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The natural gas (NG)-powered compressors/engines used in liquified natural gas (LNG) plants are a major source of methane emission. The Allam–Fetvedt cycle (AFC), an oxyfuel, carbon-neutral, high-efficiency power plant, generates pipeline-grade CO2. This work performed novel process modeling, economic analysis, and greenhouse gas emissions analysis for a heat-integrated, electrified LNG/AFC/air separation unit (ASU) complex (LAA), then compared it to standalone LNG and AFC/ASU plants (baseline) as well as an LNG plant electrified with AFC/ASU without heat integration. The low-grade heat generated from compressors of the LNG plant can enhance the AFC net power output by 7.1%. Utilizing the nitrogens cold energy reduces the compressor power requirement by 1.6%. In the integrated LAA complex, not only are GHG emissions avoided, but the energy efficiencies are also improved for both the LNG plant and the AFC power plant. A cash flow analysis of LAA was performed over a 20-year period with 5%, 7%, and 10% discount rates and three levels of LNG prices. The 45Q CO2 credit of USD 85/T as stipulated by the recent Inflation Reduction Act (IRA) of 2022 has been incorporated. The results clearly indicate the economic and environmental benefits of the proposed electrification and heat/power integration. [ABSTRACT FROM AUTHOR]

Transitioning from fossil fuels to renewable energy sources is demanded due to the gradual depletion of petroleum oil/gas and the environmental impact of carbon dioxide (CO2) emissions into the atmosphere. Electrocatalytic and photocatalytic CO2 reduction to methane (CH4) using renewable energy sources is crucial for sustainable chemical/fuel production and greenhouse gas reduction. In recent years, extensive research has focused on understanding the fundamental aspects of the two approaches, such as reaction mechanisms and active sites, and exploring/designing novel catalytic materials. This review initially discusses the reaction fundamentals, including performance evaluation indexes, reactors, and mechanisms, to understand the catalytic reactions. Subsequently, various catalyst preparation strategies and characterization methods are summarized, trying to outline the catalyst design principle based on the obtained understanding of the reaction mechanisms. Finally, research challenges and perspectives for future development in this area are discussed and presented. It is expected to provide a comprehensive understanding of the photo/electrocatalytic CO2 methanation, valuable knowledge to novice researchers, and a helpful reference for future research endeavors. [ABSTRACT FROM AUTHOR]

The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs), beginning in 2004, from over 30 current or past measurement sites around the world using solar absorption spectroscopy in the near-infrared (near-IR) region. TCCON GHG data have been used extensively for multiple purposes, including in studies of the carbon cycle and anthropogenic emissions, as well as to validate and improve observations from space-based sensors. Here, we describe an update to the retrieval algorithm used to process the TCCON near-IR solar spectra and to generate the associated data products. This version, called GGG2020, was initially released in April 2022. It includes updates and improvements to all steps of the retrieval, including but not limited to the conversion of the original interferograms into spectra, the spectroscopic information used in the column retrieval, post hoc air mass dependence correction, and scaling to align with the calibration scales of in situ GHG measurements. All TCCON data are available through https://tccondata.org/ (last access: 22 April 2024) and are hosted on CaltechDATA (https://data.caltech.edu/ , last access: 22 April 2024). Each TCCON site has a unique DOI for its data record. An archive of all the sites' data is also available with the DOI 10.14291/TCCON.GGG2020. The hosted files are updated approximately monthly, and TCCON sites are required to deliver data to the archive no later than 1 year after acquisition. Full details of data locations are provided in the "Code and data availability" section. [ABSTRACT FROM AUTHOR]

[Display omitted] Methane (CH 4) is the second most consequential greenhouse gas after CO 2 , with a substantial global warming potential. The CH 4 catalytic combustion offers an efficient method for the elimination of CH 4. However, improving the catalytic performance of Pd-based materials for low-temperature CH 4 combustion remains a big challenge. In this study, we synthesized an enhanced Pd/5NiAlO x catalyst that demonstrated superior catalytic activity and improved water resistance compared to the Pd/Al 2 O 3 catalyst. Specifically, the T 90 was decreased by over 100 °C under both dry and wet conditions. Introducing Ni resulted in an enormously enhanced number of oxygen defects on the obtained 5NiAlO x support. This defect-rich support facilitates the anchoring of PdO through increased electron transfer, thereby inhibiting the production of high-valence Pd(2+δ)+ and stimulating the generation of unsaturated Pd sites. Pd0 can effectively activate surface oxygen and PdO plays a significant role in activating CH 4 , resulting in high activity for Pd/5NiAlO x. On the other hand, the increased water resistance of Pd/5NiAlO x was mainly due to the generation of *OOH species and the lower accumulation of surface -OH species during the reaction process. [ABSTRACT FROM AUTHOR]

Heterogeneous thermal-catalytic CO2 hydrogenation to alcohols using renewable energy is a highly attractive approach for recycling greenhouse gases into high-value chemicals and fuels, thereby reducing the dependence on fossil fuels, while simultaneously mitigating the CO2 emission and environmental problems. Currently, great advances have been made on the heterogeneous catalysts, but an in-depth and more comprehensive understanding to further promote this reaction process is still lacking. Herein, we highlight the thermodynamic and kinetic analysis of CO2 hydrogenation reaction firstly. Then, various reaction pathways for CO2 hydrogenation to methanol and higher alcohols (C2+ alcohols) have been discussed in detail, respectively, by combining the experimental studies and density functional theory calculations. On this basis, the key factors influencing the reaction performance, such as metal dispersion, support modification, promoter addition and their structural optimization, are summarized on the metal-based and metal-oxide-based catalysts. In addition, the catalytic performance of CO2 hydrogenation to alcohols and the relationship between structure and properties are mainly summarized and analyzed in the past five years. To conclude, the current challenges and potential strategies in catalyst design, structural characterization and reaction mechanisms are presented for CO2 hydrogenation to alcohols. [ABSTRACT FROM AUTHOR]

Several cities worldwide are studying the replacement of their trolleybus systems with diesel buses or battery electric buses, due to their flexibility and lower operational costs. Diesel buses are considered a major cause of gas emissions in cities, while battery electric buses employ cutting-edge technology, but there is still discussion around the topic due to their technology costs, autonomy, and the sustainability of battery packs. In this study, we evaluated the trolleybus system's potential for reducing emissions, noise pollution, and greenhouse gases (GHGs) when compared to diesel buses. Furthermore, we compared the trolleybus system with battery electric buses in terms of cost and environmental benefits. To do so, a case study was conducted in São Paulo, Brazil, the largest city in Latin America, which operates the second-highest trolleybus system on the American continent. Our results show that the trolleybus system is a feasible alternative to diesel buses when considering environmental aspects. It can be seen as a complementary service for urban transport systems in the city's transition to clean energy. Finally, the study implications indicate the need for further investigation of the benefits of in-motion-charge technology to generate flexibility in trolleybus systems, and the involvement of stakeholders in the transition matrix energy process in urban bus systems beyond the direct costs. [ABSTRACT FROM AUTHOR]

Forestation is widely proposed for carbon dioxide (CO2) removal, but its impact on climate through changes to atmospheric composition and surface albedo remains relatively unexplored. We assessed these responses using two Earth system models by comparing a scenario with extensive global forest expansion in suitable regions to other plausible futures. We found that forestation increased aerosol scattering and the greenhouse gases methane and ozone following increased biogenic organic emissions. Additionally, forestation decreased surface albedo, which yielded a positive radiative forcing (i.e., warming). This offset up to a third of the negative forcing from the additional CO2 removal under a 4°C warming scenario. However, when forestation was pursued alongside other strategies that achieve the 2°C Paris Agreement target, the offsetting positive forcing was smaller, highlighting the urgency for simultaneous emission reductions. [ABSTRACT FROM AUTHOR]

This study introduces a comprehensive analytical method for assessing refrigerant purity, offering various insights into accurate and precise estimations of greenhouse gas (GHG) emissions and the reclamation of refrigerants. Samples of three different states of CH 2 FCF 3 (R134a), namely recovered R134a, reclaimed R134a, and new R134a, were prepared and analyzed for all impurities. Non-condensable gases (O 2 , N 2 , CH 4 , CO, and H 2) were analyzed using gas chromatography (GC) with a thermal conductivity detector (TCD) and a pulsed discharge detector (PDD), and unidentified complex compound impurities containing C, H, Cl, and F were investigated using GC with mass spectrometry (MS) and an atomic emission detector (AED). The purities of the three samples were determined by calculating the total quantity of impurities and their uncertainties. The calculated values for the purities of recovered R134a, reclaimed R134a, and new R134a were 953,125.38 µmol/mol (1,272.45 µmol/mol, k = 2), 998,529.67 µmol/mol (31.58 µmol/mol, k = 2), and 998,803.56 µmol/mol (32.50 µmol/mol, k = 2), respectively. The majority of impurities detected were GHGs with high global warming potentials (GWPs) up to 11,200. Certain impurities were found at concentrations exceeding 1,000 µmol/mol. The annual GHG emissions resulting only from R134a impurities in South Korea were approximately 0.01 MtCO 2 eq. Because of the large number of GHGs in refrigerants, a comprehensive examination of refrigerant impurities is necessary for refrigerant monitoring and GHG inventory management. [ABSTRACT FROM AUTHOR]

Laser absorption spectroscopy as a powerful tool for detecting trace gases has been widely used in the monitoring of atmospheric greenhouse gases, pollutions, and respiration processes, including human breath analysis. The detection is based on the light absorption when it propagates through a medium. Most inorganic and organic molecules have characteristic absorption lines in the mid-infrared (mid-IR), which correspond to fundamental vibrational modes and in the near-IR (first overtones) presenting their absorption fingerprints. Here, we summarize the recent developments of the three techniques, namely, wavelength modulation spectroscopy (WMS), cavity ringdown spectroscopy (CRDS), and frequency comb spectroscopy (FCS), and describe their main features as well as possible applications, illustrated by recent experimental results. Emphasis is made on methane detection as applied to breath analysis and atmospheric monitoring. For the WMS technique, we consider local measurements with a multipass cell and also kilometer long open-path configurations for the near-IR and mid-IR spectral regions. The results of measurements of methane in exhaled breath with the CRDS technique in the near-IR are presented for a group of subjects of different ages. We consider various schemes of the FCS that enable fast broadband detection, including direct spectroscopy, dual FCS, and Vernier FCS, and review numerous applications of this approach that revolutionized the field of absorption spectroscopy. The current trends and possible future developments and applications are also discussed. [ABSTRACT FROM AUTHOR]

Rationale: The measurement of the stable carbon and oxygen isotope ratio of (atmospheric) carbon dioxide (CO2) is a useful technique for the investigation and identification of the sources and sinks of the most abundant greenhouse gases by far. For this reason, we are presenting a measuring system here that enables a wide range of users to carry out stable isotope analysis of atmospheric CO2 using off‐the‐bench hardware and software. Methods: The fully automated system uses cryogenic and gas chromatographic separation to analyse CO2 from 12‐mL whole air samples and consists of an autosampler, a Gasbench II (GB), a downstream cryo trap and a continuous flow gas interface feeding into a sector field mass spectrometer (GC Pal/GB/Cold Trap/ConFlo IV/DeltaV Plus). The evaluation of the system performance was based on the analysis of samples prepared from eight CO2 sources (four CO2 reference gases and four artificial air tanks). Results: The overall measurement uncertainty (averaged single standard deviation (1σ) of measurement replicates from each CO2 source) in the determination of the carbon and oxygen isotope ratio was 0.04‰ and 0.09‰ (n = 24). Furthermore, we were able to show that the measurement data also allowed for the quantification of the CO2 mole fraction, with a precision of 1.2 μmol mol−1 in the analysis range of 400–500 μmol mol−1. Conclusions: Our protocol provides a detailed description of the measurement set‐up and the analysis procedure, how raw data should be evaluated and gives recommendations for sample preparation and sampling to enable a fully automated whole air sample analysis. The quantification limit of CO2 mole fractions and measurement precision for carbon and oxygen isotope ratios of CO2 should meet the requirements of a wide range of users. [ABSTRACT FROM AUTHOR]

Boron-based energy carrier materials (BEMs) encompass a group of hydrogen storage media, including borohydrides (such as NaBH 4 , LiBH 4 , and KBH 4) and boranes (such as NH 3 BH 3 , CH 3 NH 2 BH 3 , and (CH 3) 2 NHBH 3), which exhibit hydrogen densities ranging from 85 to 125 kg/m3. BEMs serve as essential reducing agents, as well as carriers of hydrogen and heat. They have garnered considerable attention for their potential application in Power-to-X technology, aiming to achieve carbon neutrality by mitigating the greenhouse gas effects associated with fossil fuel emissions. Research findings indicate that BEMs exhibit carbon dioxide (CO 2)-to-fuel yield of over 50%, offering an effective means of controlling CO 2 emissions when integrated into Power-to-X technologies. Despite the promising advances made in utilizing BEMs for carbon neutralization, their utilization in carbon capture and storage (CCS) are still at an early development stage. Consequently, further investigations are necessary to assess the scalability, effectiveness, and feasibility of these materials. This study investigates these aspects and presents future perspectives based on a comprehensive analysis of relevant literature. • BEMs are hydrogen and heat carrier mediums with a high potential for carbon dioxide reduction. • BEMs have been explored for reducing CO 2 emission via converting it into fuels. • BEMs provide carbon-neutral synthetic fuels which provide high energy for Power-toX systems. [ABSTRACT FROM AUTHOR]

The global energy industrial sector is focused on and committed to supporting clean energy usage and reducing or eliminating the emission of greenhouse gases by 2050. The most preferred technological energy source is the hydrogen‐based energy source of the future. This study investigates challenges in the context of technical and non‐technical perspectives using one of the tools under the theory of inventive problem solving (TRIZ). The TRIZ tool called S‐curve analysis helps assess the technological maturity of the hydrogen fuel cell at four stages: infant, growth, mature and decline, using specific indicators developed by the founder of TRIZ, Genrich Altshuller. The application of TRIZ expands the intervention strategies to successfully accelerate the development of hydrogen fuel cell technology towards the growth stage. Here, an S‐curve analysis application will be applied on the hydrogen fuel cell technologies patented in the selected country as a case study in automotive system innovation. The data of patent mapping can support the recommendations presented by TRIZ S‐curve analysis, and a proposal of intervention has been delivered to improve the growth of targeted country energy sectors through the strategic initiative of automotive technology evolution and revolution of the hydrogen fuel cell. [ABSTRACT FROM AUTHOR]

Background: The cattle sector is the most important economic production unit of the Irish farming and agri-food sector. Despite its relevance, there has been limited quantitative information about the structure of differing cattle production types and of the connections between them. This paper addresses this gap by providing, for the first time, an overview of the Irish cattle population structured by enterprise type. Methods & Results: We collected data from the cattle register for the period 2015 to 2019 and assigned registered herds to one of 18 different herd types using a recently published herd type classification approach. This allows, for the first time, to exploring changes in enterprise types and subtypes over time, and describing the movements between these subtypes and from these subtypes to slaughter. Conclusions: The overview and associated classification presented in this study will form the basis for a number of future comparative studies, including cross-sectoral assessments of profitability, estimation of the extent of animal health losses on Irish cattle farms or structural analysis of Greenhouse Gas (GHG) emissions across production systems. [ABSTRACT FROM AUTHOR]

Background: Poor diets lead to negative health outcomes, including increased risk of noncommunicable diseases. Food systems, most notably agriculture, contribute to greenhouse gas emissions (GHGE) that lead to climate change. Meat consumption plays a role in both health and environmental burden. Consumption of meat alternatives may reduce these harms. The aim was to compare meat products and their plant‐based alternatives on nutritional parameters, GHGE and price to examine if it is feasible and beneficial for policymakers and health professionals to recommend meat alternatives. Methods: Data on nutritional information and cost for 99 selected products were collected from five UK supermarkets. Estimates for GHGEs for 97 of these products were found through secondary articles. Median values for nutritional value, GHGE (kgCO2e) and price per 100 g were calculated to allow comparisons between meat products and their alternatives. Mann–Whitney U tests were used to look for significant differences for each nutrient, emissions and price. Results: Meat alternatives contained significantly more fibre and sugar and were significantly higher in price compared to the equivalent meat products. Meat alternatives had a significantly lower number of calories, saturated fat, protein and kgCO2e than meat products. There was no significant difference in the amount of salt between meat and meat alternatives. Conclusions: Overall, this paper found that meat alternatives are likely to be better for health according to most parameters, while also being more environmentally friendly, with lower GHGEs. However, the higher price of these products may be a barrier to switching to meat alternatives for the poorest in society. Key points: Plant‐based meat alternatives (PBMA) were compared with meat products on nutrition, environmental impact, and affordability. PBMA contained less saturated fat, protein and calories, more fibre and sugar, and similar salt content. They were more expensive but had less emissions. All plant‐based meat alternatives and most meat products were classed as ultra‐processed. [ABSTRACT FROM AUTHOR]

Termites are a significant natural source of greenhouse gases (GHGs), but quantifying emissions especially from large termite mounds is problematic as they rarely fit in measurement chambers. Predicting fluxes based on internal and atmospheric concentrations could provide an indirect way to assess mound emissions, but developing such models necessitates better understanding of the concentration levels and their variance.We used gas chromatography to measure carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) concentrations within nests of two co‐occurring species of fungus‐growing termites in both dry and wet seasons in Kenya, with termite Macrotermes michaelseni building mounds with a closed and Macrotermes subhyalinus with an open ventilation system.Gas concentrations were 3–100 times higher in mounds than the global averages in atmosphere, implying that termite mounds are sources of all three GHGs. Carbon dioxide concentrations were higher in closed than in open mounds. Methane concentrations remained constant in open mounds, whereas closed mounds exhibited considerable variation between nests and across seasons. Concentrations of both CH4 and N2O correlated positively with mound volume during the wet season, whereas interactions with mound size were not observed in CO2 concentrations or during the driest sampling period.These findings underline that among fungus‐growing termites, mound size, ventilation type and precipitation affect nest gas concentrations and with this likely the magnitude of mound GHG emissions. Potential reasons behind the observed relationships are discussed, including differences in population size, biomass of fungus gardens and CH4 oxidation. [ABSTRACT FROM AUTHOR]

The article discusses the use of bulk tank milk (BTM) testing to monitor the presence of Johne's disease (JD) in cattle herds. While BTM testing is conducted twice a year by the Department of Agriculture, Food and the Marine, it has limitations in terms of sensitivity and cannot guarantee freedom from JD. Positive results from BTM testing require further whole herd testing to draw conclusions. The article also highlights the benefits of the Irish Johne's Control Programme (IJCP) for herd owners. BTM testing is a valuable tool for epidemiologists and researchers studying JD in dairy herds, providing insights into the prevalence of the disease and aiding in its management. [Extracted from the article]

The pineapple leaves (PL) left over in the fields after pineapple harvest or burnt out, generate waste which contributes to the release of greenhouse gases. As pineapple is one of the most harvested crops in the world, the quantity of pineapple trash and its disposal methods are challenging. The composition of PL waste makes it unique to encounter the increasing demand for renewable energy and other useful products. This review is focused on the production of different biorefinery products and miscellaneous products from PL waste. The high cellulose content in PL makes it a potential feedstock for the production of different biorefinery products like bioethanol, oligosaccharides, nitrocellulose, and humic acid apart from this, waste is also useful for the production of different products like pineapple leaf fibres, fake eyelashes, organic leather, pulp and paper. Although the opportunities, future perspectives, and challenges concerning PL waste utilization to value-added goods were also addressed. It has been demonstrated that pineapple waste conversions lower waste creation, and the products produced by the conversion would promote the 'waste-to-wealth' notion. [ABSTRACT FROM AUTHOR]

Central China has been acting as a major convergence zone for sources and sinks in China, such that the climate change studies of Central China have taken on critical significance. The Jinsha atmospheric background station refers to the sole background monitoring site in Central China. It is noteworthy that the greenhouse gas attributes of the Jinsha atmospheric background station represent the greenhouse gas conditions of Central China. The seasonal and daily variations in CO2, CH4, and CO in the scope of time between October 2019 to April 2021 at the station were examined in this study. The effect of meteorological conditions on greenhouse gas concentrations at the site was evaluated. Furthermore, the primary transmission origins affecting the station were identified using the backward trajectory through potential source contribution function analysis. As indicated by the results, the background concentrations at the Jinsha station in 2020 for CO2, CH4, and CO reached 424.1 ± 0.1 ppm, 2046.2 ± 0.6 ppb, and 324.1 ± 1.1 ppb, respectively. CO2 varied on a daily basis with higher nighttime levels, which was affected by the boundary layer elevation, photosynthesis, and human activities. In autumn, CH4 levels peaked under the effect of agricultural activities in Central China. However, CO2 and CO concentrations reached the maximum in winter, majorly affected by the transmissions from the Beijing–Tianjin–Hebei region and Hubei. Under China's comprehensive carbon neutrality, more attention should be paid to the emissions from winter heating and industrial activities in the Beijing–Tianjin–Hebei region, and effects exerted by transport in the monitoring process should be differentiated in depth. [ABSTRACT FROM AUTHOR]

Greenhouse gas emissions resulted in high demand for clean and renewable energy. Hydrogen can be produced by dry reforming the methane deriving from these greenhouse gases; thus, it is an alternative to fossil fuels, as well as a potential source of clean energy. The aim of the current article is to determine a kinetic model to enable dry methane reforming based on using Ni/Si-MCM-41 catalysts. The single-site reversible Langmuir-Hinshelwood model has shown the best fit for experimental data recorded at temperature ranging from 873 to 973 K and at volumetric flow rate ranging from 300 to 600 ml/min, among the herein assessed six models. Higher temperatures enabled methane conversion and hydrogen production, as well as lower flow rates: methane conversions were higher than 85% and H 2 /CO ratio was close to 1. Methane conversion rate r obs observed under the best experimental conditions was 0.14 mol C H 4 /g cat h; the activation energy estimated for the best model was 76.6 kJ/mol. The herein presented Langmuir-Hinshelwood model can be used in the mathematical modeling and simulation of fixed-bed reactors, as well as to define preliminary conditions to produce syngas or hydrogen-rich gas. [Display omitted] • Original kinetic data for the methane dry reforming catalyzed by Ni/Si-MCM-41. • Experimental data had indicated a condition for syngas production and H 2 rich gas. • Kinetic models based on the Langmuir-Hinshelwood and Eley-Rideal mechanisms were evaluated. • Kinetic model based on the Langmuir-Hinshelwood mechanism presented the best performance. • The kinetic parameters can be used to simulate an packed bed reactor. [ABSTRACT FROM AUTHOR]

The primary aim of this systematic analysis is to highlight opportunities to improve the environmental impact of advanced therapy medicinal products (ATMP) manufacturing. We have compared the Greenhouse Gas (GHG) emissions expressed in CO2eq of a classic clean room open system (AinB) Cell Factory versus a comparable closed system equipped with isolators (AinD). We have therefore outlined a theoretical situation to simulate the use of a closed system with an equivalent production output to that obtained in the Cell Factory (CF) of the Regina Margherita Children's Hospital. Open and closed systems for ATMPs have been compared as regards energy requirements, ecological footprints, and costs by analyzing a hypothetic cell production cycle of 21 days. The results demonstrate energy saving and a reduction of 52% in GHG emissions using closed systems per process cycle. Moreover, a reduction in production costs in an isolator setting is also evident. This study shows that the closed system solution has evident advantages compared with the open one. [ABSTRACT FROM AUTHOR]

High-strength wastewaters from a variety of sources, including the food industry, domestic septage, and landfill leachate, are often hauled to municipal wastewater treatment plants (WWTPs) for co-treatment. Due to their high organic loadings, these wastewaters can cause process upsets in both a WWTP's liquid and solids treatment trains and consume organic treatment capacity, leaving less capacity available to service customers in the catchment area. A novel pre-treatment method, the Waste Activated Sludge-High Rate (WASHR) process, is proposed to optimize the co-treatment of high-strength wastewaters. The WASHR process combines the contact stabilization and sequencing batch reactor processes. It utilizes waste activated sludge from a municipal WWTP as its biomass source, allowing for a rapid start-up. Bench-scale treatment trials of winery wastewater confirm the WASHR process can reduce loadings on the downstream WWTP's liquid and solids treatment trains. A case study approach is used to confirm the economic viability and environmental sustainability of the WASHR process compared to direct co-treatment, using life-cycle cost analyses and greenhouse gas emissions estimates. [ABSTRACT FROM AUTHOR]

As a representative renewable biofuel, ethanol can reduce mankind's dependence on petroleum resources and the emission of greenhouse gases and other pollutants. In recent years, the application of ethanol in the aviation field has begun to be a concern of scholars. As ethanol is a flammable liquid, it is significant to study its explosion characteristics in aviation conditions from a safety perspective. In this work, at 20 kPa, the explosion characteristics of ethanol–air mixtures (concentration 6~12%) were experimentally and numerically studied under an initial temperature range of 303 K~363 K. The effects of the initial temperature and concentration on the maximum explosion pressure, maximum rate of pressure rise, explosion time, and fast burning time were analyzed. In addition, the heat loss fraction and sensitivity analysis were examined and discussed. The main conclusions are as follows: A linear relationship exists between the maximum explosion pressure and the reciprocal of the initial temperature. The maximum rate of a pressure rise appears to decrease or at least approach a constant value as the initial temperature increases. The explosion time is significantly dependent on the concentration. At a constant concentration, the proportions of heat loss are approximately constant except for 12%. In our sensitivity analysis, R1 (H + O2 <=> O + OH) was the dominant elementary reaction. [ABSTRACT FROM AUTHOR]

Although geothermal energy is generally considered benign, it still has its share of problems, including the emission of greenhouse gases that harm the environment. To make informed decisions about geothermal systems, it is imperative to study their environmental impacts. This study uses six approaches to propose and analyze an innovative geothermal-driven bi-evaporator cooling/electricity plan. The proposed efficient design is made of a single-flash cycle and the integration of a modified vapor compression cycle and ejector cooling system assisted by a thermoelectric power generator device. Exergoenvironmental and extended-environmental assessments are performed to examine the environmental impacts of the current devised scheme, including calculating CO 2 emissions rate and sustainability index. The suggested plan's performance in the basic design mode using 14 various working fluids showed that R143m had the highest exergetic efficiency, lowest exergoenvironmental index, and lowest cost of production at 35.9%, 0.6002, and 24.67$/GJ, respectively. This working fluid was used for parametric study and bi-objective optimization, which revealed that the vapor generator destroys 157.7 kW of exergy at the optimal point. Additionally, the vapor turbine is the most expensive component at 14.44$/h. Pareto frontier also indicates that the final chosen optimal mode (scenario C) has 27.02% energetic efficiency and 21.33$/GJ production cost, which are higher than the base scenario by 12.55% and 15.66%, respectively. In addition, the optimal scenario reduces the payback period to 8.64 years from 15.68 years in the base scenario. [ABSTRACT FROM AUTHOR]

The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs) beginning in 2004 from over 30 current or past measurement sites around the world, using solar absorption spectroscopy in the near infrared region. TCCON GHG data have been used extensively for multiple purposes, including in studies of the carbon cycle and anthropogenic emissions as well as to validate and improve observations made from space based sensors. Here, we describe an update to the retrieval algorithm used to process the TCCON near IR solar spectra and the associated data product. This version, called GGG2020, was initially released in April 2022. It includes updates and improvements to all steps of the retrieval, including but not limited to: converting the original interferograms into spectra, the spectroscopic information used in the column retrieval, post hoc airmass dependence correction, and scaling to align with the calibration scales of in situ GHG measurements. All TCCON data are available through tccondata.org and hosted on CaltechDATA (data.caltech.edu). Each TCCON site has a unique DOI for its data record. An archive of all sites’ data is also available with the DOI 10.14291/TCCON.GGG2020 (Total Carbon Column Observing Network (TCCON) Team, 2022). The hosted files are updated approximately monthly, and TCCON sites are required to deliver data to the archive no later than one year after acquisition. Full details of data locations are provided in the data availability section. [ABSTRACT FROM AUTHOR]

Inland saline-alkaline wetlands distributed in the mid-high latitude have repeatedly experienced freezing and thawing. However, the response of greenhouse gas (GHG) emission and microbially-mediated carbon and nitrogen cycle to freezing and thawing remains unclear. We monitored the GHG flux in an inland saline-alkaline wetland and found that, compared with the growth period, the average CO2 flux decreased from 171.99 to 76.61–80.71 mg/(m2‧h), the average CH4 flux decreased from 10.72 to 1.96–3.94 mg/(m2‧h), and the average N2O flux decreased from 56.17 to − 27.14 to − 20.70 μg/(m2‧h). Freezing and thawing significantly decreased the relative abundance of functional genes involved in carbon and nitrogen cycles. The aceticlastic methanogenic pathway was the main methanogenic pathway, whereas the Candidatus Methylomirabilis oxyfera was the most abundant methane oxidizer in the wetland. Ammonia-oxidizing archaea and denitrifier belonging to proteobacteria was the major microbial N2O source, while bacteria within clade II nosZ was the major microbial N2O sink. Freezing and thawing reduced the relative abundance of these genes, leading to a decrease in GHG flux. [ABSTRACT FROM AUTHOR]

The rising concentration of carbon dioxide (CO2) as one of the greenhouse gases in the atmosphere is a major source of worry. Electrochemical reduction of CO2 is one of many ways to convert CO2 gas into usable compounds. An electrochemical technique was applied in this study to reduce CO2 using a boron-doped diamond (BDD) working electrode modified with MXene (Ti3C2Tx) material to improve electrode performance. MXene concentrations of 0.5 mg/mL (MXene-BDD 0.5), 1.0 mg/mL (MXene-BDD 1.0), and 2.0 mg/mL (MXene-BDD 2.0) were drop-casted onto the BDD surface. MXene was effectively deposited on top of the BDD surface, with Ti weight loads of 0.12%, 4.06%, and 7.14% on MXene-BDD 0.5, MXene-BDD 1.0, and MXene-BDD 2.0, respectively. The modified working electrode was employed for CO2 electroreduction with optimal CO2 gas aeration. The existence of the MXene substance in BDD reduced the electroreduction overpotential of CO2. For the final result, we found that the MXene-BDD 2.0 electrode effectively generated the most formic acid product with a maximum reduction potential as low as −1.3 V (vs. Ag/AgCl). [ABSTRACT FROM AUTHOR]

Ozone trend estimates have shown large uncertainties in the upper troposphere–lower stratosphere (UTLS) region despite multi-decadal observations available from ground-based, balloon, aircraft, and satellite platforms. These uncertainties arise from large natural variability driven by dynamics (reflected in tropopause and jet variations) as well as the strength in constituent transport and mixing. Additionally, despite all the community efforts there is still a lack of representative high-quality global UTLS measurements to capture this variability. The Stratosphere-troposphere Processes And their Role in Climate (SPARC) Observed Composition Trends and Variability in the UTLS (OCTAV-UTLS) activity aims to reduce uncertainties in UTLS composition trend estimates by accounting for this dynamically induced variability. In this paper, we describe the production of dynamical diagnostics using meteorological information from reanalysis fields that facilitate mapping observations from several platforms into numerous geophysically based coordinates (including tropopause and upper tropospheric jet relative coordinates). Suitable coordinates should increase the homogeneity of the air masses analyzed together, thus reducing the uncertainty caused by spatiotemporal sampling biases in the quantification of UTLS composition trends. This approach thus provides a framework for comparing measurements with diverse sampling patterns and leverages the meteorological context to derive maximum information on UTLS composition and trends and its relationships to dynamical variability. The dynamical diagnostics presented here are the first comprehensive set describing the meteorological context for multi-decadal observations by ozonesondes, lidar, aircraft, and satellite measurements in order to study the impact of dynamical processes on observed UTLS trends by different sensors on different platforms. Examples using these diagnostics to map multi-platform datasets into different geophysically based coordinate systems are provided. The diagnostics presented can also be applied to analysis of greenhouse gases other than ozone that are relevant to surface climate and UTLS chemistry. [ABSTRACT FROM AUTHOR]

More than 500 million people will be added to Africa's cities by 2040, marking the largest urbanization in history. However, nonrenewable fossil energy sources are inadequate to meet Africa's energy needs, and their overexploitation leads to intensified global warming. Fortunately, Africa has a huge potential for biomass energy, which will be an important option for combating climate change and energy shortage. In this study, we present a typical large-scale biogas plant in Burkina Faso, West Africa (Ouagadougou Biogas Plant, OUA), which is the first large-scale biogas generation plant in West Africa. The primary objective of OUA is to treat human feces, and it serves as a demonstration plant for generating electricity for feed-in tariffs. The objectives of this study are to assess the greenhouse gas reduction capacity and economic, environmental, and social benefits of OUA and to analyze the opportunities and challenges of developing biogas projects in Africa. As a result, the net economic profit of the OUA biogas plant is approximately USD 305,000 per year, with an anticipated static payback period of 14.5 years. The OUA plant has the capacity to treat 140,000 tons of human feces and 3000 tons of seasonal mixed organic waste annually, effectively reducing greenhouse gas emissions by 5232.61 tCO2eq, improving the habitat, and providing over 30 local jobs. Finally, the development of biogas projects in Africa includes advantages such as suitable natural conditions, the need for social development, and domestic and international support, as well as challenges in terms of national policies, insufficient funding, technical maintenance, and social culture. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse specific greenhouse gas emissions savings for a variety of agricultural residues, industrial by-products, and municipal biowaste. One of the most viable alternatives to fossil fuels is bioenergy, particularly biogas produced by the anaerobic digestion of renewable feedstocks. The revised Renewable Energy Directive (D 2018/2001) recognizes that biogas production from agricultural residues, livestock production, and industrial by-products is an acknowledged greenhouse gas mitigation technology in cases where their use results in a certain level of specific greenhouse gas savings. This study delivered values for the maximum transport distance of agricultural residues and industrial by-products to achieve the greenhouse gas (GHG) emissions-saving requirement defined by Directive 2018/2001. It analysed the greenhouse gas emissions reduction for numerous feedstocks for which Directive 2018/2001 has not defined the default and typical values but which could be used as sustainable substitutes for currently dominantly used maize silage in biogas production. The results obtained in this work define the maximum transport and distribution distance for which biogas produced from considered feedstocks achieved required specific greenhouse gas emissions savings (80%), compared with fossil fuel comparator. The obtained results can be used as the constraints in the optimisation of the biomass supply chains for the feedstocks considered in this work. [ABSTRACT FROM AUTHOR]

The applicability of clinoptilolite zeolites in controlling the emission of greenhouse gases (GHGs) such as CO2, the most significant GHG, is investigated herein. In this research, Mexican natural zeolites (ATN) originating from an Atzinco deposit in the state of Puebla were used. Samples of modified clinoptilolite (ATH4, ATH3, ATH2 and ATH1) were obtained from the starting material by acid treatment of various intensities. Inverse gas chromatography was used to evaluate CO2 adsorption in clinoptilolite, natural and chemically modified. Adsorption of CO2 was investigated in the temperature range of 433–573 K, using a TCD detector, and He as a carrier gas. The experimental CO2 adsorption data were processed by Freundlich and Langmuir equations. The degree of interaction between CO2 and the dealuminated clinoptilolite samples was examined through the evaluation of the isosteric enthalpy of adsorption. This calculation was made by using the Clausius–Clapeyron equation, which established the following sequence: ATH1 > ATH2 > ATH4 > ATN > ATH3. The nanoporosity of these clinoptolite zeolites from new deposit in sedimentary rocks was studied through HRADS adsorption of N2. Simultaneously, these zeolites were, respectively, characterized by XRD, EDS, and SEM. Micropores are described by the Dubinin–Asthakov distribution. Various adsorption mechanisms that occur in these nanoporous materials at different relative pressures can be visualized. The quantitative determination of starting mineral is described as: Ca-Clinoptilolite (88.76%) >> Montmorillonite (11.11%) >> quartz (0.13%). The Si/Al molar ratio after acid treatment is: ATH4 > ATH2 > ATN > ATH3 > ATH1. The Langmuir specific surface area (ASL) varies as follows: ATN > ATH2 > ATH4 > ATH3 > ATH1. At the same time, the VΣ values are as follows: ATN > ATH4 > ATH3 > ATH1 > ATH2. [ABSTRACT FROM AUTHOR]

In addition, in new applications such as drone detection, where a dim unresolved target is embedded into a path radiance background, sensor design and performance are highly dependent on atmospheric path radiance. This Special Issue presents the latest research and developments in the field of optical and RF propagation sensing, propagation/effects/channel molding, advancements in applications, signal far-field measurements, theoretical/measurement methods for beam handling/processing, military applications, and next-generation network formations, amongst others. On the whole, the proposed low-cost GHGs estimation system performed well during both crop seasons, and it was found that the adaption of CIF treatment in rice fields could significantly reduce GHG emissions and increase rice productivity. References 1 Kurup A.R., Rozban D., Abramovich A., Yitzhaky Y., Kopeika N. Fast and enhanced MMW imaging system using a simple row detector circuit with GDDs as sensor elements and an FFT-based signal acquisition system. [Extracted from the article]

Mitigating enteric methane (CH4) emissions is crucial as ruminants account for 5% of global greenhouse gas emissions. We hypothesised that less frequent harvesting, use of crops with lower WSC concentration, ensiling at low crop dry matter (DM) and extensive lactic acid fermentation would reduce in vitro CH4 production. Timothy (T), timothy + red clover mixture (T + RC) or perennial ryegrass (RG), cut either two or three times per season, was wilted to 22.5% or 37.5% DM and ensiled with or without formic acid-based additive. Silages were analysed for chemical composition and fermentation products. In vitro CH4 production was measured using an automated gas in vitro system. Methane production was, on average, 2.8 mL/g OM lower in the two-cut system than in the three-cut system (P < 0.001), and 1.9 mL/g OM lower in T than in RG (P < 0.001). Silage DM did not affect CH4 production (P = 0.235), but formic acid increased CH4 production by 1.2 mL/g OM compared to the untreated silage (P = 0.003). In conclusion, less frequent harvesting and extensive silage fermentation reduce in vitro CH4 production, while RG in comparison to T resulted in higher production of CH4. [ABSTRACT FROM AUTHOR]

Currently, biofuels represent a solution for the European Union in the transportation sector in order to reduce the greenhouse gas (GHG) emissions and the dependency of fossil fuels. Biodiesel from vegetable oils is a solution for countries with low GDP per capita to strengthen the internal agriculture, provide jobs, and reduce the use of fossil fuels. In this study, we model and simulate a temperature regulator designed for the biodiesel transesterification process in a discontinuous batch reactor, using methanol and a homogenous basic catalyst. The simulation was based on the kinetical model of the transesterification reaction and the mathematical model of the reactor. We considered molar ratios of alcohol/oil of 6:1 and 9:1, respectively, to shift the reaction equilibrium towards the production of fatty acid methyl esters. In the design of the simulation, the methanol boiling point was considered a restriction, therefore, temperatures below 65 °C were imposed. The results demonstrate that the increase in temperature results in a decrease in the reaction time and a higher yield, especially for the 6:1 molar ratio reaction, and that the optimum temperature for the batch reactor is of 60 °C. Automatic control improves the performance and costs of production. [ABSTRACT FROM AUTHOR]

Aiming at the traditional ecological footprint model, the improved ecological footprint of the carbon footprint effectively makes up for the singularity of the ecological footprint's consideration of carbon emissions, and plays an important role in promoting high-quality development and ecological sustainability. This paper selects 2015, 2018 and 2020 as important time points for the study, corrects the ecological footprint parameter factors based on net primary productivity (NPP), measures the ecological footprint after the improvement of the carbon footprint, studies the spatial and temporal variation in the ecological footprint at the 100-m grid scale with the support of IPCC greenhouse gas inventory analysis, and analyzes the current ecological conservation status of the Yellow River Delta. Additionally, in the context of a low carbon economy, the decoupling index of carbon emissions and GDP is extended to the evaluation and analysis of high-quality development. The study showed that (1) the ecological footprint of the Yellow River Delta has increased year by year, from 0.721 hm2·person− 1 to 0.758 hm2·person− 1, an average annual increase of 2.9%; the ecological carrying capacity has decreased from 0.40 hm2·person− 1 to 0.31 hm2·person− 1, an overall decrease of 28.59%. (2) The overall ecological deficit of the Yellow River Delta grid is lightly overloaded, with most of the ecological surplus occurring in the northern and eastern parts of the study area and a few moderate and heavy overloads in the center of the core area where there is a lot of built-up land and the area is small and easy to gather. (3) Based on the low-carbon economy analysis, 2015, 2017 and 2020 reach absolute decoupling and are in the ideal scenario. However, in the rest of the years, carbon emissions and economic development are still in a large contradiction, and decoupling has fluctuated and varied greatly in the last six years. The effective combination of ecological footprint and low carbon economy analysis provides an important theoretical basis for improving ecological conservation and achieving high-quality development. [ABSTRACT FROM AUTHOR]

Nitrite anaerobic oxidation of methane (Nitrite-dependent anaerobic methane oxidation N-DAMO) is a microbial reaction process in which nitrite is used as electron acceptor to oxidize methane to carbon dioxide. As one of the key ways of greenhouse gas methane consumption, N-DAMO reaction plays a vital role in reducing methane emissions and alleviating greenhouse effect. Based on this, this paper summarized the classification and action mechanism of N-DAMO bacteria, and analyzed the distribution characteristics of N-DAMO bacteria in many kinds of natural habitats. N-DAMO bacteria were not only widely distributed in common natural environments (such as rice fields, wetlands, oceans and lakes), but also in some special habitats (such as intertidal zones, salt lakes, plateaus and desert lakes). The influencing factors in the process of enrichment and culture of N-DAMO bacteria were summarized, including temperature, methane concentration and substrate concentration. Moreover, sludge discharge can effectively increase the nitrogen removal rate of the reactor, enhance the relative abundance of N-DAMO bacteria, and promote the growth of functional microorganisms. [ABSTRACT FROM AUTHOR]

Biofuel covers major parts of the transportation sector in the global economic scenarios. Therefore, the impact assessment parameters like environmental, economic, and social are necessary to evaluate for better understanding. Keeping in mind, a life cycle assessment of biodiesel has been done using Jatropha curcas as feedstock. All the steps from cradle (cultivations, pre-treatment, and transesterification) to gate (biodiesel production) have been evaluated. The functional unit of one ton of biodiesel has been taken as reference, and environmental impacts are assessed accordingly using SimaPro. In the current paper, the conventional and room temperature process for biodiesel production is compared in terms of mid-point categories like greenhouse gas (GHG) emission and other endpoint categories like human health, ecosystems, and resources. The results from the life cycle assessment (LCA) indicates that the room temperature process is more energy-saving than the conventional process. Room temperature biodiesel produced around 1195 kg CO2 eq of emission contributing to global warming, whereas the conventional biodiesel contributed around 1228 kg CO2 eq to GHG emission. Further, the Monte Carlo analysis was carried out to quantify the uncertainty in the process in terms of normalized global warming potential. The biodiesel production from the room temperature process can be explored at the industrial level in future. [ABSTRACT FROM AUTHOR]

The use of hydrogen produced from renewable energy enables the reduction of greenhouse gas (GHG) emissions pursued in different international strategies. The use of power-purchase agreements (PPAs) to supply renewable electricity to hydrogen production plants is an approach that can improve the feasibility of projects. This paper presents a model applicable to hydrogen projects regarding the technical and economic perspective and applies it to the Spanish case, where pioneering projects are taking place via photovoltaic PPAs. The results show that PPAs are an enabling mechanism for sustaining green hydrogen projects. • Technical and economic feasibility assessment of green hydrogen projects. • An operational multi-state modeling of electrolyzers is proposed. • PPAs facilitate the decarbonization of hydrogen production facilities. • Sensitivity analysis to PPA prices, network tariffs exemption and public funding rates. [ABSTRACT FROM AUTHOR]

During its Presidency of the Group of Twenty (G20) in 2020, Saudi Arabia launched the concept of the circular carbon economy (CCE) as a framework for reducing emissions to a level consistent with the goals of the Paris Agreement. The concept, which was endorsed by both G20 leaders and energy ministers, comes at a time when Saudi Arabia appears to have stabilised its domestic emissions after decades of rapid growth. This article describes the CCE concept and positions it alongside other related sustainability concepts, and assesses how it may be meaningfully applied. To that end, the article provides an analysis of key greenhouse gas (GHG) and carbon dioxide (CO2) trends in Saudi Arabia and existing climate change-related policies and measures using the CCE as a framing tool. Prominent data sources indicate that Saudi Arabia's total CO2 emissions experienced their first-ever significant decline in 2018, of 3.93%. The analysis suggests that policy-induced variables, namely energy price reform and more robust energy efficiency measures, played a significant role in this. The article also explores the potential of key mitigation options if limiting global warming below 2°C is to be achieved. Finally, the article discusses the international significance of the CCE concept and its potential to foster stronger engagement on net-zero pathways, particularly from fossil-fuel rich countries and hard-to-abate sectors. The CCE approach aspires to promote holistic assessments of how various carbon management options fit together to achieve a carbon balance, or net-zero emissions. Saudi Arabia's adoption of the concept signals a stronger level of engagement on climate policy. CCE's game-changing potential derives from how it allows aligning fossil fuel producers' interests with net-zero emissions trajectories. A meaningful operationalisation of the CCE in Saudi Arabia will still require a stronger CO2 accounting framework, aligned with international measurement, reporting and verification (MRV) standards. Achieving an emissions pathway consistent with a 2°C global warming target in Saudi Arabia would require significantly more policy support for carbon capture and storage (CCS) and hydrogen in particular, along with a continued emphasis on renewable energy and energy efficiency. The CCE should also be seen as a tool to build bridges between fossil fuel importers and exporters for holistic discussions around energy transition.. [ABSTRACT FROM AUTHOR]

Precision, accuracy, and temporal resolution are key to making full use of atmospheric trace gas records in ice cores. These aspects will become especially crucial for ice cores that aim to extend the ice core record to the last 1.5 Myr, i.e., across the Mid-Pleistocene Transition (as currently drilled within the European project Beyond EPICA – Oldest Ice Core (BE-OIC)). The ice from this period is expected to be close to bedrock and, due to glacier flow, extremely thinned with 15 000 years of climate history contained in only 1 m of ice. Accordingly, for a century-scale resolution, the sample vertical extent must be reduced to a few centimeters containing only about 1–2 mL air STP. We present a novel combined system for the extraction and the simultaneous measurement of CO2 , CH4 , and N2O concentrations, as well as δ13CO2 , which achieves a vertical resolution of 1–2 cm (3.5×3.5 cm cross section) with precisions of 0.4 ppm, 3 ppb, 1 ppb, and 0.04 ‰, respectively, in sublimation tests with standard gas over gas-free ice. This is accomplished by employing a directional and continuous laser-induced sublimation followed by analysis of the sample gas by a quantum cascade laser absorption spectrometer (QCLAS). Besides the low sample volume requirements and the vertical resolution capabilities, the described method holds additional advantages over previous methods, including the immunity of the highly specific QCLAS analysis to drilling fluid contamination as well as the non-destructive nature of the spectroscopic gas analysis. The combined extraction and analysis system was extensively tested by sublimating gas-free ice with introduction of a standard gas to determine the accuracy and characterize potential artifacts. Moreover, Antarctic ice samples were measured to confirm the measurement performance, covering the range of variability expected in Pleistocene ice and highlighting the vertical resolution capabilities critical for its application within BE-OIC. [ABSTRACT FROM AUTHOR]

Achieving the stringent climate goals established by New York State will require significant emissions reductions across the agriculture, commercial and residential, electricity, industry and transportation sectors. This study analyzed the residential heating sector and quantified the environmental and financial impacts of four different residential heating pathways for buildings located in New York State. A conventional ultra‐low sulfur diesel pathway served as the baseline scenario against which three low‐carbon alternative pathways were compared: (1) a 'bioheat' scenario in which biomass‐based diesel is blended with heating oil; (2) a natural gas scenario; and (3) an electric scenario (air‐source heat pump). The low‐carbon alternative heating pathways incorporate the social cost of carbon as an internalized financial benefit from the conventional ultra‐low sulfur diesel baseline scenario. The bioheat pathway yielded the highest net present value (NPV) at $3 684 513 and the electric (air‐source heat pump) pathway had a NPV of $3 618 229. The electric and bioheat scenarios yielded the lowest and second lowest total cumulative emissions at 28545 Mt CO2e and 51 438 Mt CO2e, respectively. This study also incorporated a comprehensive sensitivity analysis to depict the impact of: NPV discount rates, fuel costs, carbon intensity values, system installation costs and social cost of carbon values. The study provides policymakers, researchers and other interested stakeholders with a comparison of the environmental and financial impacts of diverse residential heating systems. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Several single-platform satellite missions have been designed during the past decades in order to retrieve the atmospheric concentrations of anthropogenic greenhouse gases (GHG), initiating worldwide efforts towards better monitoring of their sources and sinks. To set up a future operational system for anthropogenic GHG emission monitoring, both revisit frequency and spatial resolution need to be improved. The Space Carbon Observatory (SCARBO) project aims at significantly increasing the revisit frequency of spaceborne GHG measurements, while reaching state-of-the-art precision requirements, by implementing a concept of small satellite constellation. It would accommodate a miniaturised GHG sensor named NanoCarb coupled with an aerosol instrument, the multi-angle polarimeter SPEXone. More specifically, the NanoCarb sensor is a static Fabry–Pérot imaging interferometer with a 2.3×2.3 km 2 spatial resolution and 200 km swath. It samples a truncated interferogram at optical path differences (OPDs) optimally sensitive to all the geophysical parameters necessary to retrieve column-averaged dry-air mole fractions of CO 2 and CH 4 (hereafter XCO2 and XCH4). In this work, we present the Level 2 performance assessment of the concept proposed in the SCARBO project. We perform inverse radiative transfer to retrieve XCO2 and XCH4 directly from synthetic NanoCarb truncated interferograms and provide their systematic and random errors, column vertical sensitivities, and degrees of freedom as a function of five scattering-error-critical atmospheric and observational parameters. We show that NanoCarb XCO2 and XCH4 systematic retrieval errors can be greatly reduced with SPEXone posterior outputs used as improved prior aerosol constraints. For two-thirds of the soundings, located at the centre of the 200 km NanoCarb swath, XCO2 and XCH4 random errors span 0.5–1 ppm and 4–6 ppb, respectively, compliant with their respective 1 ppm and 6 ppb precision objectives. Finally, these Level 2 performance results are parameterised as a function of the explored scattering-error-critical atmospheric and observational parameters in order to time-efficiently compute extensive L2 error maps for future CO 2 and CH 4 flux estimation performance studies. [ABSTRACT FROM AUTHOR]

As the threat of irreversible climate change has increased over time, the UK has continued to set increasingly ambitious policies to reduce its carbon emission. An assessment of mitigation progress to date at the local authority level clarifies the factors that have affected greenhouse gas (GHG) emissions on the path to carbon neutrality. This research uses regression analyses between local authorities' GHG emission redcutions and selected explanatory variables (including population density, household income, and manufacturing employment) identified from the literature to explore mitigation performance over time, focusing on GHG emissions changes between 2005 and 2016. Substantial and relatively consistent GHG emissions reductions were achieved in this time frame, with average total reductions across UK local authorities of 31.2%. Population density was moderately-to-strongly correlated with the success of transportation GHG emissions mitigation, though this sector has seen the smallest percentage declines over this period. Local authorities with densities below 25 inhabitants per hectare were generally among the poorest performers in transportation GHG mitigation. This underscores the need to support remote working and electrification of personal transportation in areas where public/active transportation options are not viable alternatives. Furthermore, consideration of population density in conjunction with domestic and urban planning will allow for future emissions reductions to occur across the UK. Fundamentally, GHG emissions reductions to date are largely driven by historic factors (density), shifting economic structures (deindustrialisation), and centralised initiatives (decarbonisation of electricity generation). [ABSTRACT FROM AUTHOR]

The adsorption of greenhouse gases (GHG) as a method to reduce their emissions into the atmosphere is an alternative that is easier to implement industrially and cheaper than other existing technologies, such as chemical capture, cryogenic separation, or membrane separation. The vast majority of works found in the literature have focused their efforts on capturing CO2 as it is the largest GHG. However, although N2O emissions are not as large as CO2, the impact that N2O has on the stratosphere and climate is much larger in proportion, despite which there is not much research on N2O capture. Since both gases are usually emitted into the atmosphere together (along with other gases), it is necessary to design selective adsorbents capable of capturing and separating these gases from each other and from other gases, to mitigate the effects of climate change. This review aims to compile the existing information to date on porous adsorbents, the characteristics of the N2O adsorption processes and, above all, aims to focus the reader's gaze on the importance of designing selective adsorbents for greenhouse gas mixtures. [ABSTRACT FROM AUTHOR]

• The roasting temperature was as low as 150°C. • The recovery efficiency of Li was 96 %. • NaOH was an efficient and green oxidizing agent. • Potential damage mechanism of the NaOH-assisted roasting was revealed. Decreasing the operating temperature of pyrometallurgical methods for recycling spent lithium-ion batteries (LIBs) is key to reducing energy consumption and cost. Herein, a NaOH-assisted low-temperature roasting approach is proposed to recover spent LiFePO 4. During roasting, NaOH acts as an oxidizing agent to oxidize Fe (II) to Fe 3 O 4 at 150°C, thus collapsing its stable olivine structure while PO 4 3- capturing Li+ and Na+ to form Li 2 NaPO 4 and LiNa 5 (PO 4) 2. The obtained Fe 3 O 4 is then separated, and the resulting Li salt can be further recovered as Li 3 PO 4 with a Li recovery efficiency of 96.7 % and a purity of 99.9 %. Economic and environmental analysis based on the EverBatt model shows that this low-temperature strategy reduces energy consumption and greenhouse gas (GHG) emissions, thus increasing the potential profit. Overall, NaOH-assisted low-temperature roasting is a prospective strategy that broadens the application of NaOH as an oxidant and opens up a new avenue for decreasing the temperature of recovering spent LiFePO 4 by pyrometallurgy. [ABSTRACT FROM AUTHOR]

Peatlands drained for agriculture or forestry are susceptible to the rapid release of greenhouse gases (GHGs) through enhanced microbial decomposition and increased frequency of deep peat fires. We present evidence that rewetting drained subtropical wooded peatlands (STWPs) along the southeastern USA coast, primarily pocosin bogs, could prevent significant carbon (C) losses. To quantify GHG emissions and storage from drained and rewetted pocosin we used eddy covariance techniques, the first such estimates that have been applied to this major bog type, on a private drained (PD) site supplemented by static chamber measurements at PD and Pocosin Lakes National Wildlife Refuge. Net ecosystem exchange measurements showed that the loss was 21.2 Mg CO2 ha−1 year−1 (1 Mg = 106 g) in the drained pocosin. Under a rewetted scenario, where the annual mean water table depth (WTD) decreased from 60 to 30 cm, the C loss was projected to fall to 2 Mg CO2 ha−1 year−1, a 94% reduction. If the WTD was 20 cm, the peatlands became a net carbon sink (−3.3 Mg CO2 ha−1 year−1). Hence, net C reductions could reach 24.5 Mg CO2 ha−1 year−1, and when scaled up to the 4000 ha PD site nearly 100,000 Mg CO2 year−1 of creditable C could be amassed. We conservatively estimate among the 0.75 million ha of southeastern STWPs, between 450 and 770 km2 could be rewet, reducing annual GHG emissions by 0.96–1.6 Tg (1 Tg = 1012 g) of CO2, through suppressed microbial decomposition and 1.7–2.8 Tg via fire prevention, respectively. Despite covering <0.01% of US land area, rewetting drained pocosin can potentially provide 2.4% of the annual CO2 nationwide reduction target of 0.18 Pg (1 Pg = 1015 g). Suggesting pocosin restoration can contribute disproportionately to the US goal of achieving net‐zero emission by 2050. [ABSTRACT FROM AUTHOR]

The current study took Henan Wufeng New Energy Science Technology Co. Ltd as an example to investigate a large‐scale steam heating system with biomass briquette fuel in Henan, China. Drawn on several months of field research, the economic cost and greenhouse gas emissions for peanut shell straw collection, transportation, storage and burning at Henan Wufeng New Energy Science Technology Co. Ltd were analyzed in 2021. Moreover, the economic cost and greenhouse gas emissions were used as evaluation indicators to evaluate the biomass molding fuel supply system systemically. Economic analysis shows that the steam heating system can make a profit of 1.72 × 106 yuan per year, and the input–output ratio (ROI) is 93.87%, which is much higher than the benchmark input–output ratio (30%). The very high ROI indicates that the system is difficult to operate in an economically feasible manner. Greenhouse gas emission analysis demonstrates that at the same heating level, the system can save 4.42 × 107 kg of standard coal and reduce the emissions of greenhouse gases to the environment by 1.25 × 105 tCO2eq, which has significant environmental benefits. Taken together, the government should adopt effective economic policies to promote the efficient use of biomass straw and support biomass straw recycling and heating enterprises. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]