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On the basis of "Carbon Peak and Carbon Neutral" goals, carbon sequestration projects are increasing in China. The integrity of cement sheaths, as an important factor affecting carbon sequestration projects, has also received more attention and research. When CO2 is injected into the subsurface from sequestration wells, the cement sheath may mechanically fail due to the pressure accumulated inside the casing, which leads to the sealing of the cement sheath failing. The elasticity and strength parameters of the cement sheath are considered in this paper. The critical bottom-hole injection pressures of inclined well sections under anisotropic formation stresses at different depths were calculated for actual carbon-sealing wells in the X block—the CO2 sequestration target block. The sensitivity factors of the critical bottom-hole injection pressure were also analyzed. It was found that the cement sheath damage criterion was tensile damage. The Young's modulus and tensile strength of the cement sheath are the main factors affecting the mechanical failure of the cement sheath, with Poisson's ratio having the second highest influence. An increase in the Young's modulus, Poisson's ratio, and tensile strength of the cement sheath can help to improve the mechanical stability of cement sheaths in CO2 sequestration wells. This model can be used for the design and evaluation of cement in carbon sequestration wells. [ABSTRACT FROM AUTHOR]

Carbon emissions are critical to climate change, and land-use change is an essential source of growth in carbon emissions. Research on land-use carbon emissions has become one of the hotspots in academic research. To explore the research hotspots and development trends of land-use carbon emissions in the last 20 years, CiteSpace software was used to conduct a quantitative analysis of relevant literature. This paper was based on the China National Knowledge Infrastructure (CNKI) and Web of Science (WoS) database literature on land-use carbon emissions from 2001 to 2020. The scientific research cooperation network CiteSpace software, with keyword co-occurrence, clustering, and burst word detection, was used to systematically analyze the main research strengths, hotspots and frontiers and clarify the research progress. The research results are as follows: (1) the amount of literature and the depth of research on land-use carbon emissions have increased yearly. However, there is little cooperation between research institutions and scholars, and there is still a lack of large-scale and stable research teams. (2) At the research hotspot level, the English literature focuses on building models and theoretical frameworks to study the internal mechanisms and driving factors of carbon emissions and climate change. The Chinese literature focuses on achieving regional carbon emissions reductions and carbon cycle goals and optimizing a low-carbon economy, transportation and land-use structure. (3) Research frontiers and trends show that the English literature first explored carbon sequestration, organic carbon, and carbon accounting. In China, the research frontiers are gradually becoming focused on influencing factors, decoupling analysis, and the built environment. The study will strengthen the intensity and depth of global carbon emission research and provide a reference for improving global climate change, protecting ecology and balancing economic development. [ABSTRACT FROM AUTHOR]

The realization of the value of ecological products has led to an economic means for reducing carbon emissions in China. Tea is one of the most important cash crops and one of the most popular beverages in the world. Due to the complex the tea industrial chain, it is considered to be an industry with high carbon emissions. Ecological tea products with low-carbon attributes can be considered a linkage of ecology, economy, and society. Based on this, this paper presents research on low-carbon ecological tea (LCT). Herein, we construct the formational logic of low-carbon ecological products, explore the connotations of LCT, and form a conceptual pathway for realizing LCT to contribute to climate change mitigation and adaptation. This paper starts from the upstream, midstream, and downstream of the industrial chain; it establishes three value realization pathways that keep, as a priority, the promotion of ecological industrialization, focus on restoration to improve the ecology of the industrial chain, and innovate technology to expand the industrial chain. The pathways are a set of low-emission production solutions that use techniques to enhance carbon sequestration in soil, reduce the use of fertilizers and pesticides, and help shift to clean energy from low-emission sources in the stages of plantation, processing, and distribution. In the process of realizing LCT, the government plays an important role, and its support and guidance are needed. Based on stakeholder theory, this paper builds an implementation mechanism that focuses on the micro perspective (users, organizations), integrates the mesoscopic perspective (industry), and relies on the macro perspective (government). [ABSTRACT FROM AUTHOR]

Biodiversity loss and forest degradation have received increasing attention worldwide, and their effects on forest biomass carbon storage and stability have not yet been well defined. This study examined 1275 tree plots using the field survey method to quantify the effects of tree diversity, tree sizes, and mycorrhizal symbiont abundance on biomass carbon storages (C s ) and NDVI (Normalized Difference Vegetation Index)-based ecosystem stability (standard deviation/mean NDVI = NDVI&#95;S) during the field survey period from 2008 to 2018. Our data showed C s and NDVI&#95;S averaged at 31-108 t ha -1 and 32.04-49.28, respectively, and positive relations between C s and NDVI&#95;S were observed (p < 0.05). Large forest-type and regional variations were found in these two parameters. Broadleaf forests had 74% of C s (p < 0.05) of the conifer forests, but no differences were in NDVI&#95;S. Cold regions at high latitudes had 71% of NDVI&#95;S in the warm regions at low latitudes, while no differences were in C s . Moist regions at high longitudes had 2.04 and 1.28-fold higher C s and NDVI&#95;S (p < 0.05). The >700 m a.s.l. regions had 1.24-fold higher C s (p < 0.01) than the <700 m a.s.l. regions, but similar NDVI&#95;S (p > 0.05). Nature Reserves had 1.94-fold higher C s but 30% lower NDVI&#95;S than outside Reserves (p < 0.001). > 40-year-old forests had 1.3- and 2-fold higher C s and NDVI&#95;S than the young forests. Structural equation modeling and hierarchical partitioning revealed the driving paths responsible for these variations. Tree richness was positively associated with C s and ecosystem stability, contributing 21.6%-30.6% to the total effects on them; tree sizes significantly promoted the C s , but had negligible impacts on NDVI&#95;S. MAT's total effects on NDVI&#95;S of conifer forests were 40% higher than that of broadleaf forests, MAP's total effects on C s varied with forest types; arbuscular mycorrhizal tree dominance exhibited a smaller positive impact on C s and ecosystem stability in comparison to other factors. Our findings underscore that the significance of climatic-adapted forest management, diversity conservation, and big-sized tree protections can support the achievement of carbon neutrality in China from biomass carbon sequestration and ecosystem stability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Carbon sequestration is vital to maintaining carbon neutrality and mitigating climate change's impact on humans and the environment. As the government's role in eco-advocacy is primarily designed to safeguard the environment, this paper discusses the impact of government environmental regulations on carbon sequestration. By analyzing 286 cities from 2000 to 2019 in China, we propose that government environmental regulation can lead to a 0.77% increase in carbon sequestration. Additionally, industrial agglomeration and industrial structure advancement are regarded as viable channels. As a result of the differences in city types, government intervention, and public concern across different cities, the impact is likely to vary as well., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

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

Land use change is the most important driving factor of terrestrial carbon stock change. Soil is the largest carbon reservoir of terrestrial ecosystems, and the impact of land use change on soil carbon sequestration is related to major issues such as the global warming process and food security. The research can provide a basis for land managers and policy makers to develop appropriate planning strategies for soil carbon sequestration management. Despite the widespread attention of relevant studies, macro reviews are still lacking. In order to objectively reveal the current situation of the research field, firstly this paper conducted a bibliometric analysis based on relevant papers in the Web of Science Core Collection database from 1985 to 2021. Secondly, we conducted a review study of land use change on soil carbon sequestration. The research results showed that: (1) the overall amount of the published literature in related fields showed an upward trend, and the development could be divided into three stages, growing slowly from 1985 to 1999, steadily from 2000 to 2009, and rapidly from 2010 to 2021. (2) From the perspective of national distribution, the published papers were mainly from the United States and China, which were much higher than those in other countries. There was mutual cooperation between research institutions in different countries and on a certain scale. (3) Since 2000, soil carbon sequestration has been more frequently mentioned in articles on land use change. Related research was mostly focused on exploring the impact of different land use types and different farming methods on soil organic carbon content in the context of global warming. Land use change and management among agricultural land, woodland, and grassland are the focus of research. The conversion of woodland to agricultural land and grassland is an important reason for the decrease in soil carbon sequestration. Corresponding management measures can be taken to improve soil carbon sequestration. Future research should use multidisciplinary technical means and methods to further explore the interaction mechanism between climate change, land use change, and soil carbon sequestration, so as to carry out more accurate prediction and assessment of different climate scenarios. [ABSTRACT FROM AUTHOR]

Urban development boundary (UDB) has always served as a crucial aspect of urban sprawl research. The objective of this paper is to investigate boundary delineation and carbon emission effects. Firstly, we examined the patterns of land use changes. Additionally, this paper utilized the FLUS model and land use carbon emission calculation model to delineate UDB and calculate carbon emission effects within UDB under typical scenarios. The research results are as follows: (1) Xuzhou city witnessed a significant increase in both forest land and construction land from 2010 to 2020. (2) Under the CPS, the area of cultivated land increased by 217.05 km2 compared to the NDS. The UDB area under the NDS and CPS was 971.50 km2 and 968.99 km2, respectively. (3) Compared to the NDS, the CPS led to a net carbon emission increase of 4759.93 t within the UDB. Therefore, we should enhance the carbon sequestration and emission reduction capacity of the agricultural system. This study is beneficial for expanding the depth of research on the UDB and guiding the low-carbon urban development. We sincerely encourage readers to download this paper to improve this paper. [ABSTRACT FROM AUTHOR]

The double-carbon goal proposal has made it imperative for China's power industry to address the urgent issue of reducing greenhouse gas emissions from coal-fired power plants and promoting their clean and efficient use. A new approach to achieving peak-shaving and improving grid stability is the combination of carbon capture and storage (CCS) facilities with coal-fired power plants, which offers a strategic solution for mitigating climate change. Nonetheless, the viability of CCS retrofitting for coal-fired power plants in China hinges on its economic feasibility. The technical characteristics, economic analysis, and policy implications of clean coal-fired power plant equipped with CCS (CCP-CCS) technologies are evaluated in the paper. A comparison of the characteristics of different clean coal power generation technologies, including capacity, efficiency, coal consumption, and environmental performance, is conducted. The paper analyzes the economic feasibility of four typical clean coal power generation technologies, namely Supercritical (SC), Ultra-supercritical (USC), Integrated Gasification Combined Cycle (IGCC), and Circulating Fluidized Bed (CFB), both with and without CCS, using the levelized cost of electricity (LCOE) model. Financial parameters, investment parameters, operation and maintenance parameters, tax parameters, and capacity parameters are all considered in the LCOE model. The results indicate: (1) If CCS is not installed, the LCOE of USC power plants is the lowest at 0.37 yuan/kWh, while the LCOE of IGCC power plants is the highest at 0.44 yuan/kWh. (2) If CCS is installed, the LCOE of CFB units is the highest at 0.74 yuan/kWh, while the LCOE of USC units is the lowest at 0.60 yuan/kWh. (3) In sensitivity analysis, coal prices have the most significant impact on LCOE, followed by expected annual operating hours, while the cost of carbon capture equipment is the least sensitive. (4) The cost of retrofitting CCS on clean coal-fired power plants (CCP) is currently high, with an LCOE increase of around 40 to 70%, which is comparable to that of renewable energy electricity. This paper presents policy recommendations, including preferential loans, tax incentives, and R&D funding, to promote the development of CCP in China based on the economic analysis results and challenges faced by CCP. Additionally, the paper proposes relevant policy implications such as preferential loan policies, a diversified financing system, R&D and innovation, and the establishment of a carbon trading market for CCS in China to provide practical guidance for the promotion of CCP-CCS technologies in China. [ABSTRACT FROM AUTHOR]

Forests, the ancient wooden giants, are both symbols of natural beauty and reservoirs of carbon stocks. The current climate crisis has created an urgent need for an in-depth study of forest ecosystems and carbon stocks. Based on forest inventory data from field surveys and four bioclimatic zones [Zone 1 (Z1, humid forest), Zone 2 (Z2, semi-humid forest), Zone 3 (Z3, semi-humid to semi-arid forest-grassland), and Zone 4 (Z4, semi-arid typical grassland)], two methods [Method 1 (M1) and Method 2 (M2)] were used to estimate carbon stocks in forest ecosystems in Shaanxi Province, China, and explored the spatial patterns of carbon pools and potential influences. The total forest ecosystem carbon pool amounted to 520.80 Tg C, of which 53.60% was stored aboveground, 17.16% belowground, and 29.24% in soil (depth of 0-10 cm). Spatially, there were marked north-south gradients in both biomass (Z2 > Z3 > Z1 > Z4) and soil organic carbon densities (Z1 > Z2 > Z3 > Z4). The differences between aboveground and belowground biomass carbon density across broadleaf, needle-leaf, and broadleaf and needle-leaf mixed forest were not pronounced, while soil organic carbon density had the order of broadleaf (18.38 Mg C/ha) > needle-leaf (11.29 Mg C/ha) > broadleaf and needle-leaf mixed forest (10.33 Mg C/ha). Under an ideal scenario that excludes external factors, mainly forest growth, the sequestration potential of forest biomass by 2032 was estimated by M1 as 85.43 Tg, and by M2 to be substantially higher at 176.21 Tg. As of 2062, M1 estimated 155.97 Tg of sequestration potential for forest biomass. The spatial patterns of forest biomass and soil carbon density were closely related to climatic factors, and these relationships allowed the spatial division into two distinct climatic regions. Moreover, biomass carbon density was significantly correlated with the normalized difference vegetation index, soil silt, and elevation. This study provides key information for promoting the strategic shift from light-green to deep-green forest systems in Shannxi Province and updates the estimation methods of forest ecosystems' carbon pools based on field surveys., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

China's commitment to attaining carbon neutrality by 2060 has galvanized research into carbon sequestration, a critical approach for mitigating climate change. Despite the rapid urbanization observed since the turn of the millennium, a comprehensive analysis of how urbanization influences urban carbon storage throughout China remains elusive. Our investigation delves into the nuanced effects of urbanization on carbon storage, dissecting both the direct and indirect influences by considering urban-suburban gradients and varying degrees of urban intensity. We particularly scrutinize the roles of climatic and anthropogenic factors in mediating the indirect effects of urbanization on carbon storage. Our findings reveal that urbanization in China has precipitated a direct reduction in carbon storage by approximately 13.89 Tg of carbon (Tg C). Remarkably, urban sprawl has led to a diminution of vegetation carbon storage by 8.65 Tg C and a decrease in soil carbon storage by 5.24 Tg C, the latter resulting from the sequestration of impervious surfaces and the elimination of organic matter inputs following vegetation removal. Meanwhile, carbon storage in urban greenspaces has exhibited an increase of 6.90 Tg C and offsetting 49.70% of the carbon loss induced by direct urbanization effects. However, the indirect effects of urbanization predominantly diminish carbon storage in urban greenspaces by an average of 5.40%. The degree of urban vegetation management emerges as a pivotal factor influencing the indirect effects of urbanization on carbon storage. To bolster urban carbon storage, curbing urban sprawl and augmenting urban green spaces are imperative strategies. Insights from this study are instrumental in steering sustainable urban planning and advancing towards the goal of carbon neutrality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Soil aggregates play pivotal roles in soil organic carbon (SOC) preservation and climate change. Biochar has been widely applied in agricultural ecosystems to improve soil physicochemical properties. However, the underlying mechanisms of SOC sequestration by soil aggregation with biochar addition are not well understood at a large scale. Here, we conducted a meta-analysis of 2335 pairwise data from 45 studies to explore how soil aggregation sequestrated SOC after biochar addition in agricultural ecosystems of China. Biochar addition markedly enhanced the proportions of macro-aggregates and aggregate stability, and the production of organic binding agents positively facilitated the formation of macro-aggregates and aggregate stability. Soil aggregate-associated organic carbon (OC) indicated a significantly increasement by biochar addition, which was attributed to direct and indirect inputs of OC from biochar and organic residues, respectively. Biochar stimulated SOC sequestration dominantly contributed by macro-aggregates, and it could be interpreted by a greater improvement in proportions and OC protection of macro-aggregates. Furthermore, the SOC sequestration of soil aggregation with biochar addition was regulated by climate conditions (mean annual temperature and precipitation), biochar attributes (biochar C/N ratio and pH), experimental practices (biochar addition level and duration), and agronomic managements (land type, cropping intensity, fertilization condition, and crop type). Collectively, our synthetic analysis emphasized that biochar promoted the SOC sequestration by improving soil aggregation in agricultural ecosystems of China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

CO2 capture from coal power plants is an important and necessary solution to realizing carbon neutrality in China, but CCS demonstration deployment in power sector is far behind expectations. Hence, the reduction potential of energy consumption and cost for CCS and its competitiveness to renewable powers are very important to make roadmaps and policies toward carbon neutrality. Unlike the popular recognition that capturing CO2 from flue gases is technically and commercially mature, this paper notes that it has been proved to be technically feasible but far beyond technology maturity and high energy penalty leads to its immaturity and therefore causes high cost. Additionally, the potential energy penalty reduction of capture is investigated thermodynamically, and future CO2 avoidance cost is predicted and compared to renewable power (solar PV and onshore wind power). Results show that energy penalty for CO2 capture can be reduced by 48%-57%. When installation capacity reaches a similar scale to that of solar PV in China (250 GW), CO2 capture cost in coal power plants can be reduced from the current 28-40 US$/ton to 10-20 US$/ton, and efficiency upgrade contributes to 67%-75% in cost reduction for high coal price conditions. In China, CO2 capture in coal power plants can be cost competitive with solar PV and onshore wind power. But it is worth noting that the importance and share of CCS role in CO2 emission reduction is decreasing since renewable power is already well deployed and there is still a lack of large-scale CO2 capture demonstrations in China. Innovative capture technologies with low energy penalties need to be developed to promote CCS. Results in this work can provide informative references for making roadmaps and policies regarding CO2 emission reductions that contribute towards carbon neutrality. [ABSTRACT FROM AUTHOR]

The "Dual Carbon" initiative is a two-stage carbon reduction goal proposed by China, with significant implications for global climate change mitigation. This article examines the impact of the "Dual Carbon" strategy on China's forestry development and explores how to leverage this strategy to facilitate the transformation and advancement of the forestry sector. Current review indicated that forestry has the advantage of achieving higher emission reduction targets at a low cost. Starting with an overview of the "Dual Carbon" strategy, this paper analyzes the carbon sequestration potential of plants and soil, and the challenges and opportunities faced by forestry development under this framework. Furthermore, we outline implementation pathways for forestry development, aiming to provide insights for the progress of China's forestry sector. Overall, it should be noted that the priority is to vigorously develop timber resources, and we also need to vigorously develop and protect forestry talent with the support of China's policies. By trapping into the carbon storage capabilities and leveraging carbon trading mechanisms of forests, a favorable ecological environment can be created, thus achieving the goal of carbon neutrality. Highlights: • Forest development and its carbon sinks, attributed to plant and soil have the potential in carbon sequestration process, thus helping China achieve carbon neutrality. • The supply of forest products and the balance of economic growth and environmental protection are the key difficulties under the "Dual Carbon" strategy. • Trading forest carbon sinks can boost China's sequestration. [ABSTRACT FROM AUTHOR]

After the carbon peaking and carbon neutrality goals were proposed, different institutions and scholars carried out research on China's medium- and long-term mitigation pathways. Through the literature review of China's research on carbon neutrality, this paper finds that the zero-carbon energy transition is the key to achieving carbon neutrality. The main driving factors of reducing energy-related carbon emissions include the cleanliness of primary and secondary energy supply systems, the electrification of energy consumption and the development of hydrogen energy, energy efficiency improvement, carbon capture and storage (CCS), and negative emissions. Furthermore, based on the literature, this paper conducts a quantitative comparative analysis, and selects key indicators for comparative analysis and summary from seven dimensions, including economic and social development, carbon emission pathways, primary energy consumption, final energy consumption, final hydrogen energy consumption, electricity demand and supply, and installed capacity and structure of power generation. Main conclusions are as follows: (i) In terms of carbon emission pathways, the institutions generally believed that China will peak carbon emissions around 2028 and achieve carbon neutrality between 2050 and 2060. Achieving net-zero or near-zero emissions first in the power sector is the key to carbon neutrality across the society; (ii) In terms of energy supply, it is a consensus to increase the proportion of clean energy and reduce carbon emissions from the source. The proportion of clean energy in primary energy will increase to more than 85%, and the proportion of clean energy power generation and installed capacity will reach more than 90%; (iii) In terms of energy use, electricity will become the core of final energy consumption in the future. The predicted electricity consumption across the society will range 14.3–18.4 PWh, and the predicted electrification rate will exceed 65%. [ABSTRACT FROM AUTHOR]

Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms that control forest C sinks and is helpful for developing sustainable forest management policies in the face of climate change. Using the Forest Identity concept and forest inventory data, this study quantified the spatial and temporal changes in the relative contributions of forest areal expansion and increased biomass growth to China's forest C sinks from 1977 to 2008. Over the last 30 years, the areal expansion of forests was a larger contributor to C sinks than forest growth for all forests and planted forests in China (74.6 vs. 25.4% for all forests, and 62.4 vs. 37.8% for plantations). However, for natural forests, forest growth made a larger contribution than areal expansion (60.4 vs. 39.6%). The relative contribution of forest growth of planted forests showed an increasing trend from an initial 25.3 to 61.0% in the later period of 1998 to 2003, but for natural forests, the relative contributions were variable without clear trends owing to the drastic changes in forest area and biomass density over the last 30 years. Our findings suggest that afforestation can continue to increase the C sink of China's forests in the future subject to persistently-increasing forest growth after establishment of plantation. [ABSTRACT FROM AUTHOR]

The Qinling Mountains north slope region constitutes a vital terrestrial ecosystem reserve within China. This study employs land use and land cover (LULC) data spanning from 1990 to 2020. Utilizing methodologies encompassing land use classification, transfer matrix analysis, and the application of the PLUS and InVEST models, this research endeavors to elucidate the spatial-temporal dynamics of land use patterns and associated carbon storage in the region. These analyses are conducted within the context of four prospective scenarios: Natural Development Priority, Arable Land Protection Priority, Ecological Protection Priority, and Urban Development Priority, all projected onto the landscape for 2030. Notably, our findings reveal a consistent decline in carbon storage across all four scenarios for 2030 compared to the baseline year 2020. This stark reality presents substantial challenges to achieving the region's targets of carbon peaking and eventual carbon neutrality. Furthermore, this paper meticulously delineates six key drivers contributing to this decline in carbon storage. In conclusion, it proffers nine strategic recommendations aimed at augmenting carbon storage, with an overarching objective of establishing a harmonized mechanism capable of balancing urban development, safeguarding cultivated land, fortifying ecological preservation, and enhancing carbon sequestration within the area. [ABSTRACT FROM AUTHOR]

The carbon emission trading market (carbon market) is an important policy tool for China to achieve the goal of "carbon peak and carbon neutrality" through market mechanism. This paper uses panel data of 30 provinces in China from 2005 to 2019 to examine the emission reduction effect (ERE) of China's carbon market pilots using multi-period Difference-in-Differences (DID)method, and then analyzes the factors influencing ERE and the economic impact of carbon market. According to the Bacon decomposition and a series of robustness tests, the results reveal that China's carbon market pilots have significant ERE. Both the expansion of the carbon market scale and the improvement of market activity level can significantly boost the carbon market's ERE. Meanwhile, the establishment of carbon market has no negative impact on the economic growth. Therefore, we propose to accelerate the construction of the national carbon market, incorporating more industries in a systematic manner, expand the scale of the carbon market, steadily promote the innovation of carbon financial instruments, improve the activity of the carbon market, so as to promote the transformation of China's green and low-carbon economy and achieve the emission reduction target as scheduled. [ABSTRACT FROM AUTHOR]

With the global climate change, carbon reduction in economically active regions has gradually become a focus of attention and its underlying drivers were essential for understanding alterations in ecosystems in response to human behavior. However, the exploration of Carbon Sinks/Sources Patterns (CSSP) in an Economic-Social context was lacking. Distinguished from traditional Net Ecosystem Productivity (NEP) estimation methods, we optimized model parameters, adjusted estimation logic, and revealed CSSP more reasonably. Moreover, spatial econometric model was used to reveal the spatial effects mechanism of Economic-Social Development on CSSP. Over the past 20 years, we revealed that: (a) The pattern of NEP exhibited distinct spatial heterogeneity, with higher sinks observed in the north and offshore regions. It demonstrated regular cyclic fluctuations, averaging a 3-4-year cycle, featuring a gradual ascent followed by a rapid descent; (b) The Carbon Sequestration Capacity (CSC) of vegetation significantly increased. Based on the carbon sink properties, the study area was distinctly divided into three clusters; (c) CSSP have been profoundly affected by economic-social factors. Economic growth and industrial structure optimization contributed to the enhancement of CSC, but population aggregation and urban expansion had negative impacts. The direct effect of innovation capacity and the spatial spillover effect of industrial structure optimization were negative. Overall, exploring CSSP against the backdrop of economic-social factors not only provides a new perspective for understanding the regularities of change and the underlying mechanisms driven by human factors but also offers valuable insights for achieving sustainable development and green growth in other coastal regions globally., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

With a significant share of renewable power generation integrated into the power supply, it is crucial to timely adjust the regulating peak load for coal-fired power plants equipped with CO2 capture to ensure the stable operation of the multi-energy supply system. In this paper, the effects of varying boiler loads on the techno-economic performance of the retrofitted power plant were studied. Furthermore, the potential for reducing the cost of CO2 capture was investigated, and early opportunities for demonstration were discussed. Results showed that when the boiler load decreased from 100% turbine heat acceptance condition to 50% turbine heat acceptance condition, the cost of CO2 capture increased from 37.0 $/t CO2 to 57.0 $/t CO2, cost contribution of energy penalty and extra capital investment also increased from 20.6 $/t-CO2 to 25.7 $/t-CO2, and from 16.4 $/t-CO2 to 31.3 $/t-CO2, respectively. Furthermore, by improving separation efficiency from 0.15 to 0.5, a 25% to 30% reduction in CO2 capture cost can be achieved. The cost of CO2 capture could decrease by 42.2–50.5% when the cumulative capacity reaches 250 GW under the high investment learning rate scenario. According to the distribution of coal prices and renewable energy sources in China, the early demonstration projects of multi-energy supply systems should prioritize the northern region. The results of this work can provide informative references for making roadmaps and policies for CO2 emission reduction toward carbon neutrality. [ABSTRACT FROM AUTHOR]

The scientific assessment of mariculture carbon sinks is crucial to recognize its potential as a significant component of marine blue carbon in global climate change mitigation. Therefore, the objective of the research was to estimate the seaweed and shellfish mariculture carbon sink of different varieties in various sea areas. The paper emphasized the distinction between short-term carbon sequestration in seaweed and shellfish that can be removed and long-term carbon sequestration that is deposited. Methodologically, the evaluation was based on the carbon sequestration mechanism and systematic pathways in shellfish and seaweeds. Additionally, the carbon sequestration of shellfish and seaweed aquaculture over the last decade was evaluated by the carbon sink assessment model, and the reasons for the differences in the carbon sink capacity of mariculture in China's coastal provinces were discussed by using the LMDI decomposition model. The results indicated the carbon sequestration of offshore seaweeds and shellfish mariculture in China was huge. From 2010 to 2020, offshore seaweed aquaculture in China amounted to 7.959 Mt C/a, while shellfish aquaculture contributed 33.542 Mt C/a to the carbon sinks. Sedimentary carbon sequestration by shellfish accounted for 51% of the total carbon sequestration in mariculture involving shellfish and seaweeds. Especially noteworthy is the sedimentary carbon sequestration by shellfish, which is an indispensable and crucial component of mariculture carbon sequestration estimation. It is concluded that improvements in farming efficiency exerted the greatest influence on the variations of the mariculture carbon sink, while adjustments in farming structure had a relatively minor impact in the case of little change in aquaculture yield. Enhancing farming efficiency emerges as a practical approach to bolstering the carbon sink potential of marine aquaculture fisheries in the future. [ABSTRACT FROM AUTHOR]

Soil carbon sequestration plays an essential role in mitigating CO2 increases and the subsequently global greenhouse effect. The storages and dynamics of soil organic carbon (SOC) of 0-30 cm soil depth in different landscape types including beaches, reservoir and pond, reed wetland, forest wetland, bush wetland, farmland, building land, bare land (severe saline land) and salt field in the modern Yellow River Delta (YRD), were studied based on the data of the regional survey and laboratory analysis. The landscape types were classified by the interpretation of remote sensing images of 2000 and 2009, which was calibrated by field survey results. The results revealed an increase of 10.59km² in the modem YRD area from 2000 to 2009. The SOC density varied ranging from 0.73 kgm-2 to 21.60 kgm-2 at depth of 30 cm. There were ∼3.97 x 106 t and 3.98 x 106 t SOC stored in the YRD in 2000 and 2009, respectively. The SOC storages changed greatly in beaches, bush wetland, farm land and salt field which were affected dominantly by anthropogenic activities. The area of the YRD increased greatly within 10 yr, however, the small increase of SOC storage in the region was observed due to landscape changes, indicating that the modern YRD was a potential carbon sink and anthropogenic activity was a key factor for SOC change. [ABSTRACT FROM AUTHOR]

In recent years, droughts have frequently hit China's terrestrial ecosystems. How these droughts affected carbon sequestration by China's terrestrial ecosystems is still unclear. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model, driven by remotely sensed vegetation parameters, was employed to assess the effects of droughts on net ecosystem productivity (NEP) of terrestrial ecosystems in China for the period from 2000 to 2011. Different categories of droughts, as indicated by a standard precipitation index (SPI), extensively hit terrestrial ecosystems in China, particularly in 2001, 2006, 2009 and 2011. The national total NEP exhibited a slight decline of -11.3 TgCyr-2 during the study period, mainly due to large reductions of NEP in typical drought-hit years 2001, 2006, 2009 and 2011, ranging from 61.1 TgCyr-1 to 168.8 TgCyr-1. National and regional total NEP anomalies were correlated with corresponding annual mean SPI, especially in Northwest China, North China, Central China, and Southwest China. In drought years, the reductions of NEP might be caused by a larger decrease in gross primary productivity (GPP) than in respiration (RE) (2001 and 2011), a decrease in GPP and an increase in RE (2009), or a larger increase in RE than in GPP (2006). Droughts had lagged effects of up to 3-6 months on NEP due to different reactions of GPP and RE to droughts. In east humid and warm parts of China, droughts have predominant and short-term lagged influences on NEP. In western cold and arid regions, the effects of droughts on NEP were relatively weaker and might last for a longer period of time. [ABSTRACT FROM AUTHOR]

Afforestation and reforestation are pivotal in mitigating land degradation and bolstering the carbon sink capacity of terrestrial ecosystems. However, the potential economic ramifications of afforestation and reforestation in the context of climate change remain largely unexplored. In this study, we employed an interdisciplinary methodology to establish a framework for assessing future forest potential and carbon sequestration in the Eastern Loess Plateau region of China. Our findings indicate that an estimated 17,392.99 km 2 of land suitable for afforestation still existed within the region, exhibiting a propensity to aggregate around existing forests rather than being dispersed randomly. Notably, 4385.36 km 2 was prioritized for afforestation initiatives. Projections suggest a significant enhancement of the forest carbon sink within the study area by 2050, ranging from 36.93 Mt to 105.38 Mt. The corresponding economic value for this enhancement is estimated to vary between US$3.25 billion and US$17.68 billion. Of significance is the observed polarization of the region's carbon sink capacity over time, with half of the total carbon sinks concentrated within 10% of the districts. Additionally, approximately 26% of the counties are expected to transition from carbon sinks to carbon sources. These findings underscore the substantial impact of climate change on forest distribution and suggest a targeted approach to combat forest degradation by circumventing ineffective afforestation activities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Exploring the vegetation carbon cycle and the factors influencing vegetation carbon sequestration in areas with complex plateau-basin topography and fragile ecosystems is crucial. In this study, spatial and temporal characteristics of carbon sequestration by vegetation in Sichuan and Chongqing from 2010 to 2020 and the influencing factors were investigated through simulations of net primary productivity (NPP) using the modified Carnegie-Ames-Stanford approach (CASA) and the Thornthwaite Memorial (TM) model and using chemical equations of photochemical reactions. The results indicated that: The spatial distribution of carbon sequestration capacity (CSC) trends showed an increase in the east (the most prominent increased trend along the mountainous areas of the basin) and a decrease in the west (western Sichuan plateau). Differences exist in the impact factors of CSC in different regions. In the basin margins and mountainous areas, where the proportion of forests was high, a combination of climate change and human activities contributed to the increase in CSC. The relatively warm and humid meteorological conditions in the hinterland of the basin were more conducive to the increase in CSC, and climate change also affected the region more significantly. In contrast, in the relatively high altitude of western Sichuan, controlled human activities were the key to improving CSC. The results of the study contribute to the understanding of the basic theory of vegetation carbon cycle in areas with complex plateau-basin topography and fragile ecosystems, as well as to provide suggestions for ecological shelter construction and ecological restoration in the upper Yangtze River., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Employing a time‐varying difference‐in‐differences model and a data set collected from 2,735 counties in China from 2003 to 2017, this study examines the causal relationship between Chinese government transfer payments to resource‐exhausted cities (TPREC) and carbon emissions for the first time. Our results show that TPREC could significantly reduce carbon emissions of resource‐exhausted cities in China. A variety of robustness tests supports our findings. Our further mechanism analysis shows that TPREC mainly affects carbon emissions through the following three channels: (a) promoting technological progress and industrial upgrades; (b) increasing vegetation carbon sequestration; (c) strengthening government environmental regulations. Finally, this paper analyzes the spatial heterogeneity of the carbon emission reduction effect of TPREC and finds that the most significant reduction effect of TPREC is in the western region and coal‐exhausted cities. This paper provides new empirical evidence for the role of transfer payments in promoting low‐carbon development using a unique set of data. Our findings provide new insights for decision‐makers to facilitate the low‐carbon development of resource‐exhausted cities. Plain Language Summary: By employing a time‐varying difference‐in‐differences model, we examine the causal relationship between central government transfer payments to resource‐exhausted cities and carbon emissions for the first time. We find China's TPREC can significantly reduce carbon emissions by promoting technological progress and industrial upgrades, increasing vegetation carbon sequestration, and strengthening government environmental regulations. Key Points: China's transfer payments to resource‐exhausted cities (TPREC) could significantly reduce carbon emissions, and this conclusion has also been supported by multiple robustness testsThe TPREC could achieve carbon emission reduction by promoting technological progress, industrial upgrading, and economic efficiencyThe most significant carbon emission reduction effect of TPREC is in the western region and coal‐exhausted cities [ABSTRACT FROM AUTHOR]

Urbanization is accelerating globally, causing a variety of environmental changes such as increases in air temperature, precipitation, atmospheric CO2, and nitrogen (N) deposition. However, effects of these changes on forest soil carbon (C) sequestration remain largely unclear. Here we used urban-to-rural environmental gradients in Guangdong Province, southern China, to address the potential effects of these environmental changes on soil C sequestration in Pinus massoniana forests. In contrast with our expectations and earlier observations, soil C content in urban sites was significantly lower than those in suburban and rural sites. Lower soil C pools in urban sites were correlated with a significant decrease in fine root biomass and a potential increase in soil organic C decomposition. Variation of soil C pools was also a function of change in soil C fractions. Heavy fraction C content in urban sites was significantly lower than those in suburban and rural sites. By contrast, light fraction C content did not vary significantly along the urban-to-rural gradient. Our results suggest that urbanization-induced environmental changes may have negative effect on forest soil C. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The regions near the Tropic of Cancer are a latitudinal geographical zone with typical climatic, topographic, and human landscape features. It is necessary to explore the region's net primary productivity (NPP) dynamics as it combines complex topography, various vegetation types, and intense human activities. The study sets the transect near the Tropic of Cancer (TCT) and uses the Carnegie–Ames–Stanford (CASA) model to estimate the NPP from 2000 to 2020. After using the RESTREND method, the paper calculates and compares the relative contributions of climate variability and anthropogenic activities to NPP changes. Finally, the geographical detector (Geodetector) model is applied to evaluate how anthropogenic and natural factors affect spatial distribution patterns and NPP changes. The results indicated that the average annual NPP is 820.39 gC·m−2·yr−1 during the 21 years. In addition, when the NPP varies, it increases over the entire study area, with a slope of 4.81 gC·m−2·yr−1, particularly in the western region. Across the entire research area, 63.39% and 77.44% of the total pixels positively contribute to climate variability and human activities in NPP, with a contribution of 0.90 and 3.91 gC·m−2·yr−1, respectively. Within the western, central, and eastern regions, anthropogenic activities have a stronger impact on NPP than climate variability, particularly pronounced in the eastern region. Furthermore, vegetation cover is the dominant factor in the spatial patterns and NPP trends across the TCT and the three regions. In contrast, climate factors are shown to be less influential in NPP distribution than in the western region. The results also demonstrated that the effect of population density and the GDP on NPP gradually rises. Two-factor interaction is much larger than any individual factor, with the dominant interaction factor being vegetation cover with climatic factors. Lastly, the findings revealed that anthropogenic activities positively promote NPP accumulation across the TCT, thus highlighting the importance of human activity-led ecological restoration and ecological protection measures that contribute to regional carbon sequestration and carbon balance. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The impact of air temperature in early months on the carbon sequestration of a subtropical coniferous plantation was discussed by analyzing the eddy flux observations at Qianyanzhou (QYZ) site located in southern China from 2003 to 2008. This site experienced two cold early growing seasons (with temperature anomalies of 2-5° C) in 2005 and 2008, and also a severe summer drought in 2003. Results indicated that the low air temperature from January to March was the major factor controlling the inter-annual variations in net carbon uptake at this site, rather than the previously thought summer drought. The accumulative air temperature from January to February showed high correlation (R² = 0.970, p < 0.001) with the annual net ecosystem production (NEP). This was due to the controls of early-months temperature on the plant phenology developing and the growing season length at this subtropical site. The cold spring greatly shortened the growing season length and therefore reduced the carbon uptake period. The eddy flux observations showed a carbon loss of 4.04 g C m-2 per growing-season day at this coniferous forest site. On the other hand, the summer drought also reduced the net carbon uptake strength because the photosynthesis was more sensitive to water deficit stress than the ecosystem respiration. However, the impact of summer drought occurred within a relatively shorter period and the carbon sequestration went back to the normal level once the drought was relieved. [ABSTRACT FROM AUTHOR]

The research and application of CO2 storage and enhanced oil recovery (EOR) have gradually emerged in China. However, the vast unconventional oil and gas resources are stored in reservoir pores ranging from several nanometers to several hundred micrometers in size. Additionally, CO2 geological sequestration involves the migration of fluids in tight caprock and target layers, which directly alters the transport and phase behavior of reservoir fluids at different scales. Micro- and nanoscale fluidics technology, with their advantages of in situ visualization, high temperature and pressure resistance, and rapid response, have become a new technical approach to investigate gas–liquid interactions in confined domains and an effective supplement to traditional core displacement experiments. The research progress of micro–nano fluidics visualization technology in various aspects, such as CO2 capture, utilization, and storage, is summarized in this paper, and the future development trends and research directions of micro–nano fluidics technology in the field of carbon capture, utilization, and storage (CCUS) are predicted. [ABSTRACT FROM AUTHOR]

As the largest carbon emitter in China's manufacturing sector, the low-carbon transition of the steel industry is urgent. CO2 capture, utilization, and storage (CCUS) technology is one of the effective measures to reduce carbon emissions in steel industry. In this paper, a comprehensive assessment model of source–sink matching-levelized cost in China's steel industry is constructed to evaluate the potential, economy, and spatial distribution of CCUS retrofits of blast furnaces in the BF-BOF steel industry. The results show that, if no extra incentive policy is included, the levelized cost of carbon dioxide (LCOCD) of 111 steel plants with a 420.07 Mt/a CO2 abatement potential ranges from −134.87 to 142.95 USD/t. The levelized cost of crude steel (LCOS) range of steel plants after the CCUS retrofits of blast furnaces is 341.81 to 541.41 USD/t. The incentives such as carbon market and government subsidies will all contribute to the early deployment of CCUS projects. The CCUS technology could be prioritized for deployment in North China, Northwest China, and East China's Shandong Province, but more powerful incentives are still needed for current large-scale deployment. The research results can provide references for the early deployment and policy formulation of CCUS in China's steel industry. [ABSTRACT FROM AUTHOR]

Forestry's high-quality development is crucial for China's sustainable ecological, economic, and social progress. To elevate the efficiency of carbon sequestration in forestry, continuously improve the increment of carbon sinks, and contribute to achieving carbon neutrality, it is crucial to accurately assess the level of carbon sequestration efficiency in China's forestry and explore its long-term evolution trend. In this paper, a super-efficiency SBM model, which combines the SBM model with the super-efficiency method and considers the relaxation variables, was selected to evaluate the forestry carbon sequestration efficiency of 31 provinces in China; likewise, the temporal development features of the efficacy of Chinese forests in sequestering carbon were examined using the nuclear density estimation method. Secondly, the study constructed traditional and spatial Markov probability transfer matrices to further explore the spatiotemporal evolution of carbon sequestration efficiency within Chinese forestry. Finally, combined with the Markov chain infinite distribution matrix, the future trajectory of carbon sequestration efficiency in China's forestry was scientifically forecasted. The findings indicate that: (1) The average carbon sequestration efficiency of forestry in China showed a stable increase with fluctuations and reached the optimal state in 2018. The carbon sequestration efficiency level of various forest regions was always portrayed as southwest forest region > southern forest region > northeast forest region > northern forest region. From 2003 to 2018, there were significant differences in forestry carbon sequestration efficiency among provinces. The distribution of forestry carbon sequestration efficiency exhibited a "three-pillar" distribution pattern with Xizang, Zhejiang, and Heilongjiang as the core, and the marginal regions continuously promoted the carbon sequestration efficiency to the inland. (2) The type of transfer of forestry carbon sequestration efficiency in China is stable, and it is difficult to achieve cross-stage transfer in the short term. Moreover, the forestry carbon sequestration efficiency of each province tended to converge to a high (low) level over time, showing a "bimodal distribution" of low efficiency and high efficiency, indicating the existence of the obvious "club convergence phenomenon". (3) Forecasting from a long-term evolution trend perspective, the outlook for the future evolution of forestry carbon sequestration efficiency in China is optimistic, and the overall trend was concentrated in the high-value area. Therefore, future forestry development in China should contemplate both internal structure optimization and coordinated regional development. Attention should be placed on forestry carbon sequestration's role while considering the distinctive endowments of each region and developing reasonable, differentiated, and collaborative forestry management strategies. [ABSTRACT FROM AUTHOR]

In the context of carbon peaking and carbon neutrality ("double carbon"), it is urgent to clarify the effect of marine spatial planning (MSP) on carbon sink increases and emission reductions, since such planning acts as a spatial governance tool for the earth's largest carbon pool. In this paper, a linkage model between marine spatial functional zones and carbon distribution is established. To explore the relationship between marine spatial functional zones and carbon, the study analyzed the carbon increase or reduction role of sea-use activities in each zone and considered the carbon sequestration function of the marine ecosystem itself. A marine spatial pattern of "Two Spaces and Four Carbon Areas" is proposed to present the linkage. A carbon distribution pattern in marine space is delimited using the linkage model and the current MSP in the case study of the city of Tangshan, Hebei, China. Some measures have been taken or planned to be taken in Tangshan to improve the carbon sink function of the ecosystem and the marine space. The supporting role of MSP in achieving the "double carbon" goal is studied, and the paths and suggestions for integrating the "double carbon" goal into MSP are explored. [ABSTRACT FROM AUTHOR]

Forest Farm Carbon Sink (FFCS) projects are one of the effective ways to achieve carbon neutrality and mitigate global warming. Though the existing literature has widely discussed the effect of FFCS on the allocation of agricultural factors, such as land, labor employment structure and income structure, little is known about whether FFCS projects could have an effect on agricultural development. Based on the panel data of 140 counties in Sichuan province, China, from 2002 to 2018, we examined the causal effect on agricultural total factor productivity (TFP), and revealed their dynamic effect and underlying mechanisms. Propensity score matching and the difference in difference (PSM-DID) method were used to address the endogeneity problem of FFCS implementation. Results showed that FFCS projects increased agricultural TFP by 1.7%-2.4%. Health, saving and industrial structure were the important channels through which FFCS projects affect agricultural TFP. Our findings suggest that policies promoting FFCS projects can increase agricultural TFP while achieving environmental goals-a win-win situation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Carbon sequestration in farmland ecosystems is an important link in the world carbon cycle and plays an important role in regional carbon reduction. Guangdong, a major industrial and economic province in China, was used as the study area, and the period 2001–2020 was taken as the study period. The carbon emissions, sequestration, and footprint of farmland ecosystems in Guangdong were estimated using carbon emission factors for agricultural inputs that are closer to the actual situation in China. The study showed that: (1) Carbon average emissions from farmland in Guangdong during the study period was 3.7624 million t a−1, with a balanced overall trend of change, and that nitrogen fertilize applications was the main factor contributing to carbon emissions. (2) The carbon sink capacity of Guangdong farmland ecosystems showed an overall decreasing trend of 10.32%, with an average annual carbon sink of 19.0363 million t a−1. Paddy and sugar cane cultivations were the main factor of carbon sink in farmland. (3) The average annual carbon footprint of Guangdong's farmland ecosystems was 531,100 ha a−1, which was in a carbon surplus. Carbon surplus and footprint showed a decreasing trend year by year. The paper results provide a theoretical basis for the formulation of carbon emission reduction policies and industrial restructuring in Guangdong and provinces with the same industrial structure. [ABSTRACT FROM AUTHOR]

Eucommia ulmoides Oliver. (E. ulmoides) is a species of small tree native to China. It is a valuable medicinal herb that can be used to treat Alzheimer's disease, diabetes, hypertension, and other diseases. In addition, E. ulmoides is a source of rubber. It has both medicinal and ecological value. As ecological problems become increasingly prominent, accurate information on the cultivated area of E. ulmoides is important for understanding the carbon sequestration capacity and ecological suitability zoning of E. ulmoides. In previous tree mapping studies, no studies on the spectral characteristics of E. ulmoides and its remote sensing mapping have been seen. We use Ruyang County, Henan Province, China, as the study area. Firstly, using the 2021 Gao Fen-6 (GF-6) Wide Field of View (WFV) time series images covering the different growth stages of E. ulmoides based on the participation of red-edge bands, several band combination schemes were constructed. The optimal time window to identify E. ulmoides was selected by calculating the separability of E. ulmoides from other land cover types for different schemes. Secondly, a random forest algorithm based on several band combination schemes was investigated to map the E. ulmoides planting areas in Ruyang County. Thirdly, the annual NPP values of E. ulmoides were estimated using an improved Carnegie Ames Stanford Approach (CASA) to a light energy utilization model, which, in turn, was used to assess the carbon sequestration capacity. Finally, the ecologically suitable distribution zone of E. ulmoides under near current and future (2041–2060) climatic conditions was predicted using the MaxEnt model. The results showed that the participation of the red-edge band of the GF-6 data in the classification could effectively improve the recognition accuracy of E. ulmoides, making its overall accuracy reach 96.62%; the high NPP value of E. ulmoides was mainly concentrated in the south of Ruyang County, with a total annual carbon sequestration of 540.104835 t CM−2·a−1. The ecological suitability zone of E. ulmoides can be divided into four classes: unsuitable area, low suitable area, medium suitable area, and high suitable area. The method proposed in this paper applies to the real-time monitoring of E. ulmoides, highlighting its potential ecological value and providing theoretical reference and data support for the reasonable layout of E. ulmoides. [ABSTRACT FROM AUTHOR]

Improving the carbon sequestration capacity (CSC) of an ecosystem by optimizing urban ecological networks is one of the effective ways to achieve the goal of "carbon neutrality" in the world. The contradiction between the irreplaceable ecological function and economic development of Yancheng City is prominent. Therefore, taking Yancheng City as an example, this paper adopted the morphological spatial pattern analysis–minimum cumulative resistance (MSPA-MCR) model to establish the ecological network of Yancheng City in 2020 and combined it with complex network theory to evaluate its ecological base, network quality, and CSC. The results show that the ecological network of Yancheng City has obvious characteristics of coastal cities. There is a significant positive correlation between CSC and the clustering efficiency of ecological sources, and improving the clustering efficiency of vegetation and water ecological nodes is conducive to enhancing the CSC of ecological networks. In terms of functional restoration of ecological networks, four types of 13 ecological stepping stones and 12 ecological corridors have been designed to strengthen the connectivity and balance of the network, and the improvement of network robustness before and after optimization verifies that the optimization scheme is reasonable and effective. This study improved the optimization method of ecological networks in Yancheng City based on enhancing the CSC of ecological nodes, which provided a theoretical framework and practical reference for the realization of global strategic goals of carbon neutrality. [ABSTRACT FROM AUTHOR]

Global climate change caused by greenhouse gas emissions has a direct impact on the sustainable development of human society and has gained widespread concern globally. Biological carbon sequestration measures, mainly forests, are conducive to improving the ecological carbon sink capacity and play an important role in mitigating global climate change. Therefore, assessing the efficiency of forest carbon storage (FCS) is key. In view of the lack of evaluation methods for forest carbon storage efficiency (FCSE) on a large spatial scale and long time series, a method based on Data Envelopment Analysis (DEA) was proposed in this paper. The FCS was calculated using the forest storage expansion method, and the FCSE was calculated using the DEA-Malmquist index to solve the dynamic balance between regional forestry economic input and carbon storage output efficiency. The FCSE in Chinese provinces was analyzed. The results showed that from 1999 to 2018, China's FCS increased annually, from 7558.34 million tons to 9476.73 million tons, and the spatial distribution pattern of total FCS was always different among regions. The average TFP value of FCSE was 1.089, which proves that the FCSE in China has been on the rise in the past 20 years, but the efficiency growth differed between provinces and was affected by different factors such as technical efficiency and technological progress. [ABSTRACT FROM AUTHOR]

The implementation of carbon peaking and carbon neutrality is an essential measure to reduce greenhouse gas emissions and actively respond to climate change. The net carbon sink efficiency (NCSE), as an effective tool to measure the carbon budget capacity, is important in guiding the carbon emission reduction among cities and the maintenance of sustainable economic development. In this paper, NCSE values are used as a measure of the carbon budget capacity to measure the spatiotemporal evolution of the carbon neutral capacity of three major urban agglomerations (UAs) in China during 2007-2019. The clustering characteristics of the NCSE of these three major UAs, and various influencing factors such as carbon emissions, are analyzed using a spatiotemporal cube model and spatial and temporal series clustering. The results reveal the following. (1) From the overall perspective, the carbon emissions of the three major UAs mostly exhibited a fluctuating increasing trend and a general deficit during the study period. Moreover, the carbon sequestration showed a slightly decreasing trend, but not much fluctuation in general. (2) From the perspective of UAs, the cities in the Beijing-Tianjin-Hebei UA are dominated by low-low clustering in space and time; this clustering pattern is mainly concentrated in Beijing, Xingtai, Handan, and Langfang. The NCSE values in the Yangtze River Delta UA centered on Shanghai, Nanjing, and the surrounding cities exhibited high-high clustering in 2019, while Changzhou, Ningbo, and the surrounding cities exhibited low-high clustering. The NCSE values of the remaining cities in the Pearl River Delta UA, namely Guangzhou, Shenzhen, and Zhuhai, exhibited multi-cluster patterns that were not spatially and temporally significant, and the spatiotemporal clusters were found to be scattered. (3) In terms of the influencing factors, the NCSE of the Beijing-Tianjin-Hebei UA was found to be significantly influenced by the industrial structure and GDP per capita, that of the Yangtze River Delta UA was found to be significantly influenced by the industrial structure, and that of the Pearl River Delta UA was found to be significantly influenced by the population density and technology level. These findings can provide a reference and suggestions for the governments of different UAs to formulate differentiated carbon-neutral policies.

Rational allocation of carbon quotas is the fundamental premise for the orderly operation of carbon markets. To achieve the set target of carbon peak by 2030, there is an urgent need to establish China's 2030 provincial carbon quota allocation scheme. Although some proposed schemes have been formulated, there are problems with the methods used for carbon emission forecasting and evaluating the rationality of a proposed allocation scheme. This study aimed to optimize carbon emission forecast by incorporating terrestrial carbon sinks into the mechanism for building China's 2030 provincial carbon emission quota allocation schemes. Aquila Optimizer's Double Support Vector Regression (AO-based TWSVR) that has the advantages in solving problems associated with small sample size, nonlinear and high-dimensional pattern recognition with fast training speed and insensitivity to noise was adopted to predict the net carbon emission. The results show that the application of AO-based TWSVR model allows satisfactory forecast of the net carbon emission in China for the period from 2021 to 2035. This allowed terrestrial carbon sequestration being incorporated into the mechanism to formulate China's 2030 provincial carbon quota allocation schemes. Comparison of the three provincial carbon quota allocation schemes using social network analysis suggests that the equity-based carbon quota allocation scheme is more suitable for China's national conditions compared to the efficiency-based scheme and the combined principle-based scheme. The findings obtained from this study have implications for optimizing the scheme of China's 2030 provincial carbon quota allocation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

China's state-owned forest farms are the basic sectors of forestry production, and their carbon cycle functions, such as timber processing and forest carbon sequestration, are of great significance to the national emission reduction strategy. By three-stage DEA and Tobit models, this paper measures the carbon sequestration output efficiency of 3706 state-owned forest farms involved in China's National Forestry and Grassland Administration's 2008–2018 survey. We figure out how the mechanism on the carbon sequestration impacts output efficiency of these forest farms and analyze the temporal trends and spatial distributions of their outputs in various regions. Our results indicate that the overall output efficiency of state-owned forest farms in China is relatively low compared with the international advanced level and show that distinctive north-south regional differences exist. Specifically, the carbon storage of the state-owned forest farms in Northeast China and Inner Mongolia occupies more than half of the carbon storage of total amounts, but their output efficiency is unsatisfactory. Conversely, the forest farms in Southwest China have a medium amount of carbon storage and the highest output efficiency. After improving the external environments of these farms, the efficiency value in each province appears as a significant increment. Moreover, the effects of afforestation, timber harvests, the under-forest economy, and other operating behaviors exhibit regional heterogeneity to some extent. Therefore, this paper advocates reforming the current forest cultivation strategy that emphasizes afforestation and neglects management, and relevant government departments are supposed to adjust operations according to local conditions to promote sustainable forest management. [ABSTRACT FROM AUTHOR]

China has a wetland area of 53.42 million hectares, the fourth largest in the world; it includes all types of wetlands defined by the Ramsar Convention and has a carbon sink capacity of more than 1.71 million metric tons per year. Inland wetlands in China are mainly distributed in 10 major catchments, among which the Yellow River, the Yangtze River, the rivers in the northwest, and the rivers in the northeast each have more than 8 million hectares of wetlands. There are 4220 species of plants and 4015 species of animals in China's wetland ecosystem. The wetland resources that have been developed and utilized include edible products, reeds for paper making, peat for fertilizer, fuel for power generation, and chemical, pharmaceutical, ceramic, and building materials. However, wetland areas in China have shrunk by about 54% since 1980. In recent years, China's central government has set great store by Chinese wetlands, and although 49.03% of wetland area is now officially protected, many issues have confounded the implementation of that protection. It is imperative that knowledge gained from scientific research be used to formulate a sound wetland protection and management plan that takes into consideration social, economic, and ecological issues in a way that facilitates the sustainable use of wetland resources and informs decision-makers of the paths that must be followed to achieve that goal. [ABSTRACT FROM AUTHOR]

With global climate change becoming increasingly serious, carbon neutrality, a key strategy to mitigate climate change, has attracted widespread attention. However, due to the multidisciplinary and complexity of carbon neutrality studies, as well as the diversification of research content, a comprehensive review and systematic synthesis of which is quite limited. In this paper, a bibliometric analysis on the topic of carbon neutrality is conducted to reveal the research progress from a quantitative and visual perspective and describe the evolution of research hotspots. The results show that carbon neutrality research is abundant at both the macro and micro levels. Low carbon development is the premise of carbon neutrality, and emission reduction and carbon sinks are the basis of carbon neutrality. The degree of research varies significantly in different countries, with China dominating in the number of publications, followed by the USA and the UK. The realization of carbon neutrality cannot be fully achieved by one single perspective and requires a comprehensive and systematic analysis of technology, economy, and society. Carbon neutrality is a technology-driven process guided by policy. Economically, carbon taxes and carbon markets are two important market mechanisms for reducing carbon emissions. Technically, researches of negative carbon technologies and renewable energy are growing rapidly. Carbon market, carbon negative technology, circular economy, and green energy will become the focus of future research. This paper helps scholars to understand the overall state of carbon neutrality research and provides a historical reference for future research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This paper examines the impact of cross-sectoral climate policy on forest carbon sinks. Due to the complexity of the climate change issue and the professional division of labor among government departments, cross-sectoral cooperation in formulating climate policy is a desirable strategy. Forest carbon sinks play an important role in addressing climate change, but there are few studies focusing on forest carbon sinks and cross-sectoral climate policies. Thus, based on the panel data of 30 provinces and cities in China from 2007 to 2020, this paper establishes a benchmark regression model and a spatial panel model to analyze the impact of cross-sectoral climate policies on forest carbon sinks. We find that cross-sectoral climate policies positively impact forest carbon sinks. Under the influence of the "demonstration effect", we find that cross-sectoral climate policies have a positive impact not only on the forest carbon sinks in the region but also on those in the neighboring region. Further analysis shows that for provinces with less developed forestry industry and small forest areas, the positive effect of cross-sectoral climate policies on forest carbon sinks is more obvious. Overall, this paper can serve as an important reference for local governments to formulate climate policies and increase the capacity of forest carbon sinks.

Terrestrial ecosystem carbon sink examination in China still faces great uncertainties. Determinant analysis has focused on climate change but ignored the influence of fast urban expansion. Using remote sensing images, climate variable data, and high-resolution land use data, this research improved net ecosystem productivity (NEP) simulation model based on a large number of field observations, and investigated spatial-temporal changes of NEP. This research calculated the NEP loss caused by built-up land expansion and used geographically weighted regression (GWR) model to explore the spatial heterogeneity of the relationship between NEP growth and built-up land expansion. The results showed that China contributed a carbon sink of 0.33 Pg C per year from 2000 to 2020. Southern China had a greater capacity to sequester carbon than northern China. The carbon sink capacity of most Chinese regions increased. Built-up land expansion caused 4.95 Tg C of carbon sink loss per year, which was mainly concentrated in eastern China. In GWR model, 50.8% of regions showed negative correlations between NEP growth and built-up land expansion. These two variables were mostly positively correlated in the northwest and negatively correlated in the southeast. Consequently, this study suggests that maintaining the capacity of carbon sinks in southern provinces is important for China to meet its carbon neutrality goal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The development of digital inclusive finance has greatly improved the feasibility of financial inclusion. Therefore, in the context of the constrained financing of marine carbon sink fisheries, we try to investigate whether digital inclusive finance exhibits a supportive effect on marine carbon sink fisheries and thus enhances the capacity of marine carbon sinks. Specifically, this paper empirically calculates the grey correlation between the development of digital inclusive finance and marine carbon sinks based on data in nine coastal provinces of China from 2011 to 2019. The empirical results show that the grey relational coefficients between the above two in China are more than 0.5, revealing a significant positive correlation. Then, on this basis, we estimate the digital inclusive financial support efficiency (DIFSE) for marine carbon sink fisheries by applying the Super-EBM model. In addition, the determinants affecting the DIFSE for marine carbon sink fisheries selected based on the grounded theory are explored through the Tobit model. The conclusions are as follows. First, there are time-varying characteristics and regional heterogeneity in DIFSE. Generally, the effect of China's digital inclusive financial support for marine carbon sink fisheries is expanding year by year. Among them, the DIFSE in the northern marine economic circle is currently the highest, followed by that in the south and east. Second, the input of productive factors, promotion of fishery skill, development of fishery technology, and Internet coverage will significantly increase the value of DIFSE, while output structure, income level, fishery disasters, and marine pollution will have significant negative effects on DIFSE. These empirical results can help policymakers better understand the contribution of digital inclusive finance to marine carbon sink fisheries and provide them with valuable information for the formulation of supportive policies.

Mitigating carbon emissions through forest carbon sinks is one of the nature-based solutions to global warming. Forest ecosystems play a role as a carbon sink and an important source of bioenergy. China's forest ecosystems have significantly contributed to mitigating carbon emissions. However, there are relatively limited quantitative studies on the carbon mitigation effects of forestry bioenergy in China, so this paper simulated the carbon sequestration of Chinese arbor forest vegetation from 2018 to 2060 based on the CO2FIX model and accounted for the carbon emission reduction brought about by substituting forestry bioenergy for fossil energy, which is important for the formulation of policies to tackle climate change in the Chinese forestry sector. The simulation results showed that the carbon storage of all arbor forest vegetation in China increased year by year from 2018 to 2060, and, overall, it behaved as a carbon sink, with the annual carbon sink fluctuating in the region of 250 MtC/a. For commercial forests that already existed in 2018, the emission reduction effected by substituting forestry bioenergy for fossil energy was significant. The average annual carbon reduction in terms of bioenergy by using traditional and improved stoves reached 36.1 and 69.3 MtC/a, respectively. Overall, for China's existing arbor forests, especially commercial forests, forestry bioenergy should be utilized more efficiently to further exploit its emission reduction potential. For future newly planted forests in China, new afforestation should focus on ecological public welfare forests, which are more beneficial as carbon sinks.