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Lime mud, a kind of industrial waste that produced in paper mill, was proposed as CO2 sorbent in calcium looping process. The carbonation performance of the lime mud was investigated in a dual‐fixed bed reactor (DFR) and a thermogravimetric analyzer (TGA). The carbonation kinetics of the lime mud in the chemical reaction controlled stage was analyzed by a surface reaction‐controlled kinetic model. The results show that the lime mud presents much poorer carbonation performance during the chemical reaction controlled stage compared with the limestone, mainly due to the high content of chlorine in the lime mud. A prewash treatment process was used to decrease the chlorine content to mitigate the sintering of the lime mud when calcined at high temperature. After prewash treatment, the prewashed lime mud shows much higher CO2 capture capacity during the chemical reaction controlled stage compared with the lime mud. A prolonged carbonation process successfully further enhances the microstructure and improves the carbonation performance of the prewashed lime mud in the chemical reaction controlled stage. The lime mud can be effectively used as CO2 sorbent in calcium looping process after prewash treatment and the following prolonged carbonation treatment. [ABSTRACT FROM AUTHOR]

Microbial electrosynthesis (MES) constitutes a bioelectrochemical process where bacteria uptake electrons extracellularly from a polarized electrode to incorporate them into their anabolic metabolism. However, the efficiency of current MES reactor designs can be lower than expected due to limitations regarding electron transfer and mass transport. One of the most promising bioreactor configurations to overcome these bottlenecks is the Microbial Electrochemical Fluidized Bed Reactor (ME-FBR). In this study, microbial CO 2 fixation is investigated for the first time in a ME-FBR operated as a 3-phase reactor (solid-liquid-gas). An electroconductive carbon bed, acting as a working electrode, was fluidized with gas and polarized at different potentials (-0.6, -0.8 and -1 V vs. Ag/AgCl) so it could act as an electron donor (biocathode). Under these potentials, CO 2 fixation and electron transfer were evaluated. Autotrophic electroactive microorganisms from anaerobic wastewater were enriched in a ME-FBR in the presence of 2-bromoethanosulfonic acid (BES) to inhibit the growth of methanogens. Cyclic voltammetry analysis revealed interaction between the microorganisms and the cathode. Furthermore, volatile fatty acids like propionate, formate and acetate were detected in the culture supernatant. Acetate production had a maximum rate of ca. 1 g L -1  day -1 . Planktonic cell biomass was produced under continuous culture at values as high as ca. 0.7 g L -1 dry weight. Overall, this study demonstrates the feasibility of employing a fluidized electrode with gaseous substrates and electricity as the energy source for generating biomass and carboxylic acids., (© 2023 The Authors. Microbial Biotechnology published by Applied Microbiology International and John Wiley & Sons Ltd.)

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The article focuses on plastic is ubiquitous in people's lives, when plastic-containing items have fulfilled their missions, only a small amount is recycled into new products, which are often of lower quality, compared with the original material. Topics include the waste into high-value chemicals requires substantial energy, the researchers have combined a ruthenium-carbon catalyst, and the lower-energy reaction conditions to convert plastics used in bottles and other packaging into fuels.

We present a cost model for implementing a deployment scale effort for conducting ocean iron fertilization (OIF) for marine‐based carbon dioxide removal (CDR). The model incorporates basic oceanographic parameters critical for estimating the effective export of newly fixed CO2 into biomass that is stimulated by Fe addition to an Fe‐limited region of the Southern Ocean. Estimated costs can vary by nearly 100‐fold between best‐case and worst‐case scenarios, with best‐case values of $7/net tonne C captured versus worst‐case $1,500/net tonne C captured, without accounting for verification costs. Primary oceanographic factors that influence cost are the net primary productivity increases achieved via OIF, the amount of C exported into the deep ocean, and the amount of CO2 ventilated back to the atmosphere. The model compares ship‐based versus aerial delivery of Fe to the ocean, and estimates aerial delivery can be 30%–40% more cost effective; however, the specific requirements for aerial delivery require additional research and development. The model also estimates costs associated with verification and environmental monitoring of OIF. These costs increase $/net tonne C captured by 3–4‐fold. Best, intermediate, and worst cases for aerial delivery and ship delivery are $21, $83, $2,033, and $24, $94, $4,691, respectively, inclusive of verification costs. The primary goal of this model is to demonstrate the variability in cost of OIF as a CDR method, and to better understand where additional research is needed to determine the major factors that may make OIF a tractable, nature‐based CDR method. Plain Language Summary: This paper presents a basic cost model for undertaking ocean iron fertilization (OIF) as a means of removing carbon dioxide from the atmosphere. It presents a simple application scenario that compares two different modes for delivering iron to the ocean, plane‐based and ship‐based, and estimates costs associated with verification of carbon export into the deep ocean, as well as assessing the environmental changes that may occur as result. Key findings are that, in terms of USD/tonnes carbon exported, OIF can be at the lower cost end (

The ability of satellite instruments to accurately observe long‐term changes in atmospheric temperature depends on many factors including the absolute accuracy of the measurement, the stability of the calibration of the instrument, the stability of the satellite orbit, and the stability of the numerical algorithm that produces the temperature data. We present an example of algorithm instability recently discovered in the temperature data set from the SABER instrument on the NASA TIMED satellite. The instability resulted in derived temperatures that were substantially colder than anticipated from mid‐December 2019 to mid‐2022. This algorithm‐induced change in temperature over 1 to 2 years corresponded to the expected temperature change over several decades from increasing anthropogenic CO2. This paper highlights the importance of algorithm stability in developing Geospace Data Records (GDRs) for Earth's mesosphere and lower thermosphere. A corrected version (Version 2.08) of the temperatures from SABER is described. Plain Language Summary: Instruments on Earth orbiting satellites offer the opportunity to detect long‐term changes in atmospheric temperature. Many factors may affect the ability to identify actual long‐term changes in the temperature and to distinguish these from changes in the instrument or from unintended changes in the algorithm that produces the temperature data from the instrument observations. SABER is an instrument on a NASA satellite that has been observing temperatures from 15 to 110 km (10–68 miles) in altitude for over 20 years. An "instability" in the scientific algorithm used to derive temperature from the instrument observations was recently discovered, beginning in late 2019. An unintended change was made in a parameter central to the derivation of temperature from SABER measurements. The consequence was that the atmospheric temperatures between 85 and 110 km (51–68 miles) from 2020 onward were several degrees colder than they would have been without the unintended change. This has been corrected and an updated version of the SABER temperatures and all other SABER data products, called Version 2.08, is now publicly available. Key Points: The concept of Geospace Data Records (GDRs) and their relevance to accurate detection of long‐term change is introducedAlgorithm instability in a GDR of the 20‐year record of SABER temperatures between 85 and 110 km is described and correctedThe field of Geospace Climate is emerging as a frontier with scientific and economic relevance. Accurate GDRs are essential to both [ABSTRACT FROM AUTHOR]

The ability of global transport models to go up in resolution becomes discriminating for greenhouse gas atmospheric inversions. This paper describes the porting on Graphics Processing Units of the global transport model currently used in the European operational Copernicus Atmosphere Monitoring Service (CAMS) for CO2 and N2O inversions. It represents an important milestone to achieve sub‐degree resolution. The code includes not only the direct model but also its tangent‐linear and its adjoint versions which are needed in variational inversions. Tests were carried out for CO2 at a resolution of 2.50° in longitude, 1.27° in latitude and 79 layers in the vertical, corresponding to 1,626,768 3D cells, 4.5 times more than the current standard resolution of the model used in the CAMS reanalyzes. A month's worth of computation of the tangent‐linear and of the adjoint versions now takes 2.5 min, including 50 s for reading meteorological data. Plain Language Summary: Atmospheric transport models are intensively used to infer global greenhouse gas emissions and removals, from atmospheric measurements: a single global analysis involves repeated and long transport simulations. This intensive use has limited the spatial resolution of such analyses despite an increasing need for national greenhouse gas budgets, despite an increasing number of corresponding space‐based observations at kilometer resolution, and despite an increasing number of high‐quality surface measurements made in sites marked by strong local influences. For the global transport model currently used in the European operational atmosphere monitoring service, our objective within the next 5 years is to make it reach a resolution of about 50 km over the whole globe. This paper describes an important milestone in this direction with the porting of this transport model on hardware components initially developed for video display but now used for high performance computing. Tests were carried out at a resolution of 2.50° in longitude, 1.27° in latitude and 79 layers in the vertical, corresponding to 4.5 times more 3D cells than the current standard resolution of the model. The direct model itself now takes less time than reading the input meteorological data. Key Points: The workload in a Eulerian transport model on a longitude‐latitude grid can be embarrassingly parallel enough to run efficiently on a Graphics Processing UnitThe transport model of the Laboratoire de Météorologie Dynamique was run in a new grid of 1,626,768 3D cellsThe calculation time in the direct version of the model is now less than the time to read the input meteorological data [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) is the third important long‐lived greenhouse gas next to carbon dioxide and methane and croplands are considered biogeochemical hotspots of soil N2O emissions. To reduce soil N2O and other greenhouse emissions, climate‐smart agricultural practices including biochar application have been applied. Many studies have been conducted with biochar application but results from these studies are not conclusive. To address this issue, meta‐analysis, a quantitative review that synthesizes results from multiple independent studies, has been widely used. The results from different meta‐analyses also differ but are seldomly evaluated. In this study, we evaluated meta‐analyses on the effects of biochar application on soil N2O emissions. A grand mean response ratio (RR) was further proposed to estimate an overall effect and the impacts of experiment setting, properties of biochar and soil, and agricultural practices. We found 18 meta‐analysis papers were published between 2014 and 2022. Sample size (publications or experiments) varied from less than 30 to more than 1000, with a mean sample size of 275. RR was calculated in all studies except one. While four meta‐analyses did not find a significant effect of biochar application on soil N2O emissions, all others reported reductions of soil N2O emissions, but the magnitude ranged from −10.5% to −54.8%. Synthesizing all results from these meta‐analyses, we found that biochar application overall significantly reduced the soil N2O emissions by 38.8%. The impacts increased with experimental duration till one and half years and reduced after that. Biochar application rate and C:N ratio had large influence on the effects of biochar application on soil N2O emissions. This study demonstrated that while meta‐analysis provides a more comprehensive and better estimation, the inconsistence among these studies may need to be further evaluated. A grand mean RR based on meta‐analyses could be more accurate and representative than single meta‐analysis. [ABSTRACT FROM AUTHOR]

Broadband (spectrally‐integrated) radiation calculations are dominated by the expense of spectral integration, and many applications require fast parameterizations for computing radiative flux. Here we describe a novel approach using a linear weighted sum of monochromatic calculations at a small set of optimally‐chosen frequencies. The empirically‐optimized quadrature method is used to compute atmospheric boundary fluxes, net flux profiles throughout the atmosphere, heating rate profiles, and top‐of‐the‐atmosphere forcing by CO2, in the longwave for clear skies. We evaluate the method against two modern correlated k‐distribution models and find that we can achieve comparable errors with 32 spectral points. We also examine the effect of minimizing different cost functions, and find that in order to accurately represent heating rates and CO2 forcing, these quantities must be included in the cost function. Plain Language Summary: Quantifying the way radiation flows through the atmosphere is computationally expensive, and most applications require fast approximation. In this paper, we develop an empirically‐optimized quadrature method that can compute quantities of interest in climate science and weather prediction such as radiative flux throughout the atmosphere, heating rates, and forcing by carbon dioxide. The method uses a simple optimization algorithm, combined with a linear model, to achieve accuracy and computational cost of similar order of magnitude to the modern correlated k‐distribution models. Depending on the focus of the application, the algorithm can easily be adapted to prioritize desired quantities. Key Points: Spectrally integrated radiative quantities can be estimated from a small weighted set of monochromatic calculationsTradeoffs between computational cost and accuracy are commensurate with correlated k‐distribution modelsOptimization priorities can be tailored to a specific applications [ABSTRACT FROM AUTHOR]

Adsorption‐based carbon capture has been recognized as an attractive method for mitigating global warming. Metal–organic frameworks (MOFs) are promising candidate adsorbents for this purpose due to their high adsorption uptake and selectivity for carbon dioxide. However, in real‐world applications, such as direct air capture, the presence of moisture in the feed gas may pose a grand challenge for CO2 adsorption in MOFs. This paper aims to address the issue of water–CO2 co‐adsorption in MOFs and present screening criteria for selecting MOFs that preferentially adsorb CO2 under humid conditions. First, we uncover a comprehensive overview of CO2–water co‐adsorption characteristics of various MOFs. Then, the high‐throughput screening methods are summarized. Both computational and experimental efforts have been dedicated to identify the promising MOFs for humid CO2 capture. According to the screening results and adsorption mechanism, the optimal preparation strategies are proposed to modulate the effect of water on CO2 uptake in MOFs. Finally, current MOF‐based CO2 capture prototypes are presented to evaluate their practical feasibility and performance. This work could offer valuable guidance for the development and application of MOFs for CO2 capture in the presence of water and inspire further research in this field. [ABSTRACT FROM AUTHOR]

The increasing utilization of fossil fuels and industrial activities has resulted in a surge of CO2 emissions, which have significantly impacted global climate change. Carbon capture and utilization technologies offer a promising solution to decrease atmospheric CO2 concentrations and convert CO2 into valuable products. This study focuses on the capture and storage of CO2 through the mineralization of magnesium‐containing materials. The analysis encompasses the mineralization process of solid and liquid minerals, the various mineralization processes of magnesium‐containing minerals categorized as direct and indirect mineralization, and the latest research advancements in magnesium‐containing minerals. Brine and seawater from salt lakes are considered the most appropriate materials for mineralization due to their abundance and the simplicity of the process compared to solid mineralization. This paper analyzes the impact of temperature, impurity ions, additives, and microorganisms on the process of magnesium carbonate synthesis crystallization. The use of magnesium‐containing materials for carbon dioxide sequestration can effectively reduce carbon emission. The review offers guidance on carbon dioxide mineralization and explores the potential applications of magnesium mineralization. [ABSTRACT FROM AUTHOR]

The process of preparing methanol from carbon dioxide is one of the ways to solve the environmental problems caused by greenhouse gases, the problem of fossil energy depletion, and the problem of fuel exhaust emissions. However, after decades of development, the process of preparing methanol from carbon dioxide is still unable to achieve large‐scale industrialization. This critical review sharply points out the problems and obstacles that need to be solved urgently on the industrialization road of carbon dioxide methanol preparation process and summarizes its progress. The problems faced by the methanol production industry from carbon dioxide are first the thermodynamic constraints, second the lower reaction rate and conversion effect, and finally the energy loss. In order to solve these problems, this paper first introduces the active sites, structural effects, and dynamic changes of copper‐based catalysts, as well as the unique reaction mechanism and doping modification of indium‐based catalysts. Zinc and zirconium promoters and some metal oxide supports can form unique interactions with active components to improve the catalytic performance of the catalyst. Next, various kinetic models and applications of methanol production from carbon dioxide are summarized, which is an important bridge linking laboratory and industrialization; the advantages and disadvantages of fixed bed reactor and paddle reactor were compared. Finally, the full text is summarized and prospected. [ABSTRACT FROM AUTHOR]

Across Europe, countries are reducing CO2 emissions and energy demand by lowering the temperature in public office buildings. These measures affect men and women unequally because the latter prefer and, indeed, perform better under higher temperatures than the standard temperature. Lowering the temperature thus further increases an already existing inequality. We show that the philosophical literature on discrimination provides an interesting theoretical approach to understanding such measures. On prominent understandings of what discrimination is, the policy would be considered direct discrimination against women if it could be shown to reflect a broader inattentiveness to the needs of women in society. Alternatively, and more straightforwardly, the policies can be considered indirect discrimination because of their disparate effects on men and women. The final part of the paper shows that the policies are also wrong for the reasons it is often argued that discrimination is wrong—to wit, that it harms or disrespects those who are discriminated against. The final section suggests a range of measures to offset the discriminatory aspects of the policy. [ABSTRACT FROM AUTHOR]

Atmospheric inversions provide estimates of carbon dioxide (CO2) fluxes between the surface and atmosphere based on atmospheric CO2 concentration observations. The number of CO2 observations is projected to increase severalfold in the next decades from expanding in situ networks and next‐generation CO2‐observing satellites, providing both an opportunity and a challenge for inversions. This study introduces the TRACE Regional Atmosphere–Carbon Ensemble (TRACE) system, which employ an ensemble‐based simultaneous state and parameter estimation (ESSPE) approach to enable the assimilation of large volumes of observations for constraining CO2 flux parameters. TRACE uses an online full‐physics mesoscale atmospheric model and assimilates observations serially in a coupled atmosphere–carbon ensemble Kalman filter. The data assimilation system was tested in a series of observing system simulation experiments using in situ observations for a regional domain over North America in summer. Under ideal conditions with known prior flux parameter error covariances, TRACE reduced the error in domain‐integrated monthly CO2 fluxes by about 97% relative to the prior flux errors. In a more realistic scenario with unknown prior flux error statistics, the corresponding relative error reductions ranged from 80.6% to 88.5% depending on the specification of prior flux parameter error correlations. For regionally integrated fluxes on a spatial scale of 106 km2, the sum of absolute errors was reduced by 34.5%–50.9% relative to the prior flux errors. Moreover, TRACE produced posterior uncertainty estimates that were consistent with the true errors. These initial experiments show that the ESSPE approach in TRACE provides a promising method for advancing CO2 inversion techniques. Plain Language Summary: To gain a better understanding of the main drivers behind atmospheric carbon dioxide (CO2) variations and trends, it is essential to accurately quantify CO2 exchanges—also known as fluxes—between the atmosphere and other components of the Earth system. It is generally not possible to directly measure surface CO2 fluxes at regional scales; however, fluxes can be inferred from a network of atmospheric CO2 concentration observations combined with atmospheric modeling and inversion methods, which seek to find the most likely fluxes given prior knowledge and observational evidence. This paper presents a new regional inversion framework called TRACE Regional Atmosphere–Carbon Ensemble (TRACE) for deriving CO2 fluxes at high resolution in space and time. One of the major innovations in TRACE is the ensemble‐based dual state and parameter estimation approach, which makes it computationally feasible to ingest large volumes of observations into the system. A series of experiments were carried out in a domain over North America to test the new framework in a controlled setting. In the experiments, we used synthetic tower observations of atmospheric CO2 concentrations to constrain parameters controlling terrestrial biogenic and oceanic CO2 fluxes. The results show that TRACE is capable of accurately estimating both the magnitude and spatial pattern of regional CO2 fluxes. Key Points: An ensemble‐based simultaneous state and parameter estimation approach is introduced for regional CO2 flux inversionsThe new dual‐state TRACE Regional Atmosphere–Carbon Ensemble (TRACE) framework provides a flexible platform for conducting coupled atmosphere–carbon data assimilationControlled experiments show that TRACE is effective at constraining regional CO2 fluxes using in situ CO2 concentration observations [ABSTRACT FROM AUTHOR]

This paper proposes a new idea for dramatically increasing the efficiency of CO2 reduction to CH4 at Pt/C electrocatalysts with negligibly low overpotentials. Pt catalysts have typically been disregarded in favor of other metal catalysts for CO2 reduction due to their poor performances. However, our strategically‐designed, multi‐potential‐step method, using a membrane electrode assembly with Pt/C catalysts, allows CO2 to be electrocatalytically converted to CH4 at close to the theoretical electrode potential with a net faradaic efficiency of 59.8±9.7 %. This approach is relevant and important because it provides a method of simultaneously ameliorating CO2 buildup and generating useful products. [ABSTRACT FROM AUTHOR]

Natural gas consisting mainly of methane is becoming increasingly prominent as a clean energy source. However, the major impurity, carbon dioxide, can adversely affect the performance of natural gas. Therefore, separating CO2 from CH4 is necessary to decrease the erosion of pipelines and increase the calorific value. This paper aimed at reviewing the performances, mechanisms, and novel developments of common adsorbents to adsorb pure CH4, pure CO2, and their mixtures. Several studies suggest that zeolites exhibit better separating performance than metal organic frameworks (MOFs) except the modified amine‐MIL group. Activated carbons may not be suitable adsorbents due to low selectivity between CO2 and CH4. The modified amine‐MIL group are the best type of adsorbent to separate CO2 from CH4 and its best operating conditions are at low pressure (<2 bar), low feed composition of CO2, and near room temperature using pressure swing adsorption (PSA) method. [ABSTRACT FROM AUTHOR]

In this paper, new polygeneration processes co‐producing electricity, methanol, dimethyl ether (DME), and Fischer–Tropsch (FT) fuels from different feedstock ratios of biomass, natural gas, and nuclear hydrogen generated through a copper‐chlorine (CuCl) cycle are analyzed for operation in Canada to produce transportation fuels. This combination of carbonless heat and a 'carbon neutral' biomass feedstock would contribute to the net reduction in greenhouse gas (GHG) emissions. In Part I of this work, the model for this biomass‐gas‐and‐nuclear‐to‐liquids (BGNTL) process was developed. This work expands on it and evaluates the economic and environmental impacts this plant would have in both Ontario and Alberta based on their local costs and resource availability. The analysis demonstrates that an increase in the ratio of biomass to natural gas in feedstock reduces the emissions of the process but increases the cost of carbon dioxide equivalents (CO2e) avoided. The results show that the BGNTL concept can be an economically attractive way of reducing net transportation sector GHG emissions in both Ontario and Alberta in meaningful quantities. [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide fracturing is an environmentally friendly anhydrous method. To study the propagation process during supercritical carbon dioxide fracturing, a full three‐dimensional model, coupled rock deformation, fluid transport, heat conduction, dynamic changes of carbon dioxide physical parameters, to investigate the process of fracture propagation during supercritical carbon dioxide fracturing, is established by the three‐dimensional boundary element method, the finite volume method, and finite difference method. And to solve the multiple physics coupling problems, a fully implicit solution and Newton‐Raphson iteration method are used. On the basis of this model established in this paper, the influential factors of supercritical carbon dioxide fracturing are analyzed. The results show that both of the reservoir temperature and the original in situ stress are important for carbon dioxide fracturing; The higher the reservoir temperature and the lower the initial in situ stress is, the longer and wider the fracture will be. The temperature of carbon dioxide at bottom is of no significance to the fracture length, fracture width, and the bottom hole pressure. A growing injection rate will lead to the increase of the fracture length and fracture width. This study would provide a reference for the fluid phase control of supercritical carbon dioxide fracturing technology. [ABSTRACT FROM AUTHOR]

Stratospheric temperature adjustment (STA) is often a significant component of greenhouse gas radiative forcing (RF), for both the most widely used definition of RF and effective radiative forcing. It is well established that the magnitude and sign of STA differs among greenhouse gases, being negative (at the tropopause) for CO2 increases (because it induces a cooling of the stratosphere) and positive for many halocarbons (because they induce a warming of the stratosphere); this effect is strongly related to the opacity (and hence the effective emitting temperature) of the troposphere at the wavelengths at which gases absorb. Here the spectral variation of STA is examined for the first time by systematically imposing a weak absorber in each of 300 bands of a narrow‐band radiation code. For this weak absorber, STA is negative for wavelengths greater than about 13 μm and positive in the 8‐ to 13‐μm "window" except in the vicinity of the 9.6‐μm ozone band. By combining narrow‐band and line‐by‐line model results, these findings are used to improve a widely used fast method to estimate radiative efficiency (RE, the RF per unit change in concentration) directly from laboratory measurements or theoretical calculations of halocarbon absorption cross sections; the new method reproduces detailed RE calculations to better than 1.4%. This is a significant improvement over a cruder method used to account for STA in RE tabulations in the Intergovernmental Panel on Climate Change's Fifth Assessment Report, which were used to calculate metrics such as the Global Warming Potential, for halocarbons and related substances. Plain Language Summary: Increased emissions and concentrations of greenhouse gases, due to human activity, are a major driver of climate change. Carbon dioxide is the most important such gas, but many other gases are emitted which, collectively, contribute significantly to climate change. This paper focuses on methods to calculate the climate impact of halocarbons which are used in refrigeration, insulation, air conditioning, etc. This includes chlorofluorocarbons (CFCs), whose usage has been phased out because they deplete the ozone layer; hydrochlorofluorocarbons (HCFCs) which were regarded as transitional substances to replace the CFCs; and hydrofluorocarbons, which are widely used replacements for CFCs and HCFCs. It is important to quantify the climate impacts of halocarbons and to compare the relative impact of different halocarbons; this information is used in international agreements aimed at reducing greenhouse gas emissions. This paper presents an important refinement of a widely used simple method for calculating and comparing the climate impact of different halocarbons. This refinement considers the impact of these gases on temperatures in the stratosphere (i.e., altitudes of about 10–50 km); to achieve this, the paper first develops a general understanding of the way such gases influence stratospheric temperatures. The new technique is a significant improvement over previous methods. Key Points: Stratospheric temperature adjustment is an important component of the effective radiative forcing for many greenhouse gasesThe variation of the magnitude and sign of this adjustment with the wavelength at which greenhouse gases absorb is investigatedThe results are used to enhance a widely used simple method for estimating halocarbon radiative efficiency [ABSTRACT FROM AUTHOR]

Energy is unquestionably necessary for economic progress, but it also results in carbon emissions, which are the leading cause of environmental deterioration and climate change. From this perspective, clean energy can contribute to both sustainable development and ecological sustainability, as it consists of non‐carbohydrate energy sources that do not or rarely emit greenhouse gases. In this context, this paper investigates economic policy uncertainty (EPU), economic expansion (EE) and clean energy consumption (EC) on carbon dioxide (CO2) emissions in Russia from 1995 to 2021. The autoregressive distributed lag (ARDL) model was used to illustrate the interdependence of factors. The error correction model (ECM) is also used to check the relationship among the study's desired factors. The long‐term investigation found that EPU harms the environment by increasing emission levels. The economic expansion increases CO2 emissions and reduces the environmental quality, supporting the ecological modernization argument. The consumption of clean energy negatively impacts CO2 emission; hence its higher amount reduces the carbon. Thus, the study found a causal relationship between EPU, EC, EE and CO2 emissions. Based on the study's findings, a policy framework is proposed to address the sustainable development goals and environmental quality. Adding the other variables like environmental regulations can be taken as future direction. [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]

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]

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]

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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 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]

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]

Coal seam with low permeability is widely distributed in China. Injection of flue gas (N2:CO2 = 0.85:0.15) is an effective approach to improve coal seam gas drainage efficiency. This process relates complex responses among ternary gases (CH4, CO2, and N2) competitive sorption on coals, gas diffusion, gas‐water migration by means of two‐phase flow, and coal deformation. In this paper, an improved hydraulic‐mechanical model coupling above interactions is established for flue gas injection enhanced gas drainage. This model is used to simulate flue gas enhanced drainage by finite element method. The sensitivity analyses of key factors are made to recovery a better understanding on the processes controlling flue gas enhanced drainage. Results show that the flue gas enhanced drainage can indeed improve the efficiency of gas extraction and reduce the gas pressure to the required value in a shorter duration. Due to the competitive adsorption and gas sweeping effect of injected flue gas, CH4 is driven toward drainage borehole, and CH4 pressure and content near the injection borehole decrease faster than that near the drainage borehole. The peak CH4 pressure laterally moves from the injection borehole to the drainage borehole. Higher injection pressure, initial permeability, and smaller sorption affinity ratios may lead to greater CH4 production rate at early drainage stage, but smaller CH4 production rate at late stage. The factors controlling the behavior of flue gas enhanced drainage are initial permeability, injection pressure, and sorption affinity ratios in order. This work offers useful framework to investigate important technical challenges associated with enhanced mine gas drainage, as well as unconventional gas development. [ABSTRACT FROM AUTHOR]

Copyright of Regional Science Policy & Practice is the property of Wiley-Blackwell 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.)

Geologic storage of CO2 and H2 are climate‐positive techniques for meeting the energy transition. While similar formations could be considered for both gases, the flow dynamics could differ due to differences in their thermophysical properties. We conduct a rigorous pore‐scale study of water/CO2 and water/H2 systems at relevant reservoir conditions in a Bentheimer rock sample using the lattice Boltzmann method to quantify the effects of capillary, viscous, inertial, and wetting forces during gas invasion. At similar conditions, H2 invasion is weaker compared to CO2 due to unfavorable viscosity ratios. Increasing flow rate, however, increases the breakthrough saturation for both gas systems in the range of capillary numbers studied. At isolated conditions of flow rate, viscosity ratio, and wettability, local inertial effects are found to be critical and show consistent increase in the invaded gas saturation. The effect of inertial forces persits for both gases across all field conditions tested. Plain Language Summary: We present a numerical investigation at the pore‐scale to contrast the dynamics of fluid transport for water/CO2 and water/H2 systems at reservoir conditions. Understanding such dynamics is critical to evaluate the feasibility of the geologic storage of these gases (long‐term storage of CO2 and short‐term, periodic storage of H2), which are being researched as green techniques for mitigating climate change. Through a systematic analysis, we demonstrate the importance of pore‐scale mechanisms like local inertial effects which are not well studied in the literature. These effects cause fast fluid motion and consistently allow more fluid to be injected in the rock independently from the other physical effects. Such effects should be carefully accounted for when modeling these systems for large‐scale gas storage. Key Points: At similar reservoir conditions, invasion of H2 is found to be weaker as opposed to CO2 due to unfavorable viscosity ratiosAmong the tested reservoir scenarios, P/T conditions for the saline aquifer provided the largest amount of invaded gas until breakthroughLocal inertial effects control the dynamics of the invading gas across different wettability, viscosity ratios, and capillary numbers [ABSTRACT FROM AUTHOR]

The photosynthetic amoeba, Paulinella provides a recent (ca. 120 Mya) example of primary plastid endosymbiosis. Given the extensive data demonstrating host lineage‐driven endosymbiont integration, we analysed nuclear genome and transcriptome data to investigate mechanisms that may have evolved in Paulinella micropora KR01 (hereinafter, KR01) to maintain photosynthetic function in the novel organelle, the chromatophore. The chromatophore is of α‐cyanobacterial provenance and has undergone massive gene loss due to Muller's ratchet, but still retains genes that encode the ancestral α‐carboxysome and the shell carbonic anhydrase, two critical components of the biophysical CO2 concentrating mechanism (CCM) in cyanobacteria. We identified KR01 nuclear genes potentially involved in the CCM that arose via duplication and divergence and are upregulated in response to high light and downregulated under elevated CO2. We speculate that these genes may comprise a novel CO2 delivery system (i.e., a biochemical CCM) to promote the turnover of the RuBisCO carboxylation reaction and counteract photorespiration. We posit that KR01 has an inefficient photorespiratory system that cannot fully recycle the C2 product of RuBisCO oxygenation back to the Calvin‐Benson cycle. Nonetheless, both these systems appear to be sufficient to allow Paulinella to persist in environments dominated by faster‐growing phototrophs. [ABSTRACT FROM AUTHOR]

Ocean mesoscale flows significantly influence nutrient distribution and biological productivity, yet the scarcity of eddy‐permitting observational data sets and climate modeling hinders understanding their role in carbon sequestration. Using an eddy‐resolving global simulation, this study investigates the significance of ocean mesoscales in air‐sea carbon dioxide (CO2) exchange. Results show over 30% of CO2 flux variance in energetic regions attributed to flows with horizontal scales smaller than 2°. Mesoscale flows can drive a cumulative CO2 flux that is either a net carbon sink or source depending on region, with magnitudes on the order of 105 tonnes of carbon per year. Variations in this mesoscale‐related CO2 flux are correlated with local relative vorticity and the background gradient of ocean partial pressure of CO2. This analysis underscores the importance of considering ocean mesoscales in monitoring carbon flux, highlighting the need to explore the influence of increasing eddy activity on carbon uptake in a changing climate. Plain Language Summary: This study investigates the influence of ocean flows with horizontal scales of tens to hundreds of kilometers (called mesoscale flows) on the exchange of carbon dioxide between the ocean and the atmosphere using a state‐of‐the‐art high resolution global simulation. It is shown that in certain parts of the ocean, more than 30% of the variability in carbon dioxide exchange at the ocean surface is linked to these relatively small‐scale ocean motions. It is further revealed that mesoscale flows can lead to a significant gain or loss of carbon from the ocean at the regional level, and that depends on how the flow is oriented with respect to the background distribution of carbon in the ocean. Gaining a better understanding of how the mesoscale flow features influence air‐sea carbon dioxide exchange is crucial for understanding the ocean's role in the carbon cycle and its ability to absorb and store carbon in a changing climate. Key Points: Over 30% of air‐sea CO2 flux variability is attributed to ocean spatial scales smaller than 2° in eddy‐rich regionsThe cumulative mesoscale‐induced CO2 flux is on the order of 105 tonnes of carbon per yearMesoscale‐related CO2 flux is governed by both relative vorticity and the background gradient of partial pressure of CO2 [ABSTRACT FROM AUTHOR]

N‐coordinated Ni sites (NiNx) are effective catalysts for the electrochemical reduction of CO2 to CO. In most researches, modulating the coordination environment of Ni atoms is focused on to improve electrochemical CO2 reduction (ECR) performance. However, the influence of the carbon substrate's structure on the intrinsic activity of NiNx is seldom investigated. The highly curved surface of carbon nanotubes (CNT) may provide a unique curvature effect on NiNx. It is found that the Ni residues in CNT can be atomized to form NiNx sites on the surface of CNT (Ni‐N/CNT@covalent triazine framework [CTF]) through high‐temperature pyrolysis, using a soluble CTF nanosheet as N precursor. The π‐conjugated and ultrathin 2D structure of CTF enables closer interfacial contact between CTF and CNT, which avoids the formation of a thick carbon layer to maximize the curvature effect. Theoretical data reveal that the NiN3 configuration may act as a highly active ECR site, and the curvature effect from CNT can further tune the electronic structure of NiN3, thus improving the ECR kinetics. The Ni‐N/CNT@CTF‐based flow‐cell electrolyzer exhibits a jCO of 201 mA cm−2 at −0.9 V with a high FECO of 98%. [ABSTRACT FROM AUTHOR]

In current research, achieving carbon neutrality has become a primary focus through the utilization of various conversion technologies that transform carbon dioxide (CO2) into valuable chemicals or fuels. Covalent organic frameworks (COFs), as emerging crystalline organic polymers, offer distinct advantages in CO2 conversion compared to other materials. These advantages include controllable nanoscale pores, predefined functional units, editable framework structures, and rich conjugated systems. The unique characteristics of COFs make them highly promising electrocatalysts for CO2 conversion. This review provides a comprehensive overview of pioneering works and recent research on the utilization of COF‐based materials as electrocatalysts for electrochemical CO2 reduction reaction. This review offers a comprehensive analysis of the design principles for various reactive sites, skeleton structures, pore functionalities, 3D frameworks, morphologies, and composite materials of COFs, aiming to enhance electrocatalysis. Finally, this review presents some recommendations for material design, reaction mechanisms, and theoretical computations to enhance the understanding of reaction mechanisms further and facilitate the design of high‐performance COF‐based electrocatalysts. [ABSTRACT FROM AUTHOR]

Conversion of carbon dioxide (CO2) to valuable chemicals and feedstocks through electrochemical reduction holds promise for achieving carbon neutrality and mitigating global warming. C2+ products are of interest due to their higher economic value. Since the CO2 to C2+ conversion process involves multiple steps, tandem catalytic strategies are commonly employed in the design of electrochemical CO2 reduction reaction (CO2RR) catalysts and systems/reactors. Among the diverse catalysts that are capable of reducing CO2 to CO, Cu stands out for more efficiently further converting CO to C2+ products. In this review, the emerging Cu‐based tandem catalysts and their impact on CO2RR performance, focusing on three positional relationships are summarized. It delves into the integration of tandem catalytic strategies into membrane electrolyzers, utilizing catalyst‐coated substrate (CCS) and catalyst‐coated membrane (CCM) technologies. Several typical examples are presented to illustrate this integration. Finally, the challenges and prospects of applying tandem strategies in the development of CO2RR catalysts/systems, as well as their device‐level implementation are indicated. [ABSTRACT FROM AUTHOR]

To reach their net‐zero targets, countries will have to compensate hard‐to‐abate CO2 emissions through carbon dioxide removal (CDR). Yet, current assessments rarely include socio‐cultural or institutional aspects or fail to contextualize CDR options for implementation. Here we present a context‐specific feasibility assessment of CDR options for the example of Germany. We assess 14 CDR options, including three chemical carbon capture options, six options for bioenergy combined with carbon capture and storage (BECCS), and five options that aim to increase ecosystem carbon uptake. The assessment addresses technological, economic, environmental, institutional, social‐cultural and systemic considerations using a traffic‐light system to evaluate implementation opportunities and hurdles. We find that in Germany CDR options like cover crops or seagrass restoration currently face comparably low implementation hurdles in terms of technological, economic, or environmental feasibility and low institutional or social opposition but show comparably small CO2 removal potentials. In contrast, some BECCS options that show high CDR potentials face significant techno‐economic, societal and institutional hurdles when it comes to the geological storage of CO2. While a combination of CDR options is likely required to meet the net‐zero target in Germany, the current climate protection law includes a limited set of options. Our analysis aims to provide comprehensive information on CDR hurdles and possibilities for Germany for use in further research on CDR options, climate, and energy scenario development, as well as an effective decision support basis for various actors. Plain Language Summary: Countries aiming to achieve net‐zero emissions will have to remove the remaining carbon dioxide from the atmosphere through carbon dioxide removal (CDR). However, current assessments of CDR options rarely consider socio‐cultural or institutional aspects or set the CDR options in the specific context of their implementation. In this study, researchers conducted the first context‐specific feasibility assessment of CDR options in Germany, considering six dimensions, including technological, economic, environmental, institutional, and social‐cultural aspects. The study assessed 14 CDR options, including chemical carbon capture options, bioenergy combined with carbon capture and storage, and options to increase ecosystem carbon uptake. The study found that CDR options like cover crops or seagrass restoration face low implementation hurdles but have small CO2 removal potentials, while options like woody‐biomass combustion or mixed‐feedstock biogas production have high CDR potentials but face large economic and institutional hurdles. The analysis aims to provide comprehensive information on CDR options for use in further research and as an effective decision support basis for a range of actors. Key Points: More context‐specific assessments of carbon dioxide removal (CDR) options are needed to guide national net‐zero decision makingEcosystem‐based CDR options with comparably low implementation hurdles in Germany show relatively small CO2 removal potentialsHigh CDR potential options in Germany face high institutional, technological and societal hurdles linked in many ways to geological storage [ABSTRACT FROM AUTHOR]

Large‐scale implementation of electrochemical CO2 conversion to value‐added products is currently hampered by high electrolyzer cell voltages, resulting in low energy efficiency and high operating costs. Cell voltages are typically well above 3 V and need to be significantly lowered whilst maintaining current densities greater than 200 mA cm−2 to enable energy‐efficient CO2 electroreduction. This can be addressed through modification of the resistive components of the device to reduce energy consumption and lower operating costs. Electrodes, electrolyte solutions, and the separator between compartments, provide the largest contributions to the overall cell voltage, therefore decreasing their resistance can lower the electricity input required to drive effective CO2 conversion. Here, by careful analysis and tuning of the various sources of voltage drops within the cell, an optimized diaphragm‐based CO2R device is presented, which is able to operate at an industrially relevant current density of 200 mA cm−2 with an |Ecell| as low as 2.89 V, amongst the lowest reported values to date. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction can be used to produce value‐added hydrocarbon fuels and chemicals by coupling with clean electrical energy. However, highly active, selective, and energy‐efficient CO2 conversion to multicarbon hydrocarbons, such as C2H4, remains challenging because of the lack of efficient catalysts. Herein, an ultrasonication‐assisted electrodeposition strategy to synthesize CuO nanosheets for low‐overpotential CO2 electroreduction to C2H4 is reported. A high C2H4 Faradaic efficiency of 62.5% is achieved over the CuO nanosheets at a small potential of −0.52 V versus a reversible hydrogen electrode, corresponding to a record high half‐cell cathodic energy efficiency of 41%. The selectivity toward C2H4 is maintained for over 60 h of continuous operation. The CuO nanosheets are prone to in situ restructuring during CO2 reduction, forming abundant grain boundaries (GBs). Stable Cu+/Cu0 interfaces are derived from the low‐coordinated Cu atoms in the reconstructed GB regions and act as highly active sites for CO2 reduction at low overpotentials. In situ Raman spectroscopic analysis and density functional theory computation reveal that the Cu+/Cu0 interfaces offer high *CO surface coverage and lower the activation energy barrier for *CO dimerization, which, in synergy, facilitates CO2 reduction to C2H4 at low overpotentials. [ABSTRACT FROM AUTHOR]

Summary: Leaves with stomata on both upper and lower surfaces, termed amphistomatous, are relatively rare compared with hypostomatous leaves with stomata only on the lower surface. Amphistomaty occurs predominantly in fast‐growing herbaceous annuals and in slow‐growing perennial shrubs and trees. In this paper, we present the current understanding and hypotheses on the costs and benefits of amphistomaty related to water and CO2 transport in contrasting leaf morphologies. First, there is no evidence that amphistomatous species achieve higher stomatal densities on a projected leaf area basis than hypostomatous species, but two‐sided gas exchange is less limited by boundary layer effects. Second, amphistomaty may provide a specific advantage in thick leaves by shortening the pathway for CO2 transport between the atmosphere and the chloroplasts. In thin leaves of fast‐growing herbaceous annuals, in which both the adaxial and abaxial pathways are already short, amphistomaty enhances leaf–atmosphere gas‐exchange capacity. Third, amphistomaty may help to optimise the leaf‐interior water status for CO2 transport by reducing temperature gradients and so preventing the condensation of water that could limit CO2 diffusion. Fourth, a potential cost of amphistomaty is the need for additional investments in leaf water transport tissue to balance the water loss through the adaxial surface. [ABSTRACT FROM AUTHOR]

In this paper, municipal solid waste (MSW), sewage sludge (SS), and rice straw (RS) were pyrolyzed under N2 atmosphere and at 550 and 600 °C, and then the produced biochars were used for gasification in a CO2 atmosphere. The effects of pyrolysis temperature, gasification temperature, and CO2/C ratio on the product composition and yield were studied. The results were compared with those from coal char gasification. The CO2 gasification kinetics were determined under CO2 flow by thermogravimetric analysis (TGA). CO concentration in the syngas of the gasification experiments can be organized in the following order: MSW char > RS char > SS char > coal char. Considering the energy consumption and CO yield, the recommended gasification temperature for the biomass chars is 900 °C. The activation energies of CO2 gasification calculated from the TGA data based on the most fitted reaction models can be organized in the following order: coal char > RS char > SS char > MSW char, which is consistent with the experimental results. For higher syngas field and lower CO2/C ratio, MSW char is recommended as the best feedstock for in the combined pyrolysis‐gasification process. [ABSTRACT FROM AUTHOR]

In this paper, phase behaviours and mass‐transfer mechanisms of a Bakken light crude oil‐CO2 system are studied. A series of PVT tests of the light crude oil‐CO2 system are conducted to measure CO2 solubilities, oil‐swelling factors, and CO2‐saturated oil densities at different equilibrium pressures and the actual reservoir temperature of Tres = 56.0 °C. Five CO2 diffusion tests in the light crude oil are performed at five different initial test pressures (Pi = 4.1, 5.2, 6.3, 7.7, and 9.0 MPa) and Tres = 56.0 °C by applying the pressure decay method (PDM). The graphical method (GM) is used to analyze the measured test pressure versus time data of each diffusion test and determine CO2 average diffusivity in the light crude oil. It is found that the so‐called density‐driven natural convection can occur in the CO2‐saturated light crude oil as its measured density is much higher than that of the dead light crude oil. Three distinct periods of CO2 dissolution into the light crude oil are identified: the natural convection‐dominated period (I), the transition period, and the molecular diffusion‐dominated period (II). The determined CO2 effective diffusivities (Deff) in Period I and CO2 molecular diffusivities (D) in Period II from the GM are in the ranges of 0.28–1.75 × 10−6 m2/s and 0.87–1.94 × 10−9 m2/s at the initial test pressures of Pi = 4.1–9.0 MPa, respectively. Finally, it is also found that the constant Z‐factor approximation used in the GM may cause a relatively large error in the determination of Deff or D. Measured ln[P(t)−Peq] versus time data and determined corresponding two linear regression lines for Periods I and II at Tres = 56.0 °C in Test #3 (Pi = 6251.5 kPa). [ABSTRACT FROM AUTHOR]

In this paper, Bi2O3 electrocatalysts for the electroreduction of CO2 to formate were synthesized with different morphologies, including nanoparticles and thin nanorods. Comparatively, Bi2O3 nanoparticles have higher catalytic activity than Bi2O3 thin nanorods. The Faradaic efficiency of formate formation at a moderate potential of −1.2 vs. RHE in aqueous solution could reach 91 %. In addition, a maximum current density for formate production of up to 22 mA cm−2 was achieved, which is almost 3 times higher than that of Bi2O3 thin nanorods. In particular, the catalytic activity of the Bi2O3 nanoparticle catalyst was almost stable over a 23‐hour period of electrolysis, exhibiting its application prospect in the electroreduction of CO2 to formate. Upcycling: nanoparticles and thin nanorods of Bi2O3 as catalysts for the electroreduction of CO2 to formate are synthesized. The Bi2O3 nanoparticles show higher catalytic activity than the thin nanorods. A Faradaic efficiency of 91 % at a moderate potential of −1.2 vs. RHE is found in aqueous solution. A maximum current density of up to 22 mA cm−2 is achieved, with a stable activity over a 23‐hour period of electrolysis. [ABSTRACT FROM AUTHOR]

Abstract: Power‐to‐gas technologies, combining hydrogen produced by water electrolysis with carbon dioxide to produce substitute natural gas (SNG), can support the increased penetration of renewable electricity sources. However, the technical and economic feasibility of these technologies requires the conversion efficiency of the whole process, including the methanation step. This paper provides an experimental performance comparison of three catalytic methanation reactor concepts, a fixed‐bed reactor, a millistructured reactor, and a metallic foam reactor with the same nickel‐alumina catalyst. The response of each reactor was analyzed in light of five performance criteria, representing the methane yield, the reactor compactness, and the maximum temperature elevation. The millistructured reactor channel showed a higher methane space‐time yield and volumetric productivity than the other reactors, but a significant catalyst temperature elevation. The metallic foam reactor showed a much lower space‐time yield and volumetric productivity, but very good thermal management. [ABSTRACT FROM AUTHOR]

Density-driven convection has been identified to accelerate the rate of CO2 solubility trapping during geological CO2 storage in deep saline aquifers. In this paper, we present an experimental method using the refractive properties of fluids (their impact on light transmission), and an analogous system design, which enables the study of transport mechanisms in saturated porous media. The method is used to investigate solutally induced density-driven convective mixing under conditions relevant to geological CO2 storage. The analogous system design allows us by choice of initial solute concentration and bead size to duplicate a wide range of conditions (Ra-values), making it possible to study the convective process in general, and as a laboratory analogue for systems found in the field. We show that the method accurately determines the solute concentration in the system with high spatial and temporal resolution. The onset time of convection (tc), mass flux (F), and flow dynamics are quantified and compared with experimental and numerical findings in the literature. Our data yield a scaling law for tc which gives new insight into its dependence on Ra, indicating tc to be more sensitive to large Ra than previously thought. Furthermore, our data show and explain why F is described equally well by a Ra-dependent or a Ra-independent scaling law. These findings improve the understanding of the physical process of convective mixing in saturated porous media in general and help to assess the CO2 solubility trapping rate under certain field conditions. [ABSTRACT FROM AUTHOR]

The operation of most engineered hydrogeological systems relies on simulating physical processes using numerical models with uncertain parameters and initial conditions. Predictions by such uncertain models can be greatly improved by Kalman-filter techniques that sequentially assimilate monitoring data. Each assimilation constitutes a nonlinear optimization, which is solved by linearizing an objective function about the model prediction and applying a linear correction to this prediction. However, if model parameters and initial conditions are uncertain, the optimization problem becomes strongly nonlinear and a linear correction may yield unphysical results. In this paper, we investigate the utility of one-step ahead smoothing, a variant of the traditional filtering process, to eliminate nonphysical results and reduce estimation artifacts caused by nonlinearities. We present the smoothing-based compressed state Kalman filter (sCSKF), an algorithm that combines one step ahead smoothing, in which current observations are used to correct the state and parameters one step back in time, with a nonensemble covariance compression scheme, that reduces the computational cost by efficiently exploring the high-dimensional state and parameter space. Numerical experiments show that when model parameters are uncertain and the states exhibit hyperbolic behavior with sharp fronts, as in CO2 storage applications, one-step ahead smoothing reduces overshooting errors and, by design, gives physically consistent state and parameter estimates. We compared sCSKF with commonly used data assimilation methods and showed that for the same computational cost, combining one step ahead smoothing and nonensemble compression is advantageous for real-time characterization and monitoring of large-scale hydrogeological systems with sharp moving fronts. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) geological sequestration plays an important role in mitigating CO2 emissions for climate change. Understanding interactions of the injected CO2 with network fractures and hydrocarbons is key for optimizing and controlling CO2 geological sequestration and evaluating its risks to ground water. However, there is a well-known, difficult process in simulating the dynamic interaction of fracture-matrix, such as dynamic change of matrix porosity, unsaturated processes in rock matrix, and effect of rock mineral properties. In this paper, we develop an explicit model of the fracture-matrix interactions using multilayer bounce-back treatment as a first attempt to simulate CO2 reactive transport in network fractured media through coupling the Dardis's LBM porous model for a new interface treatment. Two kinds of typical fracture networks in porous media are simulated: straight cross network fractures and interleaving network fractures. The reaction rate and porosity distribution are illustrated and well-matched patterns are found. The species concentration distribution and evolution with time steps are also analyzed and compared with different transport properties. The results demonstrate the capability of this model to investigate the complex processes of CO2 geological injection and reactive transport in network fractured media, such as dynamic change of matrix porosity. [ABSTRACT FROM AUTHOR]

The equilibrium climate sensitivity estimated from different sources is inconsistent due to its dependence on the surface warming pattern. Cloud feedbacks have been identified as the major contributor to this so‐called pattern effect. We find a large unforced pattern effect in CERES data, with cloud feedback estimated from two consecutive 125‐month periods (March 2000–July 2010 and August 2010–December 2020) changing from −0.45 ± 0.85 to +1.2 ± 0.78 W/m2/K. When comparing to models, 27% of consecutive 10‐year segments in CMIP6 control runs have differences similar to the observations. We also compare the spatial patterns in the CERES data to those in climate models and find they are similar, with the East Pacific playing a key role. This suggests that the impact of the unforced pattern effect can be significant and that models are capable of reproducing its global‐average magnitude. Plain Language Summary: Climate sensitivity, the amount of surface warming in response to increasing carbon dioxide, is often used as a metric to quantify the severity of climate change. The estimates of climate sensitivity from different sources, however, are not consistent. The main reason is that the response of clouds to surface temperature changes, called cloud feedback, depends on the spatial pattern of surface warming. We investigate the impact of this so‐called pattern effect on cloud feedback in observations and climate models. Here we find that the observed cloud feedbacks calculated from two consecutive decades have significant differences in both global mean value and spatial pattern, and the climate models produce similar results. This highlights the fact that differences of surface warming patterns can have large influences on cloud feedbacks, and climate models have the ability to reproduce what happened in the real world. Key Points: The difference in cloud feedback between two ∼10‐year periods inferred from CERES is 1.6 ± 1.1 W/m2/KThe distinct difference in cloud feedback verifies the existence of a large unforced pattern effectCMIP6 models produce unforced pattern effects of similar magnitude and spatial structure to those seen in the observations [ABSTRACT FROM AUTHOR]