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CO 2 concentration in the atmosphere has crossed an unprecedented level of 420 ppm, causing catastrophic events like climate change. Climate change mitigation via carbon capture is crucial for reducing CO 2 emissions. Among various CO 2 capture technologies, adsorption is considered one of the most efficient and promising techniques. In recent times, substantial research has been conducted on producing cost-effective and efficient adsorbents for CO 2 capture via the thermal and chemical treatments of biomass. In this review, we discuss key scientific results to give broad insight into the recent progress in biomass conversion to activated porous carbon (APC). The effects of various chemical and thermal treatments on the textural properties and CO 2 adsorption capacity of APC are comprehensively discussed. CO 2 adsorption mechanism based on interaction with the surface functionality is thoroughly explained. The economic aspects of APC synthesis and post-combustion CO 2 capture using APC are systematically reviewed. [Display omitted] • Use of biomass based activate porous carbon (APC) for CO 2 capture is reviewed. • CO 2 adsorption mechanism on APC surface is thoroughly explained. • APC surface functionalization via metal doping and heteroatom doping is discussed. • Economics of APC synthesis & large-scale CO 2 capture on APC is critically reviewed. [ABSTRACT FROM AUTHOR]

Climate change poses a significant threat to humanity and human activity is largely responsible for it. Clinical microbiology laboratories have their unintended shares in carbon dioxide (CO 2) emissions. The aim of this study is to estimate CO 2 emission of a clinical microbiology laboratory and to propose initiatives to reduce the emissions. CO 2 emission of instruments was estimated based on their electricity consumption. CO 2 emitted in producing consumables was estimated by weighing the consumables needed to perform major tests in a large academic hospital. A systematic literature review was performed to identify studies on the impact of clinical microbiology laboratories on the environment. A short survey was sent to four major manufacturers of agar plates on initiatives to reduce the environmental impact of their products. Opinion was given on activities that can reduce CO 2 emission in laboratories. The study shows that the largest amount of CO 2 emission in the microbiological laboratories comes from consumables and personnel commuting. For example, the production and transportation of agar plates needed to culture samples for a year in a hospital with 1320 beds result in 16 590 kg CO 2 is emitted. All survey participants mentioned that they were committed to reduce environmental impact of their products. The initiatives to reduce CO 2 emission can be performed at the laboratory and at policy level, such as reducing the number of tests to only the necessary amount to reduce consumables. The calculations contribute to map CO 2 -related emissions in clinical microbiology laboratory activities, and the proposed initiatives to reduce the CO 2 may serve as starting point for further discussions. [ABSTRACT FROM AUTHOR]

Bauxite residue or Red Mud (RM) is a by-product from alumina refineries. It has a high pH of 11–13 and accumulates globally at 200 million tons yearly, totalling about 4.6 billion tons. Being an alkaline anthropogenic geomaterial, its adsorption properties and reactivity with acidic gases make it a potential sink for CO 2 and SO X emissions from the aluminium industry. It offers both research challenges and opportunities for its utilisation at an industrial scale. In particular, carbon capture and mineralisation (CCM) within RM has been demonstrated in situ and waste disposal areas through direct air trapping of atmospheric CO 2. The RM-CO 2 system is also operated in ex-situ conditions in various physical states, such as powder, wet cakes, and slurry, with yields of carbonates as CaCO 3 , Na 2 CO 3 , and FeCO 3. Our contribution as a review illuminates significant advancements made and challenges for enhancing the mineral carbonation potential of RM, thereby delineating areas necessitating further exploration. Although, researchers have primarily focused on accelerating the CCM process in RM through slurry carbonation techniques. Recent advancements in filter press technologies have favoured soda recycling and wet cake disposal of RM, creating artificial mountains of RM stacks. With changing disposal trends for RM, it is vital to understand the mechanisms that govern long-term atmospheric CO 2 trapping in RM disposal areas. Recent investigations of techniques, hydrothermal treatment and dual-stage calcification-carbonation methods have expanded the domain of CCM in RM. Given the global need to reduce CO 2 emissions, CCM using RM does offer promising insights on account of its unique physicochemical and mineralogical properties. We, although presume that RM alone will not fully offset the CO 2 emissions of the aluminium industry. Enhanced weathering and mineral carbonation could reduce over 50% of refinery emissions. Uncertainties persist regarding methods of CO 2 sequestration potential and techno-economic feasibility when tested at a field scale. Moreover, contrasting results are revealed, primarily regarding changing disposal trends, variabilities in mineralogy, and limited knowledge of micro-mechanisms of the CCM process in RM. This work elucidates existing knowledge on synthesising CO 2 mineralisation, pathways, and mechanisms under various states associated with leveraging RM as a significant carbon sink in current and future climate change mitigation efforts. [Display omitted] • Illustrates RM mineral carbonation process and mechanistic models for CCM methods (slurry, semi-dry, atmospheric). • CCM potential is studied along with mechanisms using hydrothermal treatment, siderite formation and calcification-carbonation method. • Guidelines for RM sample extraction methods based on its physico-geochemical changes in BRDA with atmospheric CO 2. • Current and future research directions are discussed. [ABSTRACT FROM AUTHOR]

Efforts to enhance greenhouse gas (GHG) emission reduction in East Asia play a pivotal role on both global and regional scales in advancing climate mitigation strategies. This study aimed to better constrain anthropogenic CO 2 emission estimates by expanding the network of near-surface in-situ stations for CO 2 observations across South Korea. To achieve an optimal CO 2 network design, we conducted an Observing System Simulation Experiment (OSSE) coupled with the Stochastic Lagrangian Transport model (STILT), utilizing meteorological data from the Korean Integrated Model (KIM). Our inversion setup incorporated two CO 2 emission datasets with a 0.1o resolution: EDGAR v6 for prior emissions and GRACED for truth emissions. A uniform model-mismatch error of 3 ppm was introduced across sites. The effectiveness of the existing five in-situ stations, termed the base network, in South Korea was evaluated to gauge their ability to constrain CO 2 surface flux estimates. However, the findings revealed a reduction in flux uncertainty of only 29.2%, which fell short of the desired uncertainty reduction goal. In this base network, the Lotte World Tower (LWT: 37.5126°E, 127.1025°E) in Seoul and the Anmyeondo (AMY: 36.538576° N, 126.330071° E) site in Taean county stood as major contributors, with estimated reductions of 17.48% and 6.35%, respectively. Consequently, we proposed and developed an extended network, identifying seven candidate sites based on consideration of logistical factors, existing infrastructures, and proximity to the emission source regions. An incremental optimization scheme ranked their contributions, resulting in an additional 25% reduction, bringing the total to 54.13%. However, it is noteworthy that diminishing returns (ranging from 13% to less than 0.1%) were observed with an increase in station count mainly due to the possibility that adding a station earlier in the sequence might render subsequent stations redundant. Despite this, the proposed CO 2 network successfully reduced uncertainty in emissions, narrowing the gap with the objectives of the Global Greenhouse Gas Watch (G3W). • Designing CO 2 near-surface observation network over South Korea. • New stations selected considering logistic factors, existing infrastructures, and proximity to emission sources. • The base network was able to reduce 29.18% of the uncertainty in CO 2 emissions. • Extending network, by adding new seven candidate sites, led to a total uncertainty reduction of 54.13%. [ABSTRACT FROM AUTHOR]

Planning power system (PS) towards renewable energy is crucial for reducing carbon dioxide (CO 2) emission as well as mitigating climate change. However, the inherent uncertainty and hierarchical structure of PS pose intractable challenges to the planning process. This study develops a multi-GCM-based interval bi-level programming (MIBP) method that can balance two-level decision-making conflict between CO 2 -emisison reduction and system cost minimization. MIBP can also deal with uncertainties expressed as interval values in objective functions and constraints. Then, a MIBP-PS model is formulated to plan PS for China (2021–2050), where the upper-level objective is to minimize CO 2 emission and the lower-level objective is to minimize the system cost. The major findings are: (i) the CO 2 emission for PS would reach peak value before 2030 and then reduce by [10.2, 20.4]% in 2050, which is mainly owing to the curtailment of fossil fuel; (ii) compared with the conventional model, CO 2 emission from MIBP-PS model could decrease by [3.1, 4.8]%, which shows the superiority of the developed model; (iii) the fossil-fuel power would be gradually replaced by renewable energy, and the proportion of coal-fired power would decrease by 38.8% by 2050, especially small coal-fired facilities (i.e., below 0.3 GW) should be gradually phased down. [Display omitted] [ABSTRACT FROM AUTHOR]

Policies that incentivize the capture and geological storage of CO 2 from large point sources ('CCS'; and more recently, atmospheric removals), have so far tended to reward the resultant avoided CO 2 emissions (or CO 2 removals) achieved by operators at the point of capture. The expectation has been that geological CO 2 storage sites, as well as the connecting infrastructure, will be developed and operated based upon the funding delivered from the single point of incentive (e.g. under an emissions trading system or a carbon tax, only CO 2 capture installation operators are absolved of the obligation to acquire and surrender CO 2 emission rights or to pay the tax). Project-based crediting mechanisms (e.g. in the voluntary carbon market) tend to treat the entire chain of operations as a single entity to be supplied with emission reduction or removal credits. Consequently, there has been minimal explicit financial incentive to store CO 2. Yet a multiple gigaton-per-year scale capture and storage industry requires complex CO 2 networks to evolve, with multiple sources connecting to multiple sinks, with installations owned by different operators with different technical expertise, climate mitigation goals and obligations. This multiplicity of goals and incentives can create agency problems and cross-chain risks, which impact negatively upon investment decisions. In this paper, we review the history, evolution and potential of geological net zero (GNZ) and carbon storage (or takeback) obligation concepts applied to fossil carbon producers and suppliers as a means to address these risks alongside policies aimed at atmospheric net zero (ANZ) and fossil carbon emitters. [ABSTRACT FROM AUTHOR]

Animal production faces challenges related to thermal comfort, air quality, and carbon dioxide (CO 2) emissions, thereby the need for more efficient and sustainable systems due to climate change. This study examines green roofs and their potential to absorb atmospheric CO 2 and reduce heat load through photosynthesis and evapotranspiration, resulting in decreased energy consumption and increased CO 2 emissions. The maximum CO 2 concentration limit in animal production facilities is 3000 ppm. Depending on the ventilation system used in broiler production facilities, the CO 2 concentration can exceed 2000 ppm. Dark House poultry facilities tend to have higher concentrations reaching up to 777 ppm. In pig farming, the nursery sector has higher concentrations of CO 2 , exceeding 1200 ppm. In dairy farming, the number of milkings, the type of ventilation system and local climatic conditions can affect the CO 2 concentration, reaching values of up to 1401 ppm. C3 plants have a CO 2 saturation point at 800 ppm and C4 plants at 200 ppm. The CO 2 balance in animal production facilities that use a green roof can be done considering the CO 2 produced and the CO 2 absorbed. Green roofs are therefore considered a sustainable solution for animal production. Its implementation enhances air quality in the facilities, supporting the reduction of environmental impacts and mitigation of climate change effects caused by the agroindustry. This investigation underscores the significance of green roofs, emphasizing their environmental, social, and economic benefits, as well as their applicability in animal production. • It is possible to estimate the CO 2 balance in animal production facilities with a green roof. • Green roof can improve air quality in animal production. • Green roof can reduce the thermal stress of the animals in the premises. • Green roof can contribute to the sustainability of animal production. [ABSTRACT FROM AUTHOR]

• Indoor CO 2 exceeded 1000 ppm 33% of the time and ventilation rates were below 7 L/s. • Increasing ventilation increased CO 2 emissions, energy, and costs between 1 and 4%. • Rooftop gardens always counterbalanced increased CO 2 emissions, energy, and costs. • Enhancing plant growth increases CO 2 emissions benefits by an additional 23%. Building energy use contributes to urban carbon dioxide (CO 2) emissions while inadequate ventilation can yield indoor CO 2 build up from human respiration. However, increasing ventilation rates can add to energy costs and climate burdens. Our objective was to quantify changes in emissions, energy, and financial cost when rooftop garden and ventilation upgrades are done simultaneously, with an opportunity to enhance plant growth from exhausted CO 2. We measured indoor CO 2 concentrations, calculated ventilation rates, and modeled five scenarios to assess these impacts. The indoor CO 2 concentration maximum was 2210 ppm, median was 840 ppm, and 33% of the daytime was spent above 1000 ppm. The estimated ventilation rate was 4 L/s. Our model calculations show that increasing ventilation to recommended levels (7 L/s) would increase total CO 2 emissions, energy use, and cost (1–4%), but this could be counterbalanced by rooftop garden installation benefits, which yielded a net decrease of 23–46% in CO 2 emissions, 12–13% in energy use, and 12–16% in cost. This novel integration of data collection and modeling provides support for the co-benefits of simultaneous improved installation ventilation systems and indoor CO 2 -enhanced rooftop gardens. [ABSTRACT FROM AUTHOR]

Clean vehicle fleet will greatly benefit air quality and climate change mitigation. Here, we employ an integrated model to systematically investigated the contribution of combined clean vehicle policies to "emissions, exposure, and health benefits" from a regional perspective 2019–2035 in China. We find that driven by clean vehicle polices, the national vehicle CO 2 will likely to peak around 2028 with about 1327 million tons, and then reduce by 7.8% from 2028 to 2035. The developed region will peak CO 2 before 2030, while the developing region probably peak after 2030. In general, most air pollutants emissions from vehicles will decrease, subsequently leading to obvious PM 2.5 and O 3 exposure decrease. About 68 thousand PM 2.5 related and 33 thousand O 3 related deaths will be avoided 2019–2035 nationwide. Note that the health benefits are unequal, with higher PM 2.5 -O 3 related excess deaths be avoided per 100000 in developed region than developing region. Besides, results show that emission standard upgrade contributes largest to emission reduction and related health benefits, followed by electric vehicles, road-to-railways and waterways, and fuel consumption regulation in general. This work is able to provide valuable information for policy makers to collaboratively reduce CO 2 , air pollutants and premature deaths in China and other developing countries. [Display omitted] • Emissions in CO 2 and air pollutants were both investigated based on a dataset with 27 vehicle categories from 338 cities. • The contribution of vehicle clean policies to abated PM 2.5 -O 3 exposure and related deaths was quantified and decomposed. • This work proposed region-specific clean vehicle pathways from a national and regional perspective 2019-2035. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phase equilibria of CO 2 + DIOX hydrate for C DIOX between 0.05 mol% and 5.56 mol% • The kinetics of CO 2 + DIOX hydrate is quantified with morphology observation. • Phase separation of DIOX/H 2 O above 3.1 MPa weakens the promotion effect of DIOX. • A comprehensive evaluation of DIOX in the application of hydrate-based CO 2 storage. To reduce anthropogenic CO 2 emissions for the mitigation of climate change require novel CCUS solutions. Hydrate-based CO 2 sequestration (HCS) is a novel carbon-neutrality technology that aims to store CO 2 in solid hydrate form with long-term stability. However, imminent issues exist for the application of HCS in terms of demanding thermodynamic conditions, slow formation kinetics, and low CO 2 gas uptake. These challenges necessitate the quest for an efficient and eco-friendly CO 2 hydrate promoter. In this study, 1,3-dioxolane (DIOX) as a low-toxicity CO 2 hydrate promoter was systematically examined. The phase equilibria, cage occupancy, and the kinetics of binary CO 2 + DIOX hydrate were measured for DIOX concentrations (C DIOX) varying from 0.05 mol% to 5.56 mol%. It was confirmed that DIOX is a dual-function promoter for CO 2 hydrate, but its promotion effect is weakened for C DIOX between 0.60 mol% and 1.00 mol% and for all C DIOX at relatively high pressure. The CO 2 uptake in the hydrate phase increases with C DIOX above 2.00 mol% and is the highest for C DIOX = 5.56 mol% (57.08 ± 6.39 mmol/mol). Based on the morphology observation, hydrate transits from ice-like to slurry to mushy-like and finally to snow-like with increasing C DIOX. Interestingly, we observed that the aqueous phase separates into two phases (i.e., DIOX-rich and H 2 O-rich) at pressure above 3.09 MPa, which explains the gradual loss of the promotion effect. The results of our study provide a comprehensive evaluation on DIOX as a possible promoter for CO 2 hydrate in HCS application. [ABSTRACT FROM AUTHOR]

[Display omitted] • TUEEC in 10 urban agglomerations in China are substantially different. • TUEEC within urban agglomeration have an impact on CO 2 emissions. • Ecological construction partially mitigated emissions growth. • Guarding against unsustainable development is vital to carbon neutral. Urban agglomerations are major generators of CO 2 emissions owing to human socioeconomic activities. Evaluating the trade-offs between urban expansion and ecological construction during rapid urbanization is a crucial step towards climate change mitigation and carbon neutrality. This study investigated the impacts of trade-offs between urban expansion and ecological construction on CO 2 emissions using multi-source data and spatial and statistical analysis. Ten urban agglomerations in China, with various development levels, were selected as study areas. The results indicated that (1) urban development in the 10 urban agglomerations expanded by 90%–288.9%, while ecological land changed by −28.1–2.3%. (2) CO 2 emissions grew by 154.2–291.2% in urban agglomerations, and the south and east of China emitted more CO 2. The high-value clusters of CO 2 inside of all urban agglomerations expanded outward from cities. (3) Urban expansion increased emissions, while ecological construction partially mitigated emissions growth. Moreover, ecological development within cities helps to reduce excessive urban emissions and should be given more attention. (4) It is as important to guard against unsustainable development as it is to reduce existing high emissions. Low-carbon development paths must continue to be supported in western China. On the basis of the results, we identify important implications for meeting China's target of carbon neutrality. These contribute to an understanding of future development modes for urban agglomerations and reveal the impact of trade-offs of land use on CO 2 emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] Mitigation of climate change by reducing the anthropogenic CO 2 emissions has recently gained huge momentum. A prime pathway to achieve it in the short-medium term lies within capturing CO 2 from industries' flue gases. Post-combustion CO 2 capture (PCC) is the most mature methodology for large-scale CO 2 capture and closest to market. However, the conventional chemical absorption-based PCC process implies high regeneration energy requirements, constituting the majority of the energy load when adding PCC to the plant from which the CO 2 is going to be captured. As such, reducing the overall parasitic load of the conventional process is of interest. Changing the solvent or improving the process flowsheet are two main methodologies to achieve higher energetic efficiency and lower exergy losses. As there are several reviews dealing with novel solvents, this review critically evaluates the progress in improving the conventional PCC process through modifications of process configurations and shadowed by solvent replacements as drop-in solutions. The process configurations were grouped into absorption and stripping enhancement categories. A comparative analysis was conducted between the different available schemes in the literature and interactions between solvents and process configurations were showcased, highlighting the advantages and shortcomings of some of them. The review reveals the need for standardized framework and optimization algorithms using exergo-economic performance indicators for integrated solvent and process synthesis. [ABSTRACT FROM AUTHOR]

Promoting technology development co-operation is particularly relevant while addressing global climate change or regional pollution. Investors may contribute to increasing environmental-related patents, which may help to improve the quality of the environment as long as supported by proper regulations and policies. In the quest towards a cleaner environment via the mitigation of climate change, this study investigates the relationship between technological innovation, income level, renewable energy and carbon emissions in both the United States and China. Applying the dynamic auto-regressive distributive lag (DARDL) simulation method revealed varying impacts of regressors on CO 2 emissions in the short-run and long-run. Accordingly, this study empirically confirms that (i) technological innovation reduces carbon emissions in the United States but it is not statistically significant in China. (ii) Renewable energy reduces carbon emissions in both countries. (iii) The impact of income level on emissions decreases from short-run to long-run in both countries. Decision-makers in China should stimulate more effective environmental-related innovations to decrease CO 2 emissions and should permit easy access to environmental-related patents together with reducing its cost of registration. • Investigates the role of green technological innovation in decreasing CO 2 emissions. • Applies the novel Dynamic ARDL simulation. • Green technological innovation reduces CO 2 emissions in the U.S. Only. • Confirms that renewable energy mitigates CO 2 emissions both in the U.S. and China. [ABSTRACT FROM AUTHOR]

Shipping is associated with various environmental impacts, such as pollutants discharged to air and sea. Much of this pollution appears to be unregulated, and global emissions from shipping are expected to more than triple between 2020 and 2050. This paper reviews global, national, regional and port-level legislative approaches that have been implemented to reduce emissions of carbon dioxide (CO 2), nitrous oxides (NO x), sulphur oxides (SO x) and particulate matter (PM). Policies are identified on the basis of a systematic review of the literature in combination with a detailed analysis of the respective global, national and local policy initiatives. Findings suggest that many policies are voluntary or, in ports, incentive-based; regulatory approaches are largely limited to Emission Control Areas. Policies also focus on efficiencies, they are not concerned with absolute pollutant and greenhouse gas levels. No policies incentivizing or forcing the transition to zero-carbon fuels were identified. As ports can define limits to pollution, for instance by demanding shore power use, they can significantly affect the clean development of the sector. Further legislation will be needed nationally to counterbalance the lack of supranational ambition on pollutants and climate change mitigation. [Display omitted] • Reviewed global marine policies targeting air pollutants (CO 2 , NO x , SO x , PM). • The number of global, national and port level policies is limited. • Current policies are focused on relative improvements, not overall emissions caps. • Current policies are unlikely to sufficiently achieve pollutant reduction goals. [ABSTRACT FROM AUTHOR]

• Review of methodologies for CO2 storage capacity estimation globally • Detailed assessment of CO2 storage capacities in different Indian basins • New classification scheme proposed based on 'storage prospectivity' of basins • CO2 storage capacities through EOR and ECBMR are 3.4 Gt and 3.7 Gt, respectively • Total theoretical CO2 storage capacity for India estimated at 395-614 Gt With rising carbon dioxide emissions and ambitious global targets for climate change mitigation, carbon sequestration has become one of the most promising carbon dioxide removal technologies. It can prove especially beneficial to an emerging country such as India, which must balance its rapid economic growth with a reduction in emissions. A detailed assessment of the cumulative storage capacity is necessary to facilitate the development of CO 2 storage pathways in India. Previous assessments for India have primarily estimated the theoretical storage capacity based on limited data. In this study, we have reviewed different methodologies for estimating storage capacities globally, and based on the most current data available, in a first, developed a systematic assessment for theoretical and effective CO 2 storage capacities for different geological formations in India. Four storage pathways with adequate potential have been identified: storage through CO 2 enhanced oil recovery (EOR), enhanced coalbed methane recovery (ECBMR), storage in deep saline aquifers, and basalt formations. The results indicate considerable potential for CO 2 storage in India, especially in saline aquifers (291 Gt) and basalt (97–316 Gt). Even though the storage capacity estimated through EOR (3.4 Gt) and ECBMR (3.7 Gt) is comparatively less, it is adequate to store emissions from nearby large point sources. These methods are also highly feasible due to the ready availability of infrastructure and extensive geological information about the basins involved. In addition, we have developed novel classification systems for different basins in India to represent their prospectivity for CO 2 storage. [ABSTRACT FROM AUTHOR]

There is a lack of studies on assessing long-term impacts of different sectors on shrinking global carbon budget. Present study focuses on assessing contribution of electric vehicles (EVs) with improving electricity grids' efficiency (EGs) and minimizing 'transmission and distribution' (T&D) losses in reducing carbon dioxide (CO 2) emissions and fulfilling emission targets for 2030 and 2050. Eleven different scenarios are articulated with estimated uncertainties for Mumbai Metropolitan Regions' (MMRs') passenger transportation using data extracted from MMR's Comprehensive Mobility Plan's transportation model. A novel methodology is developed to estimate local carbon budget targets from global targets between 2018 and 2050. The estimations indicate that carbon emissions in 'business as usual' scenario are 252%, 505%, and 55% above the targets for 2 °C, 1.5 °C, and Intended Nationally Determined Contributions (INDC), respectively. Study also shows that introducing EVs in MMR without simultaneously improving EGs will generate more net CO 2 emissions than BAU. EVs with EG and T&D improvements are not enough to meet the estimated targets. However, their combined contribution significantly reduces CO 2 emission by half and reaches peak emission by 2025 from post-half-century. • Developed a novel methodology to estimate local carbon budget. • Transport emissions assessment with electric vehicle, electricity grid (EG), and T&D losses. • Interventions are unable to achieve carbon budget targets of 2 °C, 1.5 °C, and INDC. • Electric vehicles are not suitable without improving EG efficiency, and T&D losses. [ABSTRACT FROM AUTHOR]

In this paper we evaluate whether the US states have been able to achieve convergence in their carbon emission cycles which may be a key factor in taking a leap as regards the development of a US climate change policy. The use of a dynamic unobserved component approach and a time-varying parameter model enable estimation of the short run dynamics of energy convergence over the extended period 1960–2017. To date, this type of analysis has not received enough attention in the literature. The results reveal the existence of cross-state links in the fluctuations of CO 2 emissions, although the degree to which a good part of the states are co-moving is weak. We also find that cyclical convergence patterns differ considerably in both the level and trajectories across the US states. The difficulties in increasing synchronization of the US CO 2 emissions highlight the importance of the states to lead climate change mitigation actions. The present study presents valuable information of interest regarding the short-run characteristics in carbon dioxide emissions, for better understanding of factors affecting CO 2 mitigation policies. Image 1 • Short run characteristics of CO2 emissions convergence at state-level are studied. • We rank US states by the level of cross-state links in CO2 fluctuations. • Cyclical convergence patterns are distinctively different across states. • National environmental initiatives only have transitory effects on CO2 emissions. • Dataset of CO2 emissions covering 1960–2017 at state level is provided. [ABSTRACT FROM AUTHOR]

• Incorporate the emission inventory into an improved emission spatial mapping model. • Provide an estimate of emission characteristics and spatial distribution in cities. • Conduct the driving forces and emission reduction targets based on Paris Agreement. • Localized reduction policies are the keys to achieving low carbon city development. The identification of CO 2 emissions in megacities is vitally important to promote a transition to low-carbon city. This study aims to analyze the CO 2 emission characteristics and spatial distribution in megacities among different countries, which is important for climate change mitigation. In this study, 12 megacities from China, Japan, and South Korea were selected as typical case studies for analysis. Results show that Chinese cities' CO 2 emissions are among the top four cities studies and are much higher when compared to the other sample cities in Japan and South Korea. Chongqing, Incheon, Tianjin, and Shanghai were the top four cities with the highest carbon intensity. The spatial distribution of urban carbon emissions varies widely. In Seoul, Tokyo Metropolis, and Beijing, 90% of carbon emissions are concentrated on 74.17%, 55.95% and 8.93% of the land area, respectively. The results of the driving forces and emission reduction targets analysis indicate that the three countries face different challenges and there are different action plans in each city accordingly. This study proposed the carbon emissions reduction targets and countermeasures in different industrial sectors, including an increased rate of the standardization of city CO 2 emission accounting systems and the decarbonization of the power industry, among others. These countermeasures will not only contribute to the analysis of CO 2 emissions but will also promote to the low-carbon city development and encourage the realization of urban sustainable development goals. [ABSTRACT FROM AUTHOR]

Carbon capture and storage (CCS) is one of the most promising mitigation strategies for reducing the emissions of carbon dioxide (CO 2) to the atmosphere and may substantially help to decelerate global warming. There is an increasing demand for CCS sites. Nevertheless, there is a lack of knowledge of the environmental risk associated with potential leakage of CO 2 from the storage sites; and even more, what happens when the seepage stops. Can the environment return to the initial equilibrium? Potential effects on native macrofauna were studied under a scenario of a 50-day CO 2 leakage, and the subsequent leak closure. To accomplish the objective, Trondheim Fjord sediments and clams were exposed to an acidified environment (pH 6.9) at 29 atm for 7 weeks followed by a 14-day recovery at normal seawater conditions (pH 8.0, 29 atm). Growth and survival of clams exposed to pressure (29 atm) and reduced pH (6.9) did not significantly differ from control clams kept at 1 atm in natural seawater. Furthermore, bioaccumulation of elements in the soft tissue of clams did not register significant variations for most of the analysed elements (Cd, Cr, Pb, and Ti), while other elements (As, Cu, Fe, Ni) had decreasing concentrations in tissues under acidified conditions in contrast to Na and Mg, which registered an uptake (Ku) of 111 and 9.92 μg g−1dw d−1, respectively. This Ku may be altered due to the stress induced by acidification; and the element concentration being released from sediments was not highly affected at that pH. Therefore, a 1 unit drop in pH at the seafloor for several weeks does not appear to pose a risk for the clams. Image 1 • Acidification and recovery were assessed with high-pressure bioassays. • No mortality was reported for Astarte sp. for a pH 7.0 scenario. • Normal growth of shell length was recorded after CO 2 exposure and a recovery period. [ABSTRACT FROM AUTHOR]