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The paper reviews the existing applications of sensing technologies for measuring construction off-road vehicle emissions (COVE) such as earthmoving equipment. The current literature presented different measurement methods and reported the results of utilisation of new technologies for measuring COVE. However, previous papers used different technology applications covering only a part of the monitoring process with its own limitations. Since technologies are advancing and offering novel solutions, there is an urgent need to identify the gaps, re-evaluate the current methods, and develop a critical agenda for automating the entire process of collecting emissions data from construction sites, and monitoring the emission contributors across cities. This paper systematically identifies relevant papers through a search of three key databases—Web of Science, Engineering Valley and Scopus—covering the publications in the last decade from 2008 to 2017. An innovative robust research method was designed to select and analyse the relevant papers. The identified papers were stored in a data set, and a thematic algorithm employed to find the clusters of papers which might be potentially relevant. The selected papers were used for further micro-thematic analysis to find key relevant papers on COVE, and the gap in the literature. A sample of relevant papers was found relevant to COVE and critically reviewed by coding and content analysis. This paper critically reviews the selected papers and also shows that there is a considerable gap in the applications of new technologies for measuring in-use COVE in real time based on real activities toward automated methods. This review enables practitioners and scholars to gain a concrete understanding of the gap in measuring COVE and to provide a significant agenda for future technology applications. [ABSTRACT FROM AUTHOR]

With climate change, more intense weather phenomena can be expected, including pressure drops related to the arrival of an atmospheric front. Such drops of pressure are the main reason for gas emissions from closed mines to the surface, and a closed, empty mine shaft is the most likely route of this emission. Among the gases emitted, the most important are carbon dioxide and methane, creating a twofold problem—greenhouse gas emissions and gas hazards. The work presented in this paper simulated the spread of the mentioned gases near such an abandoned shaft for four variants: model validation, the most dangerous situations found during measurements with or without wind, and a forecast variant for a possible future pressure drop. It was found that a momentary CO2 emission of 0.69 m3/s and a momentary CH4 emission of 0.29 m3/s are possible, which for one hour of the appropriate drop would give hypothetically 2484 m3 CO2 and 1044 m3 CH4. In terms of gas hazards, the area that should be monitored and protected may exceed 25 m from a closed shaft in the absence of wind influence. The wind spreads the emitted gases to distances exceeding 50 m but dilutes them significantly. [ABSTRACT FROM AUTHOR]

The emission of greenhouse gases, especially carbon dioxide, accelerates global warming and poses a crisis to the environment and human society. The carbon emission of products is mainly determined by the design stage of the life cycle. However, the data in the scheme design stage has certain fuzziness and uncertainty. Therefore, it is difficult to calculate the carbon footprint directly. In this paper, a carbon footprint prediction model of linkage mechanism scheme design stage (CFPL-SDS) is proposed to help designers make decisions. Firstly, the CFPL-SDS is built to quantify the carbon performance of linkage mechanism. Secondly, according to the structural characteristics of the closed-loop cascade rehabilitation robot, a four-finger training mechanism is designed. Finally, the model is applied to the four-finger training mechanism to verify its feasibility. The results show that the CFPL-SDS can calculate the carbon footprint of the linkage in the design stage. Moreover, the CFPL-SDS establishes the mathematical model foundation for the low-carbon optimization problem of linkage mechanism. [ABSTRACT FROM AUTHOR]

This paper investigates the nexus between greenhouse gas emissions and poverty alleviation in the Economic Commission of West African States between 1985 and 2020 applying autoregressive distributed lag and Granger causality techniques. The results reveal that carbon dioxide non‐significantly relates to gross domestic product per capita positively while nitrous oxide and foreign direct investment impacts gross domestic product per capita positively. Methane negatively impacts gross domestic product per capita. The governments should use conventions to regulate greenhouse gas emissions' effects on environmental degradation regionally and globally. The study underscores that countries should diversify to cleaner energy sources. This would reduce greenhouse gas emissions in the atmosphere. Massive technological investment is required to mitigate the greenhouse gas emissions' negative impacts on the environment which create poverty. This policy implication ensures environmental sustainability and reverses the ugly trend of greenhouse gas emissions on poverty. [ABSTRACT FROM AUTHOR]

Following China and the United States, India is the third highest CO2 emitter in the world. With its fast rising population and an industry primarily reliant on coal and oil, the country's emissions will continue to rise unless appropriate measures are taken. In India generally the carbon sequestration is done by storing CO2 in sedimentary basins where it gets capped by the impermeable cap rocks. The study aims to unfold the other techniques of carbon sequestration in subsurface formations, except for narrating the different types of carbon capture and sequestration techniques along with its storage in different types of environments. For instance, abiotic and biotic environments for CO2 sequestration. It further talks about carbon injections of oceanic, geological, and terrestrial types, to name just a few. Types of carbon emission sources are discussed too. In this paper three different approaches are described for carbon mitigation, namely CarbFix, CO2 Plume technology and Carbon Trading. A prefeasibility study was done in order to implement the three techniques in Dholera geothermal region in Gujarat, India. In literature review, it can be seen how the three techniques can help in permanent mitigation of captured carbon through carbonate mineralization, power generation and industrial applications. For any project government and public participation is important. In this regard the study gives a brief understanding about the steps to be taken by government and the public to promote such projects for carbon mitigation. Besides, the steps to be taken in such projects for health and risk assessment were talked about in literature review too. [ABSTRACT FROM AUTHOR]

The technology of CO2 injection into oil reservoirs contributes to a significant increase in oil production effectively reducing greenhouse gas emissions into the atmosphere. The mechanism of enhanced oil recovery was studied on the example of large formations of the Ordos Basin. The Ordos shale oil field is characterized by low porosity, low permeability and high reservoir heterogeneity. In this paper; based on an experimental model, a mechanism of filtration of fluid in a formation rock is proposed. To verify the model, oil recovery parameters were studied experimentally during CO2 injection for the conditions of the YanChang field of the Ordos Basin. In the course of the experiments, on models of long cores of the rock, the effect of the rate and intensity of injection, the exposure time and well parameters on the displacement efficiency during cyclic injection were measured. The paper concludes that it is possible to use CO2 injection technology to improve the efficiency of oil recovery on reservoirs using the example of the YanChang field. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions from the incineration of municipal solid waste (MSW) have become a concern in the solid waste community from the perspective of climate change mitigation and response. In this study, we aimed to estimate the GHG emissions from the incineration of MSW in Seoul, with a population of about 10 million, by using the IPCC (Intergovernmental Panel on Climate Change) 2006 guideline and scenario analysis for 2030 and 2040. In 2021, Seoul generated 2899 kt of MSW/yr. Approximately 40% (1163 kt/yr) of Seoul's MSW was disposable (or non-recyclable) waste. Out of the disposable waste, about 741 kt/yr of combustible waste was treated by incineration, resulting in 545 kt CO2 eq emissions, which was about 7.5 times higher than the 74 kt CO2 eq in 2000. The dominant contributor to the GHG emissions was plastic waste, accounting for the largest fraction of 92% (501 kt CO2 eq/yr in 2021). Scenario analysis showed that if the current situation (BAU scenario) is considered, with the assumption of no reduction in MSW generation, the capacity of Seoul's four incineration facilities will be exceeded in 2029. All other scenarios (S1, S2, and S3) showed reduced amounts of MSW incineration and GHG emissions compared to the BAU scenario. Especially, S3 (waste reduction and increased recycling rate) revealed a 53% reduction when compared to the BAU scenario. Based on the results of our scenario analysis, it is expected that in 2040, the GHG emissions from incineration will be in a range of from about 389 kt CO2 eq to 832 kt CO2 eq, depending on the waste minimization policy and recycling efforts in the future. Strengthened regulations on and efforts towards plastic waste reduction and the recycling of MSW will be crucial with the perspectives of GHG emissions by incineration and resource recovery. [ABSTRACT FROM AUTHOR]

According to the construction of the cascade hydropower stations in the lower reaches of the Yalong River and the ecological environment condition of the river, a medium and long-term optimal dispatching model with the goal of maximizing the power generation benefits of the cascade hydropower stations is established, and the dynamic programming method is used to optimize the solution, so as to obtain the ten-day average maximum power generation of cascade hydropower stations. According to the latest relevant research at home and abroad, it is found that during the power generation process of the hydropower station, the discharge will produce certain greenhouse gas (GHG) emissions during the delivery process. In this paper, the greenhouse gas emissions existing in the power generation process of cascade reservoirs are considered, and the typical values are selected to calculate the average greenhouse gas (mainly CO 2) emissions from 2001 to 2018, twelve plants with strong carbon sequestration and oxygen release capacity and suitable for growing in the basin are selected, and the mitigation and improvement measures of greenhouse gas emissions around the reservoirs in the basin are given. A new research idea is provided for the Yalong River cascade reservoirs to focus on the power generation benefits while reducing the greenhouse gas emission situation to a certain extent. [ABSTRACT FROM AUTHOR]

Background: One of the most problems in developing countries is the integrated waste management and the effects on Greenhouse Gases (GHG) emission, Life Cycle Assessment (LCA) is used in this paper as a decision supporting tool in planning Municipal Solid Waste (MSW) managements. Methods: In this paper the EPA's Waste Reduction Model (WARM) that provide GHG emission factors for waste stream components that are based on life Cycle Inventory (LCI) framework were used and The MSW management methods comprised in seven scenarios. Results: The amount of GHG which was generated from Iran's waste sector estimated about 17836079 Metric Tons of Carbon dioxide Equivalents (MT CO2e) in this study. The lowest amount of GHG was generated by LFG capture system with energy recovery (557635 MT CO2e), while Incineration of materials being sent to landfill (1756823 MT CO2e), Landfill Gas (LFG) capture system with flaring (2929150 MT CO2e) and Improved source reduction and recycling (4780278 MT CO2e) emitted fewer GHG than the other scenarios. Lowest levels of gross energy consumption occur in source reduction with recycling and composting (-89356240 Mega British Thermal Unit, M BTU), recycling and composting (-86772060 M BTU) as well as Improved source reduction with recycling and composting (-54794888 M BTU). Conclusions: It appears that recycling and composting each offer significant GHG emissions and energy consumption reductions (scenarios 4, 5 and 6). Upon of the GHG emission and energy consumption results concluded that improved source reduction and recycling scenario has been the Balanced and appropriate technology for handling the solid waste streams in municipalities. [ABSTRACT FROM AUTHOR]

The paper aimed to present the evolution of green house gases emissions from entheric fermentation and manure management at nonruminants Romanian livestock during the period 2014 -2017. The emissions are based on the data provided by National Institute for Statistics. The data have been processed into the following indicators: nonruminants livestock, number of: breeding females (sows), swine youth categories as piglets (under 20 kg and 20-50 kg), fattening swine, breeding swine, horses, for entheric fermentation. For manure management were including two poultry categories: broilers and adult laying chickens. All categories included in this study were in accordance with IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, 2006, and parameters used in equations have national values (gross energy intake, digestible energy, EF, MS, Nex). The researchproved that the green house gases emission trend from entheric fermentation and manure management were descending, due to the decrease in the number of animals, and due to conversion to sustainable agriculture sustained by government subsidies for environmental measures. [ABSTRACT FROM AUTHOR]

A greenhouse gas sensor has been developed to simultaneously detect multiple gas species within a hollow-core photonic bandgap fiber (HC-PBF) structure entirely composed of fibers. To enhance sensitivity, the gas cell consists of HC-PBF enclosed between two single-mode fibers fused with a reflective end surface to double the absorption length. The incorporation of side holes for gas diffusion allows for analysis of the relationship between gas diffusion speed, number of drilled side holes, and energy loss. As the number of drilled holes increases, the response time decreases to less than 3 min at the expense of energy loss. Gas experiments demonstrated detection limits of 0.1 ppm for methane and 2 ppm for carbon dioxide, with an average time of 50 s. In-situ testing conducted in rice fields validates the effectiveness of the developed gas detection system using HC-PBF cells, establishing all-fiber sensors with high sensitivity and rapid response. [ABSTRACT FROM AUTHOR]

The CO2 capture and storage (CCS) technology is since more than ten years considered one of the key options for the future climate change mitigation. This paper discusses the implications for the further development of CCS, particularly with respect to climate change policy in an international geopolitics context. The rationale for developing CCS should be the over-abundance of fossil fuel reserves (and resources) in a climate change context. From a geopolitical point, it can be argued that the most important outcome from the successful commercialisation of CCS will be that fossil fuel-dependent economies with large fossil fuel resources will find it easier to comply with stringent greenhouse gas reduction targets (i. e. to attach a price to CO2 emissions). This should be of great importance since, from a geopolitical view, the curbing on greenhouse gas emissions cannot be isolated from security of supply and economic competition between regions. Thus, successful application of CCS may moderate geopolitical risks related to regional differences in the possibilities and thereby willingness to comply with large emission cuts. In Europe, application of CCS will enhance security of supply by fuel diversification from continued use of coal, especially domestic lignite. Introduction of CCS will also make possible negative emissions when using biomass as a fuel, i. e. in so called Biomass Energy CCS (BECCS). Yet, the development of BECCS relies on the successful development of fossil fuelled CCS since BECCS in itself is unlikely to be sufficient for establishing a cost efficient CCS infrastructure for transport and storage and because BECCS does not solve the problem with the abundant resources of fossil fuels. Results from research and development of capture, transport and storage of CO2 indicate that the barriers for commercialization of CCS should not be technical. Instead, the main barriers for implementation of CCS seem to be how to reach public acceptance, to reduce cost and to establish a high enough price on CO2 emissions. Failure to implement CCS will require that the global community, including Europe, agrees to almost immediately to start phasing out the use of fossil fuels, an agreement which seems rather unlikely, especially considering the abundant coal reserves in developing economies such as China and India. [ABSTRACT FROM AUTHOR]

This paper compares life-cycle greenhouse gas (GHG) emissions from two municipal solid waste (MSW) management options, municipal waste combustion, and landfilling, using a U.S. EPA life-cycle assessment (LCA) model, the MSW Decision Support Tool. Unlike previously reported LCAs, key combustion model inputs—total MSW carbon content and its biogenic/fossil split—are determined not from MSW composition studies, but from measurements taken at operating municipal waste combustors (MWCs). MWC measurement data show U.S. MSW carbon content averages of 30% with a biogenic/fossil split of 66%/34%. The LCA also considers a range of landfilling scenarios which account not only for alternative landfill gas (LFG) management techniques, but also for the variability of landfill methane generation and capture. The LCA found that for the range of inputs and scenarios considered, municipal waste combustion outperforms landfilling in terms of GHG emissions, regardless of the LFG management technique. [ABSTRACT FROM AUTHOR]

Copyright of Transport (16484142) is the property of Vilnius Gediminas Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: This paper aims to investigate the greenhouse gas (GHG)-related disclosure trends, content and strategies of the eight most high GHG-emitting Chinese power companies, over a period when government pressure to manage GHG emissions increased. Design/methodology/approach: Data were collected from the 2000-2009 annual reports, corporate social and environmental responsibility reports and websites of eight Chinese power companies. Content analysis results were supplemented with excerpts from documents written in English or Chinese. Legitimacy theory informed the interpretation of the findings. Findings: GHG-related disclosures increased from 2002 when the Chinese Government ratified the Kyoto Protocol and promulgated stringent environmental regulations. However, some expected types of GHG-related disclosure were absent or rare. Disclosure practices were found to be underpinned by reputation management objectives and reflected a symbolic rather than substantive legitimation strategy. Research limitations/implications: This study extends the literature on GHG-related disclosures by carbon-intensive firms and points to the need for future research to examine such disclosures in different countries to appreciate the variety in practice. Practical implications: While the Chinese Government appears to have driven the emergence of GHG-related disclosure practices, companies can effect improvement by expanding the scope and content of what they disclose. Also, the growing emphasis on website disclosures may present challenges in ensuring the reliability and assurance of GHG disclosures. Originality/value: This is the first study to examine GHG-related disclosure practices by Chinese power-generating companies, a sector crucial to managing the GHG effects of China's significant economic growth. [ABSTRACT FROM AUTHOR]

Copyright of Ánfora is the property of Universidad Autonoma de Manizales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of the efficient approaches to achieving net-zero greenhouse gas emissions is the 100% atom-economical conversion of the greenhouse gas carbon dioxide (CO2) to cost-effective, less toxic cyclic carbonates that can act as green solvents and abundant C1 synthon in organic synthesis. In this work, we have synthesized an Indium Metal–Organic Framework (MOF), functionalized with triazole MIL-68(In)-NHTr (Tr = 1-methylene-1,2,4-triazole) as a bifunctional catalyst for the synthesis of cyclic carbonates from epoxides with high yield (96%) and selectivity (100%) under solvent-free ambient reaction conditions (CO2 pressure 1 bar, temperature 50 °C, and reaction time 6 h). The synergistic acid–base effect of Indium SBU and the triazole of MIL-68(In)-NHTr make this a better catalyst than the conventional MIL-68(In)-NH2. This new catalyst was non-leachable and was reusable for six consecutive catalytic cycles without appreciable loss in the catalytic efficiency and crystallinity of the MOF framework. [ABSTRACT FROM AUTHOR]

The transport sector is responsible for 25% of greenhouse gas emissions, mainly carbon dioxide (CO2). Its emissions are the main driver of the worsening global climate change scenario. Finding feasible options to sequester this greenhouse gas is a great challenge for scientists, governments, and industry. Carbon capture, utilization, and storage (CCUS) are technologies that capture CO2 directly or indirectly by transforming it into other products of interest. In this context, biological CO2 conversion can be performed by photosynthetic microorganisms, such as microalgae and cyanobacteria, producing a wide variety of bio-based added-value products, such as third-generation (3G) bioethanol. However, the main obstacle to the spread of 3G bioethanol is economical, as it is still a recent and little-explored technology, lacking technical and scientific development for its production to become economically viable. Within this perspective, this work presents a patent-based mapping of current technological trends in 3G bioethanol production, which revealed that it is an emerging field with 171 patent deposits since 1979, with a tendency of at least 10 patents published per year in the last 15 years. The main drawbacks industries are focused on remain those from 2G bioethanol production, such as biomass hydrolysis. Therefore, with extensive cooperation between governments, scientists, and industries, it may be a matter of time before 3G bioethanol production becomes a reality. The presented data are expected to contribute to technical knowledge of 3G ethanol production, including the knowledge transfer from the academy to the industrial sector. [ABSTRACT FROM AUTHOR]

Abstract Agriculture is a significant source of anthropogenic greenhouse gas (GHG) emissions, and beef cattle are particularly emissions intensive. GHG emissions are typically expressed as a carbon dioxide equivalent (CO 2 e) 'carbon footprint' per unit output. The 100-year Global Warming Potential (GWP 100) is the most commonly used CO 2 e metric, but others have also been proposed, and there is no universal reason to prefer GWP 100 over alternative metrics. The weightings assigned to non-CO 2 GHGs can differ significantly depending on the metric used, and relying upon a single metric can obscure important differences in the climate impacts of different GHGs. This loss of detail is especially relevant to beef production systems, as the majority of GHG emissions (as conventionally reported) are in the form of methane (CH 4) and nitrous oxide (N 2 O), rather than CO 2. This paper presents a systematic literature review of harmonised cradle to farm-gate beef carbon footprints from bottom-up studies on individual or representative systems, collecting the emissions data for each separate GHG, rather than a single CO 2 e value. Disaggregated GHG emissions could not be obtained for the majority of studies, highlighting the loss of information resulting from the standard reporting of total GWP 100 CO 2 e alone. Where individual GHG compositions were available, significant variation was found for all gases. A comparison of grass fed and non-grass fed beef production systems was used to illustrate dynamics that are not sufficiently captured through a single CO 2 e footprint. Few clear trends emerged between the two dietary groups, but there was a non-significant indication that under GWP 100 non-grass fed systems generally appear more emissions efficient, but under an alternative metric, the 100-year global temperature potential (GTP 100), grass-fed beef had lower footprints. Despite recent focus on agricultural emissions, this review concludes there are insufficient data available to fully address important questions regarding the climate impacts of agricultural production, and calls for researchers to include separate GHG emissions in addition to aggregated CO 2 e footprints. Highlights • Multi-gas footprints are typically converted to a total carbon dioxide equivalent. • Different carbon dioxide equivalence metrics emphasize different climate behaviours. • Reporting emissions of all gases as a combined total loses important information. • Disaggregated data could not be retrieved from most (71%) full beef LCAs. • Relative emissions intensity is highly dependent on metric choice. [ABSTRACT FROM AUTHOR]

Emissions trading in the European Union (EU), covering the least uncertain emission sources of greenhouse gas emission inventories (CO2 from combustion and selected industrial processes in large installations), began in 2005. During the first commitment period of the Kyoto Protocol (2008–2012), the emissions trading between Parties to the Protocol will cover all greenhouse gases (CO2, CH4, N2O, HFCs, PFCs, and SF6) and sectors (energy, industry, agriculture, waste, and selected land-use activities) included in the Protocol. In this paper, we estimate the uncertainties in different emissions trading schemes based on uncertainties in corresponding inventories. According to the results, uncertainty in emissions from the EU15 and the EU25 included in the first phase of the EU emissions trading scheme (2005–2007) is ±3% (at 95% confidence interval relative to the mean value). If the trading were extended to CH4 and N2O, in addition to CO2, but no new emissions sectors were included, the tradable amount of emissions would increase by only 2% and the uncertainty in the emissions would range from −4 to +8%. Finally, uncertainty in emissions included in emissions trading under the Kyoto Protocol was estimated to vary from −6 to +21%. Inclusion of removals from forest-related activities under the Kyoto Protocol did not notably affect uncertainty, as the volume of these removals is estimated to be small. [ABSTRACT FROM AUTHOR]

Concerns about potentially dangerous changes in climate as a result of rising levels of greenhouse gases in the atmosphere are leading to restrictions on emissions of carbon dioxide (CO[sub 2]), the principal anthropogenic greenhouse gas. The main source of CO[sub 2] emissions is fossil fuel combustion; power generation is the single largest contributor. Coal is widely used for power generation, but it releases approximately twice as much CO[sub 2] compared with the use of natural gas for each unit of electricity sent out. Emission reduction could be achieved by increasing the efficiency with which coal is burnt, or by switching to another fuel. These measures can achieve significant reductions in emissions, but, for deep reductions, more substantial changes would be required in the power plant. The technology for capture and storage of CO[sub 2] has been recognized in recent years as providing a means of cutting emissions from fossil fuel combustion by at least 80 per cent. Capture and storage is based on technology already in use for other purposes, so there is limited need for development, and the risk of application will be less than is typical for novel energy technologies. Hence, this seems to be a technology that could be deployed relatively rapidly to reduce emissions from fossil fuel fired plant. In this paper, the technology for capture and storage of CO[sub 2] will be reviewed, especially the costs and potential capacity for reducing emissions. Some barriers to implementation are identified, and work necessary to overcome them is discussed. [ABSTRACT FROM AUTHOR]

The CO2 reduction by solar means has been discussed as an alternative to emission abatement, a fundamental topic for sustainable, carbon-free production in the future. However, the choice of efficient systems, starting with the catalysts, is still a critical issue, especially due to the poor activity of available options. Polyoxometalates have been extensively studied as promising photocatalysts due to their semiconducting properties. Nevertheless, the synthetic conditions of polyoxoniobate are stringent due to the low reaction activity of Nb species, the lack of soluble precursors, and the narrow pH range. Unlike the literature, in the present study, we report a simple polyoxoniobate synthesis method. This synthesis method has some remarkable features, such as low processing time and temperature and good activity and selectivity in the CO2 photoreduction process. The results revealed an outstanding efficiency for the CO2 reduction reaction with a high selectivity of CO2 to CO conversion (92.5%). Furthermore, C2 compounds (e.g., acetate) were produced in the liquid phase of the reaction system. Our findings are significant for indicating the potential of polyoxoniobate for CO2 photoreduction, which opens a way to control competitive reactions with synthesis, leading to higher selectivity. [ABSTRACT FROM AUTHOR]

Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the second phase of the REgional Carbon Cycle Assessment and Processes (RECCAP‐2) initiative, we synthesize existing estimates of GHG emissions from streams, rivers, lakes and reservoirs, and homogenize them with regard to underlying global maps of water surface area distribution and the effects of seasonal ice cover. We then produce regionalized estimates of GHG emissions over 10 extensive land regions. According to our synthesis, inland water GHG emissions have a global warming potential of an equivalent emission of 13.5 (9.9–20.1) and 8.3 (5.7–12.7) Pg CO2‐eq. yr−1 at a 20 and 100 years horizon (GWP20 and GWP100), respectively. Contributions of CO2 dominate GWP100, with rivers being the largest emitter. For GWP20, lakes and rivers are equally important emitters, and the warming potential of CH4 is more important than that of CO2. Contributions from N2O are about two orders of magnitude lower. Normalized to the area of RECCAP‐2 regions, S‐America and SE‐Asia show the highest emission rates, dominated by riverine CO2 emissions. Key Points: We synthesized estimates of river, lake and reservoir emissions of CO2, CH4, and N2O for 10 world regions and globallyWe re‐estimate global inland water emission of 5.5 (3.5–9.1) Pg CO2 yr−1, 100 (82–135) Tg CH4 yr−1, and 322 (248–590) Gg N2O yr−1At 100 or 20 years horizon, CO2 or CH4 dominate global warming potential of emissions, respectively [ABSTRACT FROM AUTHOR]

Inland waters are important emitters of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP‐2) initiative, we review the state of the art in estimating inland water GHG budgets at global scale, which has substantially advanced since the first phase of RECCAP nearly 10 years ago. The development of increasingly sophisticated upscaling techniques, including statistical prediction and process‐based models, allows for spatially explicit estimates that are needed for regionalized assessments of continental GHG budgets such as those established for RECCAP. A few recent estimates also resolve the seasonal and/or interannual variability in inland water GHG emissions. Nonetheless, the global‐scale assessment of inland water emissions remains challenging because of limited spatial and temporal coverage of observations and persisting uncertainties in the abundance and distribution of inland water surface areas. To decrease these uncertainties, more empirical work on the contributions of hot‐spots and hot‐moments to overall inland water GHG emissions is particularly needed. Key Points: We explore the state‐of‐the‐art in inland water greenhouse gas emissions, discussing existing estimates and underlying methodologiesDevelopment of models increasingly allows for assessment of spatial and temporal variability of emission fluxesThere is a persisting need for observations that capture hot‐spots and hot‐moments in emissions, including from small water bodies [ABSTRACT FROM AUTHOR]

Paddy fields are a major emission source of greenhouse gases (GHGs) [for instance, methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2)] among agricultural fields. Biochar has been deemed a potential candidate for the reduction of GHGs in paddy fields. However, there is no consistent conclusion that biochar can simultaneously reduce emissions of CH4, N2O, and CO2. Herein, we proposed the FeN3-doped biochar (FG) as an excellent material for GHGs restriction in paddy fields via the first-principles calculation. The computation results indicated that the FG exhibited satisfactory adsorption ability for CH4, CO2, and N2O, which improved the adsorption energies to −1.37 , −1.54, and −2.91 eV, respectively. Moreover, the density of state (DOS) analyses revealed that the factor responsible for FeN3-doped biochar to exhibit excellent adsorption ability was the occurrence of drastic energy up- or down-shift of the electron for Fe d, C p, O p, or N p orbital upon adsorption of CH4, CO2, or N2O. Our study suggested an advanced modified biochar material for reducing the GHGs emissions in paddy fields, in addition to exploring the adsorption properties and mechanisms of FeN3-doped biochar for GHGs mitigation, which provided a strategy to explore biochar modification and efficient emission reduction materials. Article highlights: • FeN3-doped biochar was first proposed for GHGs mitigation in paddy fields. • FeN3-doped biochar exhibited excellent GHGs adsorption ability. • FeN3-doped biochar improved physico-chemical adsorption ability for GHGs. [ABSTRACT FROM AUTHOR]

The major greenhouse gases in streams and rivers, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), can contribute significantly to regional greenhouse gas (GHG) budgets, and each appears to be responding to multiple drivers. Recent work suggests that tropical water bodies may be hot spots of GHG emissions due to high primary productivity in their watersheds, but tropical streams and rivers have historically been underrepresented in studies of GHG concentration and emissions. We use a five-year record of weekly water chemistry and dissolved gas data from eight tropical watersheds of varying lithology and redox conditions in the Luquillo Mountains of Puerto Rico to examine controls on GHG variability and estimate gas flux. Streams were frequently supersaturated in all three gases indicating that streams in this tropical landscape are sources of GHGs to the atmosphere. Concentrations of CO2 and N2O were associated with lateral inputs from the surrounding landscape, whereas CH4 concentrations correlated with in-stream oxygen availability and lithology. Our results underscore the importance of including tropical sites in global syntheses and budgets and the role of both in-stream biological and physical processes as well as landscape attributes that contribute to the export of gases to the fluvial network and atmosphere. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are globally significant sources of greenhouse gases (GHGs) to the atmosphere. Previous work has indicated that GHG flux in headwater streams is dominated by terrestrially derived gases, with in situ production limited by short organic matter residence times and high dissolved oxygen concentrations due to turbulent reaeration. However, low‐gradient headwater streams that contain pool structures with longer residence times may be conducive to the in situ production of GHG. These streams, and the longitudinal heterogeneity therein, are seldom studied. We measured continuous ecosystem metabolism alongside concentrations and fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in a low‐gradient third order stream in the North Carolina Piedmont. From autumn to the following spring, we characterized spatial and temporal patterns of GHG along an 8 km segment in the context of channel geomorphology, hydrology, and ecosystem metabolic rates using linear mixed effects models. We found that stream metabolism was responsible for most of the CO2 flux over this period, and that in‐channel aerobic metabolism was a primary predictor of both CH4 and N2O fluxes as well. Long water residence times, limited reaeration, and substantial organic matter from terrestrial inputs foster conditions conducive to the in‐stream accumulation of CO2 and CH4 from microbial respiration. Streams like this one are common in landscapes with low topographic relief, making it likely that the high contribution of instream metabolism to GHG fluxes that we observed is a widespread yet understudied behavior of many small streams. Plain Language Summary: Stream ecosystems play a role in producing greenhouse gases (GHGs) and transporting them from groundwater to be released into the atmosphere. Some of these gases are produced through the breakdown of organic matter by microbes in the stream. We don't know how important this microbial production is compared to gases coming from soil and groundwater, but comparing it to rates of ecosystem metabolism may help us learn about it. We measured GHG and metabolism along a stream and found that metabolism is directly responsible for the production of carbon dioxide and is a good predictor of methane, meaning that microbial production in the stream is likely important. N2O production was limited by competition between microbes for nitrogen, as a result, the stream was removing N2O from the atmosphere rather than releasing it. Key Points: Patterns in carbon dioxide are almost entirely accounted for by instream metabolism except during a storm eventMethane is highly variable in space and covaries with aerobic respirationThe stream shifts from a source of nitrous oxide to a sink during peak autumn respiration, likely due to nitrogen limitation [ABSTRACT FROM AUTHOR]

An unpredictable rise in greenhouse gas (GHG) emissions is a primary concern to the global scientific community. It is directly related to the rapid expansion of the human population and associated with the immense energy demand. The combustion of hydrocarbon fuels in internal combustion (IC) engines releases a large amount of carbon dioxide (CO2), which is one of the causes of GHG emissions. Mitigation of CO2 emissions is a significant challenge to the world. Although several researchers have focused on capturing CO2 from power plants, some researchers have taken initiatives in recent times to capture CO2 in IC engines. This study particularly explored the possibility of using a biomass based‐adsorbent to capture CO2 in the exhaust of a diesel engine. Initially, activated carbon was obtained from palm shells by adopting the preparation methods such as (i) carbonization and (ii) chemical activation. Then, the produced activated carbon was analyzed to examine its physicochemical characteristics and surface textural properties by adopting characterization techniques. The adsorbent sample was loaded in an in‐house fabricated adsorption chamber which was attached to the exhaust of a single‐cylinder, four‐stroke, naturally aspirated, air‐cooled, direct injection (DI), constant speed diesel test engine. The performance of palm shell‐based activated carbon was evaluated as a potential adsorbent for CO2 capture when the engine was operated with two distinct fuels, (i) 100% diesel (D100) and (ii) an optimum biodiesel‐diesel blend (JME20) comprising 80% D100 and 20% Jatropha Methyl Ester (JME). The experimental results showed that an average of about 30% and 37% of CO2 was captured by using palm shell‐based adsorbent in D100 and JME 20 operations, respectively. [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]

This paper examines the relationship between the rate of time preference and strategic reactions in dealing with climate change caused byanthropogenic greenhouse gas (GHG) emissions. Treating climate change as stock externalities, the RICE model (Nordhaus and Yang [1996]) is employed in this paper for simulation studies. The simulation results show that when regions' rate of time preference in evaluating climate change is sufficiently low, the paths of efficient GHG emission reduction measurement and the inefficient Nash equilibrium outcome areclose. The paper also provides general interpretations of such phenomena. Finally, the implications of a low rate of time preference on GHG emission reduction policies are discussed. [ABSTRACT FROM AUTHOR]