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Through extensive data research and analysis, this paper comprehensively summarizes the status and key insights of global carbon dioxide capture and storage (CCS) development. It aims to gain a comprehensive understanding of the relevant policies, technologies, and security measures adopted by major countries in their CCS development processes. Furthermore, it explores the existing status and limitations of China's offshore development efforts, while providing valuable recommendations for enhancing China's offshore CCS initiatives, as well as serving as a reference for other nations worldwide. Offshore CCS plays a crucial role for China to achieve the development target of carbon peak and carbon neutrality, due to its energy structure and industrial distribution. While China possesses significant offshore CCS potential, achieving commercialization still requires substantial efforts. To facilitate the process and draw insights from successful experiences in other countries, this paper illustrates the characteristics and generalizes the experience of offshore CCS industry practices in America, Europe and Japan, respectively. Furthermore, it is recommended that a new round of investigation into offshore CCS potential be conducted, while promoting integrated collaboration between geological surveying and marine scientific research. Additionally, further research on industrial policies and green financial strategies should be undertaken. [ABSTRACT FROM AUTHOR]

This study estimates the environmental impacts of Bitcoin mining. Employing a top-down measurement approach, this paper assesses the carbon footprint of Bitcoin mining in China from 2017 to 2021. The findings reveal that mining activities during this period contributed to a total of 77.84 million tons of carbon dioxide emissions in China. By utilizing data at the provincial level, we find that the seasonal migration of Bitcoin mining pools will lead to regional power demand shocks in China. Additionally, this study predicts future carbon emissions from Bitcoin mining in China, projecting cumulative carbon dioxide emissions of 76.40 million tons and 722.18 million tons by 2030 and 2060 respectively, in the absence of any policy interventions. Based on these findings, this paper posits that governments worldwide should make efforts to restrict the carbon emissions from Bitcoin mining and opt for environmentally friendly technological methods to fundamentally alleviate Bitcoin's reliance on energy. The implication for central banks is that carbon emission should be taken into consideration when designing the central bank digital currencies (CBDCs). [ABSTRACT FROM AUTHOR]

CO2 huff and puff is a widely used enhanced oil recovery method in many oil fields, but its implementations in shale fields is scarce. This paper reports trials of CO2 huff and puff in a shale field in China. Laboratory studies revealed that CO2 effectively reduced oil viscosity, increased oil volume, and improved oil recovery under miscible conditions. For the three wells that received CO2 huff and puff treatments, one well showed satisfactory results, while the other two wells demonstrated poor economics. Discussions and recommendations are made based on field experiences. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Low-permeability reservoirs have become an important field of oil and gas development in China. CO2 flooding technology is an effective technical means for tertiary oil recovery. Although the asphaltene in the system is deposited in the form of a solid after CO2 injection into the reservoir in contact with crude oil, which causes a certain blockage to the reservoir, the dissolution during the injection process improves the seepage capacity of the reservoir as a whole, and the damage degree of CO2 flooding to low-permeability reservoirs under different injection modes is different. In this paper, the damage degree of asphaltene precipitation to low-permeability reservoirs under different injection modes of CO2 flooding is quantitatively characterized. The mechanism experiment of organic scale plugging after continuous CO2 flooding and CO2–water alternate flooding, the wettability experiment of reservoirs, and the evaluation experiment of CO2–water solution on rock dissolution are carried out, and the variation characteristics of relative permeability curve parameters are evaluated. In this paper, the damage degree of asphaltene precipitation to low-permeability reservoirs under different injection modes of CO2 flooding is quantitatively characterized. The mechanism experiment of organic scale plugging after continuous CO2 flooding and CO2–water alternate flooding, the wettability experiment of reservoirs, and the evaluation experiment of CO2–water solution on rock dissolution are carried out. The variation characteristics of relative permeability curve parameters are evaluated. The results show that the organic scale produced by CO2 flooding will block the pore throat of the rock, but, on the whole, the dissolution caused by the reaction of CO2 and chlorite is stronger, which makes the recovery rate of low-permeability reservoirs effectively improved. The organic scale blockage caused by CO2–water alternating flooding is weaker than that caused by continuous CO2 flooding. The dissolution effect is better and the permeability is higher. It can achieve a better oil displacement effect in pores with a pore size greater than 0.2 μm. On the whole, it can increase the core pore space and seepage channel, so that the recovery rate of low-permeability reservoirs can be effectively improved. This study has important theoretical and practical significance for improving oil recovery in low-permeability reservoirs. [ABSTRACT FROM AUTHOR]

Geological storage is one of the most important measures to reduce carbon emissions. The newly developed oilfield A in the Pearl River Mouth Basin of the South China Sea is associated with a large amount of CO2 with a purity of up to 95%. Two weakly consolidated sandstone saline aquifers located above the oil reservoir can be used for CO2 storage, but the CO2 geochemical reaction characteristics in the aquifers should be investigated clearly, which may cause significant damage to the physical properties of the reservoirs and caprocks of the aquifers. In this paper, static CO2 geochemical reaction experiments and rock thin section identifications were carried out using drill cuttings and sidewall cores, respectively. A numerical simulation was conducted according to the reactor conditions to explore the equilibrium state of the CO2 geochemical reaction. Through these studies, the characteristics of the geochemical reaction, its impact on the physical properties of the formation, and the CO2 storage potential by mineral trapping in the target aquifers were revealed. The results show that the two saline aquifers have similar physical properties. The reservoirs are mostly made up of fine-to-medium-grained sandstones as quartz arenite with a considerable amount of feldspar, which can provide favorable pore space for CO2 storage, while the caprocks are fine-grained felsic sedimentary rocks that can have a good sealing effect. However, both the reservoirs and caprocks contain a certain amount of carbonate and clay minerals. Mineral dissolution dominates in the CO2 geochemical reaction process, and more Ca2+ and Mg2+ is released into the formation water. The theoretical maximum CO2 mineral trapping capacity in the aquifers is 0.023–0.0538 mol/100 g rock, but due to the dynamic equilibrium of the geochemical reaction, the amount of mineralized CO2 in most of the rock samples is negative, and the average utilization factor is only −55.43%. As a result, the contribution of mineral trapping to the CO2 storage capacity takes −0.32%, which can be ignored. In the future, it is necessary to conduct detailed research to reveal the effect of a CO2 geochemical reaction on storage safety, especially in offshore weakly consolidated sandstone saline aquifers, which could be important sites for large-scale CO2 storage in China. [ABSTRACT FROM AUTHOR]

This paper measures tourism carbon efficiency (TCE) in China by incorporating energy consumption and carbon dioxide (CO2) emissions into an efficiency assessment framework, and to further investigate the determinants of TCE by considering the spatial spillover effects. To do this, a bootstrap slacks-based measure (SBM) model was applied to assess the TCE in 30 provincial-level administrative regions of China from 2008 to 2019. Next, the Moran's index and spatial Durbin model (SDM) were adopted to explore the spatial distribution and determinants of TCE. The results indicate that regional differences affect the level of China's TCE, as do spatial spillover effects. In addition, technology innovation, urbanization rate, and government support positively affect TCE. In contrast, economic growth negatively affects TCE. Educational attainment, green infrastructure, and government support have a negative spatial spillover effect on TCE. Transportation infrastructure has a negative total effect on TCE. [ABSTRACT FROM AUTHOR]

Taking the Yangtze River Delta (YRD) of China as the research area, this paper studies the influence of freight structure adjustment and energy intensity on carbon dioxide (CO2) emission from the transportation industry. Sample data from 1990 to 2019 are selected, and co-integration analysis is performed using three independent variables: energy intensity, turnover ratio of railway to highway (R/H), and turnover ratio of railway to waterway (R/W). Then, an autoregressive distribution lag-error correction model (ARDL-ECM) is established to estimate the long-run and short-run relationships among the variables through unit root test, autoregressive distributed lag (ARDL) boundary test, and Granger test. The results show that in the long run, the growth of energy intensity leads to the long-term growth of CO2 emission in the transportation sector of the YRD, and R/W and R/H have a suppressive effect on CO2 emission. Granger causality indicates that there is a bidirectional causal relationship between energy intensity and CO2 emission. This work can be a reference for government departments to formulate policies related to carbon emissions in the transportation industry. [ABSTRACT FROM AUTHOR]

Altay Prefecture, a typical arid region in northwestern China, has experienced the climate transition from warming-drying to warming-wetting since 1980s and has attracted widespread attention. Nonetheless, it is still unclear how climate change has influenced the distribution of vegetation in this region. In this paper, a reaction–diffusion model of the climate–vegetation system is proposed to study the impact of climate change (precipitation, temperature and carbon dioxide concentration) on vegetation patterns in Altay Prefecture. Our results indicate that the tendency of vegetation growth in Altay Prefecture improved gradually from 1985 to 2010. Under the current climate conditions, the increase of precipitation results in the change of vegetation pattern structures, and eventually vegetation coverage tends to be uniform. Moreover, we found that there exists an optimal temperature where the spot vegetation pattern structure remains stable. Furthermore, the increase in carbon dioxide concentration induces vegetation pattern transition. Based on four climate change scenarios of the Coupled Model Intercomparison Project Phase 6 (CMIP6), we used the power law range (PLR) to predict the optimal scenario for the sustainable development of the vegetation ecosystem in Altay Prefecture. [ABSTRACT FROM AUTHOR]

It has been a crucial challenge for countries worldwide to reduce carbon dioxide (CO2) emissions. China is developing policies among various industries to peak CO2 emissions as soon as possible and expects the reduction of CO2 emissions through financial development. This paper explores the influencing mechanism of financial development on CO2 emissions based on panel data from provinces in China, considering constraints of technological innovation and fossil energy dependence among provinces and periods. Empirical results consistently indicate that the effect of China's financial development on CO2 emissions per capita is significantly negative, and it also presents an inverted U-shaped pattern. In those provinces or periods witnessing lower technological innovation and higher fossil energy dependence, the financial development has more significant effect on carbon emission reduction. This result suggests that regions with deficiencies in the development of technology industries, lower proportions of the tertiary industry, and a higher percentage of the secondary industry need to focus more on the value of financial development. [ABSTRACT FROM AUTHOR]

The development and renewal of gas sensor technology have enabled more and more low-cost gas sensors to form a carbon monitoring network to meet the requirements of the city. In the context of China's commitment to achieving the "double carbon" target by 2060, this paper reviews the principles of four standard gas sensors and the application of several low-cost sensors in urban carbon monitoring networks, with the aim of providing a practical reference for the future deployment of carbon monitoring networks in Chinese cities. Moreover, the types, prices, and deployment of the sensors used in each project are summarized. Based on this review, non-dispersive infrared sensors have the best performance among the sensors and are commonly used in many cities. Lots of urban climate networks in cities were summarized by many reviews in the literature, but only a few sensors were studied, and they did not consider carbon dioxide (CO2) sensors. This review focuses on the dense CO2 urban monitoring network, and some case studies are also discussed, such as Seoul and San Francisco. To address the issue of how to better ensure the balance between cost and accuracy in the deployment of sensor networks, this paper proposes a method of simultaneously deploying medium-precision and high-precision fixed sensors and mobile sensors to form an urban carbon monitoring network. Finally, the prospects and recommendations, such as different ways to mitigate CO2 and develop an entire carbon monitoring system for future urban carbon monitoring in China, are also presented. [ABSTRACT FROM AUTHOR]

In 2017, a carbon emissions trading market will be launched nationwide by the China government. Calculating the enterprise carbon emissions is an important prerequisite and basis for trading. This paper discussed types of greenhouse gases, calculation boundaries and methods, energy consumption, carbon emissions, and intensity of a representative integrated pulp and paper mill in China based on China Guidance and Greenhouse Gas Protocol Tools. The results showed that there were 435,000 tonnes (t) of CO2 emissions from that mill in 2014 that did not contain emissions of biomass energy, which was 8 times higher than that of fossil energy. The pulp carbon intensity based on the mill was 0.230 t CO2/Adt, which accounted for 7.50% to 57.4% in other pulps' based on the product. Intensity based on Gross Domestic Product (GDP) was 1.090 t CO2e/1000 USD and accounted for 56.8% intensity in the China paper industry. The intensity based on sales accounted for 52.6% in the firstclass enterprise in the developed country. It also showed that intensity was influenced by the species of raw material, energy, and products, which provided the mill with measures for energy saving and emissions reduction to obtain the redundant carbon emissions in the trading. [ABSTRACT FROM AUTHOR]

Effective management of surface emissions from abandoned gob methane (AGM) is crucial for mitigating greenhouse gas emissions and ensuring public safety. An important geochemical characteristic of near-surface AGM migration is the potential presence of abnormal component concentrations in near-surface soil gas over abandoned coal gobs. To investigate this phenomenon, a surface geochemical survey was conducted based on four survey lines in the Dongyi and Dongsan abandoned gob groups in the Xinghua Coal Mine, Jixi Basin, in China. The gas chromatography technique was used to analyze the concentrations of methane, carbon dioxide, ethane, propane, and butane in the collected 43 soil gas samples. The results revealed a significant anomaly of soil gas concentrations, particularly methane and carbon dioxide anomalies, in the near-surface soil over abandoned gobs. The background concentration for methane was determined to be 7.49 ppm, with an anomalous threshold set at 10 ppm based on a statistical analysis and an iterative method. This threshold could be confirmed by examining the coupling and decoupling relationship between methane, carbon dioxide, and C2–3 as well. A spatial correlation between regions exhibiting anomalous methane and carbon dioxide concentrations and the positions of gob areas, abandoned surface wells, and faults was observed. Abandoned and sealed coalbed methane surface wells and faults near gas-rich gob areas have the potential to act as conduits for AGM leakage to the surface. Furthermore, concentrations of methane, carbon dioxide, and C2–3 in soil gas over abandoned coal gobs were significantly higher compared to areas unaffected by mining activities. This suggests that elevated concentrations of methane, carbon dioxide, and C2–3 in soil gas may originate from underground AGM. [ABSTRACT FROM AUTHOR]

CO2 is being considered as an effective alternative working fluid for geothermal applications due to its superior fluid dynamics and heat transfer properties compared to water. Utilizing sedimentary rocks for geothermal energy recovery through a CO2-plume geothermal system, especially in carbonate reservoirs, has been shown to be a practical approach that eliminates the need for hydraulic fracturing. However, uncertainties remain regarding the thermal and hydraulic behavior, particularly the chemical interactions between CO2 and carbonate rocks. This study develops a comprehensive wellbore–reservoir coupling reactive transport model based on specific information obtained from the Ordovician limestone geothermal reservoir in Shandong, China. The model aims to assess the feasibility of heat extraction in carbonate reservoirs by evaluating the heat extraction performance and fluid–rock interaction. The results indicate a rapid temperature drop after CO2 breakthrough due to the Joule–Thomson effect. Simultaneously, the fluid transitions into and maintains a two-phase state throughout the operation. Chemical reactions within the reservoir are not aggressive since complete mixing between unsaturated water and CO2 only occurs in the vicinity of the production well, highlighting the potential of utilizing carbonate reservoirs for efficient heat extraction in geothermal systems. Further research is needed to optimize the performance of CO2-based geothermal systems in carbonate reservoirs. [ABSTRACT FROM AUTHOR]

Improving transport efficiency and optimizing freight structure are the core of achieving sustainable transport development. However, few studies have conducted an in-depth analysis of freight structure optimization and transport efficiency at the provincial level in China. Hence, a new economy and carbon dioxide (CO2) emissions evaluation model based on the slack-based measurement data envelopment analysis (SBM-DEA) with undesirable outputs was proposed to analyze the transport efficiency and optimize freight structure in five provinces of China from 2005 to 2019. And optimization potential of the freight and passenger transport sector was uncovered in the provinces. The results showed that: (1) the regional difference in transport efficiency was significant, which indicated room for improvement in these provinces. (2) Freight structure was estimated and optimized by the slack variables of the evaluation model. The slack variables of railway, road, and waterway freight transport were large among these provinces. (3) The optimization potential of the freight transport sector was greater than that of the passenger transport in the regions. It indicated optimizing freight structure should be prioritized over passenger transport. Finally, some implications were put forward for sustainable transport development in China. The results provide significant insight into freight structure optimization as well as novel perspectives into the formulation of carbon mitigation strategies. [ABSTRACT FROM AUTHOR]

China's numerous resource-based cities have confronted severe environmental and economic problems, which were substantial impediments to the regional sustainable development. In 2013, China started to implement its 'National Sustainable Development Plan of Resource-Based Cities', in order to transform the previous development patterns. This study employs the difference-in-differences (DID) method to evaluate the policy's impact on the city-level carbon dioxide (CO2) emission intensity. CO2 intensity is defined as the scale of CO2 emitted per unit of GDP. The research sample covers 326 Chinese cities during 2008—2017. Research results indicate that the policy significantly increased the CO2 intensity in resource-based cities. Moreover, it is found that the policy dampened resource-based cities' innovation levels and these cities did not strengthen their environmental regulations, which can be provided as the explanations of why the policy effect on carbon intensity was positive. Furthermore, this study reports the discrepancies in policy effects when cities have different development stages, spatial locations and marketization levels. Overall, this research discovers an undesirable policy effect. More actions should be taken to reduce the carbon intensity during the structural transformation in resource-based cities. [ABSTRACT FROM AUTHOR]

This paper investigates the impacts of new digital technology on carbon emissions in China. To better capture the feature of new digital technology, we distinctively measure it using the invention patent stock of new generation information technology industry. The empirical results show that the development of new digital technology significantly reduces carbon dioxide (CO2) intensity. The results are still robust after addressing the endogeneity issues using instrumental variable regressions. The carbon reduction mechanisms of new digital technology include reducing energy intensity, optimizing energy structure, and advancing treatment technology. We further confirm the spatial spillover and nonlinear effects of new digital technology on CO2 intensity and the moderating effect of urban digitalization in carbon reduction. The study suggests that the potential of new digital technology in reducing carbon emissions should be highly attentioned by governments. [ABSTRACT FROM AUTHOR]

With the popularization of natural gas and the requirements for environmental protection, the development and utilization of natural gas is particularly important. The status of natural gas in China's oil and gas exploration and development is constantly improving, and the country is paying more and more attention to the exploitation and utilization of natural gas. The Upper Paleozoic tight sandstone in the Ordos Basin is characterized by low porosity, low permeability and a large area of concealed gas reservoirs. By injecting carbon dioxide into the formation, the recovery rate of natural gas can be improved, and carbon neutrality can be realized by carbon sequestration. Injecting greenhouse gases into gas reservoirs for storage and improving recovery has also become a hot research issue. In order to improve the recovery efficiency of tight sandstone gas reservoirs, this paper takes the complex tight sandstone of the Upper Paleozoic in the Ordos Basin as the research object; through indoor physical simulation experiments, carried out the influence of displacement rate, fracture dip angle, core permeability, core dryness and wetness on CO2 gas displacement efficiency and storage efficiency; and analyzed the influence of different factors on gas displacement efficiency and storage efficiency to improve the recovery and storage efficiency. The research results show that under different conditions, when the injection pore volume is less than 1 PV, the relationship between the CH4 recovery rate and the CO2 injection pore volume is linear, and the tilt angle is 45°. When the injection pore volume exceeds 1 PV, the CH4 recovery rate increases slightly with the increase in displacement speed, the recovery rate of CO2 displacement CH4 is between 87–97% and the CO2 breakthrough time is 0.7 PV–0.9 PV. In low-permeability and low-speed displacement cores, the diffusion of carbon dioxide molecules is more significant. The lower the displacement speed is, the earlier the breakthrough time is, and the final recovery of CH4 slightly decreases. Gravity has a great impact on carbon sequestration and enhanced recovery. The breakthrough of high injection and low recovery is earlier, and the recovery of CH4 is about 3.3% lower than that of low injection and high recovery. The bound water causes the displacement phase CO2 to be partially dissolved in the formation water, and the breakthrough lags about 0.1 PV. Ultimately, the CH4 recovery factor and CO2 storage rate are higher than those of dry-core displacement. The research results provide theoretical data support for CO2 injection to improve recovery and storage efficiency in complex tight sandstone gas reservoirs. [ABSTRACT FROM AUTHOR]

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The purpose of this paper is to strengthen research concerning the impact of climate change on China's water resources, in order to avoid extreme weather events such as regional rainstorms and floods affecting the stable supply of energy and electricity. The goal is to reorganize energy industry allocation to make China's energy the most efficient, which would thus help achieve sustainable development goals. The biggest contribution and of this paper is not only to enlarge the scale and take into account the sustainable aspects, but also to consider climate change factors that have been ignored in the past as exogenous variables. For the first time, we take stock of the optimal allocation of new and tradition energy sources and carbon dioxide. This study uses the Dynamic ZSG-DDF model with exogenous variables and undesirable outputs to find a way to redistribute carbon dioxide, new energy, and tradition energy from different provinces on the premise of maximizing efficiency, thus achieving the goal of reducing carbon and saving the earth. The research results show that the energy efficiency of tradition energy is higher than that of new energy in various provinces. At the same time, the China government must comprehensively review the quota targets of new energy, tradition energy, and carbon dioxide (CO2) in each province as quickly as possible. Currently, the quotas of various provinces are seriously misplaced, and 26 provinces in total have great room for improvement. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction is regarded as a green and promising technology because it can convert carbon dioxide into value-added fuel or chemicals in a flexible and sustainable way. This research aimed to comprehensively analyze the research hotspots and trends in the field of CO2 electroreduction from 2005 to 2022 using bibliometric methods based on the core database of Web of Science. The results showed that 4546 papers on CO2 electroreduction were retrieved from 2005 to 2022, with a clear increasing trend. The research direction was diversified, involving multiple disciplines, and it is a comprehensive research field. ACS Catalysis is the journal with the largest number of articles. China is the country with the largest number of documents and has made significant contributions to the development and progress of this field. Copper-based catalysts are still the research focus in recent years. It is of great practical significance to develop copper-based catalysts with high efficiency, low cost, high stability, and high selectivity for the preparation of C1 products. [ABSTRACT FROM AUTHOR]

Several countries have weakened the carbon emission objectives to immediately revive the economy in the post-COVID-19 era. Therefore, it is a challenge worth addressing to readjust the economic development and carbon emissions after the COVID-19 pandemic. From the perspective of China's carbon emissions, this study shapes a multi-objective dynamic optimization model based on the material capital input and R&D support aspects. The proposed model imitates China's economic development, energy consumption, and carbon dioxide (CO2) emissions. The model provides theoretical suggestion for the government to revive economic development and reduce carbon emissions. In addition, this research paper compares the evolutionary path of carbon peak under the two scenarios. The first scenario requires maintaining the pre-epidemic development state and pace of carbon emission reduction, referred to as the baseline scenario (BS). The second scenario is termed the optimal scenario (OS) based on the model calculation. The study findings exhibit that China is not able to accomplish the 2030 CO2 emission peak objective, under the BS. However, China under the OS shall expectedly accomplish the 2030 carbon peak objective ahead of schedule, while the peak CO2 emissions shall be around 11.28 billion tons. Reportedly, at least 788 million tons of CO2 reduction contrasted with the BS. Furthermore, there is an 80.35% decline in energy intensity as compared to 2005. Consequently, the study results contribute theoretical guidance for the "green recovery" of China's economy and the adjustment of carbon emission reduction's path after the COVID-19 epidemic. Consistent with this, the research method also contributes to the theoretical research on carbon emissions at the national level while extending a new research perspective for the economic and environmental fields. [ABSTRACT FROM AUTHOR]

It is widely acknowledged that greenhouse gases (GHG) like carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) play a key role in the development of global climate change. 17% of China's GHG came from the agricultural industry. For China's future development, it is essential to investigate low-carbon emission paths in planting fields, as one of the key components of agriculture. In this study, the IPCC method was used to estimate the total carbon emission from cultivation in Eastern China. The Tapio decoupling model was used to study the relationship between economic growth and carbon emission. An extended STIRPAT stimulus model was established to predict the carbon emission of the planting industry in East China with three development paths. The results show that carbon emission in East China has shown a fluctuating downward trend with a peak in 1999, which has strong decoupling characteristics with economic growth. Adjusting agricultural structure and raising the mechanization rate can remarkably reduce agricultural carbon emission. Compared to 2020, carbon emission in 2035 will decrease by 12.50%, 13.68%, and 14.32% with Baseline, Low-carbon, and Enhanced Low-carbon scenarios, respectively. Effective measures such as optimizing planting structure by adjusting rice area, promoting intensive mechanization, and improving fertilizer use efficiency can reduce carbon emission actively. [ABSTRACT FROM AUTHOR]

Acidified CO2 fracturing is a viable method for increasing production in deep, tight sandstone reservoirs. However, the potential mechanism of changes in pore structure and mechanical properties of sandstone under acidified CO2 supercritical composite is not clear. Understanding this mechanism is important for the study of crack initiation and extension in tight sandstone reservoirs. This study utilizes sandstone samples from the Xujiahe Formation reservoir in Rongchang District as experimental specimens. The primary focus is to analyze the changes in pore structure and mechanical properties of these samples after acidification–supercritical CO2 composite action. Nuclear magnetic resonance (NMR) and uniaxial compression tests are employed as the main investigative techniques. The results show that there was a physicochemical synergy between the acidification–supercritical CO2 composite effect; the crack initial stress, damage stress, and peak stress of the sandstone after 16 MPa supercritical CO2 acidification treatment were reduced by 20%, 49.5%, and 49.8%, respectively; the crack volumetric strain accelerated and the sandstone evolved from brittle to ductile damage; and the larger pore space and microcracks of the sandstone increased significantly after the treatment, which can be attributed to the gradual dissolution of intergranular cement leading to the formation of new pores connected to the existing pore network. The change mechanism of sandstone after acidification–supercritical CO2 compound treatment is also proposed. [ABSTRACT FROM AUTHOR]

CO2 injection in coal seams, which is a significant initiative to mitigate environmental problems caused by greenhouse gases, often leads a sequence of changes in the physical properties of coal reservoirs. To look into how the pore structure changes in the process of CO2 sequestration, we selected fresh coal from Huoerxinhe coal mine in China as the object. Then, acid treatment and SC-CO2 extraction were used to dissolve Organic and inorganic components in coal. Thus, by using SEM, LTGA-N2 apparatus and XRD, the characteristics of pore parameter and fractal dimension variation were discussed. The research results show that, the APS of samples THF, HCL-HF and Y-C increase, while the total PV decreases and the pore connectivity deteriorates. The pore connectivity of Samples THF and HCL-HF is improved (THF-C, HCL-HF-C), but the total pore volume continuously reduces. In addition, solvents treatment and SC-CO2 extraction mainly act on the microporous fraction. After solvents pretreatment, the changes in the pore size distribution curves are mainly manifested in the reduction of number of micropores, especially in the micropores around 3–4 nm. There is a small increase in micropores for samples Y-C and HCL-HF-C, with the pore size mainly concentrated around 4 nm, while the pores of the sample THF-C mainly show an increase within the scope of 3–16 nm. Generally, solvent pretreatment and SC-CO2 extraction help to simplify pore structure. However, the sample HCL-HF-C shows opposite change characteristics. In a short period of time, the larger pore fractal dimension, the less beneficial it is to the flow of CO2, while pore fractal dimension becomes progressively less useful in assessing pore connectivity with increasing time. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) is the most important long-lived greenhouse gas and can be retrieved using solar absorption spectra recorded by a ground-based Fourier-transform infrared spectrometer (FTIR). In this study, we investigate the CO2 retrieval strategy using the Network for the Detection of Atmospheric Composition Change–Infrared Working Group (NDACC–IRWG) type spectra between August 2018 and April 2022 (~4 years) at Xianghe, China, aiming to find the optimal observed spectra, retrieval window, and spectroscopy. Two spectral regions, near 2600 and 4800 cm−1, are analyzed. The differences in column-averaged dry-air mole fraction of CO2 (XCO2) derived from spectroscopies (ATM18, ATM20, HITRAN2016, and HITRAN2020) can be up to 1.65 ± 0.95 ppm and 7.96 ± 2.02 ppm for NDACC-type 2600 cm−1 and 4800 cm−1 retrievals, respectively, which is mainly due to the CO2 differences in air-broadened Lorentzian HWHM coefficient (γair) and line intensity (S). HITRAN2020 provides the best fitting, and the retrieved CO2 columns and profiles from both 2600 and 4800 cm−1 are compared to the co-located Total Column Carbon Observing Network (TCCON) measurements and the greenhouse gas reanalysis dataset from the Copernicus Atmosphere Monitoring Service (CAMS). The amplitude of XCO2 seasonal variation derived from the NDACC-type (4800 cm−1) is closer to the TCCON measurements than that from the NDACC-type (2600 cm−1). Moreover, the NDACC-type (2600 cm−1) retrievals are strongly affected by the a priori profile. For tropospheric XCO2, the correlation coefficient between NDACC-type (4800 cm−1) and CAMS model is 0.73, which is higher than that between NDACC-type (2600 cm−1) and CAMS model (R = 0.56). [ABSTRACT FROM AUTHOR]

This paper presents the failure analysis of the crack and leakage accident of a crude oil pipeline under CO2-steam flooding in the western oilfield of China. To analyze the failure behavior and cause, different testing, including nondestructive testing, chemical composition analysis, tensile property testing, metallographic analysis, and microanalysis of fracture and chloride stress corrosion cracking (SCC) testing, are applied in the present study. The obtained results showed that the pipeline under the insulation layer of high humidity, high oxygen content, and high Cl− environment occurred pit corrosion, and the stress concentration area at the bottom of the corrosion pit sprouted cracks. Besides, it is demonstrated that the cracks were much branched, mostly through the crystal, and the fracture showed brittle, which is consistent with the typical characteristics of chloride SCC. Meanwhile, the insufficient Ni content of the pipeline material promoted the process of chloride SCC, and the high-temperature working conditions also aggravated the rate of chloride SCC. In addition, efficient precautions were provided to avoid fracture. [ABSTRACT FROM AUTHOR]

Marginal abatement cost (MAC) plays an essential role in pricing pollutants and guiding environmental policies. Considering the heavy polluting nature of China's coal power industry, this paper aims at providing companies and policymakers with more comprehensive information on the cost of abatement by estimating the MACs of CO2 and SO2 for coal-fired power plants (CFPPs) in China. This study contributes to the literature by considering an interconnected two-stage production system to investigate. The estimation framework is advanced in combining the electricity production and pollution abatement process of CFPPs into a convex quantile regression (CQR) model. The results show that the averages of MAC for CO2 and SO2 are estimated to be 367.56 Yuan/ton and 662.30 Yuan/ton, respectively, indicating that the reduction of such emissions is still costly. The heterogeneous analysis then indicates that large CFPPs, central-government-owned power plants (CGOPPs), and low-regulated CFPPs tend to possess lower MACs for CO2. Regarding SO2, large and medium-sized power plants show significantly larger MACs than small plants. In addition, the MACs of SO2 for CGOPPs and high-regulated CFPPs are more concentrated at high levels. In the second part, the Tobit regression analysis was used to discuss the determinants of MACs for CO2 and SO2. Factors like carbon emission intensity, load, and operating hours can notably decrease MACs for CO2, while MACs for SO2 tend to be positively affected by the total abatement cost and the abatement rate of the FGD equipment. In addition, the MACs for the large CFPPs, CGOPPs, and high-regulated CFPPs are more likely to be affected by the selected influence factors. Based on these results, we conclude with some policy recommendations. [ABSTRACT FROM AUTHOR]

Understanding the effect of freight structure (FS) on carbon dioxide (CO2) emissions is significant for policymakers in the transport sector. However, few studies have investigated fully how the freight structure influences transport CO2 emissions. In the paper, a comprehensive freight structure index is proposed to assess the freight structure in 16 provinces of China during 2005–2019. Then, the heterogeneous effect of the freight structure and other factors on CO2 emissions are quantified by the quantile regression model developed. The mediating effect between freight structure and CO2 emissions is further examined. And the panel causality test is used to explore the directions of causality among variables. The main results indicate that (1) the level of freight structure shows a distribution of increase from western and central regions to eastern regions in 16 provinces. (2) Freight structure has a positive effect on transport CO2 emissions, and its effect is significantly heterogeneous in all quantiles. (3) Freight structure has an indirect impact on CO2 emissions through the scale effect. (4) The bidirectional causality is confirmed between economic growth, industrial structure, and information and communication technology with carbon emissions. A unidirectional causality from CO2 emissions to freight structure is also found. Finally, some policy recommendations are proposed for sustainable transport development in China. The results facilitate the formulation of the regionally tailored carbon emission reduction strategy in the transport sector. [ABSTRACT FROM AUTHOR]

The geological storage of CO2 is a critical technique for reducing emissions, which significantly contributes to the mitigation of the greenhouse effect. Currently, CO2 is often geologically stored in coal seams, hydrocarbon reservoirs, and saline aquifers in order to store CO2 and improve the oil and gas recovery simultaneously. Shale formations, as candidates for CO2 storage, are drawing more attention because of their rich volumes. CO2 storage through shale formations in the Sichuan Basin, China, has tremendous potential because of the readily available CO2 injection equipment, such as abandoned shale gas wells. Therefore, we review the potential of using these wells to store CO2 in this paper. Firstly, we review the status of the geological storage of CO2 and discuss the features and filed applications for the most studied storage techniques. Secondly, we investigate the formation properties, shale gas field development process, and characteristics of the abandoned wells in the Sichuan Basin. Additionally, after carefully studying the mechanism and theoretical storage capacity, we evaluate the potential of using these abandoned wells to store CO2. Lastly, recommendations are proposed based on the current technologies and government policies. We hope this paper may provide some insights into the development of geological CO2 storage using unconventional reservoirs. [ABSTRACT FROM AUTHOR]

Aviation emission accounting is the key to establishing market measures to control aviation pollutant emissions. Based on the fuel percentage method (FPM), this paper applies the improved BFFM2-FOA-FPM (Boeing Fuel Flow Method 2–First Order Approximation FPM) to calculate the emissions of six pollutants (CO 2 , CO, HC, NO x , SO 2 , and PM 2.5) between Chinese and foreign cities from 2014 to 2019, including CCD (climbing, cruising, and descending) emissions and LTO (landing and take-off) emissions. The error rate between the calculated results and the official data is about 2.75 %. The results show that the emissions of six pollutants changed before and after the proposal of the "Carbon Neutral Growth 2020" strategy (CNG2020 strategy). Although the total amount has increased, the average emission per tonne-kilometer of CO 2 , CO, HC, NO x , SO 2 , and PM 2.5 has decreased by 17.77 %, 17.26 %, 25.15 %, 14.32 %, 17.77 %, and 16.35 %, respectively. The results of this paper can provide a data basis and method reference for implementing the CNG2020 strategy and realizing global carbon emission reduction goals. The dataset is available from https://doi.org/10.6084/m9.figshare.20071751.v1 (Cui., 2022). [ABSTRACT FROM AUTHOR]

Methane (CH4) is the second-largest greenhouse gas emitted by human activity and natural sources after carbon dioxide (CO2). Its relatively short lifetime in the atmosphere (about 12 years) means that we can mitigate the human impacts of climate change in a relatively short period of time by reducing CH4 emissions. The creation of CH4 emissions management policies can be based on the distribution maps of surface CH4 concentration that are in large-scale and at high-resolution. The estimate of CH4 emissions with broad coverage are provided by currently extensively used satellite data supplemented with data from model simulations. However, it is at low spatial resolution. In this paper, through the combination of atmospheric CH4 observations from the TROPOMI sensor and wind data from the ECMWF global reanalysis, a straightforward divergence method is proposed to estimate the surface CH4 emissions in China from March 2019 to September 2022 at a resolution of 7 km × 7 km. This method was compared with the average annual CH4 emissions of Emissions Database for Global Atmospheric Research (EDGARv7.0), and the Root Mean Square Error (RMSE) is 2.53 kg/km2/h and within error envelop (EE) is 72.93%, which represents the proportion of reliable values under certain uncertain conditions. We estimated that the average annual CH4 emissions in China from 2019 to 2022 is 81 Tg, with the lowest emissions in 2021 (75 Tg) due to the impact of COVID-19. In 2021, the largest anthropogenic emissions in China are from agriculture, energy activities and livestock, accounting for 28% (20.8 Tg), 25% (18.9 Tg) and 19% (13.9 Tg) of total emissions, respectively, while wetlands, as the largest natural source, produce 14% (10.5 Tg) of CH4 emissions. [ABSTRACT FROM AUTHOR]

There are large, heavy oil reserves in Block X of the Xinjiang oilfields, China. Due to its large burial depth (1300 m) and low permeability (26.0 mD), the traditional steam-injection technology cannot be used to obtain effective development benefits. This paper conducts experimental and simulation research on the feasibility and mechanism of CO 2 -energized fracturing of horizontal wells and N 2 foam huff-n-puff in deep heavy oil reservoirs with low permeability in order to further explore the appropriate production technology. The foaming volume of the foaming agent at different concentrations and the oil displacement effect of N 2 foam at different gas/liquid ratios were compared by the experiments. The results show that a high concentration of foaming agent mixed with crude oil is more conducive to increasing the foaming volume and extending the half-life, and the best foaming agent concentration is 3.0∼4.0%. The 2D micro-scale visualization experiment results show that N 2 foam has a good selective blocking effect, which increases the sweep area. The number of bubbles per unit area increases as the gas/liquid ratio increases, with 3.0∼5.0 being the optimal gas/liquid ratio. Numerical simulation results show that, when CO 2 -energized fracturing technology takes into account the advantages of fracturing and crude oil viscosity reduction by CO 2 dissolution, the phased oil recovery factor in the primary production period can reach approximately 13.7%. A solvent pre-slug with N 2 foam huff-n-puff technology is applied to improve oil recovery factor following primary production for 5∼6 years, and the final oil recovery factor can reach approximately 35.0%. The methodology formulated in this study is particularly significant for the effective development of this oil reservoir with deeply buried depth and low permeability, and would also guide the recovery of similar oil deposits. [ABSTRACT FROM AUTHOR]

Following China and the United States, India is the third highest CO2 emitter in the world. With its fast rising population and an industry primarily reliant on coal and oil, the country's emissions will continue to rise unless appropriate measures are taken. In India generally the carbon sequestration is done by storing CO2 in sedimentary basins where it gets capped by the impermeable cap rocks. The study aims to unfold the other techniques of carbon sequestration in subsurface formations, except for narrating the different types of carbon capture and sequestration techniques along with its storage in different types of environments. For instance, abiotic and biotic environments for CO2 sequestration. It further talks about carbon injections of oceanic, geological, and terrestrial types, to name just a few. Types of carbon emission sources are discussed too. In this paper three different approaches are described for carbon mitigation, namely CarbFix, CO2 Plume technology and Carbon Trading. A prefeasibility study was done in order to implement the three techniques in Dholera geothermal region in Gujarat, India. In literature review, it can be seen how the three techniques can help in permanent mitigation of captured carbon through carbonate mineralization, power generation and industrial applications. For any project government and public participation is important. In this regard the study gives a brief understanding about the steps to be taken by government and the public to promote such projects for carbon mitigation. Besides, the steps to be taken in such projects for health and risk assessment were talked about in literature review too. [ABSTRACT FROM AUTHOR]

With the proposal of China's national "double carbon" strategic goal, carbon capture, utilization and storage (CCUS) technology has attracted more and more attention. Due to the high cost, high energy consumption and high risk of CCUS technology, this technology is still in the initial stage of development in China. Among them, CO2 geological storage is one of the risks, and the environmental monitoring technology of CO2 storage leakage is particularly important in the large-scale popularization and application of CCUS technology in China. On the basis of extensive research on the related literature concerning CO2 storage and leakage, this paper begins with the types and mechanisms of CO2 storage, analyzes the ways and risks of CO2 storage and leakage and then summarizes the existing environmental monitoring technologies of CO2 geological storage and leakage. In the future, China can promote the progress of CO2 geological storage monitoring technology and help achieve the goal of "double carbon" by strengthening the research on CO2 storage mechanism and main control factors, perfecting the risk assessment method of CO2 storage, constructing the monitoring technology system of the CO2 storage life cycle, and standardizing the CO2 storage risk response system. [ABSTRACT FROM AUTHOR]

China's economy has made significant strides in the past three decades. As a direct result of China's "one belt, one road" (OBOR) initiative, the country's rate of industrialization and urbanization is currently the fastest in the entire world. This rapid development is largely dependent on the enormous amounts of energy currently being consumed and forms the foundation of the world's high levels of carbon emissions. It is generally agreed that the production of greenhouse gases, particularly carbon dioxide, is the primary contributor to the current state of climate change. In this paper, a CO2 emission prediction model based on Bi-LSTM is constructed. In order to conduct empirical tests on the model, this study uses data from South Asian countries and China from 2001 to 2020. China's CO2 emissions from 2022 to 2030 were predicted along with those of other countries in order to study the combined effects of the scientific and technological progress, industrial structures, and energy structure factors affecting CO2 emissions. When compared with the LSTM and GRU methods, the Bi-LSTM model's results produced lower MAE, MSE, and MAPE values, indicating that it performs better. According to the findings, carbon emissions represent a significant problem that will become much worse in the future due to China and India's high emissions, particularly in the next 10 years, if the government does not implement policies that help reduce those emissions. [ABSTRACT FROM AUTHOR]

The high-intensity partial pressure of CO2 (pCO2) in karst underground rivers rapidly releases in open-flow sections. This is an important process affecting the global karst carbon cycle. This study focuses on the diurnal variation patterns and driving factors of CO2 exchange flux at the water–air interface in the open-flow sections of typical karst underground rivers in southwestern China. The inorganic carbon in water and water–air interface exchange fluxes are observed. Three representative survey stations, i.e., the outlet of the underground river (Q1), the river sections without submerged plants (H1), and the river sections with submerged plants (H2), are selected to study the CO2 exchange process and its influencing factors. The results show that the CO2 release flux at Q1 exhibits high pressure in the daytime and low pressure in the nighttime, while H1 and H2 exhibit the opposite pattern. The photosynthesis of submerged plants significantly inhibits the carbon release flux of the river, and in the river sections where submerged plants are distributed, their biological effects have inhibited approximately 0.131 Tg C/yr of carbon emissions. This study emphasizes the significant contribution of submerged plants in restraining the release of CO2, thereby promoting carbon sequestration and storage in karst water systems. [ABSTRACT FROM AUTHOR]

Environmental degradation has been recognized as a global issue due to high energy consumption and economic growth. This situation needs researchers to focus on, thereby, the current article examined the impact of renewable energy production (REP), energy import, renewable energy consumption (REC), gross domestic product (GDP), inflation, and foreign direct investment (FDI) on the carbon dioxide (CO2) emission in China. The study considered secondary data and extracted it from the World Bank database covering the period 1981 to 2018. The current article has examined the stationarity of the constructs using Augmented Dickey-Fuller tests and investigated the association among constructs using the quantile autoregressive distributed lag (QARDL) model. The data revealed that REP, energy import, and REC, had a significant and negative linkage with CO2 emission in China. In contrast, GDP, inflation, and FDI are linked with CO2 emission in a positive manner. The article also guided the policymakers regarding the policy development related to reducing carbon emissions using renewable energy production and consumption. [ABSTRACT FROM AUTHOR]

The development in uncrewed aerial vehicle (UAV) technologies over the past decade has led to a plethora of platforms that can potentially enable greenhouse gas emission quantification. Here, we report the development of a new air sampler, consisting of a pumped stainless coiled tube of 150 m in length with controlled time stamping, and its deployment from an industrial UAV to quantify CO 2 and CH 4 emissions from the main coking plant stacks of a major steel maker in eastern China. Laboratory tests show that the time series of CO 2 and CH 4 measured using the sampling system is smoothed when compared to online measurement by the cavity ring-down spectrometer (CRDS) analyzer. Further analyses show that the smoothing is akin to a convolution of the true time series signals with a heavy-tailed digital filter. For field testing, the air sampler was mounted on the UAV and flown in virtual boxes around two stacks in the coking plant of the Shagang Group (steel producer). Mixing ratios of CO 2 and CH 4 in air and meteorological parameters were measured from the UAV during the test flight. A mass-balance computational algorithm was used on the data to estimate the CO 2 and CH 4 emission rates from the stacks. Using this algorithm, the emission rates for the two stacks from the coking plant were calculated to be 0.12±0.014 t h -1 for CH 4 and 110±18 t h -1 for CO 2 , the latter being in excellent agreement with material-balance-based estimates. A Gaussian plume inversion approach was also used to derive the emission rates, and the results were compared with those derived using the mass-balance algorithm, showing a good agreement between the two methods. [ABSTRACT FROM AUTHOR]

The massive increase in the amount of greenhouse gases in the atmosphere, especially carbon dioxide (CO2), has had a significant impact on the global climate. Research has revealed that lakes play an important role in the global carbon cycle and that they can shift between the roles of carbon sources and sinks. This study used Landsat satellite images to analyze the spatiotemporal characteristics and factors influencing the CO2 changes in Chagan Lake in China. We conducted six water sampling campaigns at Chagan Lake in 2020–2021 and determined the partial pressure of carbon dioxide (pCO2) from 110 water samples. Landsat surface reflectance was matched with water sampling events within ±7 days of satellite overpasses, yielding 75 matched pairs. A regression analysis indicated strong associations between pCO2 and both the band difference model of the near-infrared band and green band (Band 5-Band 3, R2 = 0.83, RMSE = 27.55 μatm) and the exponential model [((exp(b3) − exp(b5))2/(exp(b3) + exp(b5))2, R2 = 0.82, RMSE = 27.99 μatm]. A comparison between the performances of a linear regression model and a machine learning model found that the XGBoost model had the highest fitting accuracy (R2 = 0.94, RMSE = 16.86 μatm). We used Landsat/OLI images acquired mainly in 2021 to map pCO2 in Chagan Lake during the ice-free period. The pCO2 in the surface water of Chagan Lake showed considerable spatiotemporal variability within a range of 0–200 μatm. pCO2 also showed significant seasonal variations, with the lowest and highest mean values in autumn (30–50 μatm) and summer (120–150 μatm), respectively. Spatially, the pCO2 values in the southeast of Chagan Lake were higher than those in the northwest. The CO2 fluxes were calculated based on the pCO2 and ranged from −3.69 to −2.42 mmol/m2/d, indicating that Chagan Lake was absorbing CO2 (i.e., it was a weak carbon sink). Temperature, chlorophyll a, total suspended matter, and turbidity were found to have reinforcing effects on the overall trend of pCO2, while the Secchi disk depth was negatively correlated with pCO2. The results of this study provide valuable insights for assessing the role of lakes in the carbon cycle in the context of climate change. [ABSTRACT FROM AUTHOR]

The evaluation method for determining the pore production range during CO2 displacement in shale cores is established based on CO2 displacement experiments, core analysis using online nuclear magnetic resonance (NMR), and pore size analysis using high-pressure mercury injection. By transforming the abscissa of the NMR T2 spectrum into pore-throat radius using the conversion formula between relaxation time and pore radius, the production behavior of crude oil in pores of different scales during CO2 displacement is analyzed. The target shale oil reservoir, located in eastern China, consists of two sets of salt beds. Crude oil is predominantly found in mesopores and smaller macropores. While water injection can saturate the salt and enhance seepage, the reactive areas of water imbibition are still smaller compared to those of CO2 injection. It is observed that the displacement efficiency of CO2 injection exhibits a negative correlation with the clay mineral content, with the swept pores mainly consisting of mesopores and small macropores. The proportion of crude oil produced from pores with diameters less than 0.1 μm during CO2 displacement is significantly higher than that during water displacement. The displacement effect of CO2 in mesopores and smaller macropores improves with increasing injection pressure. Above the miscible pressure condition, the oil displacement efficiency of CO2 is 11% higher than that of water displacement, indicating that CO2 displacement is more suitable for this shale oil reservoir. Exploiting oil from shale formations through water injection is challenging due to the presence of micrometer or nanoscale pores. However, in the target reservoir, which is a typical saline deposition, both water injection and gas injection, such as supercritical CO2 injection, are suitable for enhancing oil recovery. When compared to water injection, supercritical CO2 injection offers advantages such as higher injection capacity, wider swept volume, and better displacement effect. It is particularly effective in producing oil from pores smaller than 0.1 μm. Furthermore, increasing the CO2 injection pressure improves the displacement efficiency. In this type of shale oil reservoir, the average oil displacement efficiency of CO2 displacement is nearly 11% higher than that of water displacement. This method not only provides energy for the reservoir and enhances shale oil recovery but also contributes to carbon storage, making it an advanced approach for shale oil reservoir development. [ABSTRACT FROM AUTHOR]

Transgenic Bt rice (abbr. Bt rice) has provided a powerful tactics to control the striped stemborer Chilo suppressalis as one key lepidopteran pest in the paddyfields of China. Globally rising carbon dioxide (i.e., CO2) concentration has been predicted to affect the Cry protein contents in plant tissues of Bt rice and thus might affect its control efficiency to target insect pests. To reveal the resistance ability and the corresponding mechanism of C. suppressalis to Bt rice during different growth stage under elevated CO2 (eCO2), we carried out this experiment to measure the Bt toxin contents in Bt rice stems grown under ambient CO2 (aCO2) (400 ppm) and eCO2 (800 ppm) at seedling, tillering and heading stages, and to observe the larval mortality and bioassay the activity of midgut protease and the expression levels of Bt-toxin-receptor genes, aminopeptidases (APNs) in C. suppressalis larvae. Compared with aCO2, eCO2 increased the Bt-toxin content of Bt rice at seedling stage (+6.66%), and decreased that at heading stages (−13.99%), and significantly reduced the Bt-toxin content at tillering stage (−15.21%). And the larval mortality of C. suppressalis was lower as reared with Bt rice stems during tillering stage grown under eCO2 in contrast to aCO2. In addition, eCO2 significantly increased the activity of total protease, tryptase-like enzyme and aminopeptidase of C. suppressalis larvae fed on Bt rice during seedling stage, and significantly reduced the activity of tryptase-like enzyme and aminopeptidase of C. suppressails larvae fed on Bt rice during tillering and heading stages respectively. Moreover, eCO2 significantly increased the expression level of APN1 and APN5 of C. suppressails larvae fed on Bt rice during seedling stage, and significantly reduced the expression level of APN5 of C. suppressalis larvae fed on Bt rice during tillering and heading stages respectively. In summary, the control efficiency of Bt rice to target insect pests under eCO2 showed a downward trend during tillering and heading stages, and especially during tillering stage. [ABSTRACT FROM AUTHOR]

The (ultra-)mafic mine tailings pond revealed a weathering discrepancy in the tailings profile, which provided a valuable analog to assess the role of carbonate and silicate weathering of the basalt. In this study, drill-cores samples were selected from the Wanniangou V–Ti–Fe mine tailings pond (Sichuan province, China) to investigate the mineralogicand geochemical characteristics in the tailings profile. The results reveal (1) the tailings pond profile consist of upper and lower layers. The upper layer is composed of carbonate weathering (1.4 %), which was formed in the initial stages of tailings exposure and represented a minimal weathering degree. (2) The lower layer was primarily observed at the aquifer zone of the tailings pond, and was consistent with 0.45 % carbonate weathering and 48.4 % silicate weathering. (3) The weathering discrepancy in the tailings profile could be due to the sulfide oxidation and aerobic/flowing aquifer, which facilitate the water-tailings reactions. The tailings profile provides an analog to studying basalt weathering, as it spans both carbonate and silicate weathering. This research reinforces the idea that silicate weathering is predominant in basaltic areas and plays a crucial role in regulating atmospheric CO2 (carbon dioxide) levels on Earth. [ABSTRACT FROM AUTHOR]

Most conventional air pollutants and carbon dioxide (CO2) are simultaneously emitted from the same sources, providing a sound theoretical basis for the synergistic governance of these emissions. At present, China faces severe challenges in protecting the eco-environment, such as reducing conventional pollutants, improving environmental quality, and peaking CO2 emissions. Internationally, the control of greenhouse gas (GHG) emissions has been incorporated into the comprehensive environmental management system in major developed economies such as the United States (US) and the European Union (EU), where, based on GHG emissions monitoring and statistical data, decision-making support is provided for the national governments in the form of policy evaluation, thus forming a management mode that enables overall planning, coordination, and unified regulatory at the national level and participation of multiple departments under the national government. The synergistic control of conventional air pollutants and GHGs is becoming an important measure to strengthen the environmental management and achieve low-carbon development. This paper summarizes the synergistic effects of reducing air pollution and carbon emissions from the aspects of synergistic policies, strategic planning, and institutional systems, and conducts an analysis based on existing synergistic practices. [ABSTRACT FROM AUTHOR]

Spatiotemporal variations of industrial carbon emissions (IE) must be scientifically understood, which will be helpful to formulate reasonable emission reduction strategies. Given that spatial distribution of IE is irrelevant to space agents commonly used (such as population and nighttime light), estimation and spatialization methods for total carbon dioxide (CO2) emissions are not entirely suitable for IE. Therefore, this paper used greenhouse gases observing satellite level 4A product to estimate IE at the city level and used industrial land density to obtain the distribution of IE within the administrative districts. Sectoral emission inventories of 182 cities and a mosaic Asian anthropogenic emission inventory named MIX were used to verify the results. Then, spatiotemporal variation characteristics of China's IE were analyzed from multiple levels. Results showed that (1) the mean relative error of estimation results was 56.11%, among which 62 cities had relative error of less than 30%. Gridded IE in this paper had high consistency with MIX. (2) Cities with high IE experienced rapid growth from 2009 to 2012, followed by slower growth from 2012 to 2017. (3) Centroid of significant cold and hot spots moved to the southeast and northwest, respectively. Most cities with high annual IE growth had relatively low emission efficiency, mainly located in Inner Mongolia and Xinjiang. Aggregation of medium and high IE grids may represent high emission efficiency. Significant differences still exist between cities in IE, and sustainable development strategies should be formulated according to local conditions. Regions with high annual growth or low emission efficiency are the key to achieving IE reduction targets in future. [ABSTRACT FROM AUTHOR]

Marginal abatement cost (MAC) of CO2 plays a fundamental role in formulating industry environmental policies. In this paper, we measured the MACs of energy‐related CO2 among 40 industrial sectors during 2005–2017 based on parametric directional distance function, and there were significant differences between the results. Then, industrial sectors were classified into four categories, and we found 'low carbon intensity' type (type I, II) has higher MACs of CO2 than 'high carbon intensity' type (type III, IV); under the same level of carbon intensity, industrial sectors with lower CO2 emissions have higher MACs (type I>II, type III>IV). Moreover, capital intensity, technology progress, and ownership structure have positive effects on MACs, while energy intensity and energy consumption structure are negatively correlated with MACs. The research suggests: (1) The 'double control' of carbon intensity and CO2 emissions is necessary, however, reducing carbon intensity is still the primary target, and CO2 emission should also be controlled appropriately at the present stage. (2) Industrial sectors in type IV should be chosen as key industrial sectors to be supervised. (3) China should consider industry characteristics and implement "common but differentiated" emission reduction policies. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Since China's reform and opening up, the social economy has achieved rapid development, followed by a sharp increase in carbon dioxide (CO2) emissions. Therefore, at the 75th United Nations General Assembly, China proposed to achieve carbon peaking by 2030 and carbon neutrality by 2060. The research work on advance forecasting of CO2 emissions is essential to achieve the above-mentioned carbon peaking and carbon neutrality goals in China. In order to achieve accurate prediction of CO2 emissions, this study establishes a hybrid intelligent algorithm model suitable for CO2 emissions prediction based on China's CO2 emissions and related socioeconomic indicator data from 1971 to 2017. The hyperparameters of Least Squares Support Vector Regression (LSSVR) are optimized by the Adaptive Artificial Bee Colony (AABC) algorithm to build a high-performance hybrid intelligence model. The research results show that the hybrid intelligent algorithm model designed in this paper has stronger robustness and accuracy with relative error almost within ±5% in the advance prediction of CO2 emissions. The modeling scheme proposed in this study can not only provide strong support for the Chinese government and industry departments to formulate policies related to the carbon peaking and carbon neutrality goals, but also can be extended to the research of other socioeconomic-related issues. [ABSTRACT FROM AUTHOR]

China is the largest carbon dioxide emitter in the world. Over the past decades, China has made great efforts to retard the carbon emission growth. This paper aims to quantify the driving forces of stagewise provincial carbon emission changes and expound the bottom-up provincial efforts aligned with China's carbon abatement targets. During 2007–2012, economic growth as the major contributing factor posed a great increase in provincial carbon emissions, especially in underdeveloped provinces such as Inner Mongolia, Anhui, Guangxi, Shaanxi, and Ningxia. During 2012–2017, the energy intensity effect replaced economic growth as the largest contributor to provincial carbon emission changes. In both two periods, industrial structure upgrading and renewable energy expansion are conducive to mitigate provincial carbon growth, and the power sector will continue to contribute to national decarbonization. Lastly, this paper provides insight into national and provincial carbon emission abatement. [ABSTRACT FROM AUTHOR]

As the largest carbon dioxide emitter, China is working towards the direction of a green economy. As an irreplaceable part of establishing a green economy, the low-carbon city pilot (LCCP) policy is implemented in many large cities in China, and the scope of implementation will be further expanded. However, to date, there has been an absence of empirical studies basing on prefecture-level cities about the evaluation of China's LCCP policy. Evaluating and optimizing the LCCP policy is constructive to achieve the goal of China's green economic transition. In this paper, we evaluated the effect of the LCCP policy on China's low-carbon economic transition by using the difference-in-difference (DID) approach which can effectively alleviate endogenous problems and better evaluate this effect and the panel data of 210 prefecture-level cities in China from 2008 to 2016. The empirical analysis revealed that the LCCP policy inhibited China's low-carbon economic transition in general. Specifically, the policy worked well in the eastern region but failed in the central region and western region by studying the regional heterogeneity and influence mechanism. The reason is that the LCCP policy can stimulate low-carbon innovation with the help of innovation offset effects in the eastern region, but it failed to do so in the central region and western region. In addition, this paper analyzed the performance of three types of policy tools adopted by local governments to implement the policy, we found that market-economic tools are valuable to improving the low-carbon economic transition in pilot areas, but command-mandatory tools and voluntary tools have failed to achieve the expected objectives. The research results of this article can provide policy recommendations for optimizing the low-carbon policy and provide a reference for countries that are determined to develop a green economy. [ABSTRACT FROM AUTHOR]

Information and communication technology (ICT) has exerted a great impact on the socio-economic development; however, this development has come with some potential influence on climate change. The academics are divided over this issue; some argue that ICT has contributed to carbon reduction, while others consider that ICT has increased carbon dioxide (CO2) emissions. Undoubtedly, the existing literature abounds in the relationship between ICT and CO2 emissions, but little attention has been paid to the spillover effect of ICT and CO2 emissions, especially in developing countries. Hence, with the panel data of 285 China's prefecture-level cities from 2004 to 2018, this study innovatively discusses the spatial and mechanism effects of ICT on CO2 emissions, further exploring the heterogeneous impact of ICT on CO2 emissions from multiple perspectives. The empirical results confirm the positive relationship between ICT and CO2 emissions and identify the spatial spillover effect in the relationship. Furthermore, notably, the intermediary effect of energy consumption on the impact of ICT on CO2 emissions is identified. Finally, due to the differences in the geographical position, population size, and urban agglomeration of prefecture-level cities in China, the impact of ICT on CO2 emissions varies in different cities. The findings not only contribute to advancing the existing literature but also have a significant and targeted policy guiding significance for the cities to maximize the favorable influences of ICT and promote the low-carbon transformation of the whole society. [ABSTRACT FROM AUTHOR]

CO2 sequestration in saline aquifers is one of the most potential sequestration modes, and saline aquifers are ideal sites for CO2 geological sequestration. After CO2 is injected into a saline aquifer, it will have a long-term complex geochemical reaction with the formation of minerals and water, and the minerals will undergo multiple reactions such as dissolution and reprecipitation. Therefore, an in-depth study of the geochemical reaction mechanisms between CO2 and formation minerals is of great significance to the accurate calculation and prediction of CO2 storage volume and the safety evaluation of long-term CO2 sequestration. In China, continental saline aquifers are widely distributed, whose mineral compositions and texture maturity are markedly different from those of the marine sedimentary basins in North America, and their stratigraphic environments are more complicated. The studies on the CO2–water–rock (mineral) still have many research gaps or insufficiencies, and there is no report on the dissolution mechanisms of individual minerals in the reaction. Taking one certain block of Daqing Oilfield, which is a typical continental deposit in China, as an example, we analyze the dissolution laws and four types of typical continental deposited minerals under the effect of CO2 and the change features of ionic compositions and pH of the formation water in the process of geochemical reaction. The research results indicate that CO2 has different dissolution degrees for the four types of minerals, among which, feldspar, as the main mineral in continental sedimentary formations, has the lowest dissolution rate. Furthermore, in terms of the water type (Na+-enriched NaHCO3) of the saline aquifer in the deep part of the continental deposit, feldspar can precipitate into the secondary minerals represented by dawsonite in the later stage, which can act as the potential minerals of carbon fixation to increase the CO2 mineralization storage volume in continental deposited saline aquifers. [ABSTRACT FROM AUTHOR]