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In future decarbonised energy systems, residual carbon emissions require strategic planning and management. In environmental management, an evaluation of carbon removal considering local geographic frameworks is needed. This paper introduces a scalable and adaptable model for evaluating the economics and geography of future carbon capture and storage (CCS) configurations across geographical scales, covering capture, transport, and storage of carbon. The model is applied to the North Denmark Region, showing that future energy production carbon sources will be concentrated in Thisted and Jammerbugt, while industrial sources remain in Aalborg and Rebild municipalities. Carbon transport configurations, including truck, pipeline, and shipping are assessed, for the carbon to be stored in onshore and offshore geological storages. The regional scale findings suggest that pipelines and onshore storage provide the most economical configuration. However, a sensitivity study using a smaller geographical scope indicates potential for optimising carbon transport by evaluating both carbon volume and distance. The paper discusses how the model's flexibility and scalability enable the integration of alternate cost components, thereby supporting the calculation of the carbon repurposing potentials, including carbon capture, utilisation, and storage (CCUS) configurations. • Develops a scalable geographical cost model for CCS. • Quantifies CO 2 from future energy production and industrial facilities by 2045. • Estimates 2.45 million tonnes of annual capturable CO 2 for CCS by 2045. • Transport analyses show trucking and piping cost benefits for smaller CO 2 sources. • Locates infrastructure opportunities for CO 2 utilisation via CCS geographic routing. [ABSTRACT FROM AUTHOR]

In the global context, countries must reduce carbon dioxide emissions to "net zero" by 2050 to limit global warming to 1.5 °C above pre-industrial levels. China's Nationally Determined Contributions (NDCs) are to peak carbon dioxide emissions by 2030 and achieve the carbon neutrality target by 2060. To monitor the achievements of the NDCs, establishing an annual-based accounting mechanism is necessary to record the carbon stocks in China, especially for Blue Carbon. The paper aims to present China's first national-scale systematic Blue Carbon accounting for mangroves, salt marshes, and seagrasses, covering the accounting subjects of physical and monetary assets, as well as relevant indicators for investors. It focuses on the design of the accounting method and system, the selection of data categories applied to this system, and the application of China's Blue Carbon accounting based on this accounting system. Taking Blue Carbon accounting as a starting point, this paper analyses the restoration prospects of these ecosystems and their application potential for NDCs in China compared with the terrestrial ecosystems. The results indicate that mangroves are the most cost-effective type of ecosystem, even compared to terrestrial forests. Thus, the paper provides policymakers with a new perspective on the decision-making of carbon sequestration relevant decisions, aiming to promote the monitoring, restoration, and expansion of China's coastal blue carbon ecosystem through the establishment of a sound Blue Carbon accounting system, and to help achieve the carbon neutrality goal in China's NDCs through regular and systematic monitoring of its national Blue Carbon inventories. • China's coastal blue carbon ecosystems are carbon sources rather than carbon sinks. • Mangroves are the most cost-effective coastal blue carbon ecosystem compared to salt marshes and seagrass beds. • The Blue Carbon of mangroves is more cost-effective than the Green Carbon of terrestrial forests when meeting China's Nationally Determined Contributions target of increasing forest stocks. • Establishing guidelines for Blue Carbon data requirements will lay a scientific foundation for formulating strategies and policies to cope with global climate change. [ABSTRACT FROM AUTHOR]

Carbon sequestration is vital to maintaining carbon neutrality and mitigating climate change's impact on humans and the environment. As the government's role in eco-advocacy is primarily designed to safeguard the environment, this paper discusses the impact of government environmental regulations on carbon sequestration. By analyzing 286 cities from 2000 to 2019 in China, we propose that government environmental regulation can lead to a 0.77% increase in carbon sequestration. Additionally, industrial agglomeration and industrial structure advancement are regarded as viable channels. As a result of the differences in city types, government intervention, and public concern across different cities, the impact is likely to vary as well. • Environmental regulation can effectively enhance carbon sequestration. • The heterogeneity considers city type, government intervention and public attention. • The mechanisms include industry agglomeration and industrial structure optimization. [ABSTRACT FROM AUTHOR]

This paper introduces an energy transition model featuring a carbon-intensive manufacturer that adopts sustainable insurance, participates in a cap-and-trade scheme, and implements carbon capture and storage (CCS) transit, all aimed at achieving the net-zero carbon emission target. The model utilizes a down-and-out call (DOC) approach to evaluate the manufacturer's equity, considering the bankruptcy risk prior to maturity due to carbon intensity. The equity of the life insurer providing funds is assessed using a capped DOC method to address the capped credit risk from the manufacturer. The findings reveal that increased adoption of CCS transit diminishes manufacturer equity, heightens default risk, and reduces insurer equity, with these effects exacerbated by advanced CCS technology and stringent cap-and-trade caps. Both stringent cap-and-trade schemes and rapid advancements in CCS transit practices, particularly with the use of advanced CCS technology, deviate from the net-zero target. A critical policy implication is the necessity for the precise calibration of cap-and-trade schemes and the pace of CCS transit adoption to ensure alignment with net-zero targets. • We develop an energy transition model with carbon capture and storage (CCS) transit. • Increased CCS transit adoption reduces manufacturer and insurer equity. • Adoption of advanced CCS technology exacerbates the effects of CCS transit adoption. • Stringent caps in cap-and-trade schemes amplify impacts of advanced CCS adoption. • Stricter cap and rapid CCS transit advancement diverge from net-zero targets. [ABSTRACT FROM AUTHOR]

In this paper, we propose a multi-RREH (Remote Renewable Energy Hub) based optimization framework. This framework allows a valorization of CO 2 using carbon capture technologies. This valorization is grounded on the idea that CO 2 gathered from the atmosphere or post combustion can be combined with hydrogen to produce synthetic methane. The hydrogen is obtained from water electrolysis using renewable energy. Such renewable energy is generated in RREH, which are locations where RE is cheap and abundant (e.g., solar PV in the Sahara Desert, or wind in Greenland). We instantiate our framework on a case study focusing on Belgium and 2 RREH, and we conduct a techno-economic analysis under uncertainty. This analysis highlights, among others, the interest in capturing CO 2 via Post Combustion Carbon Capture (PCCC) rather than only through Direct Air Capture (DAC) for methane synthesis in RREH. By doing so, a notable reduction of 10% is observed in the total cost of the system under our reference scenario. In addition, we use our framework to derive a carbon price threshold above which carbon capture technologies may start playing a pivotal role in the decarbonation process of our industries. • We demonstrate PCCC technology potential for reducing RREH's CH4 production cost. • We derive a carbon price threshold for crucial industrial decarbonization. • An uncertainty analysis has been carried out on the reference scenario. [ABSTRACT FROM AUTHOR]

At present, biochar has a large application potential in soil amelioration, pollution remediation, carbon sequestration and emission reduction, and research on the effect of biochar on soil ecology and environment has made positive progress. However, under natural and anthropogenic perturbations, biochar may undergo a series of environmental behaviors such as migratory transformation, mineralization and decomposition, and synergistic transport, thus posing certain potential risks. This paper outlines the multi-interfacial migration pathway of biochar in "air-soil-plant-animal-water", and analyzes the migration process and mechanism at different interfaces during the preparation, transportation and application of biochar. The two stages of the biochar mineralization process (mineralization of easily degradable aliphatic carbon components in the early stage and mineralization of relatively stable aromatic carbon components in the later stage) were described, the self-influencing factors and external environmental factors of biochar mineralization were analyzed, and the mineral stabilization mechanism and positive/negative excitation effects of biochar into the soil were elucidated. The proximity between field natural and artificially simulated aging of biochar were analyzed, and the change of its properties showed a trend of biological aging > chemical aging > physical aging > natural aging, and in order to improve the simulation and prediction, the artificially simulated aging party needs to be changed from a qualitative method to a quantitative method. The technical advantages, application scope and potential drawbacks of different biochar modification methods were compared, and biological modification can create new materials with enhanced environmental application. The stability performance of modified biochar was compared, indicating that raw materials, pyrolysis temperature and modification method were the key factors affecting the stability of biochar. The potential risks to the soil environment from different pollutants carried by biochar were summarized, the levels of pollutants released from biochar in the soil environment were highlighted, and a comprehensive selection of ecological risk assessment methods was suggested in terms of evaluation requirements, data acquisition and operation difficulty. Dynamic tracing of migration decomposition behavior, long-term assessment of pollution remediation effects, and directional design of modified composite biochar materials were proposed as scientific issues worthy of focused attention. The results can provide a certain reference basis for the theoretical research and technological development of biochar. [Display omitted] • Analyzed the migration process and mechanism of biochar at different interfaces. • Analyzed the mineralization process and stability mechanism of biochar in soil. • Compared the properties of biochar under artificial simulation and natural aging. • Summarized the modification strategies and characterization methods of biochar. • Summarized the potential environmental risks in the application process of biochar. [ABSTRACT FROM AUTHOR]

The present paper compared, through life cycle assessment (LCA), the production of aviation biofuel from two hydrothermal routes of microalgae cultivated in wastewater. Hydrothermal liquefaction (HTL) and gasification followed by Fischer-Tropsch synthesis (G + FT) were compared. Both routes included biomass production, hydrotreatment for biofuel upgrading, and product fractionation. Secondary data obtained from the literature were used for the cradle-to-gate LCA. G + FT had a higher impact than HTL in the 18 impact categories assessed, with human carcinogenic toxicity exerting the most harmful pressure on the environment. The catalysts were the inputs that caused the most adverse emissions. The solvent used for bio-oil separation also stood out in terms of impacts. In HTL, emissions for global warming were −51.6 g CO 2 eq/MJ, while in G + FT, they were 250 g CO 2 eq/MJ. At the Endpoint level, HTL resulted in benefits to human health and ecosystems, while G + FT caused environmental damage in these two categories, as well as in the resources category. In the improvement scenarios, besides considering solid, aqueous, and gaseous products as co-products rather than just as waste/emissions, a 20% reduction in catalyst consumption and 90% recovery were applied. Thus, in HTL, 39.47 kg CO 2 eq was avoided, compared to 35.44 kg CO 2 eq in the base scenario. In G + FT, emissions decreased from 147.55 kg CO 2 eq to the capture of 8.60 kg CO 2 eq. [Display omitted] • Gasification + Fischer-Tropsch caused more impacts than liquefaction. • The environment has suffered more harmful pressure on human carcinogenic toxicity. • The catalysts used were the inputs that most caused adverse emissions. • Liquefaction route captured 39.47 kg CO 2 eq with improvement scenario. • Gasification + Fischer-Tropsch captured 8.6 kg CO 2 eq with the improvement scenario. [ABSTRACT FROM AUTHOR]

This research paper delves into the intricate interplay between decarbonisation and sustainability, focusing on adopting chemical looping technologies. Deep decarbonisation scenarios necessitate a profound transformation in various sectors to mitigate climate change, and oil refineries, as pivotal players, must adapt to these changes. Employing the BLUES integrated assessment model, we evaluate the evolution of the refining sector in decarbonisation pathways, emphasising its potential for sustainability through repurposing and emissions mitigation. Additionally, we delve into chemical looping technologies, including Solar Thermal Chemical Looping (STCL), Reverse Water Gas Shift Chemical Looping (RWGS-CL), Chemical Looping Reforming (CLR), and Super Dry Reforming (SDR), elucidating their principles and contributions to carbon dioxide (CO 2) conversion. These technologies offer promising routes for CO 2 capture and present opportunities for sustainable carbon loop cycles, potentially revolutionising industries' emissions reduction efforts. In a world of climate change, this research illuminates a sustainable path forward by integrating decarbonisation and innovative CO 2 management strategies. • Chemical looping technologies offer innovative routes for sustainable carbon capture and utilisation. • Oil refineries can play a pivotal role in reducing emissions through asset repurposing. • Integration of the BLUES model provides insights into refining sector evolution for decarbonisation. • Solar Thermal Chemical Looping (STCL) utilises solar energy for CO 2 conversion. • Methane-utilising CO 2 CL processes like CLR and SDR offer promising sustainability solutions. [ABSTRACT FROM AUTHOR]

Despite increasing interest, a lack of comprehensive knowledge regarding the efficient design and implementation of carbon farming schemes remains. These schemes must efficiently achieve higher carbon sequestration, incentivize farmers, and increase farmers' participation in global carbon markets. Our study systematically reviews, describes, and maps available evidence related to carbon farming contracts to assess different incentive mechanisms for carbon farming. We conduct a systematic mapping review of articles extracted from various databases employing the Collaboration for Environmental Evidence method. We shortlist 52 articles and analyze about 40 global case studies, identifying three main incentive mechanisms of carbon farming contracts, namely, result-based, action-based, and hybrid payments. We examine how these incentive mechanisms are designed, in addition to associated payment types, monitoring approaches, and barriers to implementation. Result-based payments include stringent monitoring and can be implemented through auctions, carbon credits, product labels or certificates. Action-based payments are found to be simpler, with lower monitoring requirements for farmers and can be paid upfront or after contract implementation. Hybrid payments combine both techniques, offering low-risk and guaranteed payments for farmers and definite environmental mitigation impacts. Result-based and hybrid payments motivate farmers to innovate to meet environmental objectives while also connecting them to carbon markets. The major challenges to developing a successful carbon farming project include lack of permanence, non-additionality, and the absence of stringent monitoring, reporting, and verification standards, all of which affect farmers' incentives. This study determines that carbon farming contract design and efficiency can be improved by analyzing the lessons learned from previous experiences. By examining and improving the attributes that define different incentive mechanisms, farmers can be better motivated to enroll in carbon farming schemes and benefit from increased access to carbon markets to potentially transform agriculture into a viable tool for climate action. • Systematic mapping reviewed 52 papers, which encompassed 40 global cases. • Three incentive mechanisms: result-based, action-based, and hybrid payments. • Results-based payments: stringent MRV, high risk but high profitability to farmers. • Action-based payments: simple MRV, low risk but low profitability to farmers. • Hybrid payment: low-risk and high profitability; connect farmers to carbon markets. [ABSTRACT FROM AUTHOR]

In recent years, the importance of capturing CO 2 has increased due to the necessity of minimizing climate change and the detrimental effects of CO 2 emissions from industrial processes. CO 2 absorption, as one of the most mature carbon capture technologies, has been improved by introducing nanosized particles into liquid absorbents. Nanofluids have been the subject of interest in many studies recently due to their tremendous impact on absorption. This review comprehensively examines the CO 2 absorption behavior for nanofluids through the investigation of different absorption systems. Potential mechanisms for improving the absorption/regeneration performance of nanoabsorbents as well as the synergistic effects of physicochemical properties of nanofluids, such as viscosity and density on CO 2 capture behavior, are reviewed. Nanofluid enhancement factors in terms of absorption rate and capacity towards CO 2 are also compiled. Mathematical models, which have been proposed for calculating mass transfer coefficient and mass diffusivity, are comprehensively outlined. The paper discusses conventional methods for nanofluid preparation affecting the physicochemical properties of nanofluids. Strategies for enhancing nanofluid stability, as well as approaches to examine their stability are discussed. Finally, nanoparticle concentration, types and size of them, and selection of the base liquid absorbent as the key factors influencing the CO 2 removal process by nanofluids, are considered in this paper, as well. [Display omitted] • Synthesis of nanofluids (NFs) and techniques to promote and inspect their stability. • Experimental apparatus and calculation methods for CO 2 absorption by NFs. • Mathematical models for estimating mass transfer coefficient and diffusivity in NFs. • Effective factors in enhancement of nanofluids' CO 2 absorption capacity and rate. [ABSTRACT FROM AUTHOR]

Calcium carbide residue (CCR) is a waste obtained from the production of acetylene gas by the hydration reaction of calcium carbide. This residue is generated in large quantities annually and requires appropriate disposal. The main composition of the residue is calcium hydroxide (Ca(OH) 2). Ca(OH) 2 can react with CO 2 gas and form CaCO 3 particles. This process is well known but not very attractive since Ca(OH) 2 is obtained from limestone using an energy-intensive thermal conversion process. This paper examined the synthesis of CaCO 3 from CCR solutions by capturing CO 2 with the aid of triethanolamine (TEA) solutions at doses of 0, 5, 10 and 20% w/w. The precipitated CaCO 3 was characterized, and the application of CaCO 3 as a filler in epoxy resin was tested. The results showed that the precipitated CaCO 3 was mainly calcite, with a 76.6% yield. Cubic calcite was primarily obtained in TEA solutions, whereas small and agglomerated spherical vaterite and cubic calcite particles were formed in non-TEA solutions. The CaCO 3 -filled epoxy composites showed higher compressive strength than the neat resin. However, the transparency of specimen plates was reduced. These results can serve as guidelines for the application of CCR slurry filtrate obtained from the sedimentation ponds of acetylene plants and help to reduce the amount of wastewater that needs to be treated. CO 2 gas from industrial flue gas combined with TEA solution could be applied to precipitate CaCO 3 for carbon-neutral manufacturing. • CaCO 3 was synthesized from CCR solutions by capturing CO 2 /triethanolamine. • Precipitated CaCO 3 was mainly cubic calcite with 76.6% yield. • Compressive strength of CaCO 3 -filled epoxy composites was improved. • Transparency of CaCO 3 -filled specimen plates was reduced to translucent object. [ABSTRACT FROM AUTHOR]

To mitigate global warming and the greenhouse effect, biochar (BC) has been regarded as an important way of carbon sink. Therefore, this research explored the development trend of BC for soil carbon sequestration and mitigation from 2001 to 2020 based on bibliometric analysis. The results show that Yong Sik Ok and Johannes Lehmann are the top 2 high-impact authors. China, America, and Germany are the most widely collaborated countries, but China's research impact is lower than that of America. The Chinese Academy of Sciences has far more publications than any other institution, but Cornell University and Kangwon National University lead the way in terms of impact. Research hotspots can be divided into five clusters: (1) pyrolysis, nutrient, and microbial communities; (2) the immobilization of heavy metals; (3) crop yield and soil properties; (4) greenhouse gas, meta-analysis, and field experiment; (5) carbon fraction and sequestration. Reviews account for 60 % of the top 10 most highly cited papers, and eight of the top 10 focus on the early research period, setting the stage for the development of the BC field. Science of the Total Environment has the highest number of publications and total citations, and literature published in Soil Biology and Biochemistry is to some extent more likely to be cited. In the future, we need to carry out research in the following aspects: (1) Interaction mechanisms between BC, soil, and soil microbial communities. (2) Designing low-cost, high-yield, and high-effect optimization methods to improve the characteristics of BC. (3) Effect of BC on the environment and human health in long-term localization experiments. (4) Carbon sinks of BC need to be further evaluated on a global scale. [Display omitted] • The research progress was reviewed by bibliometrics analysis and bibliometrics. • China, America, and Germany are the most widely collaborated countries. • Research hotspots can be divided into five categories by cluster analysis. • The prospects of biochar for carbon sequestration and mitigation are presented. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential use of date palm leaf biochar as a climate change solution through CO 2 capture and sequestration. The pyrolysis of date palm leaf was performed at different temperatures 300°, 400°, 500°, and 600 °C. The physicochemical characteristics of the synthesized biochar were examined using Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX), Fourier transforms infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD). Direct gas-solid interaction was carried out in an integrated Fluidized Bed Reactor (FBR), connected with a gas analyzer for maximum and effective mixing between the biochar and CO 2. LabView program was used as data acquisition for an instantaneous calculation of CO 2 adsorption. This study showed that the date palm biochar as porous carbon-based materials has high CO 2 adsorption capacity through physisorption and chemisorption progressions. The adsorption results showed a maximum CO 2 capture percentage of 0.09 kg CO 2 /kg, 0.15 kg CO 2 /kg, 0.20 kg CO 2 /kg, and 0.25 kg CO 2 /kg palm biochar synthesized at 300 °C, 400 °C, 500 °C, and 600 °C, respectively. This paper paid attention to the inexpensive technology applied in CO 2 sequestration, where fluidization provides well mixing of biochar particles with low operation cost. • This study aims to prepare different biochar from date palm leaf (DPL) waste and evaluate its CO 2 capture and sequestration capacity. • Biochar samples were pyrolyzed at different temperatures and were characterized using SEM-EDS, FTIR, TGA, and XRD. • The gas-solid reaction was achieved in the integrated fluidized bed reactor on the different DPL biochar particles. Results indicated that the DPL biochar has a high CO 2 adsorption capacity. • The CO 2 sequestration of the DPL ranged from 07 to 25%, based on different temperatures of biochar pyrolysis. [ABSTRACT FROM AUTHOR]

Carbon sequestration in concrete has attracted increasing research attention. CO 2 may be permanently stored in the cement paste of concrete by chemical reaction with the hydration products of cement, but this method leads to a significant reduction of the pH value of the concrete pore solution and may thus put the steel reinforcement at risk of corrosion. This paper proposes a new method for carbon sequestration in concrete using the space in porous coarse aggregates; the method involves presoaking the porous aggregates in an alkaline slurry and then using them for CO 2 sequestration. The potential of utilising the space in the porous aggregates and the cations in the alkaline slurry is first discussed. An experimental study aiming to demonstrate the feasibility of the proposed method is then presented. The results show that CO 2 can be successfully sequestrated and fixed as CaCO 3 in the open pores of coarse coral aggregate presoaked in a Ca(OH) 2 slurry. The amount of CO 2 sequestration by concrete produced using the presoaked coral aggregate was around 20 kg/m3. Importantly, the proposed CO 2 sequestration method did not affect the strength development of the concrete or the pH value of the concrete pore solution. • A new method for CO2 sequestration in concrete using the space in porous aggregates is proposed. • Porous aggregates with alkaline slurry soaking have excellent potential for CO2 sequestration. • The amount of CO2 sequestration by concrete with the porous aggregates was around 20 kg/m3. • The CO2 sequestration method has little effect on the pH value of the concrete pore solution. [ABSTRACT FROM AUTHOR]

Nowadays, there is an increasing use of digital technologies and Artificial Intelligence (AI) such as Machine Learning (ML) models that leverage data to optimize the performances of systems in almost all activity sectors, including ML models for optimizing solutions related to CO2 capture from the atmosphere or CO2 emissions reduction from human activities. However, on the other hand, the use of AI models is leading to an increasing energy consumption that also raises environmental issues (in terms of CO2 emissions) which are less studied in the literature. This then raises the new question of a more realistic estimate of the carbon footprint (CO2 emissions in particular) of AI models in general, and particularly AI models aimed at reducing CO2 emissions. Thus, in this paper, for an AI model in this latter context, we propose a method to quantify both his negative impacts (quantity of CO2 emissions emitted by the training and use of the model) and his positive impacts (quantity of CO2 emissions saved when the model is used). The method is evaluated with three state-of-the-art AI models: (i) an artificial neural network model for managing the energy demand of Brazilian households, (ii) an adaptive neuro-fuzzy inference system for photovoltaic power forecast in Tunisia, (iii) and a Bayesian regression model for the electric vehicle routing problem in Sweden and Luxembourg. Results show that, if only the positive impacts are considered, the reduction of CO2 emitted due to the usage of the models is significant, but depends on each context (34%, 73%, and 9%, respectively). However, when both positive and negative impacts are considered, the negative impacts are sometimes higher than the positive impacts (the first and the third model) for a nominal use (1 user). Nevertheless, the balance becomes highly positive again, when these two projects are scaled up (realistic projections with many users). The second model cannot be scaled up, but the balance remains positive, even if the gains are much smaller. More generally, the CO2 emissions gain metrics provided by our method can be used as new metrics for comparing the efficiency of AI models (for reducing CO2 emissions) beyond predictive capacity-based traditional ML evaluation metrics. Based on the lessons learned from our study, we also provide seven global recommendations that can contribute to the reduction of the carbon footprint of ML models in general. • Increase of the use of AI models for optimizing solutions to reduce CO2 emissions. • Training and using AI models also generates CO2 emissions. • Method to quantify positive and negative environmental impacts of AI models. • Evaluations based on three state-of-the-art AI models. • Seven global recommendations for reducing CO2 emissions of AI models. [ABSTRACT FROM AUTHOR]

Increasing soil organic carbon (SOC) stocks in agricultural soils removes carbon dioxide from the atmosphere and contributes towards achieving carbon neutrality. For farmers, higher SOC levels have multiple benefits, including increased soil fertility and resilience against drought-related yield losses. However, increasing SOC levels requires agricultural management changes that are associated with costs. Private soil carbon certificates could compensate for these costs. In these schemes, farmers register their fields with commercial certificate providers who certify SOC increases. Certificates are then sold as voluntary emission offsets on the carbon market. In this paper, we assess the suitability of these certificates as an instrument for climate change mitigation. From a soils' perspective, we address processes of SOC enrichment, their potentials and limits, and options for cost-effective measurement and monitoring. From a farmers' perspective, we assess management options likely to increase SOC, and discuss their synergies and trade-offs with economic, environmental and social targets. From a governance perspective, we address requirements to guarantee additionality and permanence while preventing leakage effects. Furthermore, we address questions of legitimacy and accountability. While increasing SOC is a cornerstone for more sustainable cropping systems, private carbon certificates fall short of expectations for climate change mitigation as permanence of SOC sequestration cannot be guaranteed. Governance challenges include lack of long-term monitoring, problems to ensure additionality, problems to safeguard against leakage effects, and lack of long-term accountability if stored SOC is re-emitted. We conclude that soil-based private carbon certificates are unlikely to deliver the emission offset attributed to them and that their benefit for climate change mitigation is uncertain. Additional research is needed to develop standards for SOC change metrics and monitoring, and to better understand the impact of short term, non-permanent carbon removals on peaks in atmospheric greenhouse gas concentrations and on the probability of exceeding climatic tipping points. Overview of the challenges associated with using soil carbon certificates as privately traded, voluntary emission offsets. [Display omitted] • Soil-based carbon certificates are sold as voluntary emission offsets. • Private certification schemes provide financial incentives for carbon farming. • However, they are not a suitable tool for climate change mitigation. • Permanence, additionality and monitoring are not ensured; leakage effects may occur. • Accountability in case of re-emissions of stored carbon is low. [ABSTRACT FROM AUTHOR]

The carbonation of alkaline wastes is an interesting research field that may offer opportunities for CO 2 reduction. However, the literature is mainly devoted to studying different waste sequestration capabilities, with lame attention to the reliability of the data about CO 2 reduction, or to the possibilities to increase the amount of absorbed CO 2. In this work, for the first time, the limitation of some methods used in literature to quantify the amount of sequestered CO 2 is presented, and the advantages of using suitable XRD strategies to evaluate the crystalline calcium carbonate phases are demonstrated. In addition, a zero-waste approach, aiming to stabilize the waste by coupling the use of by-products and the possibility to obtain CO 2 sequestration, was considered. In particular, for the first time, the paper investigates the differences in natural and accelerated carbonation (NC and AC) mechanisms, occurring when municipal solid waste incineration (MSWI) fly ash is stabilized by using the bottom ash with the same origin, and other by-products. The stabilization mechanism was attributed to pozzolanic reactions with the formation of calcium silicate hydrates or calcium aluminate hydrate phases that can react with CO 2 to produce calcium carbonate phases. The work shows that during the AC, crystalline calcium carbonate was quickly formed by the reaction of Ca(OH) 2 and CaClOH with CO 2. On the contrary, in NC, carbonation occurred due to reactions also with the amorphous Ca. The sequestration capability of this technology, involving the mixing of waste and by-products, is up to 165 gCO 2 /Kg MSWI FA, which is higher than the literature data. [Display omitted] • The limitations of some methods used to quantify the sequestrated CO2 are presented. • The use of XRD to evaluate the crystalline calcium carbonate phases is validated. • An approach, aiming to stabilize fly ash and obtain CO2 sequestration, is considered. • In the first hours, CaCO3 is formed by the reaction of Ca(OH)2 and CaClOH with CO2. • After the first days, carbonation occurs due to a reaction with the amorphous. [ABSTRACT FROM AUTHOR]

Converting industrial wastes into value-added building products in an environmental management strategy is a challenging yet vital component of the industrial process. Steel slag (SS), an industrial waste by-product from the steel-making process, is typically disposed of in landfill which consumes land resources and pollutes the environment. This paper explores the possibility of a closed-loop system to convert steel slag into a cement material through carbonation activation, thereby significantly reducing the amount of steel slag waste sent to landfills across Canada. The production of this cementing material can occur next to the steel mill, utilizing steel slag and carbon dioxide collected on-site to fabricate carbon-negative products. To save energy and allow production to be feasible on an industrial scale, ambient pressure (AP) carbonation is developed to reduce carbon emissions while improving their performance. High pressure (HP) carbonation curing and normal hydration (NH) references were also implemented at the same time to justify the application of AP carbonation in reducing CO 2 emission. The results of this study found AP carbonation-activated SS compacts have comparable CO 2 uptake (about 7.5 tons CO 2 /100 tons slag) and mechanically compressive strength values as those subjected to HP carbonation, suggesting that AP could be used to replace HP in carbonation curing to ensure a lower energy input. Additionally, AP seemed to possess as effective carbonation as HP. The studies investigated by multiple techniques including X-ray diffractometer (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopic analysis, and scanning electron microscopy (SEM) aim to identify the microstructure development of carbonated SS paste to assess carbonation results. Developed with life cycle assessment (LCA), environmental impact evaluation shows that AP presents a smaller global warming potential (GWP) value than HP. The comparable CO 2 sequestration, satisfactory engineering properties, enhanced microstructure and lesser environmental impact in AP carbonation confirm the feasibility of replacing high pressure with extremely low pressure to cure concrete products. The use of AP carbonation for cement material created using steel slag reduces carbon emissions, energy usage, and natural resource consumption. • Ambient pressure can be used to replace high pressure in early carbonation curing. • Ambient pressure carbonation can turn steel slag into a clean cementing material. • The production of carbon-negative products can be set next to the steel mill. • Ambient pressure carbonation presents a relatively uniform and effective reaction. • Life cycle assessment confirms ambient pressure carbonation reduces CO 2 emission. [ABSTRACT FROM AUTHOR]

A new dual-cage-based porous metal-organic framework (MOF, termed DZU-113) assembly from the triazole-carboxylate linker and the Cu(II) paddle-wheel unit was solvothermally constructed. The structure of DZU-113 was determined by single-crystal X-ray diffraction, being consisted of the octahedral cage with an internal diameter of approximately 0.4 ​nm, and the spindle nano-cage with internal pores of about 0.8 ​nm ​× ​2.2 ​nm, respectively. Specially, the uncoordinated N atoms of triazole groups are distributed in the bottleneck windows of the spindle nano-cage, serving as open functional sites. DZU-113 has permanent porosity with the Brunauer−Emmett−Teller surface area of 1207 ​m2 ​g−1. The CO 2 adsorption test demonstrated that the total uptake of DZU-113 can reach 66.7 ​cm3 ​g−1 ​at 298 ​K, and 112.0 ​cm3 ​g−1 ​at 273 ​K, 1 ​bar. Moreover, it achieves robust catalytic performance for the cycloaddition of CO 2 and epoxides under mild conditions. In this paper, a new dual-cage-based porous metal-organic framework (termed DZU-113) assembly from the triazole-carboxylate linker and the Cu(II) paddle-wheel unit was solvothermally constructed, which has good CO 2 adsorption capacity and catalytic performance for the cycloaddition of CO 2 and epoxides under mild conditions, owing to the cage structure and the uncoordinated N atoms in its structure. [Display omitted] • A porous Cu-MOF (DZU-113) featuring octahedral and spindle cages was successfully synthesized. • Uncoordinated N atoms of ligand were distributed in the bottleneck windows of the spindle cage to serve as functional site. • DZU-113 exhibited good CO 2 capture and can catalyze the cycloaddition reaction of CO 2 with epoxides under mild environments. • The relatively high solvents and thermal stability endows the DZU-113 with high reusability. [ABSTRACT FROM AUTHOR]

In recent years, global warming has become an important topic of public concern. As one of the most promising carbon capture technologies, solid amine adsorbents have received a lot of attention because of their high adsorption capacity, excellent selectivity, and low energy cost, which is committed to sustainable development. The preparation methods and support materials can influence the thermal stability and adsorption capacity of solid amine adsorbents. As a supporting material, it needs to meet the requirements of high pore volume and abundant hydroxyl groups. Industrial and biomass waste are expected to be a novel and cheap raw material source, contributing both carbon dioxide capture and waste recycling. The applied range of solid amine adsorbents has been widened from flue gas to biogas and ambient air, which require different research focuses, including strengthening the selectivity of CO 2 to CH 4 or separating CO 2 under the condition of the dilute concentration. Several kinetic or isotherm models have been adopted to describe the adsorption process of solid amine adsorbents, which select the pseudo-first order model, pseudo-second order model, and Langmuir isotherm model most commonly. Besides searching for novel materials from solid waste and widening the applicable gases, developing the dynamic adsorption and three-dimensional models can also be a promising direction to accelerate the development of this technology. The review has combed through the recent development and covered the shortages of previous review papers, expected to promote the industrial application of solid amine adsorbents. [Display omitted] • The review is based on studies about solid amine adsorbents. • The technology of solid amine adsorbents provide a novel solution to global warming. • Waste-derived support materials contribute both carbon dioxide capture and waste recycling. • The application to biogas and ambient air is a promising development direction. • Novel kinetic and isotherm models should be developed to study adsorption process. [ABSTRACT FROM AUTHOR]

Quantifying fossil fuel CO 2 (CO 2 ff) in the atmosphere provides a benchmark method to monitor anthropogenic carbon emissions. Radiocarbon (14C) in atmospheric CO 2 ff has been widely studied using the 14C in plants to document regional CO 2 ff patterns. However, annual CO 2 ff variations, reflecting spatial distributions based on plant samples, are still scarce. In this paper, the spatial distribution and temporal CO 2 ff changes in the Guanzhong Basin is established using Δ14C measurements from maize leaves collected in 2011 and 2012. With regard to spatial distribution, samples collected around Xi'an City showed lower Δ14C values (more CO 2 ff), while sites located near the perimeter of the basin showed higher Δ14C values (less CO 2 ff). This is likely due to the concentration of anthropogenic activities in the center of the Guanzhong Basin. The observed CO 2 ff mole fractions generally matched with PKU CO 2 inventory and the ODIAC CO 2 inventory data in the spatial distribution trend. However, it seems that thermal power plants were not well captured by the PKU CO 2 inventory. Our results provide useful information for the improvement of the inventory and verification of regional carbon cycle models. • The Δ14C in maize leaves for 2011 and 2012 were analyzed in Guanzhong Basin. • Spatial distribution of CO 2 ff mole fractions in Guanzhong Basin were studied. • The spatial pattern of observed CO 2 ff matches with the CO 2 inventory. [ABSTRACT FROM AUTHOR]

Seagrass meadows, through their large capacity to sequester and store organic carbon in their sediments, contribute to mitigate climatic change. However, these ecosystems have experienced large losses and degradation worldwide due to anthropogenic and natural impacts and they are among the most threatened ecosystems on Earth. When a meadow is impacted, the vegetation is partial- or completely lost, and the sediment is exposed to the atmosphere or water column, resulting in the erosion and remineralisation of the carbon stored. This paper addresses the effects of the construction of coastal infrastructures on sediment properties, organic carbon, and total nitrogen stocks of intertidal seagrass meadows, as well as the size of such stocks in relation to meadow establishing time (recently and old established meadows). Three intertidal seagrass meadows impacted by coastal constructions (with 0% seagrass cover at present) and three adjacent non-impacted old-established meadows (with 100% seagrass cover at present) were studied along with an area of bare sediment and two recent-established seagrass meadows. We observed that the non-impacted areas presented 3-fold higher percentage of mud and 1.5 times higher sedimentary organic carbon stock than impacted areas. Although the impacted area was relatively small (0.05–0.07 ha), coastal infrastructures caused a significant reduction of the sedimentary carbon stock, between 1.1 and 2.2 Mg OC, and a total loss of the carbon sequestration capacity of the impacted meadow. We also found that the organic carbon stock and total nitrogen stock of the recent-established meadow were 30% lower than those of the old-established ones, indicating that OC and TN accumulation within the meadows is a continuous process, which has important consequences for conservation and restoration actions. These results contribute to understanding the spatial variability of blue carbon and nitrogen stocks in coastal systems highly impacted by urban development. • Seagrass organic carbon (OC) stock was impacted by coastal infrastructures. • OC stocks at impacted areas were 1.5 times lower than at non-impacted areas. • Non-impacted areas presented 3-fold higher percentage of mud than impacted areas. • Recently established meadow presented 30% lower OC than the old-established ones. [ABSTRACT FROM AUTHOR]

Decarbonizing the cement manufacturing sector presents an interesting and pressing challenge as it is one of the largest energy consumers in industry (i.e., 7%), emitting considerable amounts of anthropogenic carbon dioxide (i.e., 7%). This paper performs a technical and environmental assessment of decarbonisation of cement production through process modelling and simulation, thermal integration analysis, and Life Cycle Assessment (LCA). Integration of three post-combustion capture methods for a conventional cement plant with an annual productivity of one million tons and a carbon capture rate of 90% is evaluated in comparison to the reference case without carbon capture and storage (CCS). Mass and energy balances derived from simulations are used for the assessment of three innovative capture systems: reactive gas-liquid absorption using Methyl-Di-Ethanol-Amine, reactive gas-solid adsorption using calcium looping (CaL) technology and membrane separation. For the LCA study, a "cradle-to-gate" approach is carried out using GaBi software, according to the ReCiPe impact assessment method. The general conclusion is that integrating the CCS methods into the cement production process leads to a decrease in global warming potential (GWP) in the range of 69.91%–76.74%. Of the CCS technologies analysed, CaL technically outperforms the others as it requires 34% less coal and provides 1.6 times higher gross energy efficiency. From an environmental perspective, CaL integration ranks first, with the lowest scores in six of the nine impact categories and a GWP reduction of 76.74% compared to the baseline scenario without CCS. [Display omitted] • Decarbonisation of the cement industry by post-combustion CO 2 capture technologies. • Thermal integration, technical and environmental evaluation were carried out. • Chemical scrubbing and calcium looping are self-sufficient in terms of heat and power. • Calcium looping exhibits better environmental performances than other two cases. [ABSTRACT FROM AUTHOR]

Biochar can achieve multiple benefits including solid waste management, polluted water remediation, carbon sequestration, and emission reduction. However, various environmental factors (such as temperature variations and dry-wet alternation) and microbial activity may lead to the fragmentation, dissolution, and oxidation of biochar. These accelerate the dissolution of biochar-derived dissolved organic matter (DOM) and then influence disinfection byproducts formation potential (DBPFP) throughout the water treatment process. In this paper, biochars from six biomass feedstocks with five aging processes were prepared, and the DBPFP of biochar and its derived DOM were first studied systematically. Different aging processes might increase the DBPFP of biochar by increasing DOM content and changing the fraction distribution of DOM derived from biochar. Especially, the DBPFP of biochar increased apparently with the chemical aging process. Coexisting with the environmental concentration of humic acid, even aged biochar showed the potential to reduce DBPFP and integrated toxic risk value of the mixed system. In this study, the DBPFP of biochar-derived DOM during the disinfection process is confirmed, and the results can give information to the selection of biomass feedstocks of biochar and its service life in the water treatment process. [Display omitted] • Disinfection byproducts formation potential of aged biochar was first evaluated. • DBPFP of biochar influenced by feedstocks and pyrolysis temperature. • ITRV of chemical aged biochar-derived DBPs increased by 100 times. • Even aged biochar can reduce toxicity of simulated raw water during chlorination. [ABSTRACT FROM AUTHOR]

Although there are some review papers on carbon capture, utilization and storage (CCUS), hardly any of these reviews are focused on the role of CO 2 enhanced oil recovery (EOR) in accelerating carbon neutrality in China. In this review, strategies to achieve carbon neutrality is briefly but critically discussed, followed by a review of CO 2 -EOR as a promising technology. Especially, data analysis, including the number of publications on China's carbon neutrality, per capita CO 2 emissions, China's power generation, and the crude oil production of China's large oilfields, is carried out to make the discussion more comprehensive. Given the large amount of coal consumed in China, the high percent of electricity generated with coal, and the slow penetration of renewables already observed, it seems unlikely that 2060 targets will be met without CCUS. In order to achieve carbon neutrality, both reduction in carbon emissions and increase in carbon sequestration are inevitable. Furthermore, it is concluded that CO 2 storage through EOR is likely to have a bright future. However, there are some critical issues to be solved, including the technical issues, leakage and safety issues, cost issues, policy issues, etc. In order to turn CO 2 -EOR into a reliable and more favorable technology, more research and efforts are needed to solve these issues, including advancing carbon capture technologies, improving storage technologies, developing effective monitoring technologies, deploying government support and incentive policies, etc. • CO 2 emission reduction and sequestration are needed to achieve carbon neutrality. • Carbon capture and storage without utilization is not suitable for China. • CO 2 -enhanced oil recovery (EOR) is more viable as a cost-effective CCUS technology. • CO 2 -EOR is likely to make great contributions to China's carbon neutrality target. • CO 2 leakage risk exists and more research is needed to ensure CO 2 is safely stored. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) emissions from fossil fuel combustion have been linked to increased average global temperatures, a global challenge for many decades. Mitigating CO 2 concentration in the atmosphere is a priority for the protection of the environment. This is a comparison of the three main technological categories available for CO 2 capture and storage. They include: oxy-fuel combustion, pre-combustion, and post-combustion. Each capture technology has inherent benefits and disadvantages in cost, implementation, and flexibility, but post-combustion CO 2 capture has demonstrated the most promising results in typical power plant configurations. This paper presents a review of different post-combustion CO 2 capture materials; solvents, membranes, and adsorbents, focusing on economical and environmentally safe low to high temperature solid adsorbents. Furthermore, the authors summarize the advantages and limitations of the materials investigated to provide insight into the challenges and opportunities currently facing the development of post-combustion CO 2 capture technologies. The solid sorbents currently available for CO 2 capture are also reviewed in detail, including physical and chemical properties, reactions, and current research efforts on improvement. [Display omitted] • Emerging trends in post-combustion CO 2 capture are introduced and compared. • Recent advances in solid sorbents for post-combustion CO 2 capture is investigated and summarized. • New development in solid adsorbents and factors that affect treatment performance. • Review of economics, environmental analysis and policy in post-combustion CO 2 capture. [ABSTRACT FROM AUTHOR]

Agroforestry has a potentially important role in helping agriculture address both the climate and biodiversity crises. It provides a means of producing additional marketable goods from agricultural land and enhancing biodiversity at the same time as increasing carbon sequestration and, in silvo-pastural systems, reducing carbon emissions if livestock stocking rates are reduced. However, the uptake of agroforestry in the UK has been limited. This paper adopts Real Options techniques to explore how the decision to adopt agroforestry is influenced by the relative levels of returns from agriculture, forestry and the price of carbon under the scenario where there are financial penalties from livestock Greenhouse Gas (GHG) emissions, financial benefits from carbon sequestration in trees and reversibility in land use decisions. The results are compared to the equivalent findings from a Land Equivalent Value capital budgeting approach to agroforestry adoption. Analysis is based on data from a case study upland livestock farm in Scotland, comparing the impacts of introducing agroforestry into the hill sheep enterprise or the low ground cattle and sheep enterprise. The results suggest that the adoption of agroforestry is far less likely than would be suggested by standard budgeting approaches, especially in more extensive upland enterprises (hill area) where sequestration benefits are low relative to more productive farmland areas (low ground area). Upfront support payments are shown to increase the likelihood of agroforestry adoption. They also have the effect of reducing the rotation length of forestry in such systems. • Real Options techniques are useful for understanding agroforestry adoption. • Agroforestry adoption is unlikely at current carbon price levels. • Biophysical factors have a significant influence on agroforestry adoption. • Upfront payments will significantly increase agroforestry adoption. • Standard budgeting approaches fail to recognise key barriers to agroforestry. [ABSTRACT FROM AUTHOR]

Globally, all countries have producing different levels of carbon emissions and also facing both the problems of climate change and global warming due high carbon emissions in the atmosphere. Therefore, it is important to cutting carbon emissions in the atmosphere. This is only possible by switching to cleaner fuels, use of innovation technologies and development of carbon capture storages. These can substantially help the nations to reaching carbon neutrality. Given this background, t his paper examines the effect of disaggregated energy consumption, technological innovations, capital on economic output and CO 2 emissions in India for the period of 1990–2018. Based on empirical analysis, our long-run elasticities indicate that disaggregated energy consumption and technological innovations have a positive impact on economic growth, while renewable energy consumption and technological innovations have a positive impact on CO 2 emissions. It implies that more use of energy consumption producing significant amount of CO 2 emissions and by using renewable energy consumption and technological innovations (i.e. carbon capture storages) can significantly lowering CO 2 emissions, which is clearly indicating that India has moving towards carbon neutrality. The causality analysis further indicates a unidirectional causal relationship running from disaggregated energy usage to economic growth and carbon emissions. These empirical findings suggest that the increased consumption of renewable power does not lead to rise carbon emissions, which, in turn, ensures sustainable economic growth. • Examines the disaggregated energy consumption, technological innovations, capital on economic output and CO 2 emissions. • Time series data from 1990 to 2018 was used to analyze the empirical results. • Disaggregated energy consumption and technological innovations have a positive impact on economic growth. • Renewable energy consumption and technological innovations have a positive impact on CO 2 emissions. • Suggest that increased in consumption of renewable power does not lead to rise carbon emissions. [ABSTRACT FROM AUTHOR]

Ecosystem service (ES) mapping has been developed with the aim of supporting ecosystem management, but ES maps often lack information about uncertainty and risk, which is essential for decision-making. In this paper, we use a risk-based approach to map ES in mountain forests, which are experiencing an increasing rate of natural disturbances, such as windthrow, bark beetle outbreaks, and forest fires. These disturbances affect the capacity of forests to provide essential ecosystem services, such as protection from natural hazards, wood production, and carbon sequestration, thus posing a challenge for forest management. At the same time, disturbances may also have a positive effect on certain services, e.g. by improving habitats for species that rely on dead wood. We integrate forests' susceptibility to natural disturbances into probabilistic Bayesian Network models of a set of ES (avalanche protection, carbon sequestration, recreation, habitats, and wood production), which combine information from remote sensing, social media and in-situ data, existing process-based models, and local expert knowledge. We use these models to map the level of the services and the associated uncertainties under scenarios with and without natural disturbances in two case study areas in the Swiss Alps. We use clustering to identify bundles of risk to ES, and compare the patterns of risk between the non-protected area of Davos and the strictly protected area of the Swiss National park with its surroundings. The spatially heterogeneous pattern of risk to ES reflects topographic variability and the forest characteristics that drive disturbance susceptibility, but also the demand for ecosystem services. In the landscape of Davos, the most relevant risks to ES are related to decreases in the protection against avalanches and carbon sequestration, as well as some risk to wood production and recreation. In the strictly protected Swiss National Park, the overall level of ES risk is lower, with an increase in habitat quality under the disturbance scenario. This risk-based approach can help identify stands with high levels of ES that are particularly susceptible to disturbances, as well as forests with a more stable ES provision, which can help define priorities in forest management planning. • Mountain forest ecosystem services are at risk due to natural disturbances. • We map risks to ecosystem services in (non)protected areas in the Swiss Alps. • Disturbances have spatially heterogeneous effects on ecosystem services. • The spatial pattern of risk is influenced by demand for ecosystem services. • Risk to ecosystem services is lower in a strictly protected area. [ABSTRACT FROM AUTHOR]