impact of GDP growth, industrialization, energy use, and urbanization on CO2 emissions in developing countries: Evidence from the panel ARDL approach

Developing economies are an important engine of world economic growth. However, ensuring the quality of environmental assets is maintained amid rapid economic change remains a major challenge for most developing countries. Using the Panel Autoregressive Distributed Lag (ARDL) approach and the heterogeneous causality test, this study analyzes the combined effects of energy usage, industrialization, gross domestic product (GDP) growth, and urbanization on CO₂ emissions for 23 developing countries across the 1995 to 2018 period. From our analysis, the long-run results reveal that a 1% increase in energy use, economic growth, industrialization, and urbanization increases CO₂ emissions by 0.23%, 0.17%, 0.54%, and 2.32%, respectively. Moreover, our model's short- to long-term equilibriums are adjusted at a yearly rate of 0.19%. Finally, to verify the panel ARDL long-run results, robustness tests were carried out using the Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS) approaches. Our results confirm that in the case of developing countries, CO₂ emissions are primarily influenced by GDP growth, energy use, industrialization, and urbanization. Furthermore, the panel causality analysis identified a bidirectional causal relationship between energy use, GDP growth, urbanization, industrialization, and CO₂ emissions. While these results can play an instrumental role in formulating CO₂ emission policies among our selected countries, our research can also assist policy makers and stakeholders in other developing economies implement important policy initiatives. These include, tax incentives and infrastructural developments that nurture environmentally friendly industrialization, deploy low-carbon technologies, promote sustainable forms of urbanization and urban planning, while also facilitating increases in both the investment in and adoption of renewable energy platforms. The establishment of such a comprehensive policy agenda can help emerging economies achieve strong and environmentally sustainable GDP growth over the long-term.

Life cycle CO2 emissions for the new energy vehicles in China drawing on the reshaped survival pattern

Promoting new energy vehicles (NEVs) is the key to achieving net-zero emissions in the transportation sector. NEVs' total life cycle CO₂ emissions are mainly determined by average vehicle lifespan, annual mileage traveled, energy carbon intensity and energy mix in the production stage. Current studies mainly adopt assumptions about NEVs' average lifespan due to limited available data. This paper expands on the previous studies by examining the NEVs' age and distribution based on the national representative China Compulsory Traffic Accident Liability Insurance for Motor Vehicles (CTALI) database from 2018 to 2020. Then, the survival patterns and lifespan of NEVs are assessed using Weibull distribution. New energy passenger vehicles' life cycle CO₂ emissions are further evaluated based on the reshaped representative survival patterns. The results show that there are significant differences in survival patterns between conventional vehicles and NEVs. NEVs generally show a shorter average lifespan compared with conventional vehicles. Among NEVs, the average lifespan of plug-in hybrid electric vehicles (PHEVs) is better than that of battery electric vehicles (BEVs). The survival patterns of several types of electric vehicles (including passenger battery electric vehicles, non-operating light battery electric buses, and light battery electric trucks) do not have a stable period in their first few years of operation. The life cycle assessment results show that the total life cycle CO₂ emissions of passenger BEVs and PHEVs are lower than those of conventional vehicles. However, the short lifespan dramatically increases the passenger BEV and PHEV total life cycle CO₂ emissions per kilometer, resulting in passenger BEV total life cycle CO₂ emissions per kilometer being higher than those of conventional vehicles.

Effect of polyethylene microplastics and acid rain on the agricultural soil ecosystem in Southern China

The increasing microplastics (MPs) pollution and continuous acid rain coincide in many areas of the world. However, how MPs interact with acid rain is still unclear. Herein, we conducted a microcosm experiment to decipher the combined effect of polyethylene (PE) MPs (1%, 5%, and 10%) and acid rain (pH 4.0) on the agricultural soil ecosystem of Southern China, in which edaphic property, microbial community, enzymatic activity and CO₂ emission were investigated. The results showed that PE MPs significantly decreased soil water retention and nitrate nitrogen content regardless of acid rain. Soil total nitrogen significantly decreased under the co-exposure of 10% PE MPs and acid rain. However, PE MPs did not alter soil microbial biomass, i.e., the content of microbial biomass carbon, total phospholipid fatty acids, with or without acid rain. 10% PE MPs and acid rain treatment significantly increased the activity of catalase and soil CO₂ emission. PE MPs addition did not affect the temperature sensitivity (Q₁₀) of soil CO₂ emission regardless of acid rain. These findings suggest that MPs may interact with acid rain to affect soil ecosystems, thus underscoring the necessity to consider the interaction between MPs and ambient environmental factors when exploring the impact of MPs on the soil biodiversity and function.

Unravelling the spatiotemporal variation of pCO2 in low order streams: Linkages to land use and stream order

Headwater streams make the majority of cumulative stream length in a river basin, carbon dioxide (CO₂) emission from headwater (low order) streams is thus an essential component. Anthropogenic activities in headwater areas such as land use change and land use practices can strongly modify terrestrial carbon and nutrient input, which could affect the level of partial pressure of dissolved carbon dioxide (pCO₂) and CO₂ degassing from streams. However, there are large uncertainties in estimates due to the lack of data in subtropical rivers of rapidly developing rural regions. The spatiotemporal variation and driving factors of the pCO₂ and CO₂ degassing from low-order streams remain to be explored. In this study, we assess multi-spatial scale effects of land use on pCO₂ dynamics in seven headwater tributary rivers in Central China during 2016, 2017 and 2018 in rainy and dry seasons. Our results reveal that the stream pCO₂ level consistently increases as the stream order increases from 1 to 3 under apparent seasonal variations. Riverine pCO₂ is positively related to the percentage of urban land and cropland surrounding the river segments, but is negatively related to the percentage of forest land. The stream pCO₂ is more closely correlated with the 1000 and 2000 m diameters of circular buffers at upstream sampling sites than the circular buffers with 100 and 500 m diameters. There exist significant relationships of pCO₂ with the concentrations of TN, TP, DO, and DOC in the low-order streams. The partial redundancy analysis quantifies the relative importance of anthropogenic land uses, natural factors and water chemical variables in mediating stream pCO₂, showing that influences of anthropogenic land uses (urban and cropland) on pCO₂ decrease, with a percentage role of 34%, 14%, and 4% in the 1st-, 2nd- and 3rd-order streams, respectively. The impact of nutrients on pCO₂, however, increases as the stream order increases. Urban influence on stream pCO₂ also decreases as stream order increases. Our study highlights the effect of land use/land cover types and stream order on riverine pCO₂ and provides new insight into estimating CO₂ emission in headwater streams. Future studies are needed on the linkage between riverine CO₂ degassing and stream orders under changing land use conditions.

Does travel closer to TOD have lower CO2 emissions? Evidence from ride-hailing in Chengdu, China

Despite contributions to reducing private car dependency and carbon emissions, impacts of transit-oriented development (TOD) on ride-hailing usage are largely overlooked in existing studies. Using massive ride-hailing trips data in Chengdu, the influence of subway proximity on vehicle kilometers traveled (VKT) and corresponding CO₂ emissions of ride-hailing is examined at the disaggregated level. Similarly, moderated multiple regression is adopted to investigate the interaction effects of subway proximity at pick-up and drop-off on VKT of ride-hailing. Results suggest that for each additional kilometer in subway proximity at pick-up/drop-off position, the VKT of ride-hailing trips is reduced by 0.315 km/0.273 km, resulting in the CO₂ emission reduction of 0.063 kg/0.055 kg. Moreover, the influence of pick-up proximity on VKT change is negatively moderated by drop-off proximity and vice versa. Our results suggest that the carbon emission reduction can benefit from "T (Transit)" however the problem of regional imbalances in "D (Development)" needs to be addressed.

Green-resilient supply chain network design for perishable products considering route risk and horizontal collaboration under robust interval-valued type-2 fuzzy uncertainty: A case study in food industry

A green and resilient (G-Resilient) supply chain network is designed for perishable products under disruption risks and epistemic uncertainties. This study aims to minimize effects of the disruption by presenting new strategies, such as multiple sourcing, financial suppliers, horizontal collaboration, route risk, and coverage radius, in designing a new multi-objective mixed-integer linear programming model for multi-product, multi-period, multi-modal G-Resilient supply chain. Then, a novel robust possibilistic programming (RPP) approach is presented using credibility measure and membership functions of generalized interval-valued type-2 fuzzy variables to face the epistemic uncertainties, such as supply capacity of facilities, customer demand, transportation cost, and CO₂ emission factor, in the proposed mathematical model. An improved version of augmented ε-constraint method (AUGMECON2) is also employed to produce separate Pareto-optimal solutions. Moreover, the study compares the proposed RPP with possibilistic chance-constrained programming model and illustrates its advantages; in the standard deviation of CO₂ emission objective function, its performance has improved by about 44.91%. Finally, the model's performance has been verified by a real case study in the food industry, and managerial implications have been provided.

Analysis of vehicular CO2 emission in the Central Plains of China and its driving forces

The Central Plains of China, represented by Henan province, faces a dramatic rise in vehicular stock and CO₂ emissions. The refined-resolution(1 km × 1 km) vehicular CO₂ emission inventory for Henan province was developed to identify emission patterns. Results show that CO₂ emissions in Henan province reached 77.04 Mt in 2019, and LDGV and HDDT were the major sources that emitted 42.34% and 35.96% of CO₂ emissions, respectively. Based on gridded emission, Moran's Index was used to identify spatial distribution patterns of vehicular CO₂. The higher CO₂ emission intensity areas were concentrated in the central and northern of the province and urban areas in each city, especially in Zhengzhou and its surrounding cities. Moreover, the analysis of the driving forces behind the differences in emissions among cities using the multi-regional (M-R) spatial decomposition model revealed that income and population-scale are significant impacts. In cities such as Zhengzhou, emissions may be dramatically increase owing to high economic growth expectations. 'Polarization phenomenon' of CO₂ emission distribution should be vigilant. Findings provided insights for refined policy-making in Henan province to limit CO₂ emission: (1) Take cities as transportation hubs, e.g., Zhengzhou and Shangqiu, and that in the traffic radiation circle, e.g., Jiaozuo and Zhoukou, as the critical areas for CO₂ emission reduction; (2) Promote electric vehicles as replacement for traditional fuel vehicles; especially for cities with large passenger car emissions, such as Zhengzhou, and cities with large truck emissions, such as Shangqiu and Zhoukou; actively guide new consumer groups to choose EVs, especially in cities with high growth expectations such as Zhengzhou; (3) Rely on the advantages of transportation network to promote the 'road to railway' of bulk cargo transportation and mainly focus on highways with higher CO₂ density, such as Beijing-Hong Kong&Macao Expressway, Shanghai-Xi'an Expressway, Da Guang Expressway, and Lian Huo Expressway.

The environmental impact of mass coronavirus vaccinations: A point of view on huge COVID-19 vaccine waste across the globe during ongoing vaccine campaigns

The vaccine innovation is a ubiquitous preventive measure to the transmission of highly infectious SARS-COV-2. The ongoing mass coronavirus vaccination programmes have inadvertently become the bulk producers of biomedical and plastic waste triggering severe impact on the environment. The sustainable management of bio hazardous vaccine waste in particular; syringes, needles, used/un-used vials and single-use plastic equipment is of utmost importance. This perspective presents a critical point of view in terms of the generated vaccine waste and the subsequent knock-on effect on all aspects of ecosystem. The discussion includes dire consequences due to the release of huge amount of plastic-based personal protective equipment into marine environment. The pivotal crisis of CO₂ emission during the manufacture and storage of different vaccines has contributed to global warming. The unavoidable generation of microfibers upon incineration, autoclaving, pyrolysis and open dumping of vaccine waste has further jeopardized the environment. In this vein, exploration of biodegradable materials for vaccine inoculation and development of green technologies for sound waste management is suggested to mitigate the environment pollution.

Transport and transformation of dissolved inorganic carbon in a subtropical groundwater‑fed reservoir, south China

Most reservoirs in subtropical areas experience periodic variations in the thermal structure of their water columns, with times of strong thermal stratification being succeeded by periods of mixing, over the course of the year. Understanding of the transport and transformation of dissolved inorganic carbon over such thermal cycles in artificial reservoirs remains poor. To address this problem, this study examined the spatiotemporal behavior of dissolved inorganic carbon (DIC), the partial pressure of CO2 (pCO2), carbon isotope ratios (δ13CDIC), and CO2 emission (FCO2), from 2014 to 2018 in a subtropical, groundwater-fed reservoir in southern China. It was found that CO2 emissions during mixing periods are much higher than in thermally stratified periods (particularly during transition from stratified to mixing) as a result of upwelling and release of dissolved CO2 (CO2aq) accumulated in the hypolimnion. CO2 emission fluxes at the water-gas interface accounted for only a small proportion of the DIC in the reservoir. The relationships between of DIC and δ13CDIC displayed two distinct modes, due to spatial differences in water depths and to strong thermal stratification during warmer seasons: (1) DIC concentrations increase and δ13CDIC values decrease from epilimnion to hypolimnion, and (2) δ13CDIC values decrease with increasing DIC concentrations but δ13CDIC is progressively enriched near the bottom during periods of thermal stratification. In addition, this study found three distinct processes of DIC accumulation and consumption in the reservoir: (1) DIC accumulated in the hypolimnion during thermal stratification periods, due to carbon retention but (2) DIC was substantially consumed in the epilimnion during such periods, and (3) average DIC concentrations and pCO2 increased significantly from upstream to downstream along the reservoir, while average δ13CDIC values became lighter. These results highlight that carbon behavior in groundwater‑fed reservoirs is often controlled by a combination of biogeochemical processes and seasonal variations in thermal structure. Sampling and monitoring strategies should consider these factors in order to accurately estimate carbon budgets in reservoirs, lakes or ponds.

Impact of COVID-19 on greenhouse gases emissions: A critical review

The global outburst of coronavirus 2019 (COVID-19) has posed severe challenges to human health, environment, energy and economy all over the world. The stringent measures to control the spread of COVID-19 results a significant slowdown in economic activities which in turn affected the environment by reducing the greenhouse gas (GHG) emissions, specifically lower atmospheric CO₂ levels. Considering that, the present study intends to highlight the substantial impact of COVID-19 pandemic on GHG emissions, by systematically reviewing the available scientific literatures. The study further outlined the variation in GHG emissions by comparing the data focused on pre-pandemic, during pandemic, and post-pandemic (predictions) scenarios. Further, the assessment on elevating CO₂ levels, global economic, and energy impacts of COVID-19 has also been reviewed. Also, the possible recovery plan for the framework of sustainable environmental and energy development is presented. Finally, the review concludes with an insightful summary involving the challenges and future outlook towards sustainable development goals in a hope that the present study can help the researchers to assess the global environmental and energy related consequences.

The effects of green growth, environmental-related tax, and eco-innovation towards carbon neutrality target in the US economy

This study aims to examine the nexus between green growth and carbon neutrality targets in the context of the USA while observing the role of ecological innovation, environmental taxes, and green energy. For this purpose, data were collected from 1970 to 2015 for all the variables of interest. This research utilized the quantile autoregressive distributed lag (QARDL) method due to its various benefits, such as depicting the causality patterns based on different quantiles for different variables like green growth, ecological innovation, environmental taxes, and renewable energy. The findings through the QARDL method showed that the error correction coefficient was significant and negative with the expected negative sign for the different quantiles. The findings showed a significant and negative impact of green growth, square of green growth, ecological innovation, and environmental taxes in determining the carbon dioxide (CO₂) emissions for the USA's economy under the long-run estimation. Meanwhile, the outcome for the short-term estimation confirmed that the past and lagged values of CO₂ emission were significantly and negatively linked with the current and lagged values of CO₂ emission. On the other hand, it was found that green growth and square of green growth, ecological innovation, environmental taxes, and renewable energy played their vital role in reducing haze pollution like PM2.5. Besides, this research also covers the limitations and policy implications.

Modeling the effect of green technology innovation and renewable energy on carbon neutrality in N-11 countries? Evidence from advance panel estimations

After the Paris Climate Conference (Conference of the Paris COP: 21), most developing countries face challenges to attain a sustainable economy and carbon neutrality targets with minimum CO₂ emission. The next eleven (N-11) economies are in line with the global phenomena of environmental degradation; very few studies have analyzed the effects of green technology innovation on environmental degradation in N-11 countries. Therefore, the present study addresses the gap and examines green technology innovation and renewable energy with CO₂ emission from 1980 to 2018. The present study considers all the issues related to panel data analysis, such as cross-sectional dependence, stationarity, heterogeneity in slope parameters, and structural break with advanced panel estimators. Moreover, the cross-sectional augmented autoregressive distributed lags (CS-ARDL) test results show the negative and significant impact of green technology innovation and renewable energy with CO₂ emission in the long run. However, the short-run association of green technology innovation is not significant-further, the results endorsed by the robustness tests such as AMG and CCEMG. To reduce environmental deterioration in N-11 countries, governments are suggested implementing some policies to support green innovation technologies and renewable energy resources.

The role of green innovation and tourism towards carbon neutrality in Thailand: Evidence from bootstrap ADRL approach

The recent years have been marked by the role of green tech innovation in decreasing carbon emissions worldwide to attain the carbon neutrality target. Despite many studies examining the nexus between the former and energy consumption, tech innovation's effects on CO2 releases have not been extensively researched, and the extant empirical findings are often contradictory. Also, a major concern regarding the available literature is the scarcity of papers that scan the impact of tourism on carbon emissions, even though the industry has a high potential to affect ambient air pollution. In this case, the evidence is mixed, and no consensus among academics on the relationships between the two. Therefore, this study seeks to investigate the relevance of green innovation and tourism in decreasing environmental damage in Thailand based on the bootstrapping ARDL causality model suggested by (McNown et al., 2018). This specification includes a new cointegration feature and conventional ARDL bounds tests, which increases the power of the t- and of the f-test and has several advantages, being more adequate for dynamic models with more than one explanatory variable. Our findings reveal that green innovation and tourism lead to lower environmental damage by reducing CO₂ emissions, similar to foreign investments and that green tech innovation improves the environmental quality via lower carbon emissions.

An empirical analysis of the non-linear effects of natural gas, nuclear energy, renewable energy and ICT-Trade in leading CO2 emitter countries: Policy towards CO2 mitigation and economic sustainability

Achieving reliable energy supply and environment sustainability whereby mitigating CO₂ emissions and promoting sustainable development has become a global effort. Thus, the current study intends to verify the non-linear influence effects of natural gas, nuclear energy, renewable energy and information and communication technology trade on economic growth and carbon dioxide emission in ten leading CO₂ emitter countries from 20002016. The panel regression, such as pooled regression, model fixed effect, random effects, robust least squares and panel causation procedures are applied for panel data appraisal. The regression analysis results mention that nuclear energy, renewable energy, and Information and communication technology (ICT-trade) stimulate economic growth, whereas environmental results illustrate that renewable energy and ICT-trade contribute to eliminating CO₂ emissions. The causality findings indicate that renewable energy consumption and ICT trade cause economic growth as well as CO₂ emissions. Therefore, policymakers should invigorate to exploit renewable energy and achieve the benefits from the significant influence of economic growth and a clean environment through the potential of green ICT-trade.

A study of consumer behaviour towards food-waste in Ireland: Attitudes, quantities and global warming potentials

This study aimed to investigate consumer behaviour towards food waste in Ireland by analysing their attitudes and quantities of food waste generated. Global warming potential of the food waste generated weekly is then assessed. A total of 2115 participants from all over the Republic of Ireland contributed to the survey (of which 2062 were included in this research). Using factor and cluster analysis, two clusters of consumers were formed based on their attitudes towards food waste, and it was found that 62.56% of the sample were 'uncaring' consumers and 37.44% were 'caring' consumers. The uncaring consumers consisted of more young males and were relatively unphased by food waste and take minimal precautions to reduce food waste at all stages of consumption. In contrast, caring consumers consisted of older and female consumers and were deeply disturbed by food waste, taking all precautions to reduce food waste at every stage of consumption. Regarding food waste quantities, uncaring consumers produced on average, 0.74 kg of food waste weekly, accounting for 2.74 kg of CO₂ equivalent in global warming potential, whereas caring consumers produced only half this amount. Our results thus suggest that consumers attitudes towards food waste directly impact the food waste quantities they generate and consequently the global warming effects. However, in Ireland all consumer groups can benefit from more information about food waste and our study contributes by providing information that can inform strategic communication campaigns at policy or organisational level, to educates consumers about food waste and how they are contributing to global warming.

Investigating the impact of in situ soil organic matter degradation through porewater spectroscopic analyses on marsh edge erosion

Marsh edge erosion results in soil organic matter (SOM) loss from coastal wetlands and is differentially affected by wind waves, soil properties, and vegetation cover. The degradation of SOM may make the marsh edge susceptible to erosion. The objective of this study was to investigate the effect of in situ biogeochemical degradations of SOM on marsh edge erosion using porewater spectroscopic analyses. Edge erosion was monitored at 12 transects in one of the highly eroding coastal basins of Louisiana. A total of 36 cores were collected at different distances from the edge of the marsh. Porewater was extracted and analyzed for dissolved organic carbon (DOC) and spectroscopic indicators. The north and west side had greater erosion rates (102.38 ± 5.2 cm yr^-1) than east and south side (78.47 ± 3.3 cm yr^-1). However, the north and east side had greater DOC and refractory carbon but less microbial activity indicating SOM degradation alone did not correlate to edge erosion. The intersecting trend between erosion rate and SOM degradation among four sides of the island indicates the complex nature of edge erosion drivers. The estuarine bottom indicators suggest the eroded SOM is not reburied but rather degraded and emitted back into the atmosphere as CO₂, potentially contributing to global change. The coastlines projected to experience high sea-level rise in the coming century are vulnerable to losing a large amount of stored carbon in the absence of efficient mitigation measures.

The environmental footprint of China-Africa engagement: An analysis of the effect of China - Africa partnership on carbon emissions

China has strategically engaged with African countries through different routes. However, the growing presence of China in Africa has attracted a lot of praise and criticism. As a leader in smart technology, China may fill the technological gaps in Africa, which improve the environment. Conversely, China may be exploiting natural resources and rapidly deteriorating the environment. Therefore, in this paper, we examine the impact of different routes of the China-Africa relationship on the environment. Using Fully Modified Ordinary Least Square (FMOLS) model on data from 50 African countries, we find that different Chinese activities affect the environment differently. We find a positive relationship between construction revenue and carbon emission, suggesting that China's construction activities negatively affect the environment. Similarly, export increases carbon emission and harms the environment. However, we find a negative relationship between importation from China and carbon emissions, implying a positive environmental footprint by China in Africa. In the case of foreign direct, the results show that foreign direct investment improves the environment, and the relationship is stronger in non-resource countries. Given that most exports from Africa are natural resources, our results imply that African non-resources-rich countries are likely to benefit from China's large investment in cleaner energy in the long-run, especially after the construction of the infrastructures. Our findings highlight the potential environmental risks associated with the different routes of China partnership with African countries.