Search

Assessments of greenhouse gas (GHG) emissions in managed areas are facing various challenges. A non-flow-through, non-steady-state (NFT-NSS) chamber coupled to a frame permanently inserted into the landfilled substrates is a standard method for quantifying GHG emissions in managed areas, such as pulp and paper mill sludge (PPMS) landfill sites. Frequent measurements are needed to minimize uncertainties on GHG emission factors at the landfill site scale. However, maintaining a frame inserted into the substrates for a long time period is often impossible due to landfilling management operations. Therefore, GHG measurements using NFT-NSS chambers placed directly on substrates' surface could be an interesting option. Our objectives were to determine the relationships between CO 2 , CH 4 , and N 2 O fluxes measured with (F + ) and without (F-) a frame inserted in the substrates' surface and to develop correction factors for fluxes measured without a frame. Measurements were made at different PPMS landfill sites in the province of Québec, Canada. Stronger GHG flux relationships were observed at the provincial (across sites) than the specific site scale: the variance in GHG fluxes from F- chambers explained up to 80 % of variance in fluxes from F + chambers. The measured CO 2 , CH 4 , and N 2 O fluxes in F- chambers were on average 53, 78, and 63 % lower, respectively, than those estimated by the models at provincial scale. The correction factors developed with this approach could greatly extend the number of sites where in situ GHG measurements can be done and would help refining GHG inventories at the provincial and national levels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Growing consumption is both necessary to end extreme poverty 1 and one of the main drivers of greenhouse gas emissions 2 , creating a potential tension between alleviating poverty and limiting global warming. Most poverty reduction has historically occurred because of economic growth 3-6 , which means that reducing poverty entails increasing not only the consumption of people living in poverty but also the consumption of people with a higher income. Here we estimate the emissions associated with the economic growth needed to alleviate extreme poverty using the international poverty line of US $2.15 per day (ref.  7 ). Even with historical energy- and carbon-intensity patterns, the global emissions increase associated with alleviating extreme poverty is modest, at 2.37 gigatonnes of carbon dioxide equivalent per year or 4.9% of 2019 global emissions. Lower inequality, higher energy efficiency and decarbonization of energy can ease this tension further: assuming the best historical performance, the emissions for poverty alleviation in 2050 will be reduced by 90%. More ambitious poverty lines require more economic growth in more countries, which leads to notably higher emissions. The challenge to align the development and climate objectives of the world is not in reconciling extreme poverty alleviation with climate objectives but in providing sustainable middle-income standards of living., (© 2023. The World Bank.)

Climate change is altering ecological systems and poses a serious threat to human life. Climate change also seriously influences on livestock production by interfering with growth, reproduction, and production. Livestock, on the other hand, is blamed for being a significant contributor to climate change, emitting 8.1 gigatonnes of CO2-eq per year and accounting for two-thirds of global ammonia emissions. Methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) are three major greenhouse gases (GHG) that are primarily produced by enteric fermentation, feed production, diet management, and total product output. Ruminants account for three-quarters of total CO2-equivalent (CO2-eq) emissions from the livestock sector. The global dairy sector alone emits 4.0% of global anthropogenic GHG emissions. Hence, dairy farming needs to engage in environmental impact assessment. Public concern for a sustainable and environmentally friendly farming system is growing, resulting in the significant importance of food-based life cycle assessment (LCA). Over the last decade, LCA has been used in agriculture to assess total GHG emissions associated with products such as milk and manure. It includes the production of farm inputs, farm emissions, milk processing, transportation, consumer use, and waste. LCA studies on milk production would assist us in identifying the specific production processes/areas that contribute to excessive greenhouse gas emissions when producing milk and recommending appropriate mitigation strategies to be implemented for a clean, green, and resilient environment., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

This research aims to investigate the presence of environmental Kuznets curve hypothesis while considering the financial sector variables such as financial innovation, financial inclusion, and financial development on the environmental quality as well as achieving the energy efficiency in the Middle Eastern region. Current research employs a panel conditionally homogenous autoregressive (PCHVAR) specification for the annual dataset covering the time 2001-2021. The estimates reveal that in the short run, economic growth and financial sector variables adversely affect the environment quality by emitting more greenhouse gases, whereas in the long run, higher economic growth and developed financial sector help to improve the quality of the environment and energy efficiency. These findings are also verified through the Granger causality test. This research provides insights to establish long-term policies for facilitating investments in green technology and energy conservation in the Middle Eastern region., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The environmental situation of our planet is seriously degraded due to the massive spread of greenhouse gases. Several aspects can influence the quality of the environment. The present study debates the effect of financial inclusion (FI) and renewable energy consumption (REC) on the emissions of carbon dioxide (CO 2 ) emissions of the top ten countries in technological advancement (TTCTA) over the period 2004-2019. Other deterministic factors are included in the empirical study such as real gross domestic product (GDP), non-renewable energy consumption (NREC), and technological advancement (ATECH) to check their influence on environmental indicators. PMG-ARDL approach, cointegration techniques, and Granger causality tests are applied for the empirics part. In the long run, the outcomes show that real GDP, REC, and technological advancement contribute to decreasing CO 2 emissions, while NREC and FI contribute to increasing emissions levels. In the short run, only GDP and NREC significantly deteriorate the environmental quality. Granger shows a long-run bidirectional causality between CO 2 emissions, economic growth, REC, NREC, and ATECH., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This article examines the hypothesis of deterministic emissions convergence for a panel of the BRICS and Indonesia to advanced countries' emissions levels as well as to Sweden (which is a country that has clearly gone through decoupling) using a novel dataset with ten series of annual estimates of anthropogenic emissions comprising aerosols, aerosol precursor and reactive compounds, and carbon dioxide from 1820 to 2018. For that purpose, we employ four novel panel unit root tests allowing for several forms of time-dependent and state-dependent nonlinearity. The evidence supports deterministic convergence following a linear process for carbon dioxide, whereas the adjustment is asymmetric and nonlinear for carbon monoxide. Methane and nitrogen oxides exhibit logistic smooth transition converging dynamics. In contrast, black carbon, ammonia, nitrous oxide, non-methane volatile organic compounds, organic carbon, and sulfur dioxide emissions diverge. These results have implications for the abatement of greenhouse gases emissions at the global level, given the high share of emissions of the BRICS., (© 2022. The Author(s).)

Carbon dioxide (CO 2 ) is the most prevalent greenhouse gas that triggers climate change, which in turn leads to catastrophic effects on trade, business, human health, and other areas. Understanding the characteristics and tendency of CO 2 emissions will improve policy making and mitigation strategies. Understanding the linearity or nonlinearity and convergence or divergence of CO 2 emissions is essential for selecting appropriate modeling techniques and for designing reliable policies. Therefore, this paper investigates the nonlinearity and nonlinear convergence of CO 2 emissions among the world's top 20 highest emitting countries, which account for 80% of the world's total emissions. To check the nonlinearity of CO 2 emissions, the McLeod-Li nonlinearity test, the Terasvirta nonlinearity test, and the Brock-Dechert-Scheinkman-LeBaron nonlinearity test are employed. The convergence or divergence of CO 2 emissions is checked by using the Kilic nonlinear unit root test, the Hu and Chen nonlinear unit root test, and the Park and Shintani nonlinear unit root test. The findings revealed that the CO 2 emissions process in all the 20 countries is nonlinear; 17 countries exhibit convergence in CO 2 emissions while the other 3 countries diverged from 1960 to 2018. Based on the results, the nonlinear nature of CO 2 emissions requires special attention from scholars when selecting estimation techniques for CO 2 emissions. For countries with convergence, emissions trends can be used to forecast future values of CO 2 emissions. Moreover, strong policy actions are required to achieve convergence in the countries with divergence., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Climate change resulting from a rapid increase in greenhouse gas (GHG) emissions is adversely affecting humanity. If the GHG emission continues to rise at the current pace, humanity will face severe consequences and reverse all the progress made. This paper, therefore, uses relevant data from 14 developing countries in Asia from 1990 to 2018 to examine the potential impact of environmental innovation on CO 2 emissions by controlling globalization, urbanization, and economic growth. The number of environmental-related technology patents is used as a measure of environmental innovation. We employed a panel long-run regression model - FMOLS, PCSE, and FGLS to estimate the elasticity of CO 2 emissions. For causal association among variables, we used Dumitrescu-Hurlin Granger causality tests. Our results show that renewable energy consumption and globalization have a significant impact in reducing CO 2 emissions, while environmental technology innovations play a meager role in reducing emissions and only when economic growth support those type of investment. Furthermore, we found urbanization, oil consumption, and economic growth is detrimental to the environment, which is also evident in past studies. Therefore, countries should invest in renewable energy and environmental innovation aligned with the growth to reduce GHG emissions., (© 2022. The Author(s).)

Computable general equilibrium models (CGE) are used to estimate the ex-ante quantitative impact of a change in economic policy. There is a bulk of research in the field of sustainable development applying it for testing implementation of carbon taxation, analyzing reductions of greenhouse gas (GHG), or addressing agricultural issues to work the land efficiently. The main objective of this review is to provide an exhaustive analysis of the literature about these models and their evolution over the last 50 years. The search was conducted in the main academic databases (Scopus and Web of Science), where 1353 articles were found from 1966 to 2019 related to the topic. The results of the descriptives, relational, and content analyses carried out show the current state of the-art, trends, subfields of research, and future gaps to fulfill. This article contributes to the literature that uses CGE models providing an overview of its different applications in the field of sustainability. It gives useful insights to academics who want to further research the field., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

CO 2 emission performance evaluation is crucial to make abatement policies. Knowledge about the potential and costs of CO 2 reduction could provide information guides for policymakers and help them implement targeted measures. However, relevant studies are rarely subdivided into detailed industrial sectors, and results are lack of inter-industry comparisons. To fill this gap, this study estimates provincial technical inefficiency, abatement potential, and shadow price of CO 2 from fuel combustion in China's 25 industries in 2001-2017. Results show that China's industry could ideally reduce CO 2 emissions by a further 22.01-33.27%, averaging 1645.96 MtCO 2 . Technical efficiency, abatement potential, and cost vary across provinces and industries and should therefore be fully considered when designing emission reduction targets and control policies. Provinces and industries with low technical efficiency, large-scale emissions, great abatement potential and low shadow price are the key to emission reduction. We thus identify key provinces and industries that need to take on more abatement responsibility. Those findings are of great significance to the formulation of carbon reduction targets and the implementation of abatement policies, and prove the feasibility of China's trans-regional carbon trading. It is suggested to prioritize key industries into the trading system and further promote inter-provincial cooperation through carbon trading., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Cement industry is one of the main contributors to greenhouse gas (GHG) emissions, specifically carbon dioxide (CO 2 ). This paper presents the cement production and the CO 2 emissions from the cement industry in Nepal. We compute emissions for the process-related, combustion-related (fuel use), and electricity-related activities during the cement production. We used eight emission factors (EFs) for the process-related, two EFs for the combustion or fuel-related, and two for the electricity-related activities using the previous researches. We computed the emissions as a product of the activities and the EFs. The estimated CO 2 emission in 2019 from the cement production is 3.45 ± 0.50 million metric tons (mMt) for Nepal. In 2019, the emissions are 1.87 ± 0.16 mMt from the process-related, 1.52 ± 0.34 mMt from the combustion-related, and 0.062 ± 0.004 mMt from the electricity use activities during the cement production in Nepal. Cumulative CO 2 emission was 22.73 ± 3.82 mMt from 1987 to 2019. Per capita CO 2 emission is 0.12 mMt for Nepal in 2019. Nepal contributes about 0.06% CO 2 emission from cement production to the global CO 2 emission (2.08 Gt) from the cement industry. By evaluating per capita gross domestic product (GDP) (from 1987/1988 to 2019/2020) and the human development index (HDI) (from 1990 to 2019) with the cement production, the result shows that cement production increases significantly (p < 0.01) with an increase in the GDP and the HDI. We emphasize that the study's outputs are directly relevant to the country's emission inventory, mitigation planning, and developing a strategy for cleaner production., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The current trend in the European biogas industry is to shift away from electricity production towards the production of biomethane for the need to replace natural gas. The upgrading of biogas to biomethane is normally performed by separating the biogas in a stream containing natural gas grid quality methane and a stream containing mostly CO 2 . The CO 2 stream is normally released into the atmosphere; however, part of the methane may still remain in it, and, if not oxidized, even a small fraction of methane released may jeopardise all the GHG emissions savings from producing the biomethane, being methane a powerful climate forcer. Scope of this work is to assess the opportunity cost of installing an Off Gas Combustion (OGC) device in biomethane upgrading plants. The currently available technologies for biogas upgrading to biomethane and the most common technology of OGC (the Regenerative Thermal Oxidisers, RTO) are described according to their performances and cost. Then the cost per tonne of CO 2 eq avoided associated to the adoption of RTO systems in relation to the upgrading performance is calculated to identify a potential threshold for an effective and efficient application of the RTO systems. It is found that, in case of upgrading technologies which can capture almost all biomethane in the upgrading off-gas (i.e. 99.9%), currently the adoption of an RTO to oxidise the methane left in the off-gas would add costs and need additional fuel to be operated, but would generate limited GHG emission savings, therefore the cost per tonne of CO 2 eq emissions avoided would result not competitive with other GHG emissions mitigation investments. While the installation of RTOs on upgrading systems with a methane slip of 0.3%, or higher, normally results cost competitive in reducing GHG emissions. The installation of an RTO on systems with a methane slip of 0.2% results in a cost per tonne of CO 2 eq emissions avoided of 50-100 euro, which is comparable to the current cost of CO 2 emissions allowances in the EU ETS carbon market, representing therefore a reasonable choice for a threshold on methane slip regulation for biogas upgrading systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The present work has estimated greenhouse gas emissions in aerobic and anaerobic Wastewater Treatment Plants in Southern Italy. Greenhouse gases emissions from each treatment unit were calculated based on emission factors related to Chemical Oxygen Demand removal for biogenic CO 2 and CH 4 assessment and on Nitrogen removal for N 2 O. N 2 O, biogenic CO 2, and CH 4 emissions vary for aerobic and anaerobic-based WWTPs respectively from 73 kgCO 2eq /PE*y for anaerobic plants to 91 kgCO 2eq /PE*y for aerobic plants. In aerobic and anaerobic digestion systems WWTPs the contributions to CO 2eq total emissions from N 2 O, CH 4 , biogenic CO 2 , and fossil CO 2 are 30 %-33 %, 20 %-29 %, 22 %-25 %, and 26 %-16 %, respectively. N 2 O emissions from biological processes were found the most contributing sources of greenhouse gases while in the physical processes higher contribution is indirect carbon dioxide related to energy consumption. Compensatory measures are reported to reduce greenhouse gases emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Mollisols rich in natural organic matter are a significant sink of carbon (C) and selenium (Se). Climate warming and agricultural expansion to the cold Mollisol regions may enhance soil respiration and biogeochemical cycles, posing a growing risk of soil C and Se loss. Through field-mimicking incubation experiments with uncultivated and cultivated soils from the Mollisol regions of northeastern China, this research shows that soil respiration remained significant even during cold seasons and caused co-emission of greenhouse gases (CO 2 and CH 4 ) and methylated Se. Such stimulus effects were generally stronger in the cultivated soils, with maximum emission rates of 7.45 g/m 2 /d C and 1.42 μg/m 2 /d Se. For all soil types, the greatest co-emission of CO 2 and dimethyl selenide occurred at 25 % soil moisture, whereas measurable CH 4 emission was observed at 40 % soil moisture with higher percentages of dimethyl diselenide volatilization. Molecular characterization with three-dimensional fluorescence and ultra-high resolution mass spectrometry suggests that CO 2 emission is sensitive to the availability of microbial protein-like substances and free energy from organic carbon biodegradation under variable moisture conditions. Predominant Se binding to biodegradable organic matter resulted in high dependence of Se volatilization on rates of greenhouse gas emissions. These findings together highlight the importance of dynamic organic carbon quality for soil respiration and consequent Mollisol Se loss risk, with implications for science-based management of C and Se resources in agricultural lands to combat with Se deficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

To achieve net-zero emissions by 2050, we need economic means of sequestering carbon dioxide (CO 2 ) and reducing greenhouse gas emissions (GHG). We analyze the sequestration potential of the Intermountain West (I-West) region, US, as a primary energy transition hub through analysis of wellbore retrofit potential and emission reduction in both fugitive gas abatement and flare gas. We selected the I-West region due to its abundant energy sources and oil and gas production legacy. Preliminary analysis hints that well retrofits can breathe new life into a well at a fraction of the cost of a new drill. With millions of potential candidates in the US, even a modest fraction (1% or less) suitable for retrofit could accelerate the shift to large-scale CO 2 sequestration. Fugitive gas, the unintentional release of wellbore gases such as methane, is a significant emissions source. Through conservative analysis, it is estimated that wellhead leakage alone may account for 5 million tonnes of carbon dioxide equivalent (CO 2 e) emissions. We conclude by assessing the CO 2 emissions from flaring, which is the burning of associated gas during well operations, conservative analysis indicates flaring contributes another 2 million tonnes of CO 2 emissions to the region. We find that with targeted retrofit and better controls on emissions sources, the I-West region can make a significant impact in the nation's push to become net-zero. This study outlines economic feasibility and actionable items to achieve the critical reductions in emissions and increases in sequestration necessary to attain net zero., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Mangroves forests may be important sinks of carbon in coastal areas but upon their death, these forests may become net sources of carbon dioxide (CO 2 ) and methane (CH 4 ) to the atmosphere. Here we assessed the spatial and temporal variability in soil CO 2 and CH 4 fluxes from dead mangrove forests and paired intact sites in SE-Brazil. Our findings demonstrated that during warmer and drier conditions, CO 2 soil flux was 183 % higher in live mangrove forests when compared to the dead mangrove forests. Soil CH 4 emissions in live forests were > 1.4-fold higher than the global mangrove average. During the wet season, soil GHG emissions dropped significantly at all sites. During warmer conditions, mangroves were net sources of GHG, with a potential warming effect (GWP100) of 32.9 ± 10.2 (±SE) Mg CO 2 e ha -1 y -1 . Overall, we found that dead mangroves did not release great amounts of GHG after three years of forest loss., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Much of the existing research analyses on emissions and climate policy are dominantly based on emissions data provided by production-based accounting (PBA) system. However, PBA provides an incomplete picture of driving forces behind these emission changes and impact of global trade on emissions, simply by neglecting the environmental impacts of consumption. To remedy this problem, several studies propose to consider national emissions calculated by consumption-based accounting (CBA) systems in greenhouse gas (GHG) assessments for progress and comparisons among the countries. In this article, we question the relevance of PBA's dominance. To this end, we, firstly, try to assess and compare PBA with CBA adopted in greenhouse gas emissions accounting systems in climate change debates on several issues and to discuss the policy implications of the choice of approach. Secondly, we investigate the convergence patterns in production-based and consumption-based emissions in 35 Annex B countries for the period between 1990 and 2015. This study, for the first time, puts all these arguments together and discusses possible outcomes of convergence analysis by employing both the production- and consumption-based CO 2 per capita emissions data. The empirical results found some important conclusions which challenge most of the existing CO 2 convergence studies.

The calculation of marginal abatement costs of CO 2 plays a vital role in meeting China's 2020 emission reduction targets by providing reference for determining carbon tax and carbon trading pricing. However, most existing researches only used one method to discuss regional and industrial marginal abatement costs, and almost no studies predicted future marginal abatement costs from the perspective of CO 2 emission efficiency. To make up for the gaps, this paper first estimates marginal abatement costs of CO 2 in three major industries of 30 provinces in China from 2005 to 2015 based on three assumptions. Second, based on the principle of fairness and efficiency, China's 2020 emission reduction targets are decomposed by province. Based on the ZSG-C-DDF model, the marginal abatement costs of CO 2 in all provinces in China in 2020 are estimated and compared with the marginal abatement costs of 2005 to 2015. The results show that (1) from 2005 to 2015, marginal abatement costs of CO 2 in all provinces show a fluctuating upward trend; (2) compared with the marginal abatement costs of primary industry or tertiary industry, most provinces have lower marginal abatement costs for secondary industry; and (3) the average marginal abatement costs of CO 2 for China in 2020 are 2766.882 Yuan/tonne for the 40% carbon intensity reduction target and 3334.836 Yuan/tonne for the 45% target, showing that the higher the emission reduction target, the higher the marginal abatement costs of CO 2 . (4) Overall, the average marginal abatement costs of CO 2 in China by 2020 are higher than those in 2005-2015. The empirical analysis in this paper can provide multiple references for environmental policy makers.

Microplastics (MPs) are emerging contaminants in aquatic ecosystems that can profoundly affect carbon and nitrogen cycling. However, the impact mechanisms of MPs on sedimentary greenhouse gas (GHG) emissions at distinct altitudes remain poorly elucidated. Here, we investigated the effects of polyvinyl chloride (PVC) and polylactic acid (PLA) on sedimentary CO 2 , CH 4 , and N 2 O emissions at distinct altitudes of the Yellow River. PVC increased the relative abundance of denitrifiers (e.g., Xanthobacteriaceae, Rhodocyclaceae) to promote N 2 O emissions, whereas PLA reduced the abundance of AOA gene and denitrifiers (e.g., Pseudomonadaceae, Sphingomonadaceae), impeding N 2 O emissions. Both PVC and PLA stimulated the growth of microbes (Saprospiraceae, Aquabacterium, and Desulfuromonadia) associated with complex organics degradation, leading to increased CO 2 emissions. Notably, the concurrent inhibition of PLA on mcrA and pmoA genes led to its minimal impact on CH 4 emissions. High-altitude MQ sediments, characterized by abundant substrate and a higher abundance of functional genes (AOA, AOB, nirK, mcrA), demonstrated higher GHG emissions. Conversely, lower microbial diversity rendered the low-altitude LJ microbial community more susceptible to PVC, leading to a more significant promotion on GHG emissions. This study unequivocally confirms that MPs exacerbate GHG emissions via microbiome-mediated mechanisms, providing a robust theoretical foundation for microplastic control to mitigate global warming., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Accurate measurements of methane (CH 4 ) and carbon dioxide (CO 2 ) fluxes from tree stems are important for understanding greenhouse gas emissions. Closed chamber methods are commonly employed for this purpose; however, leaks between the chamber and the atmosphere as well as gas accumulation, known as the concentration buildup effect, can impact flux measurements significantly. In this study, we investigated the impacts of concentration buildup and leaks on semi-rigid closed chamber methods. Field measurements were conducted on six tree species, including three species from a Mexican mangrove ecosystem and three species from a Magellanic sub-Antarctic forest. Systematic observations revealed significant leak flow rates, ranging from 0.00 to 465 L h -1 , with a median value of 1.25 ± 75.67 L h -1 . We tested the efficacy of using cement to reduce leaks, achieving a leak flow rate reduction of 46-98 % without complete elimination. Our study also demonstrates a clear and substantial impact of concentration buildup on CH 4 flux measurements, while CO 2 flux measurements were relatively less affected across all tree species studied. Our results show that the combined effects of leaks and concentration buildup can lead to an underestimation of CH 4 emissions by an average of 40 ± 20 % and CO 2 emissions by 22 ± 22 %, depending on the bark roughness. Based on these findings, we recall a straightforward yet effective method to minimize experimental errors associated with these phenomena, previously established, and reiterated in the current context, for calculating emissions that considers effects of leaks and concentration buildup, while eliminating the need for separate determinations of these phenomena. Overall, the results, combined with a literature review, suggest that our current estimates of GHG flux from tree stems are currently underestimated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

To effectively combat global warming, an enormous reduction in CO 2 emissions is required. Cameroon, which is currently the largest emitter of CO 2 in the CEMAC subregion, has committed to reducing its greenhouse gas emissions by 32% by 2035. However, previous studies in Cameroon have only addressed the relationship between economic growth, energy consumption, and CO 2 emissions without estimating all causal relationships at the same time. Moreover, no study has yet decomposed this country's CO 2 emissions to date. To fill these research gaps and further assess the determinants of these CO 2 emissions, an extended Kaya identity and the Logarithm Mean Divisia Index (LMDI I) have been applied in this paper to identify, quantify, and explain the main drivers of Cameroon's CO 2 emissions from 2007 to 2014. Seven effects were measured and the main findings show that carbon intensity and the emission factor increased by 0.57% and 107.50% respectively. Regarding contributions to the increase of CO 2 emissions, the population effect was the most positive followed by the activity effect, whereas the energy intensity, the substitution of fossil fuels and the penetration of renewable energies have contributed to reduce the CO 2 emission. To enable Cameroon to not only achieve the goals of its vision but also develop a low-carbon economy, this paper provides some proposed avenues that should be considered by policymakers.

Hybrid calcium carbonate (HCC) is prepared by pre-flocculating calcium oxide and ground calcium carbonate (GCC) with ionic polymers, and by injecting carbon dioxide to the pre-flocculated flocs until termination of the reaction at neutral pH. When used in papermaking, HCC gave higher bulk, higher stiffness, and higher tensile strength than GCC did. Furthermore, when higher wet pressing pressure was applied to the paper containing HCC, higher solid content was achieved with still better stiffness, smoothness, and tensile strength in comparison with the paper containing GCC. Actually, very high bulk of the HCC containing paper was compromisingly reduced to obtain high solid content by applying higher wet pressing pressure. Higher solid content achieved by combination of HCC technology and higher wet pressing pressure resulted in paper drying energy savings of more than 10%, while a high quality of all the essential printing paper properties was maintained. Drying energy savings may contribute to greenhouse gas (GHG) reduction and lowering of the paper production cost. [ABSTRACT FROM AUTHOR]

Although saline aquatic ecosystems are significant emitters of greenhouse gases (GHGs), dynamic changes in GHGs at the sediment-water interface remain unclear. The present investigation carried out a total of four sampling campaigns in Daihai Lake, which is a eutrophic saline lake situated in a semi-arid area of northern China. The aim of this study was to investigate the spatio-temporal dynamics of carbon dioxide (CO 2 ) and methane (CH 4 ) fluxes at the sediment-water interface and the influencing factors. The mean concentrations of porewater CO 2 and CH 4 were 44.98 ± 117.99 μmol L -1 and 124.36 ± 97.00 μmol L -1 , far exceeding those in water column of 11.14 ± 2.16 μmol L -1 and 0.33 ± 0.23 μmol L -1 , respectively. The CO 2 and CH 4 fluxes at the sediment-water interface (F S - W CO 2 and F S-W CH 4 ) exhibited significant spatial and temporal variations, with mean values of 9.24 ± 13.84 μmol m -2  d -1 and 3.53 ± 4.36 μmol m -2  d -1 , respectively, indicating that sediment is the source of CO 2 and CH 4 in the water column. However, CO 2 and CH 4 fluxes were much lower than those measured at the water-air interface in a companion study (17.54 ± 14.54 mmol m -2 d -1 and 0.50 ± 0.50 mmol m -2 d -1 , respectively), indicating that the diffusive flux of gases at the sediment-water interface was not the primary source of CO 2 and CH 4 emissions to the atmosphere. Regression and correlation analyses revealed that salinity (Sal) and nutrients were the most influential factors on porewater gas concentrations, and that gas fluxes increased with increasing gas concentrations and porosity. The microbial activity of sediment is greatly affected by nutrients and Sal. Additionally, Sal has the ability to regulate biogeochemical processes, thereby regulating GHG emissions. The present investigation addresses the research gap concerning GHG emissions from sediments of eutrophic saline lakes. The study suggests that controlling the eutrophication and salinization of lakes could be a viable strategy for reducing carbon emissions from lakes. However, further investigations are required to establish more conclusive results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

The greatest environmental issue of the twenty-first century is climate change. Human-caused greenhouse gas emissions are increasing the frequency of extreme weather. Carbon dioxide (CO 2 ) accounts for 80% of human greenhouse gas emissions. However, CO 2 emissions and global temperature have risen steadily from pre-industrial times. Emissions data are crucial for most carbon emission policymaking and goal-setting. Sustainable and carbon-neutral sources must be used to create green energy and fossil-based alternatives to reduce our reliance on fossil fuels. Near-real-time monitoring of carbon emissions is a critical national concern and cutting-edge science. This review article provides an overview of the many carbon accounting systems that are now in use and are based on an annual time frame. The primary emphasis of the study is on the recently created carbon emission and eliminating sources and technology, as well as the current application trends for carbon neutrality. We also propose a framework for the most advanced naturally available carbon neutral accounting sources capable of being implemented on a large scale. Forming relevant data and procedures will help the "carbon neutrality" plan decision-making process. The formation of pertinent data and methodologies will give robust database support to the decision-making process for the "carbon neutrality" plan for the globe. In conclusion, this article offers some opinions, opportunities, challenges and future perspectives related to carbon neutrality and carbon emission monitoring and eliminating resources and technologies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Agricultural activities immensely contribute to greenhouse gas emissions (GHGs). This study investigates the heterogeneous effect of agricultural production (AGRIP) on three major GHGs emissions, i.e., carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ) under the Environmental Kuznets Curve (EKC) framework using a balanced panel data of 90 countries from the period 1991 to 2019. Second-generation panel unit root and cointegration tests are conducted to account for cross-sectional dependence. The findings suggest that there is a long run equilibrium among target variables. Evidence from panel quantile regression suggests that AGRIP significantly reduced CO 2 emissions, and the effect is stronger in lower quantiles (least carbon emitters). On the other hand, AGRIP increases N 2 O and CH 4 emissions in all quantiles. However, AGRIP is homogeneously distributed across N 2 O quantiles while the effect is stronger in higher quantiles (high methane emitters) in the case of CH 4 model. Concerning agricultural trade, exports impede CO 2 emissions but increase N 2 O and methane emissions. Agricultural imports are positively associated with all GHGs emissions. The effect of agricultural trade is largely heterogeneous and varies across different quantile levels of GHGs emissions. The EKC is fully valid for CO 2 and N 2 O but not for the methane emissions model. Based on the results, it is suggested that high GHGs emitter should shift their agricultural activities from traditional to sustainable approaches along with green trade policies to achieve climate neutrality targets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Inland waters have been increasingly viewed as hotspots for greenhouse gas (GHG) emissions owing to their strong capability to intercept and mineralize carbon from the terrestrial environment. Although small waterbodies in humid subtropical climates have the potential to emit considerable amounts of GHG, their emission patterns have remained understudied. This study involved intensive measurements of carbon dioxide (CO 2 ) emissions from a small reservoir and its upstream and downstream reaches located in subtropical Hong Kong. Our results revealed that a variety of metabolic, hydrological, and hydrochemical processes play a critical role in regulating its CO 2 dynamics. The reservoir was an overall source of CO 2 to the atmosphere with an average areal flux of 24.6 mmol m -2 d -1 , and it occasionally functioned as a sink for atmospheric CO 2 under intense solar radiation when primary productivity was high. This flux is on the low side relative to that of global (sub)tropical reservoirs, which was likely attributable to the prolonged history of the reservoir (>150 years) and the occasional undersaturation of CO 2 in the water column. We also noticed pronounced differences in the underlying controls of CO 2 dynamics between the reservoir and its upstream and downstream reaches, emphasizing the importance of taking into account the distinct characteristics of both lentic and lotic waters when evaluating catchment-scale CO 2 fluxes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Investigating the effect of renewable energy on the drivers of climate change correctly is significant as it is the basic source of climate change mitigation. In the extant literature, its effect on climate change has been estimated predominantly by regressing aggregate rather than sectoral renewable energy use either on aggregate greenhouse gas emissions or the components of greenhouse gases (GHGs) like carbon dioxide emissions. Against this backdrop, the paper investigates if we should estimate the nexus (i) by the causal effects running from aggregate or sectoral renewable energy use to GHG emissions and (ii) by the causal effects running from renewable energy consumption to aggregate GHG emissions or to its components like carbon dioxide (CO 2 ) emissions. To this end, the paper introduces negative and positive (functional) complementarity between sectoral renewable energy consumptions in reducing or increasing GHG emissions, takes 20 OECD countries from 1990 to 2019, and uses augmented and non-augmented auto-regressive distributed lag approach and vector error correction mechanism. The study finds substantial differences among the results coming out of (i) regressing aggregate and sectoral renewable energy consumption on GHG emissions and (ii) regressing renewable energy consumption on aggregate GHG emissions and on CO 2 emissions. The paper suggests regressing sectoral rather than aggregate renewable energy consumption on the components of aggregate GHG emissions like CO 2 emissions rather than on aggregate GHG emissions to produce workable, specific, and conclusive policy alternatives., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Although the past twenty years have witnessed China's remarkable economic development, the cost in terms of greenhouse gas emissions and a deteriorating environment has been enormous. Numerous studies have revealed the influence of household factors on household carbon dioxide emissions (HCEs) and called for a reduction of HCEs to mitigate climate change, but few have focused on assessing the most significant household driving factors of HCEs. Using statistical data between 2005 and 2019 in Jiangsu, China, this study developed an extended stochastic impact by regression on population, affluence, and technology (STIRPAT) model to assess the most significant driving factors of HCEs. The results show that the most significant driving factors are household size, total population, unemployment, and urbanisation rate. The study found that HCEs are positively impacted by household size while negatively impacted by the unemployment rate. Based on the study's findings, the following suggestions are proposed to lower HCEs: (i) establish an optimal consumption concept to guide residents towards consuming reasonably; (ii) cultivate a low-carbon concept among residents and promote low-carbon emissions living; and (iii) pay close attention to population structure factors and formulate effective measures accordingly. The study provides insightful information on the key driving factors of HCEs, which can facilitate achieving carbon emissions neutrality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

As the most abundant greenhouse gas, atmospheric carbon dioxide (CO 2 ) is considered one of the main attributors to climate change. Atmospheric CO 2 concentrations can be measured by ground-based monitoring networks, mobile monitoring campaigns, and carbon-observing satellites. However, the worldwide ground-based monitoring networks are composed of sparsely distributed sites and are inadequate to represent the spatiotemporal distributions of CO 2 . Satellite-based remote sensing features repeated, long-term, and large-scale measurements, so it plays a crucial role in monitoring the global distributions of atmospheric CO 2 . However, due to the presence of heavy clouds (or aerosols) and the limitation of satellite orbiting tracks, there exist large amounts of missing data in satellite retrievals. Various methods, including chemical transport models (CTMs), geostatistical methods, and regression-based models, have been employed to derive full-coverage spatiotemporal distributions of CO 2 based on the limited CO 2 measurements. This review summarizes the strengths and limitations of these methods. However, CTMs simulation results can have high uncertainty due to imperfect knowledge of the real world, and the interpolation accuracy of all geostatistical methods is limited by the large amount of data gaps in current satellite retrieved CO 2 products. To overcome these limitations, regression-based methods (especially machine learning models) have the ability to predict CO 2 with superior predictive performance, so this review also summarizes the framework of the machine learning approach. Leveraging the ongoing advancements of satellite instrumentation, the satellite-based CO 2 products have been improving dramatically in recent decades, and this review will describe and critically assess the advantages and disadvantages of the currently used systems in detail. For future improvements, we recommend the fusion of data from multiple satellite retrievals and CTMs by using machine learning algorithms in order to obtain even longer-term, larger-scale, finer-resolution, and higher-accuracy CO 2 datasets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Despite their acute climatic susceptibility, the hot, arid Middle Eastern countries are among the world's largest energy consumers and emitters of greenhouse gases, particularly carbon dioxide (CO 2 ). Nonetheless, no study has been conducted to decompose regionally the influential primary factors of the Middle East's carbon emissions. This study utilized the logarithmic mean Divisia index (LMDI) method to fill this knowledge gap and investigate the driving forces of CO 2 emissions in 12 Middle Eastern countries, namely, Bahrain, Iran, Iraq, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates, and Yemen (1990-2020). The research confirmed that, with a contribution rate of 53.89 %, population growth is the primary driver of CO 2 emissions in the Middle East, followed by energy intensity (31.97 %) and economic growth (18.42 %); and the most straightforward approach to reduce emissions, are boosting energy efficiency and reforming energy subsidies. It also concluded that the West Asian economy is gradually decoupling from CO 2 due to the effective decarbonization of countries, such as Saudi Arabia and Kuwait, based on the Tapio decoupling model results. Furthermore, each country's future emissions (2020-2026) were projected using a novel group method of data handling (GMDH) approach based on the main identified factors. The countries' decoupling status confirms the accuracy of the projected data on CO 2 emissions growth. The region's CO 2 emissions are expected to rise 13.28 % by 2026, with Syria and Yemen experiencing the most significant increases (129.45 % and 112.14 %, respectively) due to post-civil war economic growth. Other aspects of regional conflicts and migration impacts on the CO 2 emission influencing factors were also explored. Indeed, besides providing a comprehensive analysis of the current and future status of CO 2 emissions in the Middle East, the effects of military conflicts on CO 2 emissions have been investigated using this regional case study for global application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Gas separation of carbon dioxide (CO 2 ) and methane (CH 4 ) from landfill gas (LFG) is very crucial to be undertaken to treat significant greenhouse gases (GHG) emitted to the atmosphere. Among the well-developed conventional technologies, membrane has drawn a huge attraction from many researchers to leverage on its application, which favors an efficient and environmentally safe process. In membrane technology, inorganic membrane type requires a complex and pricey fabrication process which is contradictory from the polymeric membrane features. The impressive gas permeability and acceptable value of selectivity possessed by polymeric membranes has contributed to its main attractiveness over the other types of membranes available. Besides, the frequent approach used which is through experimental methods requires complicated procedures and possess high difficulty to obtain a defect-free membrane sample. In this work, 6FDA-durene has been investigated by employing a molecular simulation approach to further examine its fractional free volume within the membrane matrix and transport properties. The structure creation of complete framework and the analysis of project deliverables has been adopted through a molecular dynamic simulation in Materials Studio software. FFV value obtained based on the simulated framework is 0.1743 which establishes about 3.15% deviation to the published experimental works. Upon the increment of operating temperature, most of the gasses would be in their activation condition and possess higher gas diffusivities and permeabilities. However, with increasing operating pressure simulation, the membrane framework was compressed and reached its asymptotic limit at 7 atm which acts as a maximum point when the membrane system becomes saturated. In both cases, the selectivity of CO 2 /CH 4 gas pairs are validated with low percentage deviation (less than 10%) towards the reported experimental works hence affirms the reliability of results and methodology conducted., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Carbon dioxide (CO 2 ) emission reduction has become an important concern worldwide. During the past century, human activities have been a significant cause of the increase in the level of greenhouse gases. Past research mainly focuses on evaluating the nexus between unidimensional population factors and CO 2 emissions, while few prior studies in a developing country have reported the impact of multidimensional demographic factors on CO 2 emissions. As an initial attempt, this study investigates the short- and long-run associations between population factors, low-carbon innovation, and carbon dioxide emissions (CO 2 ) for a panel consisting of 285 cities by employing the pooled mean group (PMG) estimator under the framework of the panel autoregressive distributed lag (ARDL) model. Our main findings are as follows: (1) Population size and population density could increase CO 2 emissions, while population quality and low-carbon innovation were essential factors that alleviate carbon emission pressure in the long run. (2) Economic development, foreign direct investment, and industrial development were found to be factors causing the increase in carbon emissions. (3) The split-sample analysis demonstrated that the improvement of population quality still has a positive and significant long-run effect on environmental quality. Simultaneously, low-carbon innovation could realize the enormous dividends of carbon emission reduction in the long run, especially in existing relatively larger CO 2 emission areas. Finally, the paper presents important policy implications., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Riparian zones have been found to be hot spots of greenhouse gas (GHG) production and have attracted increasing attention in recent decades. The occurrence of autogenic vegetation in riparian zones is prevalent, but little information is available concerning the influence of the occurrence and decomposition of this vegetation on carbon mitigation. We conducted a 220-day (110 days for the dry season and 110 days for the flooded season) microcosm experiment to study the mitigation and transformation of carbon regulated by the vegetation. The results revealed that there was a carbon dioxide (CO 2 ) flux in the treatment with vegetation, and that without vegetation harvesting (835.58 mg/m 2 /h) was close to that with vegetation harvesting (796.22 mg/m 2 /h) under the simulated dry season conditions, but it was significantly higher than that without vegetation seedlings (411.55 mg/m 2 /h). After being flooded, the decomposition of the vegetation residues increased the total organic carbon (TOC) content of the sediment, the dissolved organic carbon (DOC) concentration of the water, and the dissolved CO 2 and methane (CH 4 ) contents of the sediment. This effect was reversed by harvesting the vegetation biomass. During the flooded season, the CO 2 flux reached 222.95 mg/m 2 /h in the vegetation seeded treatment, but it decreased to -53.71 mg/m 2 /h when the vegetation biomass was harvested before being submerged. This was due to the decrease in the substrate available for CO 2 production, the altered microorganism communities, and the decrease in the abundance of carbon metabolizing related enzymes. As a result, vegetation harvesting reduced the net carbon emissions by 48 % compared to that without vegetation regulation during the 220-day incubation period. The results of this study are significant to implementing measures to reduce GHG emissions from the riparian zone., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

With the growing development of hydropower projects all over the world, the excessive greenhouse gas (GHG) emissions from increasing reservoirs have drawn public concern. While precise evaluations of GHG emissions are urgently needed, the widely applied methods including floating chamber (FC) method and thin boundary layer (TBL) method are unsatisfactory. In this paper, a new methodology of estimating CO 2 emission coupling FC and TBL methods was proposed. Three efforts were achieved stepwise:1) the CO 2 transfer coefficient was determined combining the measurements of FC method and TBL model; 2) a semi-empirical model connecting gas-water transfer coefficient and near-surface water turbulence in reservoir was proposed; 3) finally, since surface turbulence in the reservoir could be describe in detail by numerical simulation, integration thousands of discrete cells of local fluxes could be applied to estimate the total CO 2 emission with an improved precision. Nine locations in Xiangjiaba Reservoir were selected as a demo study for applying the method, the CO 2 emission in the whole reservoir was about 1.37 kg/s. With a deeper insight into the law of gas transfer and an elaborate consideration of the whole reservoir, this study is expected to provide a new approach and technical support to estimate the CO 2 emissions accurately in reservoirs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

CO 2 utilizations are essential to curbing the greenhouse gas effect and managing the environmental pollutant in an energy-efficient and economically-sound manner. This paper seeks to critically analyze these technologies in the context of each other and highlight the most important utilization avenues available thus far. This review will introduce and analyze each major pathway, and discuss the overall applicability, potential extent, and major limitations of each of these pathways to utilizing CO 2 . This will include the analysis of some previously underreported utilization avenues, including CO 2 utilization in industrial filtration and the processing of raw industrial materials such as iron and alumina. The core theme of this paper is to seek to treat CO 2 as a commodity instead of a liability., (Copyright © 2021. Published by Elsevier B.V.)

China has announced to launch a national emission trading system (ETS). The heterogeneity of marginal abatement cost (MAC) is prerequisite for trading, and the knowledge about the evolutionary characteristics of MAC is particularly necessary. However, the β convergence theory has been proved to be suitable yet rarely applied to the study of MAC of CO 2 . To fill this gap, this paper connects them creatively, and the convergence of MAC during 2001-2015 and the influential factors are explored by spatial panel data models. Results show that China's MAC converges during the study period whether the spatial effect is considered or not. When evaluating the convergence of MAC, the spatial effect should not be ignored, because it will improve the explanatory power of models and promote the convergence. The size of labor force, emission level, coal consumption, foreign direct investment, and industrial structure significantly affect the growth rate of MAC. Low-carbon policies could be formulated fully considering the factors and their spillover effects. Those findings are certainly significant in imposing carbon reduction targets and adopting policy instruments. In addition, a national ETS is more applicable to China's reality at this stage and suggested to introduce carbon tax in due course in the future., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

With the change of social economic system and the rapid growth of agricultural economy in China, the amount of agricultural energy consumption and carbon dioxide emissions has increased dramatically. Based on the estimation of agricultural carbon dioxide emissions from 1991 to 2018 in China, this paper uses EKC model to analyze economic growth and agricultural carbon dioxide emissions. The Kaya method is used to decompose the factors affecting agricultural carbon dioxide emissions. The experimental results show that there is a co-integration relationship between economic growth and the total intensity of agricultural carbon emissions, and between economic growth and the intensity of carbon emissions caused by five types of carbon sources: fertilizer, pesticide, agricultural film, agricultural diesel oil and tillage. Economic growth is the main driving factor of agricultural carbon dioxide emissions. In addition, technological progress has a strong role in promoting carbon emission reduction, but it has a certain randomness. However, the impact of energy consumption structure and population size on carbon emissions is not obvious., Competing Interests: The authors have declared that no competing interests exist.

It is estimated that about 1/4th of all greenhouse gas (GHG) emissions may be caused by the global food system. Reducing the GHG emissions from food production is a major challenge in the context of the projected growth of the world's population, which is increasing demand for food. In this context, the goal should be to achieve the lowest possible emission intensity of the food production system, understood as the amount of GHG emissions per unit of output. The study aimed to calculate the emission intensity of food production systems and to specify its determinants based on a panel regression model for 14 countries, which accounted for more than 65% of food production in the world between 2000 and 2014. In this article, emission intensity is defined as the amount of GHG emissions per value of global output. Research on the determinants of GHG emissions related to food production is well documented in the literature; however, there is a lack of research on the determinants of the emission intensity ratio for food production. Hence, the original contribution of this paper is the analysis of the determinants of GHG emissions intensity of food production systems. The study found the decreased of emission intensity from an average of more than 0.68 kg of CO2 equivalent per USD 1 worth of food production global output in 2000 to less than 0.46 in 2014. The determinants of emission intensity decrease included the yield of cereals, the use of nitrogen fertilizers, the agriculture material intensity, the Human Development Index, and the share of fossil fuel energy consumption in total energy use. The determinants of growth of emission intensity of food production systems included GDP per capita, population density, nitrogen fertilizer production, utilized agriculture area, share of animal production, and energy use per capita., Competing Interests: The authors have declared that no competing interests exist.

The household sector, which plays a critical role in emission reduction, is a main source of greenhouse gas (GHG) emissions. Although numerous academic journals have published papers on household CO 2 emissions (HCEs), great challenges remain in research on assessments, determinants, and further research prospects. This work reviews and projects HCEs using a bibliometric analysis and a systematic review based on the data from the Web of Science (WOS) platform from 1991 to 2020. Over the last 30 years, there has been a rapid and active trend of research on HCEs. We find that (1) the scale of the bibliometric analysis shows that research on HCEs is interdisciplinary and must consider overall cognition of the environment, the economy, society, and technology. It also needs to strengthen cooperation between different countries/territories to emphasize the quality and influence of papers on HCEs. (2) A review of previous literature shows that research on HCEs mainly focuses on the research object, mainstream assessments, and influencing factors. The following six main aspects impact HCEs: demographic, income, social, technological, policy, and natural factors. (3) The research discussion suggests that more micro-level research needs to be conducted, such as research on the city level and the individual level, which is important for sustainable development and low consumption. A comparative analysis of the differences in HCEs is a future research direction. Additionally, localized carbon emission reduction measures need to be implemented.

To tackle climate change, Chinese government has applied an array of mitigating measures to reduce CO2 emissions. During the 11th Five-year Plan, Chinese government set the emission reduction target policy to reduce energy consumption per unit of gross domestic product (GDP) by 20%. This paper attempts to estimate the effect of this emission reduction target policy on industrial performance from complexity perspective. The result shows more complex industrial structure is related to less coal consumption. In general, emission reduction target policy has a negative effect on the probability of branching into new industries and lower the productivity and profitability of a given industry. However, this negative effect is weaker for more complex industries. Only for industries with very high complexity, emission reduction target policy can improve the performance of an industry rather than exerting a negative effect. Our finding not only helps to design a more effective policy to achieve industrial development strategy, but also provides a potential way to achieve economic growth while reduce the emission of greenhouse gases at the same time., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

To address the climate change caused by anthropogenic emissions of greenhouse gases into the atmosphere, it is essential to understand and quantitatively elucidate their cycling on the Earth's surface. This paper first presents an overview of the global cycling of three greenhouse gases, carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O), followed by a description of their variations in the atmosphere. This paper then presents the recent global budgets of these greenhouse gases estimated using two different approaches, top-down and bottom-up. Discussions on our current knowledge regarding the global cycling of the three gases are also presented.

Digging and mound-building by rodents lead to considerable disturbances in the topsoil and may affect plant composition, soil properties. However, little is known about the effects of these activities on GHG emissions, especially under different grazing management. This paper aimed to measure changes in CO 2 and CH 4 efflux with varying grazing management during the warm and cold seasons and to relate CO 2 and CH 4 efflux to pika burrow density and zokor mound density with different grazing management. Results of this study showed that CO 2 efflux was significantly affected by the grazing season, whereas CH 4 efflux was significantly affected by the grazing system. There were significant relationships between GHG efflux and rodent population density which were regulated by grazing management. CO 2 efflux increased linearly with rodent density under seasonal continuous grazing in warm season. CO 2 and CH 4 efflux and rodent population density showed a significant quadratic convex relationship under rotational grazing at 24 SM/ha in warm and cold seasons and rotational grazing at 48 SM/ha in cold season. Under rotational grazing at light stocking rate (24 SM/ha), appropriate populations of rodents were beneficial for decreasing GHG emissions. This results also used to help drive a best-practices model for grazing practices of local herders.