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Increased ecological land (IEL) such as forests and grasslands can greatly enhance ecosystem carbon sinks. Understanding the mechanisms for the magnitude of IEL-induced ecosystem carbon sinks is crucial for achieving carbon neutrality. We estimated the impact of IEL, specifically the increase in forests and grasslands, as well as global changes including atmospheric CO 2 concentration, nitrogen deposition, and climate change on net ecosystem productivity (NEP) in National Key Ecological Function Zones (NKEFZs) in China using a calibrated ecological process model. The NEP in NKEFZs in China was calculated to be 119.4 Tg C yr -1 , showing an increase of 42.6 Tg C yr -1 from 2001 to 2021. Compared to the slight contributions of climate change (-8.0%), nitrogen deposition (11.5%), and reduction in ecological land (-3.5%), the increase in NEP was primarily attributed to CO 2 (66.5%) and IEL (33.5%). Moreover, the effect of IEL (14.8 Tg C yr -1 ) surpassed that of global change (13.1 Tg C yr -1 ) in the land use change zone. The IEL-induced NEP is significantly associated with CO 2 fertilization, regulated by precipitation and nitrogen deposition. The high values of IEL-induced NEP occurred in areas with precipitation exceeding 800 mm and nitrogen deposition exceeding 25 kg N ha -1 yr -1 . We recommend prioritizing the expansion of ecological land in areas with sufficient water and nutrients to enhance CO 2 fertilization, while avoiding increasing ecological land in regions facing unfavorable climate change conditions. This study serves as a foundation for comprehending the NEP response to ecological restoration and global change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Carbon dioxide (CO2) capture and separation constitute an important field of research as we seek to reduce the effects of climate change. Because of their porosity, resilient crystallinity, high adsorption capacity, and affinity for CO2, cyclodextrin-based metal-organic frameworks (CD-MOFs) have emerged as attractive materials for carbon capture. This paper gives an overview of CD-MOFs and their applications in CO2 capture and separation. Several studies have been conducted to synthesize and characterize CD-MOFs for CO2 capture. The causes of the high binding affinity of CO2 in CD-MOFs were discovered through mechanistic studies on CO2 adsorption. Furthermore, CD-MOF modifications have been carried out to improve the sorption capacity and selectivity of CO2 adsorption. Meanwhile, several researchers have reported using CD-MOFs for gaseous CO2 membrane separation. This paper also highlights the current gaps in CD-MOF research and future outlooks in carbon capture and separation using CD-MOFs. [ABSTRACT FROM AUTHOR]

The roles digital media-technologies play in raising public issues relating to emerging technologies and their potential for engaging publics with science and policy assessments is a lively field of inquiry in Science and Technology Studies (STS). This paper presents an analysis of controversies over proposals for the large-scale removal of atmospheric carbon dioxide (CDR). The study combines a digital method (web-querying) with document analysis to map debates about two CDR approaches: bioenergy with carbon capture and storage (BECCS) and afforestation. In the first step, we locate actors using the web to engage with BECCS and afforestation and map their alignments in relation to competing framings of CDR. In a second step, we examine the devices deployed by UK-based actors to evidence and contest the feasibility of BECCS and afforestation. Our analysis shows that policy distinctions between "natural" and "engineered" CDR are used flexibly in practice and do not map neatly onto actor engagement with BECCS and afforestation. We highlight the predominance of cross-cutting techno-economic expertise and argue that framings of CDR as a solution to governing climate change may contribute to public disengagement from climate policy processes. The paper reflects on methods for studying controversies, publics, and issues emerging around processes of technoscientific assessment. [ABSTRACT FROM AUTHOR]

The global warming and climate change caused by the continuing rise in carbon dioxide (CO2) emissions have attracted the attention of the public, scientists, and governments in recent years. An effective approach to limit the impact of such emissions is the implementation of advanced carbon capture and storage systems. This paper provides an overview of technologies and recent advances in carbon capture and utilization. The main methods include postcombustion, precombustion, and oxyfuel-combustion, adsorption, and membrane capture. In addition, various problems associated with the storage, transportation, and utilization of CO2 are discussed. [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]

Development of negative emission technologies is key in meeting climate change targets. Offshore wind-powered CO 2 direct air capture (DAC) coupled with deep-water, submarine basalt reservoirs has the potential to offer a reliable way to permanently store CO 2 while avoiding grid-energy and land-use competition. This paper analyzes the incorporation of a DAC system into a reference floating wind turbine (FWT) concept, the IEA 15 MW RWT atop the UMaine VolturnUS-S semi-submersible. The resulting FWT-DAC platform's total mass and its distribution is adapted as needed to preserve floating stability, prevent any wave splashing on the DAC system, and ensure minimum power production disturbances. The system's fully coupled motion responses are analyzed for relevant design load conditions and compared to those from the reference design demonstrating good agreement with the benchmark. The research findings suggest that the hybrid FWT-DAC platform behaves in a similar way to the reference one and can serve as a viable modular deployment approach. • CO 2 direct air capture (DAC) integration onto a floating wind turbine (FWT). • Floating stability and air gap assessment of the hybrid FWT-DAC system. • Dynamic analysis using various design load conditions. • Results show similar system responses between the reference FWT and the FWT-DAC platforms. [ABSTRACT FROM AUTHOR]

CO 2 capture, utilization, and storage (CCUS) are critical technical measures to effectively mitigate the global climate change problem. However, most of the existing research has focused on the capture end and lacks in-depth analysis of subsequent processes such as compression, leading to limitations in the improvement of system economics. Therefore, a novel CCS system for a 300 MW coal-fired power plant was proposed in this paper with two strategies: (1) a CCS system integrating CO 2 refrigeration cycle (CFPP-CCS-CRC); and (2) a CCS co-generation plant integrating CO 2 refrigeration cycle (CHP-CCS-CRC). The proposed systems' performance was comparatively evaluated by applying energy, exergy, and economic (3E) analyses. The results demonstrated that at different CO 2 capture percentages (13.1 %∼72.9 %), the CHP-CCS-CRC system has improved energy utilization efficiency by 1.2 %∼5.6 % and exergy efficiency by 7.7 %∼25.8 %, compared to the conventional CCUS system (CFPP-CCS). In particular, at a percentage of 13.1 %, the combined energy consumption of the CHP-CCS-CRC system was 0.39 GJ/tCO 2 , a 79 % reduction compared to 1.87 GJ/tCO 2 of the CFPP-CCS system, which resulted in a static payback period of less than 2 years. In general, the newly proposed system features more adequate energy utilization, lower operating costs, and higher economic efficiency. [Display omitted] • A novel CCUS system coupled with CO 2 refrigeration were proposed. • The performance of the proposed systems is comparatively evaluated by 3E analysis. • The energy consumption of the proposed CCUS systems is reduced by 29.24 %–79 %. • The exergy efficiency of the proposed CCUS systems is reduced by 7.7 %–25.8 %. • The static payback period for the proposed systems is reduced to less than 2 years. [ABSTRACT FROM AUTHOR]

Carbon capture and storage is vital for reducing greenhouse gas emissions and mitigating climate change. Most projects involve the permanent geological storage of CO2 within deep sedimentary rock formations, but accurately constraining storage capacity usually involves detailed and computationally demanding reservoir modeling and simulation. Efficiency factors can also be used but these often lead to capacity overestimations. To address this, a workflow is proposed harnessing various existing, reduced complexity models that account for the surface topography and dynamic fluid behavior in a computationally efficient manner. This workflow was tested in an area of the Malay Basin mapped from three-dimensional seismic data but with illustrative reservoir parameters. A static analysis was first undertaken using algorithms within MRST-co2lab. Structural traps, spill paths and spill regions were identified using the reservoir topography. This provided initial indications into optimal well placement and led to refinement of the total capacity of the area into the capacity available within structural traps. This was followed with a dynamic analysis, also within MRST-co2lab, using computationally efficient Vertical Equilibrium models. Hundreds of simulations were undertaken and the optimal well placement was determined based on the maximum storage efficiency achieved. The results indicated that the amount that can be contained within this area is 15 times less than equivalent predictions using static storage efficiency factors. The advantage of such a light approach is that sensitivity and uncertainty analysis can be carried out at speed, before targeting certain parameters/areas for more detailed study. [ABSTRACT FROM AUTHOR]

According to the Intergovernmental Panel on Climate Change (IPCC) of the United Nations (UN), rise in atmospheric concentration of carbon dioxide (CO 2 ) due to anthropogenic factors is considered as the primary driver for global climate change. With almost every major corporation around the world working towards their "net-zero goals", it is becoming increasingly important to have more technologies that can help reduce carbon footprint. Achieving sequestration of CO 2 in the subsurface through Carbon Capture Utilization and Storage (CCUS) technologies like CO 2 -Enhanced Oil Recovery, CO 2 -Enhanced Geothermal Systems, CO 2 -Enhanced Coal Bed Methane, etc. is well accepted. We introduce yet another attractive CCUS opportunity through well rehabilitation. Aqua Freed® and Aqua Gard® are well-known well rehabilitation and preventive well maintenance technologies that utilize (inject underground) liquid CO 2 for the purpose. The goal of this study was to quantify the storage capacity of Aqua Freed® and Aqua Gard®, and establish their CCUS credentials. Depending on the well being serviced, these technologies can inject up to 40 US tons of CO 2 per well. Based on field data collection and statistical modeling, we estimated that 82–96% (median 90%) of the injected CO 2 remains in the subsurface post injection. Overall, our results and analysis of the US market suggest that using CO 2 for well rehabilitation and maintenance has a storage potential of several megatonnes of CO 2 annually in the US alone. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage (CCUS) technology has emerged as a pivotal measure in mitigating global climate change. Notably, CO2-EOR is esteemed for its dual function of sequestering CO2 and enhancing oil recovery. However, this process presents challenges related to asphaltene deposition during CO2 flooding, leading to reservoir damage, such as pore plugging. This study systematically manipulated the factors inducing CO2-induced asphaltene deposition, elucidating the mechanisms and magnitudes of asphaltene precipitation. Additionally, the study investigated the efficacy of carbon quantum dots (CQDs) in mitigating asphaltene deposition. Experimental findings indicated a positive correlation between asphaltene deposition and level of asphaltene content, CO2 injection ratio, and temperature. Moreover, with an increase in experimental pressure, the asphaltene deposition rate demonstrated an initial increase followed by a subsequent decline. Leveraging their favorable compatibility with asphaltene, CQDs effectively suppressed the aggregation behavior of asphaltene. In the presence of CQDs, the onset of asphaltene precipitation was delayed from 45 V% to 55 V%, with the highest inhibition rate reaching approximately 36% at an optimal CQD concentration of 20 mg/L. This study proposes a novel approach to address asphaltene deposition issues in CO2-EOR processes, contributing to the enhancement of recovery rates in low-permeability reservoirs. [ABSTRACT FROM AUTHOR]

Geological carbon storage is considered to be an effective measure to mitigate climate crisis. The method in which CO2 is stored depends on its phase state and the depth at which it is injected. In this study, the fault-reservoir system is constructed to elucidate the fault leakage behaviors and CO2 migration in different geological storage environments. Whether CO2 is buoyant or sinking depends on the fluid density difference between CO2 and H2O. When carbon dioxide is injected into deep saline aquifer, CO2 would preferentially migrate upward along the fault plane due to CO2 buoyancy forces, and CO2 plume accumulates beneath the caprock and floats at the top of the reservoir eventually. For CO2 storage in deep ocean reservoir and volcanic basalt, no upward migration of CO2 plume is observed during carbon storage. Fault plane is the preferential pathway for carbon downward transportation during ocean-based CO2 storage, providing a virtually unlimited environment. Compared with deep ocean storage, the much shorter sinking times makes volcanic basalt for carbon storage safer and more effective. It is illustrated that the fluid density difference between CO2 and H2O is the decisive factor in determining CO2 sinking velocity. This investigation of searching CO2 sinking reservoirs provides a promising alterative reference for remove and storage large volumes of the greenhouse gas. [ABSTRACT FROM AUTHOR]

Biomass Waste Derived Porous Carbon (BWDPC) is widely used for its ability to adsorb carbon dioxide (CO 2) in large-scale industrial operations, making it a leading solution for combating air pollution and climate change issues. However, factors such as temperature, pressure, and surface area can influence its performance in adsorbingcarbon dioxide. To maximize CO 2 adsorption, it is vital to determine the relationships among these variables. In this paper, we use several preprocessing techniques and various machine learning algorithms, such as Gradient Boosting Regressor, Convolutional Neural Networks, Multi-Layer Perceptron, and Long Short-Term Memory, to explore the efficacy of these algorithms in predicting CO 2 capture capacities. We augment our datasets by generating new features and in turn our ML models achieve a better performance on the augmented datasets compared to the original dataset. Our models achieved r 2 score of 90.7 % on the training set and 85.73 % on the test set of the augmented datasets. Furthermore, we were able to determine that the ratio of carbon to pressure as well as temperature, and aspects tied to the physical conditions of the adsorbent material emerge as the most influential factors in CO 2 adsorption. A python implementation of all our experiments is publicly available in Github https://github.com/mmaheri/CO2_Capturing.git. • We apply various preprocessing steps and augment the original dataset by generating new features. • We compare the performance of various machine learning algorithms on the original and augmented datasets. • The machine learning algorithms show a better performance on the augmented dataset in terms of r2 score. • Convolutional Neural Network and Gradient Boosting Regression exhibit the best performance. • The ratio of carbon to pressure as well as temperature, and aspects tied to the physical conditions of the adsorbent material emerge as the most influential factors in CO2 adsorption. [ABSTRACT FROM AUTHOR]

The Climate Change Conference of Parties (COP) 21 in December 2015 established Nationally Determined Contributions toward reduction of greenhouse gas emissions. In the years since COP21, it has become increasingly evident that carbon dioxide removal (CDR) technologies must be deployed immediately to stabilize concentration of atmospheric greenhouse gases and avoid major climate change impacts. Biochar is a carbon-rich material formed by high-temperature conversion of biomass under reduced oxygen conditions, and its production is one of few established CDR methods that can be deployed at a scale large enough to counteract effects of climate change within the next decade. Here we provide a generalized framework for quantifying the potential contribution biochar can make toward achieving national carbon emissions reduction goals, assuming use of only sustainably supplied biomass, i.e., residues from existing agricultural, livestock, forestry and wastewater treatment operations. Our results illustrate the significant role biochar can play in world-wide CDR strategies, with carbon dioxide removal potential of 6.23 ± 0.24% of total GHG emissions in the 155 countries covered based on 2020 data over a 100-year timeframe, and more than 10% of national emissions in 28 countries. Concentrated regions of high biochar carbon dioxide removal potential relative to national emissions were identified in South America, northwestern Africa and eastern Europe. Highlights: Biochar production via biomass pyrolysis is one of few carbon dioxide removal (CDR) technologies that can be deployed at scale. Modeled biochar CDR potential of nearly every country, based on available biomass residues and national average soil temperature. Biochar can offset over 10% of national emissions in many countries, with concentrated impacts in three global regions. [ABSTRACT FROM AUTHOR]

Summary: Many tree genera in the Malesian uplands have Southern Hemisphere origins, often supported by austral fossil records. Weathering the vast bedrock exposures in the everwet Malesian tropics may have consumed sufficient atmospheric CO2 to contribute significantly to global cooling over the past 15 Myr. However, there has been no discussion of how the distinctive regional tree assemblages may have enhanced weathering and contributed to this process. We postulate that Gondwanan‐sourced tree lineages that can dominate higher‐elevation forests played an overlooked role in the Neogene CO2 drawdown that led to the Ice Ages and the current, now‐precarious climate state. Moreover, several historically abundant conifers in Araucariaceae and Podocarpaceae are likely to have made an outsized contribution through soil acidification that increases weathering. If the widespread destruction of Malesian lowland forests continues to spread into the uplands, the losses will threaten unique austral plant assemblages and, if our hypothesis is correct, a carbon sequestration engine that could contribute to cooler planetary conditions far into the future. Immediate effects include the spread of heat islands, significant losses of biomass carbon and forest‐dependent biodiversity, erosion of watershed values, and the destruction of tens of millions of years of evolutionary history. [ABSTRACT FROM AUTHOR]

• A novel decarbonization concept applied to offshore natural gas wells benefiting CCUS technology. • A comprehensive CFD model considers real gas EOS and the behaviours of gas, droplets, liquid film. • Compatible with pure CO 2 and CH 4 -CO 2 models to study condensation and separation characteristics. • The maximum CO 2 condensation amount under high pressure and low temperature is 10.33 ton/h. • The maximum CO 2 capture capacity is 4.43 ton/h with high heterogeneous droplet mass concentration. Carbon capture, utilisation and storage (CCUS) is of unique significance for building a green and resilient energy system, and it is also a key solution to tackle the climate challenge. The concept of supersonic decarburization, a joint product of non-equilibrium condensation and swirling separation, can contribute to CCUS technology in a clean way. In this paper, a numerical model is established and validated to investigate the complex physical phenomena of supersonic decarbonization in a high-pressure environment based on the real gas equation of state. The model is compatible with the pure CO 2 model and CH 4 -CO 2 model. Through the simulation of the supersonic nozzle and supersonic separator, the condensation and separation performance of supersonic decarbonization technology was evaluated. For the condensation performance of carbon dioxide, the results show that higher pressure makes it much easier to achieve the condensation process. When the pressure is supercritical, the decrease of inlet temperature or the increase of inlet mole fraction of CO 2 leads to a higher liquid fraction. For separation performance, when the mass concentration of inlet heterogeneous droplets increases from 0.1 kg/m3 to 7.5 kg/m3, the carbon separation amount increases from 3.33 ton/h to 4.43 ton/h, while the exergy loss of condensed CO 2 drops from 436.57 kJ/kg to 329.56 kJ/kg. It demonstrates that the decarburization process is easier, and exergy required for condensation decreases when the concentration of the foreign core is larger. This new concept is beneficial to CCUS technology and can be applied to carbon capture in offshore natural gas processing. [ABSTRACT FROM AUTHOR]

In today's world, owing to industrial expansion, urbanization, the rapid growth of the human population, and the high standard of living, the utilization of the most advanced technologies is unavoidable. The enhanced anthropogenic activities worldwide result in a continuous increase in global warming potential, thereby raising a global concern. The constant rise in global warming potential forces the world to mitigate greenhouse gases, particularly carbon dioxide. Carbon dioxide is considered as the primary contributor responsible for global warming and climatic changes. The global anthropogenic carbon dioxide emissions released into the atmosphere can eventually deteriorate the environment and endanger the ecosystem. Combating global warming is one of the main challenges in achieving sustainable development. Carbon capture and storage is a potential solution to mitigate carbon dioxide emissions. There are three main methods for carbon capture and storage: post-combustion, pre-combustion, and oxy-fuel combustion. Among them, post-combustion is used in thermal power plants and industrial sectors, all of which contribute a significant amount of carbon dioxide. Different techniques such as physical and chemical absorption, physical and chemical adsorption, membrane separation, and cryogenic distillation used for carbon capture are thoroughly discussed and presented. Currently, there are various materials including absorbents, adsorbents, and membranes used in carbon dioxide capture. Still, there is a search for new and novel materials and processes for separating and capturing carbon dioxide. This review article provides a comprehensive review of different methods, techniques, materials, and processes used for separating and capturing carbon dioxide from significant stationary point sources. [ABSTRACT FROM AUTHOR]

Underground coal gasification (UCG) has a huge potential in extracting energy from deep coal seams with a low environmental footprint. A vast void space created in a UCG operation serves as an effective sink to anthropogenic CO 2 storage and sequestration. To advance the knowledge base regarding CO 2 storage in post-UCG cavities, a 3D commercial-scale 990m × 60m × 24 m multi-cavity scenario was constructed to model the transport and fate of the stored CO 2 plume at around 1000 m depth for centuries using a coalbed methane (CBM) and CO 2 storage dedicated simulator. The effects of the import multiphysics were analyzed. It was revealed that transport phenomena entered a stabilized steady state in 50 years in a multicomponent adsorption system. In addition, the matrix-cleat diffusion exhibited a substantially strong trapping mechanism with an at-equilibrium spread-out speed of 0.24 m/year. Dynamic changes in a cleat system and an injection process were shown to play a minor role. Furthermore, two effective means were proposed for a protracted thousands-of-year simulation of CO 2 storage in post-UCG multiple cavities. The relevant findings in this paper would promote the utility and applicability of UCG in the world's deep coal seams for the transition of the coal industry in a carbon-conscious world. • Explored the fate of the stored CO2 in deep coal seams for centuries under the effects of very important multiphysics. • Constructed a 3D 990m × 60m × 24 m multi-cavity for a commercial-scale modelling. • The differing importance of effects was analyzed. • Proposed useful ways for predicting CO2 transport in deep unmineable coal seams for hundreds to thousands of years. [ABSTRACT FROM AUTHOR]

Carbon capture and storage is a necessary action for the reduction of CO2 emissions, and thereby mitigation of climate change and its impacts. Especially, in India, with its growing fuel needs and very little attention paid towards carbon capture and storage, mineral carbonation technology is a suitable option as it is cost-effective and could be retrofitted to existing plants that emit CO2. Given the development of carbon capture and storage technology, this study attempts direct mineral carbonation of steelmaking slag with flue gas. Response surface methodology was employed to design gas-solid and slurry phase aqueous carbonation experiments. A maximum reduction of about 36.1% was achieved through aqueous carbonation at 61.1 °C, 46.24 bar, and a liquid-to-solid ratio of 14.5, corresponding to a sequestration capacity of 127.4 g of CO2/kg of slag. The temperature was found to be the most vital parameter in both the aqueous and gas-solid carbonation processes. Regression models used to study the carbonation process were found to be statistically significant. The carbonated slag consisted of mineral phases, namely, calcite and dolomite. The results demonstrated the sequestration potential of Indian steelmaking slag with flue gas. Carbonation of steelmaking slag with flue gas poses to be a promising option for the development of carbon capture and storage technology in the country. [ABSTRACT FROM AUTHOR]

Reaching net‐zero for global greenhouse gas emissions by the year 2050 will require a portfolio of new technologies and approaches, potentially requiring direct removal and sequestration of atmospheric carbon dioxide using negative emissions technologies (NETs). Since energy and climate systems are fundamentally interconnected it is important that we understand the impacts of policy decisions and their associated controversies in other related technologies and sectors. Using a secondary analysis of data from a series of deliberative workshops conducted with lay publics in the United Kingdom, we suggest that perceptions of CO2 removal technologies were negatively impacted by risk perceptions and recent policy decisions surrounding shale gas and fracking. Using the social amplification of risk framework, we argue that heightened risk perceptions have extended via "ripple effects" across these technologies. Participants' attitudes were underpinned by deeper misgivings regarding the actions and motives of experts and policymakers; a pervasive discourse of "but they told us it was safe" regarding fracking negatively affected people's trust in assurances of the safety and efficacy of CO2 removal. This has the potential to undermine attempts to build societal agreement around future deployment of CO2 removal technologies. [ABSTRACT FROM AUTHOR]

Rising CO2 emissions call for actions to urgently address climate change and its impacts. To avoid the harmful consequences of climate change, limiting anthropogenic emissions of CO2 are a sensible response recognized by the global scientific community. Carbon capture and storage technologies are an integral part of the climate change mitigation portfolio. Among the various technologies, mineral carbonation shows promising potential as it is safer and offers a permanent solution for carbon capture and storage in the form of solid carbonates. In this regard, direct mineral carbonation of alkaline solid residues is viewed with global interest as they offer permanent and leakage-free storage of CO2. In this research work, CO2 sequestration using Indian coal fly ash (class F type- CaO < 10%) has been studied through the direct mineral carbonation process using flue gas concentration of CO2. Response surface methodology was used to design the carbonation experiments through gas–solid and aqueous routes. Aqueous carbonation of coal fly ash at optimum conditions (temperature-61.6 °C, pressure-48.7 bar, liquid/solid ratio-13.35, reaction time-50 min) resulted in a reduction of about 23% in the concentration of CO2. The waste exhibited a maximum sequestration capacity of 50.72 g of CO2/kg under aqueous carbonation and 20.03 g of CO2/kg under gas–solid carbonation. Both temperature and pressure were found to be significant factors impacting the gas–solid carbonation process. In aqueous carbonation, temperature and liquid/solid ratio were the significant factors. The carbonation process was evidenced using Fourier-transform-infrared spectroscopy, X-ray diffraction, and scanning electron microscope studies. The results suggest that Indian coal fly ash could be considered a potential feedstock for sequestration of CO2 with flue gas and requires further improvement for large-scale implementations. [ABSTRACT FROM AUTHOR]

Carbon capture and sequestration technology has been a ground-breaking tool in tackling carbon dioxide (CO2) emissions worldwide but has limitedly been researched and practised in Africa at present. Considering the vast growth and developmental level in the continent, there is a need to consider this option of mitigating global climate change. In this study, a systematic and process-based incorporation of seismic and well logs datasets was used to characterize the structural and stratigraphic framework of sandstone reservoirs within the field in order to determine their capacities for effective CO2 sequestration. Petrophysical analysis, fault modelling as well as geostatistical techniques were used to build facies and property models which enabled a qualitative assessment of the sealing potential of faults associated with the reservoirs based on prediction of key properties such as shale gouge ratio, lithological juxtaposition, fault permeability and fault transmissibility across the fault faces. Nine water-bearing sandstone reservoirs (reservoirs A–J) with varying reservoir quality were identified in the field. The dominance of high SGR, low permeability, higher fault throws and low fault transmissibility values at the lower parts of the faults indicates the deeper structural traps of the field are low-risk zones and might serve as good storage areas for CO2. [ABSTRACT FROM AUTHOR]

Soil represents the largest carbon pool in the terrestrial system, storing up to 5 times as much carbon as in the atmosphere. The number of annual publications pertaining to both soil and climate change has grown 18‐fold between 2001 and 2020, on average now accounting for 18.6% of all publications relating to climate change. Despite the significance of the soil system in combating climate change and a growing body of scientific knowledge, international negotiations, including COP26 that has just been held in Glasgow, UK, tend to overlook the role that soil must play in combating climate change. The importance of soil systems is multi‐faceted in a world of changing climate conditions. The most vulnerable population facing climate change tend to be smallholder farmers whose living depends on healthy and productive soil. Climate adaptation initiatives and financial assistance from developed countries to developing countries must put this as a high priority. On the other hand, soil renders high potential in carbon sequestration, and soil amendments like biochar are particularly promising as a carbon‐negative technology. However, the cost of producing biochar on a large scale must be significantly reduced in order to make it commercially viable. Soil also represents a significant source of greenhouse gases besides carbon dioxide. Technologies must be further developed to ensure food production and food security, while effectively reducing the emission of methane and nitrous oxide from agricultural soils. We conclude that expediting sustainable and climate‐smart soil management is an imperative in mitigating and adapting to global climate change. [ABSTRACT FROM AUTHOR]

Agricultural landscapes are the largest source of anthropogenic nitrous oxide (N2O) emissions, but their specific sources and magnitudes remain contested. In the US Corn Belt, a globally important N2O source, in-field soil emissions were reportedly too small to account for N2O measured in the regional atmosphere, and disproportionately high N2O emissions from intermittent streams have been invoked to explain the discrepancy. We collected 3 y of highfrequency (4-h) measurements across a topographic gradient, including a very poorly drained (intermittently flooded) depression and adjacent upland soils. Mean annual N2O emissions from this corn-soybean rotation (7.8 kg of N2O-N ha-1.y-1) were similar to a previous regional top-down estimate, regardless of landscape position. Synthesizing other Corn Belt studies, we found mean emissions of 5.6 kg of N2O-N ha-1.y-1 from soils with similar drainage to our transect (moderately well-drained to very poorly drained), which collectively comprise 60% of corn-soybeancultivated soils. In contrast, strictly well-drained soils averaged only 2.3 kg of N2O-N ha-1.y-1. Our results imply that in-field N2O emissions from soils with moderately to severely impaired drainage are similar to regional mean values and that N2O emissions from well-drained soils are not representative of the broader Corn Belt. On the basis of carbon dioxide equivalents, the warming effect of direct N2O emissions from our transect was twofold greater than optimistic soil carbon gains achievable from agricultural practice changes. Despite the recent focus on soil carbon sequestration, addressing N2O emissions from wet Corn Belt soils may have greater leverage in achieving climate sustainability. [ABSTRACT FROM AUTHOR]