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Mitigation of carbon dioxide (CO2) from various sources is a major challenge in the world today. Apart from attempts to control CO2 emissions from large CO2 emitting sources such as coal‐fired power plants and significant fossil fuel‐consuming industries, there have also been attempts made to control CO2 in internal combustion (IC) engines. Compression ignition (CI) engines find their applications mainly in automotive vehicles, decentralized power generation units, standby power requirements in hospitals and educational institutions. In recent years, there has been a great interest in developing eco‐friendly and low‐cost adsorbents for CO2 capture via the adsorption method. This investigation explores the possibility of using activated carbon obtained from coconut shell for capturing CO2 in a CI engine exhaust. Surface texture characteristics and physicochemical properties of the coconut shell‐based activated carbon are determined for their suitability as a potential adsorbent for CO2 adsorption. Furthermore, an attempt is made to combine a postcombustion carbon capture device in a CI engine. For this purpose, an in‐house fabricated adsorption chamber is packed with activated carbon and attached to a single‐cylinder, four‐stroke, naturally aspirated, direct injection (DI) diesel engine exhaust. The test engine is operated on two different fuels; (i) diesel (D100) and (ii) biodiesel‐diesel blend comprising 20% of Jatropha methyl ester (JME) and 80% of diesel (JME20). The engine performance and CO2 emission without and with the adsorption chamber are evaluated for D100 and JME20 operations. Further, the performance parameters of the adsorption chamber packed with activated carbon are also evaluated in both fuel operations. The results are analyzed, discussed, and presented in this paper. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Across Canada's boreal forest, disturbances from in situ oil sands mining, including well‐pads, significantly impact vast areas of the landscape. The creation of well‐pads requires removal of vegetation and placement of mineral fill, which essentially stops any carbon (C) sequestration on the once peatland ecosystem. It is important that, once no longer in use, these well‐pads are restored as long‐term C (peat) accumulation is what defines peatland ecosystem. However, little is known about the recovery of greenhouse gas exchange post‐restoration of these features. We studied a decommissioned well‐pad located in a treed poor fen that was restored using three soil adjustment treatments (SATs): (1) complete mineral fill removal (Peat‐Dec); (2) partial pad removal and burial under peat layer (BUPL); and (3) mixing mineral and peat by inversion (Mixed‐P‐M). The recreated peat surface was revegetated with donor peatland species using the moss layer transfer technique (MLTT). The objectives of this paper were to (1) quantify plot‐scale seasonal carbon dioxide (CO2) and methane (CH4) exchange of the SATs, 2–4 years post‐restoration compared to reference sites and (2) determine the influence of several environmental variables on CO2 and CH4 exchange. All SATs proved effective in recreating a soil surface needed to support peatland vegetation as shown by similar rates of net ecosystem exchange (NEE). Equally, both types of vegetation reintroduced led this site on a trajectory toward functioning as a net C sink. [ABSTRACT FROM AUTHOR]

There is increasing demand for superhydrophobic materials, which can be used for separating oil and water efficiently. To avoid secondary pollution, it is desirable to prepare such materials with green technology. Here, we present an environmentally benign method for fabricating superhydrophobic materials by using organic base based solvents in which cellulose can be dissolved and activated. The dissolved cellulose could be chemically modified with a silanization reagent, and the solvent could be recycled after CO2 was removed. The obtained cellulose nanocoating exhibited excellent hydrophobic effects. By spraying it on filter paper (water contact angle (WCA)=165°) for oil and water separation, the separation efficiency of more than 95 % was achieved; ultrasonication of an ordinary sponge in its dispersion (WCA=163°), meant it could be used as an oil absorber. It can also absorb a certain amount of bisphenol A (BPA), with the concentration decreasing by 66 % from the original concentration (0.1 m m). Besides the high separation efficiency, it is resistant to a wide range of pH solutions, which means that it could be used in harsh environments. More importantly, the process is cost-effective, the solvent can be recycled, and the whole process is green. Thus, the activation method provides a green route for the preparation of other cellulose-based materials. [ABSTRACT FROM AUTHOR]

The continued rise in anthropogenic carbon dioxide (CO2) emissions and increase in atmospheric CO2 concentration has led to calls from experts, including the Intergovernmental Panel on Climate Change that has estimated that global warming needs to be limited to 1.5 °C above preindustrial levels to avoid the worst effects of climate change, and that carbon neutrality would need to be achieved globally by 2050 to meet this target. Achieving carbon neutrality by mid‐century will rely on successful implementation and widespread adoption of technologies for reducing emissions from large point sources of CO2, direct CO2 capture from the air, as well as storage and utilization technologies that would convert CO2 to a form that would ensure safety and permanency of storage. In this paper, engineering solutions for CO2 capture, utilization, and storage are reviewed with a focus on technology readiness level, and cost. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

As part of the Integrated Midcontinent Stacked Carbon Storage Hub (IMSCS‐Hub) project led by Battelle Memorial Institute, a study was conducted to determine the feasibility of storing carbon dioxide (CO2) in the stacked saline rock formations of the Sleepy Hollow Field (SHF), located in Red Willow County, southern Nebraska. A series of CO2 injection simulation scenarios, with and without active reservoir management (ARM; brine extraction), were evaluated to investigate the feasibility of storing 50+ million tonnes (Mt) of CO2. The results indicated CO2 injection combined with ARM may enable permanent storage of 50+ Mt of CO2. The area of review (AOR), the area in which underground sources of drinking water (USDWs) might be endangered during CO2 injection, was assessed for the simulation scenarios. In comparison to a case without ARM, brine extraction resulted in a much smaller AOR, covering an area of 42 square miles (108.8 km2), roughly one‐fourth the size of an AOR resulting from CO2 injection without ARM. The findings presented in this paper indicate that CO2 injection with ARM can improve the CO2 storage capacity of a geologic storage complex up to 100% while also reduce the rate of pressure buildup in the subsurface, resulting in a 75% reduction in AOR. This may help in lowering carbon capture and storage project costs, risks, and effort needed to meet monitoring requirements for a storage project. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Scholars and practitioners acknowledge the benefits of organizations understanding their contribution to global warming and implementing carbon management strategies to address climate change concerns. A key element of a carbon management strategy is to reduce emissions, which requires an assessment of a firm's greenhouse gas emissions. For most organizations the indirect (scope 3) emissions represent the largest portion of their total carbon footprint. When facility-specific data are not available, firms are encouraged to use standard emission factors to calculate scope 3 emissions. This paper investigates how sampled Australian organizations assess their scope 3 emissions with respect to the emission factors they are using to convert activity data into units of carbon dioxide equivalent emission (CO2-e), and the implications for producing an accurate emission assessment. The research study found that, where conversion information was not available in a recognized government publication, the use of varying conversion value sources resulted in wide discrepancies in reported emissions for like activities. This undermines the assessment quality, makes comparison of results across organizations difficult and can lead to inappropriate carbon management strategy choices and misallocation of resources. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Understanding our place in the universe is important. If we are to make sense of our place, we have to examine this not only within the context of 'deep time', the geological history of our planet, but also within the role of other key organisms, specifically plants. Scientists present this history to the public, but we must be aware of the biases that can often be part of these representations, no matter how well intentioned or seemingly objective. Too often images are focused on animals, especially higher animals, and ignore other vital parts of our ecosystems. This has consequences for understanding Earth's history, and also how we treat organisms today. Summary 'Plant blindness' is a feature of our modern world, and of popular science narratives of the evolution of life. Plants are often overlooked and certainly poorly represented in the visual representations of past life on Earth (deep time). They tend to form the backdrop to the teeming activity of evolving animal life and are only mentioned (with appropriate images) at a few significant waypoints: the movement of life to land, the great coal‐forming forests of the Carboniferous period and the evolution of the flowering plants. While plant life is essential for animal life to thrive on land, chapter titles such as 'The invasion of land' and discussion thereof are still generally reserved for animals, and even then, the vertebrates. This paper explores the genesis of this approach to representing deep time as essentially a parade of animal life and shows that during the early period of popular scientific representation, plants were given their due place in some key publications by, for example, Franz Unger and Josef Kuwasseg in the 19th century and Zdenek Burian in the 20th century. Part of the problem appears to be the seemingly static nature of plants and the apparent demand for activity (often predation) that has its origins in science as spectacle, beginning with Henry de la Beche. [ABSTRACT FROM AUTHOR]

Carbon capture and storage (CCS) is an important low‐carbon management technology used to reduce CO2 emissions with the captured anthropogenic CO2 for enhanced oil recovery (EOR). This paper provides an overview and analysis of current issues related to CCS projects and CCS technologies. The paper also assesses risks and costs as well as policy, legal, and regulatory frameworks relevant for CCS and the major countries with CCS deployment. Currently, the few CCS projects in operation are mostly for EOR purposes. However, miscible CO2‐EOR in depleted oil and gas reservoirs appears to be the industry's first choice for CO2 sequestration and increasing oil production. Potential CO2 leakage is a major risk for pipelines and geological storage and a comprehensive monitoring program needs to be developed to ascertain its impact on pipeline material integrity, humans, and the environment. The cost of the CCS chain largely depends on the compression solvent for the synthesis gas or flue gas treatment for separation, heat rate, energy required for capture, capital costs of capture equipment, pipeline diameter, and flow capacity, and the homogeneity and permeability of the geological formations. An effective carbon pricing and cap‐and‐trade system as a part of national carbon policy is needed to achieve the goal of CCS. This paper finally discusses China's carbon capture utilization and storage (CCUS) systems and proposes a new CCUS‐LNG transportation process system for the coastal areas of China. Special attention was focused on CO2 transportation, CCUS‐EOR, and a new CCUS‐LNG process system for China. [ABSTRACT FROM AUTHOR]

The effects of a local dust storm on the upper atmosphere of Mars are researched through the observations of the lower and upper Martian atmosphere in the MGS (Mars Global Surveyor) radio occultation experiments. The ionosphere profiles in the high‐latitude region of northern hemisphere are thought to be under the influence of a local dust storm occurring in the low‐latitude areas during Ls 135–150°, Mars Year (MY) 27. A method to estimate the Martian upper neutral densities via the heights of ionospheric main peak is presented. Through the method, the 130‐km atmospheric neutral densities (or CO2 densities) of the area during the dust storm were calculated. MCD V4.3 (Mars Climate Database, Version 4.3) is used to derive the normal (or dust‐storm‐free) neutral densities of the same region and period. By analyzing the differences between the calculated densities and MCD (V4.3) simulated ones, the influence of the local dust storm on the upper atmosphere densities can be quantitatively derived. Based on the variation of the upper atmosphere densities, the behavior of regional ionospheric main peak under the dust storm can be simulated by a photochemical equilibrium model. The simulated ionosphere parameters are compared with the MGS‐observed ones, and it is found that two profile data sets are consistent with one another, thus indicating that the method employed to estimate the upper neutral densities is accurate. Plain Language Summary: The paper introduces the responses of the neutral atmosphere of Mars at 130 km to dust storms. The characters of the neutral atmosphere at this level are important for the missions to Mars with aerobraking, aerocapture, and landing. The dust storm occurs at surface of Mars has great influence on the neutral atmosphere. The study in this paper will help us understand the behaviors of the whole atmosphere of Mars during dust storms. Key Points: The effects of a local dust storm on the upper atmosphere and ionosphere of Mars was studied with MGS‐RS dataThe increase of the neutral atmospheric density at 130 km during the dust storm was derived quantitativelyThe electron density profiles during the storm were reproduced by a photo‐chemical equilibrium model based on the derived neutral density [ABSTRACT FROM AUTHOR]

The development of efficient non‐noble‐metal hydrogen evolution electrocatalysts in alkaline media is crucial for sustainable, ecofriendly production of H2 through water electrolysis. An alkaline hydrogen evolution reaction (HER) catalyst composed of Ni(OH)2‐decorated thungsten phosphide (WP) nanorod arrays on carbon paper was synthesized by thermal evaporation and electrodeposition. This hybrid catalyst displayed outstanding HER activity and required a low overpotential of only 77 mV to obtain a current density of 10 mA cm−2 and a Tafel slope of 71 mV dec−1. The hybrid catalyst also showed long‐term electrochemical stability, maintaining its activity for 18 h. This improved HER efficiency was attributed to the synergetic effect of WP and Ni(OH)2: Ni(OH)2 effectively lowers the energy barrier during water dissociation and also provides active sites for hydroxyl adsorption, whereas WP adsorbs hydrogen intermediates and efficiently produces H2 gas. This interfacial cooperation offers not only excellent HER catalytic activity but also new strategies for the fabrication of effective non‐noble‐metal‐based electrocatalysts in alkaline media. A non‐royal wedding! Ni(OH)2‐WP hybrids on carbon paper were prepared by thermal evaporation and electrodeposition. The non‐noble metal hydrogen evolution reaction catalyst displayed excellent catalytic activity and long‐term electrochemical stability. A low overpotential of only 77 mV was required to obtain a current density of 10 mA cm−2 and a Tafel slope of 71 mV dec−1. [ABSTRACT FROM AUTHOR]

The presence of calcium‐cemented ash beds serving as caprocks in hydrothermal systems calls for the examination of any chemo‐mechanical processes that may undermine or enhance their sealing capacity. Understanding these processes provides new information regarding how to model time‐dependent observations associated with seismicity and/or deformation in volcanic areas. In addition, since these ash beds are inherently similar to ash‐based concrete, a bridge of knowledge can be built across disciplines in the earth sciences and engineering. This paper investigates how the permeability of a volcanic ash cemented with hydrated lime changes upon exposure to carbon dioxide (CO2) in humid and hydrous conditions relevant to natural or human‐driven processes such as those found in hydrothermal settings or near wellbores used for secondary oil recovery, CO2 plume geothermal energy, or carbon storage. We characterized samples by their permeability during carbonation and subsequent changes in pore pressure and confining pressure. Products from the reaction of CO2 with the cemented ash matrix reduced permeability and entrapped fluids. The regions within samples permeated with unreacted CO2 were susceptible to fracturing upon rapid depressurization, but only when the effective stress state was sufficiently low. Altogether, the results indicate that lime‐cemented volcanic ash beds are particularly suited to act as flow barriers to CO2‐rich fluids. Plain Language Summary: This paper examines some of the physical characteristics of materials that are comprised of volcanic sediments and cemented together by a lime‐rich fluid. Such materials can be described as either concrete‐like rocks or rock‐like concretes; thus, they are of interest to geophysical and engineering communities (and their hybrids), especially in regard to natural or human‐made barriers for gases and fluids. A notable example of a gas that can be, or is desired to be, contained underground by rock formations and/or cemented structures is carbon dioxide (CO2). However, it is important to realize that some of the most relevant properties of a rock or concrete serving as a barrier may actually be evolving during exposure to CO2. Consequently, there is a need to understand the processes involved if we are to accurately predict the long‐term efficacy of these seals. We injected CO2 into samples of cemented volcanic ash and subsequently monitored the changes in their permeability while they chemically reacted. Our observations indicate that this particular material, when located at sufficient depth in the subsurface, can serve as a barrier to CO2‐rich fluid flow. Key Points: Carbonation products block gas flow through lime‐cemented volcanic ash, making permeability a time‐dependent, rock physical propertyCascading reaction rims of CaCO3 form upon repeated injection of CO2Rapid depressurization of CO2 gas enhances the permeability of cemented volcanic ash via fracturing when it occurs at low effective stress [ABSTRACT FROM AUTHOR]

Abstract: A significant amount of global carbon dioxide emissions is due to steel mill gases. One promising approach for the reduction of these emissions is their chemical conversion. In this regard, the conversion to urea is very advantageous, since common urea processes are already using carbon dioxide as a feedstock. In the present paper, urea capacities are determined that can be realized using steel mill gases. The capacities are estimated based on new process concepts that are presented in this paper. Exemplarily, the steel mill of thyssenkrupp Steel in Duisburg, Germany, is considered. It could be shown that reasonable urea capacities can be reached. By this means, a great impact can be made on the reduction of steel mill carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

In this paper, we present an optimization model for the management of the green area in order to find the optimal green surface to absorb CO2 emissions of industrialized cities. We obtain a minimization problem and the related variational inequality. We study the Lagrange theory to better understand the process that regulates the possible increase in green space. Then, we propose a computational procedure, based on the Euler method, to find the optimal solution to the variational inequality associated with our minimization problem and, finally, some numerical examples based on real scenarios. [ABSTRACT FROM AUTHOR]

Aquaculture becomes very popular in economic where aquatic organisms, like fishes and prawns, are mainly dependent on the quality of water in aquaculture pond. Also, the water quality constraints, which include turbidity, carbon dioxide, temperature, pH level, dissolved oxygen and phosphorus, are considered for achieving better performance. Hence, this paper presents an approach for aqua status prediction based on Deep Long Short‐Term Memory (Deep LSTM) classifier. The sensor nodes are placed in the aqua pond for measuring the parameters of water quality, and then the cell network transformation is done using the Voronoi partition. After that, the Cluster Head (CH) selection is carried out using Piecewise Fuzzy C‐means clustering (piFCM). Once the clusters are selected, the Chronological Harris Hawks (Chronological HH) optimization algorithm is introduced for optimal sink placement where the constraints for enabling the optimal sink placement are the distance and energy of the nodes. Finally, the aqua status is predicted using Deep LSTM. The performance of the Chronological HH‐based Deep LSTM is computed in terms of accuracy, energy and the number of dead nodes. The proposed Chronological HH‐based Deep LSTM outperformed other methods with maximal accuracy of 92.65%, maximal energy of 0.976 and the minimal dead nodes of 32. [ABSTRACT FROM AUTHOR]

Strains occur at shallow depths in response to pressure changes during well tests in an underlying aquifer, and recent developments in instrumentation have made it feasible to measure essentially the full strain tensor. Simulations using poroelastic analyses indicate that shallow normal strains are approximately proportional to the logarithm of time when a well is injecting into or pumping from a deep aquifer or reservoir. The drawdown is also a linear function of log time, as shown by the classic Cooper‐Jacob type‐curve analysis. The time when the semilog straight line intercepts the zero‐strain axis is similar to the time determined from the Cooper‐Jacob pressure analysis, and it can be used to estimate hydraulic diffusivity, suggesting that horizontal strain data can be used directly to estimate aquifer properties. This approach was validated using measurements from shallow (30‐m deep) borehole strainmeters during an injection test at a 530‐m‐deep sandstone aquifer/reservoir in Oklahoma. The results show intercept times for the shallow normal strain data are essentially the same as for deep pressure data from an equivalent radial distance. The slopes of the semilog plots of the pressure and the strain increase at the same time, suggesting that they both respond to a lateral aquifer boundary. Significantly, though, strain was measured at shallow depths while the pressure data were measured at 530‐m depth. This suggests that strain data from shallow depths could be an effective way to improve the characterization of an underlying aquifer. Plain Language Summary: Drilled wells are used to recover water, oil and gas, minerals, heat, and other valuable resources, and they are also used to dispose of carbon dioxide, sewage, and other unwanted wastes. Most tests to evaluate well performance involve measuring the pressure change in a monitoring boring that taps a permeable layer, such as an aquifer or reservoir. The pressure change is analyzed by fitting it to an appropriate mathematical analysis, called a "type curve." This is an effective approach, but monitoring borings can be expensive and they are almost always in short supply, so we are interested in evaluating alternatives. Dropping the pressure in an aquifer causes it to shrink by a tiny amount, and this in turn deforms the overlying rocks. We used high precision instruments called borehole strainmeters to measure the very small strains that occurred at shallow depths (30 m) when a well test was being conducted in a much deeper permeable sandstone at 530‐m depth. We also measured the pressure at three monitoring wells completed in the sandstone. Data from the tests show that the strain signal at shallow depths is similar to the pressure signal in the sandstone. Pressure measurements from the monitoring wells were analyzed using a type curve that is standard for the test that was conducted. We show in the paper that a similar type curve function can be used to analyze the strain signal and the results are similar to those from the pressure analysis. This finding is significant because it shows that strain measurements made at shallow depths can be analyzed using a straightforward approach to help characterize much deeper aquifers and reservoirs. This can reduce risk and cost, and improve the reliability of wells used recover resources or store wastes. Key Points: New method that uses strain measurements for interpreting well tests are suggestedStrain measured at shallow depths above the aquifer can be used instead of the pressure in the aquifer itself to estimate aquifer propertiesThe suggested method of strain measurements could lead to a new way for characterizing aquifers using pumping tests [ABSTRACT FROM AUTHOR]

The jet flow fields reported on in this paper were created by an unconventional gun head intended for polymer powder flame deposition. These flow fields are discussed in earlier papers by Payne et al. This paper reports on how the air or CO2 used in place of propane with this gun head mixed inertly with an isothermal coax­ial air jet. Flow visualization with a sheet of laser light described by Payne et al. showed that the jets, air or CO2, emanating from the propane nozzles were rapidly entrained in the coaxial air jet regardless of the presence or absence of a particle stream from the central nozzle. A gas analyzer measured the gas composition in the flow field downstream of the entrainment volume. The time-averaged CO2 concentration on the nominal centreline of the jet was constant or nearly so. In contrast, the variation in CO2 concentration increased dramatically with the radius at which the gas was sampled, up to a radius of ∼1.5 cm at a distance of 10 cm from the nozzle, after which this fluctuation decreased to 0 at the edges of the flow field. The magnitude of these fluctuations also decreased with the axial distance changing from 10 to 30 cm. Again, the presence or absence of a particle stream from the central jet nozzle had very little effect on the amount of CO2 measured. The irregular entrainment of CO2 caused the variations in the CO2 measured in the flow field. [ABSTRACT FROM AUTHOR]

Invited for this month′s cover is the Advanced Catalytic Materials Research Group of Prof. Zhongkui Zhao at Dalian University of Technology. The image shows an innovative capsule strategy with a core–shell structure containing different Cu‐based catalyst components for more efficient conversion of CO2 to methanol. The Full Paper itself is available at10.1002/cssc.201902485. [ABSTRACT FROM AUTHOR]

Solution‐based amine absorption technologies have been widely applied for CO2 capture, but they have several drawbacks. This paper reports on the synthesis of the first solid‐state amine adsorbent prepared through a simple plasma polymerization and deposition on physicochemically modified natural mordenite–clinoptilolite zeolite. The plasma deposition of amine polymer under certain conditions resulted in a significant increase in surface area‐weighted CO2 adsorption capacity as the natural zeolite. The strength of the interaction between CO2 and the adsorbent was weaker for the plasma polymer‐modified zeolite than without the plasma coating, which may facilitate regeneration. Both indications make the amine plasma polymer‐based zeolite adsorbent a good candidate for CO2 adsorption and separation. [ABSTRACT FROM AUTHOR]

Sunlight can oxidize dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) in freshwaters. The importance of complete photooxidation, or photomineralization, as a sink for DOC remains unclear in temperate rivers, as most estimates are restricted to lakes, high latitude rivers, and coastal river plumes. In this study, we construct a model representing over 75,000 river reaches in the Connecticut River Watershed (CRW), USA, to calculate spectrally resolved photomineralization. We test the hypothesis that photomineralization is a negligible DOC sink across all reaches and flow conditions relative to DOC fluxes. Our model quantifies reaction rates and transport drivers within the river reaches for the ranges of flow conditions, incoming solar irradiance, and canopy cover shading observed throughout the year. Our model predicts average daily areal photomineralization rates ranging from 1.16 mg‐C m−2 day−1 in low flow river reaches in the winter, to 18.33 mg‐C m−2 day−1 in high flow river reaches during the summer. Even for high photomineralization fluxes, corresponding photomineralization uptake velocities are typically at least an order of magnitude smaller than those reported for other instream processes. We calculate DOC elimination by photomineralization relative to DOC fluxes through individual stream reaches as well as the entire riverine portion of the CRW. We find that relative photomineralization fluxes are highest in summer drought conditions in low order streams. In median flows and mean light intensities, for an average watershed travel distance, 3%–5% of the DOC fluxes are eliminated, indicating that photomineralization is a minor DOC sink in temperate rivers. Plain Language Summary: Rivers are an important part of the carbon cycle, moving carbon compounds from land to the ocean. Within rivers, dissolved organic carbon molecules can be broken down into inorganic carbon molecules, including the greenhouse gas carbon dioxide. Sunlight shining into rivers can cause these organic molecules to break down in a process called photomineralization, but it is not clear if this process is important compared to the total amount of organic carbon that travels through rivers every day. In this paper, we build a model for the river sections of temperate Connecticut River Watershed, which calculates photomineralization for possible river flow conditions, dissolved organic carbon concentrations, and seasons, and compares the size of the sunlight‐driven breakdown of dissolved organic carbon to the amount of dissolved organic carbon in the river. This is the first model that puts photomineralization rates in the context of a flowing temperate river network. We show that compared with the dissolved organic carbon amounts present in the river at any time of the year or any flow conditions, photomineralization is essentially an unimportant process, removing on average 3%–5% of the dissolved organic carbon through an average watershed river route. Key Points: We build a model calculating reaction and transport drivers for photomineralization in 75,000 temperate river reachesPhotomineralization is a negligible dissolved organic carbon (DOC) sink relative to DOC fluxesDOC elimination by photomineralization in temperate rivers is limited by short water residence times and canopy cover [ABSTRACT FROM AUTHOR]

In this paper, it is reported the fabrication of a new dense ceramic‐molten carbonate membrane used for the selective separation of carbon dioxide (CO2) and oxygen (O2) at elevated temperatures (850‐950°C). First, it was chemically synthesized a fluorite/perovskite ceramic oxide with mixed ionic‐electronic conduction properties and general formula Ce0.9Pr0.1O2‐δ/Pr0.6Sr0.4Fe0.5Co0.5O3‐δ (CP‐PSFC, 60:40 wt%) by the citrate‐ethylene‐diamine‐tetra acetic acid (EDTA) route. Then, a disk‐shaped porous ceramic support partially sintered was infiltrated with a ternary mixture of molten salts of Li2CO3/Na2CO3/K2CO3 composition. The permeation measurements at high temperatures suggest a concurrent separation of both species CO2 and O2. The system exhibits high permeance of CO2 and O2 by rising to maximum values of 2.17 × 10−7 and 0.69 × 10−7 mol m−2 s−1 Pa−1, respectively at 950°C. Moreover, the possibility of modulating the permeate CO2:O2 ratio is envisaged by changing the fluorite to perovskite proportion in the membrane composition. The stability performance of the obtained membrane was studied under a long‐term permeation test. It exhibits a remarkable thermal and chemical stability during 110 h at 875°C. This way, it corroborated the proposed new ceramic phase's excellent properties for the fabrication of supported ceramic‐molten carbonate membranes. [ABSTRACT FROM AUTHOR]

Among thousands of known metal‐organic frameworks (MOFs), the University of Oslo's MOF (UiO‐66) exhibits unique structure topology, chemical and thermal stability, and intriguing tunable properties, that have gained incredible research interest. This paper summarizes the structural advancement of UiO‐66 and its role in CO2 capture, separation, and transformation into chemicals. The first part of the review summarizes the fast‐growing literature related to the CO2 capture reported by UiO‐66 during the past ten years. The second part provides an overview of various advancements in UiO‐66 membranes in CO2 purification. The third part describes the role of UiO‐66 and its composites as catalysts for CO2 conversion into useful products. Despite many achievements, significant challenges associated with UiO‐66 are addressed, and future perspectives are comprehensively presented to forecast how UiO‐66 might be used further for CO2 management. [ABSTRACT FROM AUTHOR]

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Corrugated package designers are focused on balancing the need for product protection, material use efficiency and the packaging material's impact on the environment in the supply chain. The purpose of this paper is to develop a conceptual sustainable packaging model that integrates the variables of technical design, supply chain systems and environmental factors and then use the model to identify to improve upon corrugated container design. A model was developed, from the extant literature, and a case study was performed on a corrugated container. This is believed to be a unique integrated model of most relevant agents related to the design and implementation of a corrugated box through a supply chain from design to potential post-consumer reuse. From this study, we found opportunities to improve the environmental design of the corrugated container through four ex ante design stages, and two ex post facto supply chain stages. Further, research can evaluate and refine this model via a 'live supply chain' for use in guiding corrugated box material selection design and reuse/recycling. Integration of the design criterion for a unit load in the supply chain creates opportunity to observe the packaging system holistically. Waste in the manufacturing process and CO2 emissions are traced along the material flow until the end of its useful life to provide an overall picture of the packaging system. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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In their Full Paper, L. R. Borges et al. proposed the easy preparation of materials containing controllable platinum species depending on the ceria materials' surface energy. EN ceria platinum species oxygen vacancies CO oxidation. Cover Feature: Towards the Effect of Pt0/Pt + and Ce3+ Species at the Surface of CeO2 Crystals: Understanding the Nature of the Interactions under CO Oxidation Conditions (5/2021). [Extracted from the article]

The design of catalysts with high activity, selectivity, and stability is key to the electroreduction of CO2. Herein, we report the synthesis of 3D hierarchical metal/polymer–carbon paper (M/polymer‐CP) electrodes by in situ electrosynthesis. The 3D polymer layer on CP (polymer‐CP) was first prepared by in situ electropolymerization, then a 3D metal layer was decorated on the polymer‐CP to produce the M/polymer‐CP electrode. Electrodes with different metals (e.g. Cu, Pd, Zn, Sn) and various polymers could be prepared by this method. The electrodes could efficiently reduce CO2 to desired products, such as C2H4, CO, and HCOOH, depending on the metal used. For example, C2H4 could be formed with a Faradaic efficiency of 59.4 % and a current density of 30.2 mA cm−2 by using a very stable Cu/PANI‐CP electrode in an H‐type cell. Control experiments and theoretical calculations showed that the 3D hierarchical structure of the metals and in situ formation of the electrodes are critical for the excellent performance. [ABSTRACT FROM AUTHOR]

Northern peatlands play an important role in the regulation of the atmospheric greenhouse gas (GHG) balance, functioning as a net carbon sink with low rates of organic decomposition. However, perturbations such as drainage increase peat oxidation, which may lead to enhanced gaseous release of carbon. For this reason, the number of restoration projects that aim to rewet blanket bogs has increased in the last few years, but there is still a lack of understanding of the impact of restoration on emissions of greenhouse gases, such as methane, particularly in sites restored from forestry. In this paper, we investigate the seasonal greenhouse gas dynamics in a forest‐to‐bog restoration site in Scotland. We analyse the effects of restoration on both carbon dioxide and methane fluxes, and investigate which site factors (microtopography, vegetation type, soil moisture and temperature) drive the processes of gaseous exchange between the bog surface and the atmosphere. Our results show that the original surface is near greenhouse gase equilibrium at −0.28 gCO2eq m2·day−1 and that microtopographic features act as a net greenhouse gas sink (ridges = −0.94 gCO2eq m2·day−1 and furrows = −0.86 gCO2eq m2·day−1), whereas the bog pool is a net source of greenhouse gases (0.98 gCO2eq m2·day−1). We found different vegetation species play a key role in greenhouse gas flux dynamics, especially in forestry‐derived microtopographical features, and their presence and influence on greenhouse gas dynamics should be accounted for to provide a more comprehensive understanding of emissions associated with restoration management practices. Highlights: GHG (CO2 and CH4) dynamics in a boreal peatland restored from forestry are mainly affected by microtopography and vegetation.Forestry‐derived microforms (ridges and furrows) are better GHG sinks than pools (GHG emitters) and original surfaces (near GHG equilibrium).The presence of Trichophorum cespitosum leads to higher CH4 emissions.Restoration practices like terraforming may create a short‐term pulse net GHG emission due to an increase of both CH4 and CO2 fluxes. [ABSTRACT FROM AUTHOR]

Deployment of bioenergy with CO2 capture and storage (BECCS) is projected to be crucial in reducing the United States' CO2 emissions intensity. In this paper, we utilize a spatially explicit costing model to evaluate how regional biophysical factors and geography affect BECCS viability. We find that the cost of biomass provision and CO2 transport and storage are an average of $20/t‐CO2 and $16/t‐CO2 for aquatic and terrestrial BECCS, respectively. Assuming rapid technological development in the CO2 capture domain, this corresponds to 40–72% of land area in the conterminous United States exhibiting systems integration costs compatible with 2030 carbon prices (median $90/t‐CO2). Results are strongly influenced by the cost of geologic sequestration, in particular storage quality (as driven by depth, permeability, etc.) and available capacity, rather than simply proximity to nearby CO2 sources. For this reason, the Southeast presents appealing BECCS readiness owing to high biomass productivity (several counties with yield >100 000 dry ton of biomass per year) interspersed with well‐explored sinks with large sequestration potential and optimal reservoir quality with permeability >500 mD. We also find that geologic storage capacity is unlikely to be a major biophysical constraint, as sink utilization in most states would likely remain below 10% at the projected rates of BECCS deployment to achieve the 2 °C target and as low as 1% in Texas, Oklahoma, and Alabama. The analysis also reveals subtle secondary outcomes; for example, to what extent different regions may be well poised to adopt different, complementary negative emissions technologies based on specific confluences of circumstances. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The topology and chemical functionality of metal–organic frameworks (MOFs) make them promising candidates for membrane gas separation; however, few meet the criteria for industrial applications, that is, selectivity of >30 for CO2/CH4 and CO2/N2. This paper reports on a dense CAU‐10‐H MOF membrane that is exceptionally CO2‐selective (ideal selectivity of 42 for CO2/N2 and 95 for CO2/CH4). The proposed membrane also achieves the highest CO2 permeability (approximately 500 Barrer) among existing pure MOF membranes with CO2/CH4 selectivity exceeding 30. State‐of‐the‐art atomistic simulations provide valuable insights into the outstanding separation performance of CAU‐10‐H at the molecular level. Adsorbent–adsorbate Coulombic interactions are identified as a crucial factor in the design of CO2‐selective MOF membranes. [ABSTRACT FROM AUTHOR]

The regeneration reaction characteristics of the K2CO3/Al2O3 sorbent were investigated with a thermogravimetric apparatus. The effects of the gas composition and temperature on the regeneration conversion and reaction rate were analysed extensively. The results of the thermogravimetric experiment revealed that the regeneration characteristics of K2CO3/Al2O3 are better than those of pure K2CO3 and that temperature is the key parameter for the K2CO3/Al2O3 regeneration process. It was also observed that the regeneration process of K2CO3/Al2O3 occurred in three stages. As the regeneration temperature increased, regeneration occurred in the following sequence: KHCO3 on the external surface, KHCO3 on the internal surface and KAl (CO3)2(OH)2. The activation energy (E, kJ/mol) and pre‐index factor (A, min−1) of the three stages were 69.7, 73.8 and 84.5 and 1.36 × 107, 1.86 × 107 and 2.74 × 106, respectively. The reaction kinetic parameters were calculated by the thermal analysis method. A comprehensive model based on the Avrami–Erofeev reaction mechanism model was proposed for the regeneration process of K2CO3/Al2O3. The model data and test values agreed well, thereby establishing the model's accuracy. This paper provides fundamental data for further study on the capture of carbon dioxide from flue gas using potassium‐based sorbents. [ABSTRACT FROM AUTHOR]

Changes in concentrations of greenhouse gases lead to changes in radiative fluxes throughout the atmosphere. The value of this change, the instantaneous radiative forcing, varies across climate models, due partly to differences in the distribution of clouds, humidity, and temperature across models and partly due to errors introduced by approximate treatments of radiative transfer. This paper describes an experiment within the Radiative Forcing Model Intercomparision Project that uses benchmark calculations made with line‐by‐line models to identify parameterization error in the representation of absorption and emission by greenhouse gases. Clear‐sky instantaneous forcing by greenhouse gases is computed using a set of 100 profiles, selected from a reanalysis of present‐day conditions, that represent the global annual mean forcing from preindustrial times to the present day with sampling errors of less than 0.01 W m−2. Six contributing line‐by‐line models agree in their estimate of this forcing to within 0.025 W m−2 while even recently developed parameterizations have typical errors 4 or more times larger, suggesting both that the samples reveal true differences among line‐by‐line models and that parameterization error will be readily identifiable. Agreement among line‐by‐line models is better in the longwave than in the shortwave where differing treatments of the water vapor continuum affect estimates of forcing by carbon dioxide and methane. The impacts of clouds on instantaneous radiative forcing are estimated from climate model simulations, and the adjustment due to stratospheric temperature changes estimated by assuming fixed dynamical heating. Adjustments are large only for ozone and for carbon dioxide, for which stratospheric cooling introduces modest nonlinearity. Key Points: Mean clear‐sky instantaneous radiative forcing by greenhouse gases is computed with six benchmark models using 100 atmospheric profilesSampling error is several times smaller than the level of disagreement among models, which is itself smaller than parameterization errorThe impacts of clouds and stratospheric adjustment are roughly estimated; adjustments are large only for carbon dioxide and ozone [ABSTRACT FROM AUTHOR]

The development of electrochemical CO2 conversion allows green carbon utilization. Formate and syngas are two typical products of electrochemical CO2 reduction, and the coproduction of these two products will maximize the energy efficiency of CO2 conversion. However, few works have successfully achieved the cogeneration of formate and syngas. This paper describes a novel strategy to maximize the efficiency of CO2 conversion through coproduction of formate and syngas on ultrasmall SnO2 nanodots (NDs) homogeneously anchored on carbon nanotubes (CNT#SnO2 NDs) electrodes. The CNT#SnO2 NDs not only decreased the adsorption energy of *OCHO but also reduced the adsorption energy difference of *COOH and *H. High energy efficiency toward formate and adjustable H2/CO ratio were obtained over a broad potential window with long‐term stability. In addition, CNT#SnO2 NDs and Ir foil were coupled together to construct an electrolyzer for electrochemical CO2 reduction reaction and oxygen evolution reaction (CO2ERR–OER), which also produced formate and syngas with 24 h stability. A promising approach is presented for the electrochemical CO2 conversion in fuel production. [ABSTRACT FROM AUTHOR]

Solid oxide electrolysis cell (SOEC) is a device that can efficiently convert excessive power of renewable energy, such as wind or solar energy into chemical energy. High temperature CO2 electrolysis based on solid oxide electrolysis cell has been proved as an effective method to produce sustainable fuels and reduce greenhouse emissions. The performance of cathodes as the place where the electrolysis reaction takes place for fuel gas affects the efficiency of SOEC, whereas traditional cathodes show relatively low catalytic activity towards CO2 electrolysis. In recent years, in addition to the optimization of traditional Ni‐based cathodes, the research on perovskite cathodes with better redox stability has been carried out rapidly. In this paper, the development of different cathodes of solid oxide electrolysis cell used for CO2 electrolysis is summarized, from the study of new materials with different doping ratios for CO2 electrolysis, to the microstructure optimization of electrode. It was found, that both durability and catalytic activity for the cathode materials could significantly improve the performance of single cells of SOEC. Finally, more prospects for future research work are put forward. [ABSTRACT FROM AUTHOR]

In this paper, we construct three kinds of hydrate replacement models: N2, CO2 and N2‐CO2. The molecular dynamics (MD) method is used to study the dynamic process of N2‐CO2 replacement for natural gas hydrate. The replacement efficiency of N2/CO2 is simulated, and the influence of gas replacement on the stability of the water cage is assessed. The results show that CH4 molecules in the driving hydrate are all enriched in the gas‐liquid interface or gas region. Compared with the replacement of methane hydrate with CO2, when N2‐CO2 mixed gas is used to replace methane hydrate, the diffusion rate of CO2 is increased by 2 times, and the replacement efficiency of hydrate is significantly improved. The radial distribution function and free energy calculation results show that although the barrier of the water cage is significantly reduced after replacement, the water molecules in the cage still have difficulty jumping over the free energy barrier compared with the thermal motion energy, so the water cage structure remains highly stable. [ABSTRACT FROM AUTHOR]

In this "Grand Challenges" paper, we review how the carbon isotopic composition of atmospheric CO2 has changed since the Industrial Revolution due to human activities and their influence on the natural carbon cycle, and we provide new estimates of possible future changes for a range of scenarios. Emissions of CO2 from fossil fuel combustion and land use change reduce the ratio of 13C/12C in atmospheric CO2 (δ13CO2). This is because 12C is preferentially assimilated during photosynthesis and δ13C in plant‐derived carbon in terrestrial ecosystems and fossil fuels is lower than atmospheric δ13CO2. Emissions of CO2 from fossil fuel combustion also reduce the ratio of 14C/C in atmospheric CO2 (Δ14CO2) because 14C is absent in million‐year‐old fossil fuels, which have been stored for much longer than the radioactive decay time of 14C. Atmospheric Δ14CO2 rapidly increased in the 1950s to 1960s because of 14C produced during nuclear bomb testing. The resulting trends in δ13C and Δ14C in atmospheric CO2 are influenced not only by these human emissions but also by natural carbon exchanges that mix carbon between the atmosphere and ocean and terrestrial ecosystems. This mixing caused Δ14CO2 to return toward preindustrial levels in the first few decades after the spike from nuclear testing. More recently, as the bomb 14C excess is now mostly well mixed with the decadally overturning carbon reservoirs, fossil fuel emissions have become the main factor driving further decreases in atmospheric Δ14CO2. For δ13CO2, in addition to exchanges between reservoirs, the extent to which 12C is preferentially assimilated during photosynthesis appears to have increased, slowing down the recent δ13CO2 trend slightly. A new compilation of ice core and flask δ13CO2 observations indicates that the decline in δ13CO2 since the preindustrial period is less than some prior estimates, which may have incorporated artifacts owing to offsets from different laboratories' measurements. Atmospheric observations of δ13CO2 have been used to investigate carbon fluxes and the functioning of plants, and they are used for comparison with δ13C in other materials such as tree rings. Atmospheric observations of Δ14CO2 have been used to quantify the rate of air‐sea gas exchange and ocean circulation, and the rate of net primary production and the turnover time of carbon in plant material and soils. Atmospheric observations of Δ14CO2 are also used for comparison with Δ14C in other materials in many fields such as archaeology, forensics, and physiology. Another major application is the assessment of regional emissions of CO2 from fossil fuel combustion using Δ14CO2 observations and models. In the future, δ13CO2 and Δ14CO2 will continue to change. The sign and magnitude of the changes are mainly determined by global fossil fuel emissions. We present here simulations of future δ13CO2 and Δ14CO2 for six scenarios based on the shared socioeconomic pathways (SSPs) from the 6th Coupled Model Intercomparison Project (CMIP6). Applications using atmospheric δ13CO2 and Δ14CO2 observations in carbon cycle science and many other fields will be affected by these future changes. We recommend an increased effort toward making coordinated measurements of δ13C and Δ14C across the Earth System and for further development of isotopic modeling and model‐data analysis tools. Key Points: Carbon isotopes, 14C and 13C, in atmospheric CO2 are changing in response to fossil fuel emissions and other human activitiesFuture simulations using different SSPs show continued changes in isotopic ratios that depend on fossil fuel emissions and, for 13C, BECCSApplications using atmospheric 14C and 13C in studies of the carbon cycle or other fields will be affected by future changes [ABSTRACT FROM AUTHOR]

Unique capabilities of various systems for studying the impacts of rising atmospheric CO2 concentration and other environmental factors on growth and yield of plants are presented. These systems include soil–plant–atmosphere research (SPAR) chambers, free‐air carbon dioxide enrichment (FACE) facilities, temperature‐gradient greenhouses (TGG), and open top chambers (OTC). The SPAR chambers have several advantages compared to FACE and other facilities, including: (a) constant CO2 concentration and stabile setpoints; (b) CO2 concentration controlled to any range of sub‐ambient through supra‐ambient levels, providing comparison of plant responses to past and future climates; (c) precise air and dewpoint temperature setpoints; (d) calculation of whole‐canopy photosynthesis and evapotranspiration rates at short time intervals; (e) calculation of whole‐canopy respiration rates during the night; (f) determination of plant responses to temperature alone or including other factors; (g) multiple chambers for simultaneous comparison of plant responses to varying environments, providing data for plant growth modeling; (h) low operating expense for CO2 concentration; and (i) capability of measuring N2 fixation rates in the rooting zone of legumes or methane emissions from rice (Oryza sativa L.). SPAR systems were better suited than FACE systems for more than half of the attributes of enrichment systems identified in this paper. Limitations of plant responses due to fluctuating elevated CO2 concentration and limitations of range of elevated CO2 concentration exist for FACE systems. Controlled environments are needed for developing mathematical growth response functions under a wide range of conditions. Finally, we identified a use of portable SPAR chambers within FACE experiments for confirmation of diminished plant photosynthesis in fluctuating CO2 concentration. [ABSTRACT FROM AUTHOR]

Nowadays, the assimilation of satellite observations, particularly radiances from infrared sounders, into numerical weather prediction (NWP) models plays a dominant role in improving weather forecasts. One of the keys to make optimal use of radiances is to simulate them with a radiative transfer model (RTM). At Météo‐France, the RTTOV RTM is used for NWP models. Currently, simulations are carried out taking into account single chemical profiles. However, neglecting the spatial and temporal variability of these gases can affect the accuracy of the simulations and thus the quality of the subsequent analyses and forecasts. To reduce the impact of this assumption on weather forecasts, we use a variational bias correction but it would be more appropriate to correct the bias directly at the source. Ozone is one of the atmospheric constituents with significant impacts on spectral radiances measured by hyperspectral infrared sounders. Thus, the objective of this paper is to replace the use of a single ozone profile with a realistic and variable ozone field in RTTOV for the simulation of infrared observation. The results show that the use of a variable ozone allows us to further reduce biases in simulation of ozone‐sensitive channels but also of channels sensitive mainly to other parameters such as CO2 for example. This has positive effects on the analyses and improves the fit of the short‐range forecasts (or analyses) to other observations such as radiosondes, microwave radiances, GNSS‐RO bending angles, etc. All of these positive impacts allow us to significantly improve weather forecasts. [ABSTRACT FROM AUTHOR]

In this paper, the heterogeneity of adsorption pores in middle and high rank coal samples were analyzed by using low temperature N2 and CO2 adsorption technology and fractal theory. The following results were achieved. 1) According to the results of volume and surface fractal dimension, meso‐pores can be classified into Mep‐1, Mep‐2, and Mep‐3, respectively. Micro‐pore can be classified into Mip‐1, Mip‐2, and Mip‐3, respectively. 2) Pore types play an important role in affecting the heterogeneity of meso‐pores. The volume heterogeneity (VHY) of Mep‐1 is simpler than that of Mep‐2 and Mep‐3 in type A samples. However, the VHY of Mep‐1 becomes gradually larger than that of Mep‐2 and Mep‐3 from type A to type B and C. The VHY of open pore in the same diameter is higher than that of semi‐open or closed pore. Meanwhile, the surface heterogeneity (SHY) of types A and B samples is significantly larger than that of type C, the SHY of semi‐open or closed pores is more complicated than that of open pores. 3) Coal rank mainly affects the heterogeneity of micro‐pores. The heterogeneity of type A is always smaller than that of type B and C. The VHY of Mip‐1 is more complicated than that of Mip‐2 and Mip‐3 in the same samples, and the sensitivity of the VHY of Mip‐1 and Mip‐2 to the degree of coal rank is smaller than that of Mip‐3. Meanwhile, the SHY of Mip‐1 and Mip‐2 is simpler than that of Mip‐3 in the same sample, the SHY of micro‐pores remains stable as the pore size decreases, and the affect of coalification level on SHY decreases with the decrease in pore diameter. Full‐scale fractal characterization has enabled quantitative characterization of adsorption pore properties and provided useful information with regards to the similarity of pore features in different coal reservoirs. [ABSTRACT FROM AUTHOR]

The traditional capillary radiant air conditioning system based on back propagation (BP) neural network optimization model of carbon dioxide refrigerant filling, using neural network algorithm to optimize the carbon dioxide refrigerant filling, there is a big error. Aiming at this problem, a carbon dioxide refrigerant charging and filling optimization model in capillary radiant air conditioning system based on genetic algorithm (GA) is constructed. Based on the idea of solving multiobjective optimization problem with genetic algorithm, an adiabatic capillary steady‐state distribution model is constructed to analyze the change of refrigerant flow rate and critical temperature in capillary tube. Corresponding data samples, the GA‐BP neural network model is calculated based on the sample data, and the optimization of carbon dioxide refrigerant filling capacity is realized through the interpolation and extrapolation test model of condenser heat transfer and refrigerant outlet temperature. The experimental results show that the model has a significant application in optimizing the charging capacity of carbon dioxide refrigerant. The error of optimizing the charging capacity of carbon dioxide is small, and the error range is between (−0.03, 0.03). [ABSTRACT FROM AUTHOR]

Computational requirements often impose limitations on the spatial and temporal resolutions of atmospheric CO2 inversions, increasing aggregation and representation errors. This study enables higher spatial and temporal resolution inversions with spatial and temporal error structures similar to those used in other published inversions by representing the prior flux error covariances as a Kronecker product of spatial and temporal covariances and by using spectral methods for the spatial correlations. Compared to existing inversion systems that are forced to degrade the resolution of the problem in order to bring the dimensionality down to computationally tractable levels, this inversion framework is able to take advantage of mesoscale transport simulations and more of the complexity of spatial and temporal covariances in the surface CO2 fluxes. This approach was successfully implemented over one month with an identical‐twin observing system simulation experiment (OSSE) using a set of assumptions about the prior flux uncertainties compatible both with continental‐scale uncertainty estimates and with comparisons of vegetation models to flux towers. The demonstration illustrates the potential of the newly developed inversion system to use high‐temporal‐resolution information from the North American tower network, to extract high‐resolution information about CO2 fluxes that is inaccessible to coarser resolution inversion systems, and to simultaneously optimize an ensemble of prior estimates. This demonstration sets the stage for regional flux inversions that can take full advantage of the high‐resolution data available in tower CO2 records and mesoscale atmospheric transport reanalyses, include more realistic prior error structures, and explore specifying prior fluxes with ensembles. Plain Language Summary: This paper describes a new inverse framework for deriving surface carbon dioxide (CO2) fluxes at high spatial and temporal resolutions from atmospheric mole fraction measurements. We demonstrate the potential of the system over North America by inverting for subdaily biogenic CO2 fluxes while accounting for the complexity of spatio‐temporal structures in flux error covariances in a data‐based manner. Key Points: A new inversion system uses spectral methods for spatial correlations to do a 27 km subdaily inversion over North AmericaThe software package allows simultaneous optimization of multiple prior mean flux estimatesThe system is demonstrated over continental North America for a network of seven towers [ABSTRACT FROM AUTHOR]

In this study, copper nanoparticles are supported on porous carbon papers by airbrushing; they are then coupled with a Nafion 117 membrane to form working electrodes for the continuous production of methane through gas-phase electroreduction of CO2 in a filter-press electrochemical cell. The methane production and Faradaic efficiency (FE) are evaluated and compared at different applied voltages (from −1.8 to −2.4 V vs. Ag/AgCl) and catalyst loadings (0.25, 0.5, 1, and 1.5 mg cm−2). The maximum methane production rate is achieved at −2 V and 0.5 mg cm−2 (4.4 μmol m−2 s−1) whereas the highest Faradaic efficiencies can be obtained at 1 mg cm−2 ( FE=10.1 %) and at −1.8 V ( FE=12.1 %). The role of the porous carbon support and the possibility of humidifying the CO2 stream before it enters the cell are also tested. These results may provide a new understanding of the use of gas-liquid electrochemical membrane reactors for the direct conversion of CO2 in the gas phase. [ABSTRACT FROM AUTHOR]

A process development unit (PDU) for amine-based post-combustion carbon capture located at Clean Coal Technologies Centre in Zabrze, Poland, was used to validate split-stream configuration. A PDU having capacity up to 100 m³n /h was designed to test the amine scrubbing carbon capture process from flue gases or mixtures of technical gases. Flexible process flow sheet of the unit allowed investigation of the split flow process. The split-flow flowsheet modification was compared with a standard system for chemical absorption-based CO2 capture. The tests were conducted using well-accepted baseline solvent: 30 wt% aqueous monoethanolamine solution. The flow sheet modification resulted in a decrease of reboiler heat duty by ~1.6% and an increase in CO2 recovery by ~1.2 p.p. Split-flow process modification was examined together with standard process flow sheet, and vast number of process parameters recorded during the trials have been presented. The explanation of beneficial effects of split-flow designs have been shown together with detailed analysis of experimental trials carried out using PDU for amine-based post-combustion carbon capture. This paper is also a valuable source of experimental data useful during validation of models. [ABSTRACT FROM AUTHOR]

Estimates of the marginal value of carbon dioxide-the social cost of carbon (SCC)-were recently adopted by both the U.S. and U.K. Governments in order to satisfy requirements to value estimated greenhouse gas (GHG) changes of new federal regulations. However, the development and use of SCC estimates comes with significant challenges and controversial decisions. This paper summarizes the key issues and then derives guidance for developing, selecting, and applying the estimates that follows from the fundamental scientific nature and economic principles associated with GHGs and climate change, as well as an understanding of the state of the art for estimating the SCC. The paper evaluates recent estimates in light of the guidance and finds the estimates inconsistent with the guidance in a number of significant areas. The paper also differentiates SCC policy applications in terms of policies with incremental versus nonincremental implications for global GHGs, and identifies serious issues for application of the SCC in setting and evaluating climate policy targets. WIREs Clim Change 2012, 3:163-195. doi: 10.1002/wcc.163 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

In this paper, three fuzzy nonlinear mathematical models, corresponding to crisp models described in Devi and Gupta (2018), are formulated to study the comparative behavior of carbon dioxide concerning vegetation biomass in crisp and fuzzy environments. Logistic growth and regrowth of vegetation biomass are considered in the first two models, and delay is incorporated in the regrowth of vegetation biomass in the third one. Conditions for boundedness and persistence of the solutions, the existence of equilibrium points, and the stability of equilibrium points are carried out for each model. We also derived the formula for the critical value of time delay. Further, we also analyzed the existence, stability, and direction of the Hopf bifurcation. Numerical simulations were performed to complement analytical findings and to see the comparison between crisp and fuzzy environments. In fuzzy environment, it is observed that increment in the minimum value of regrowth rate shifts the destabilizing value of delay forward while if the maximum value of regrowth rate decreases, variables will become unstable before the estimated time. The overall analysis demonstrates that the behavior of the models in crisp and fuzzy environments is quite different. Recommendations for resource managersAn increasing level of CO2 is the major factor for greenhouse effect, therefore to reduce the destructive effects of global warming, implementation of policies related to mitigation of the atmospheric CO2 is of paramount importance.Vegetation biomass has considerable regrowth rate as compared with the rest of the plants. But, there is some time lag in the process of regrowth, therefore for the growth rate of vegetation biomass regrowth with delay must be considered to avoid the fluctuations in the results.In the real world, the biological parameters are not always fixed because they vary according to the environment. So, scientists should consider fuzzy parameters for more precise results. [ABSTRACT FROM AUTHOR]

The penetration depth of broad spectrum solar irradiation over the wavelength range 300–1,100 nm has been experimentally measured for water and carbon dioxide ices of different grain size ranges. Both of these ice compositions are found on the surface of Mars and have been observed as surface frosts, snow deposits, and ice sheets. The e‐folding scale of snow and slab ice has been previously measured, but understanding the behavior between these end‐member states is important for modeling the thermal behavior and surface processes associated with ice deposits on Mars, such as grain growth and slab formation via sintering, and carbon dioxide jetting leading to the formation of araneiforms. We find the penetration depth increases in a predictable way with grain size, and an empirical model is given to fit these data, varying with both ice composition and grain size. Plain Language Summary: Most water on Mars exists as ice, both on the polar caps and in the subsurface (like permafrost on Earth). Temperatures fall low enough for carbon dioxide to also freeze. Carbon dioxide is the main constituent of Mars' seasonal polar caps. During spring, the increased sunlight results in warming within and sometimes below the ice, resulting in a "Solid‐State Greenhouse Effect." This internal heating can cause the ice sheets to break up. Understanding this process requires quantifying the amount of sunlight transmitted through samples of water and carbon dioxide ice. In this paper, we have combined new and previous measurements to achieve an empirical model that predicts the penetration depth of sunlight as a function of the grain size and ice composition. This model may be used to aid the understanding of unusual ice‐related features observed on the surface of Mars. Key Points: The penetration depth of broad spectrum solar irradiation is greater in carbon dioxide ice than in water icePenetration depth varies with grain size in a predictable manner, which has been modeledThe difference in penetration depth between water and carbon dioxide ices increases with grain size [ABSTRACT FROM AUTHOR]

This paper presents a systematic comparison study of the surface redox reaction mechanism for reverse water‐gas shift (RWGS) over Ni(111) and Ni(311) surfaces. Specifically, the most stable surface intermediates and the reaction kinetics involved in the direct CO2 activation and water formation steps are computed with density functional theory calculations and compared for the two different Ni surfaces. The results show that CO2, CO, O, H, OH, and H2O species adsorb stronger on Ni(311) than on Ni(111). Compared to Ni(111), the overall barriers for direct CO2 activation and water formation on Ni(311) are lower by 23 and 17 kJ/mol, respectively. These observations indicate that the RWGS reaction through the surface redox mechanism should be preferred on Ni(311). [ABSTRACT FROM AUTHOR]

Increasing atmospheric carbon dioxide (CO2) is the main factor of global warming. Carbon satellites have proven that CO2 concentrations have nonuniform spatio‐temporal distributions. The relationship between unevenly distributed CO2 and global surface air temperature (SAT) is seldom known. The success of complex networks provides an opportunity to address this issue. This paper proposes a multilayer climate network approach to identify the impacts of nonuniform CO2 on SAT. The results show that the probability density function (PDF) of degrees, weighted degrees, and link lengths follows power‐law distributions. A large fraction of strong correlation links resides in proximal distance (smaller than 2,000 km), indicating that CO2 nodes are strongly connected to the surrounding SAT nodes. The enhanced distributions of large positive weights, time delays, and degree patterns are all consistent with the properties of Rossby waves. This framework can be useful for predicting future climate changes and policy‐making for carbon reduction. Plain Language Summary: Carbon dioxide (CO2) is a prominent anthropogenic greenhouse gas in the atmosphere, and the increasing CO2 is the main reason for global climate warming. The CO2 concentration from satellites has revealed that the spatial distribution of CO2 is uneven. In previous studies, the relationship between CO2 and temperature is based on global CO2 concentration mean assumptions. Here, we propose a multilayer climate network approach to identify their relations using satellite data. We find that the PDF of degrees, weighted degrees, and link lengths follows power‐law distributions. The most dominant links, with a geographical distance larger than 2,000 km, are found for distances of 7,000 km, coinciding with the wavelengths of atmospheric Rossby waves. The time delays associated with these distances are in agreement with the group velocity of the atmospheric Rossby waves. Moreover, the pronounced band over 50°S, the dominance in the Southern Hemisphere relative to the Northern Hemisphere, and the similar patterns to transient heat flux are consistent with the properties of Rossby waves. The proposed approach leads to a better understanding of the role played by CO2 in forcing global temperatures and future climate change. Key Points: There are short‐term correlations between global mid‐troposphere CO2 concentrations and global surface air temperatureThe degrees, weighted degrees, and link lengths of CO2 and SAT multilayer climate network are conformed to power‐law distributionsSignificant correlation links of the constructed climate network yield a clear association with Rossby waves [ABSTRACT FROM AUTHOR]

Foresight is 2020: ChemSusChem Editors David Smith and Halgard Staesche introduce Volume 13 of the journal, look back on some of the major events in 2019 at the journal and in sustainable chemistry as a whole, and look forward to some of the exciting developments that 2020 has in store. [ABSTRACT FROM AUTHOR]

Manufacturing output, employment, and resource use were entirely missing from the Millennium Development Goals but now play a central role in the newly formulated Sustainable Development Goals (SDGs). In this paper, we analyze the quality of databases for assessing progress by Sub‐Saharan African countries towards meeting industry‐related SDG targets. We find data quality issues least severe for two out of the five conventional economic indicators but extremely severe for the other three economic indicators, moderately severe for the one employment indicator, and extremely severe for the six environmental indicators except for energy consumption and carbon dioxide emissions. We also assess the feasibility of meeting conventional economic, employment, and energy targets by the year 2030 and find that they are overly optimistic for most countries. We propose setting additional and more realistic targets based on past country performance. [ABSTRACT FROM AUTHOR]

This special issue reports the latest results on long‐term variations and trends in the middle and upper atmosphere, in particular, in the mesosphere and thermosphere. The issue is based on selected papers from the 10th IAGA/ICMA/SCOSTEP workshop on Long‐term changes and trends in the atmosphere, held in Hefei, China, 14–18 May 2018. This introduction highlights recent progress in key science areas of long‐term changes in the upper atmosphere. Key Points: Long‐term change in the middle and upper atmosphere is caused by increasing carbon dioxide and ozone changeLong‐term decrease in thermosphere density increases risks of space trafficThis introduction highlights of recent progress on long‐term changes in the middle and upper atmosphere [ABSTRACT FROM AUTHOR]