Search

One was the Planetary Boundaries framework, introduced by Johan Rockström and colleagues in 2009, which aims to provide a natural-science based framework for describing a Holocene-like state of the Earth System and the intrinsic boundaries of the Earth System that should not be transgressed if such a stable state is to be maintained (Rockström et al. [10]). Introducing the Anthropocene: The human epoch: This article belongs to Ambio's 50th Anniversary Collection. The other is the polycentric governance systems approach introduced by the late Elinor Ostrom ([9]), which, in the context of the S et al. paper, was proposed as a more appropriate governance system for the Anthropocene than the present governance systems that are driving us deeper towards a planetary crisis. The SCM paper foreshadowed the debate on the start date for the Anthropocene, which became prominent from 2009 with the formation then of the Anthropocene Working Group to explore the Anthropocene as a potential new interval in the Geologic Time Scale (AWG [1]). [Extracted from the article]

This paper reflects on the legacy of the Ambio papers by Sombroek et al. (1993), Turner et al. (1994), and Brussaard et al. (1997) on the study of agricultural land use and its impacts on global carbon storage and nutrient dynamics. The papers were published at a time of transition in ecology that involved the integration of humans as components of ecosystems, the formulation of the ecosystem services, and emergence of sustainability science. The papers offered new frameworks to studying agricultural land use across multiple scales in a way that captured causality from interacting components of the system. Each paper argued for more comprehensive data sets; foreseeing the power of network-based science, the potential of molecular technologies to assess biodiversity, and advances in remote sensing. The papers have contributed both conceptual framings and methodological approaches to an ongoing movement to identify a pathway to study agricultural land use and environmental change that fit within the concepts of ecosystem services, planetary boundaries and sustainable development goals. [ABSTRACT FROM AUTHOR]

In the global ecosystem, wetlands are vital carbon sinks, playing a crucial role in absorbing greenhouse gases such as carbon dioxide and mitigating global warming. Accurate estimation of wetland carbon content is essential for research on wetland carbon sinks. However, the carbon cycle of wetlands is complex, and the carbon sinking of wetlands is affected by climate, topography, water level conditions, vegetation types, soil types, and other factors. This has caused significant challenges in the estimation of wetland carbon sinks. In current studies, most research has focused on the impact of individual factors on wetland carbon sinks, often ignoring the interaction between various factors, which further leads to uncertainty in wetland carbon measurements. This paper aims to elucidate the process of the wetland carbon cycle, summarize the factors affecting wetland carbon sinks, and explore the interplay between various factors and their influence on wetland carbon sinks, aiming to provide theoretical support for the study of wetland carbon sinks. Additionally, this paper reviews the advantages and disadvantages of current wetland carbon measurement methods, proposes research directions for combining machine learning methods, identifies existing difficulties in current wetland carbon measurement, and offers suggestions to serve as a reference for future wetland carbon sink estimation and wetland management.Highlights: The potential and significance of wetland carbon sinks are explained. The advantages and disadvantages of current wetland carbon measurement techniques are summarized. The prospective method for integrating machine learning into integrated wetland carbon measurement is proposed. [ABSTRACT FROM AUTHOR]

Urban green space is a direct way to improve the carbon sink capacity of urban ecosystems. The carbon storage assessment of megacity green spaces is of great significance to the service function of urban ecosystems and the management of urban carbon zoning in the future. Based on multi-period remote sensing image data, this paper used the CASA model and the InVEST model to analyze the spatio-temporal variation and driving mechanism of carbon storage in Shenzhen green space and discussed the applicability of the two models to the estimation of carbon storage in urban green space. The research results showed that, from 2008 to 2022, in addition to the rapid expansion of construction land, the area of green space and other land types in Shenzhen showed a significant decrease trend. The estimation results of the carbon storage model showed that the carbon storage of green space shows a significant trend of reduction from 2008 to 2022, and the reduction amounts are 0.8 × 106 t (CASA model) and 0.64 × 106 t (InVEST model), respectively. The evaluation results of the model show that, in megacities, the spatial applicability of InVEST model is lower than that of CASA model, and the CASA model is more accurate in estimating the carbon storage of urban green space. The research results can provide a scientific basis for the assessment of the carbon sink capacity of megacity ecosystems with the goal of "dual carbon". [ABSTRACT FROM AUTHOR]

The poverty-stricken counties on the Qinghai-Tibet Plateau are characterized by ecological vulnerability and ecological degradation, which are vulnerable to economic development and human activities, thereby leading to frequent alterations of Land carbon sink changes. Therefore, it is of great significance to study the changes of land carbon sink capacity during the process of eradication of extreme poverty in poverty-stricken counties. Using remote sensing images and socio-economic data, this paper constructed land transfer matrix and land carbon sink model to analyze the changes of land carbon sink capacity in poverty-stricken counties and identified the relevant impact factors through geographic detectors. The results show significant changes in carbon sink-type land and a continuous decrease in the snow area, resulting in an obvious trend of grassland area decrease and barren area increase. Land carbon sink capacity of poverty-stricken counties during the eradication of extreme poverty is higher with an added value of 2.74 times than that before this period. Using the geographic detector to analyze the related factors, strong explanatory power was found in cash crops per capita, share of secondary industry, population density and per capita savings on the changes of carbon sink capacity in poverty-stricken counties. [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]

Background: China has made great progress in ecological restoration. However, there have been no analyses on ecological restoration for specific terrestrial ecosystems. This study identified the important knowledge gaps and advances related to terrestrial ecological restoration in China. Results: 7973 papers published between 1978 and 2020 were investigated and about 962 articles were used in this analysis after manually screening. Since the first large national ecological restoration project in 1978, the most frequently studied ecosystem has shifted from farmland ecosystems in 1978–2000 to forest ecosystems after 2000. Forests were the most common ecosystem type investigated, while less attention was paid to wetlands and riparian systems. Meanwhile, the most common ecological issue shifted from environmental pollution in 1978–2000 to the declining resource-carrying capacity of ecosystems after 2000. Studies of ecoregions on the Loess Plateau catchment accounted for more than 40% of papers reviewed in this study, with predominant emphasis on soil and water conservation functionality. Besides, revegetation and afforestation characterized most ecological restoration projects in China, but the natural restoration was relatively less adopted. Additionally, the important tool of reference ecosystem was only used in four studies. Conclusions: Ecological restoration has made significant progress in China. We investigated how the ecological restoration can be implemented more effectively. More projects should be implemented for restorative work in wetlands and riparian systems in future. The tradeoff between restorative activities, water resources, and carbon sink needs further research efforts. More emphasis on biodiversity conservation is warranted. Newly developed theory (e.g., stepwise ecological restoration) and the recently issued Chinese National Guidelines for Ecological Restoration Projects should be more effectively implemented in future restorative works. This study provides essential information for future restorative work in China. It also provides insights into the development of policy relevant to restoration and adaptive management during the U.N. restoration decade. [ABSTRACT FROM AUTHOR]

Background: Carbon (C) sink and stock are among the most important ecosystem services provided by forests in climate change mitigation policies. In this context, old-growth forests constitute an essential reference point for the development of close-to-nature silviculture, including C management techniques. Despite their small extent in Europe, temperate old-growth forests are assumed to be among the most prominent in terms of biomass and C stored. However, monitoring and reporting of C stocks is still poorly understood. To better understand the C stock amount and distribution in temperate old-growth forests, we estimated the C stock of two old-growth stands in the Dinaric Alps applying different assessment methods, including direct and indirect approaches (e.g., field measurements and allometric equations vs. IPCC standard methods). This paper presents the quantification and the distribution of C across the five main forest C pools (i.e., aboveground, belowground, deadwood, litter and soil) in the study areas and the differences between the applied methods. Results: We report a very prominent C stock in both study areas (507 Mg C ha− 1), concentrated in a few large trees (36% of C in 5% of trees). Moreover, we found significant differences in C stock estimation between direct and indirect methods. Indeed, the latter tended to underestimate or overestimate depending on the pool considered. Conclusions: Comparison of our results with previous studies and data collected in European forests highlights the prominence of temperate forests, among which the Dinaric Alps old-growth forests are the largest. These findings provide an important benchmark for the development of future approaches to the management of the European temperate forests. However, further and deeper research on C stock and fluxes in old-growth stands is of prime importance to understand the potential and limits of the climate mitigation role of forests. [ABSTRACT FROM AUTHOR]

The atmospheric carbon dioxide (CO2) concentration has been increasing rapidly since the Industrial Revolution, which has led to unequivocal global warming and crucial environmental change. It is extremely important to investigate the interactions among atmospheric CO2, the physical climate system, and the carbon cycle of the underlying surface for a better understanding of the Earth system. Earth system models are widely used to investigate these interactions via coupled carbon-climate simulations. The Chinese Academy of Sciences Earth System Model version 2 (CAS-ESM2.0) has successfully fixed a two-way coupling of atmospheric CO2 with the climate and carbon cycle on land and in the ocean. Using CAS-ESM2.0, we conducted a coupled carbon-climate simulation by following the CMIP6 proposal of a historical emissions-driven experiment. This paper examines the modeled CO2 by comparison with observed CO2 at the sites of Mauna Loa and Barrow, and the Greenhouse Gases Observing Satellite (GOSAT) CO2 product. The results showed that CAS-ESM2.0 agrees very well with observations in reproducing the increasing trend of annual CO2 during the period 1850–2014, and in capturing the seasonal cycle of CO2 at the two baseline sites, as well as over northern high latitudes. These agreements illustrate a good ability of CAS-ESM2.0 in simulating carbon-climate interactions, even though uncertainties remain in the processes involved. This paper reports an important stage of the development of CAS-ESM with the coupling of carbon and climate, which will provide significant scientific support for climate research and China's goal of carbon neutrality. [ABSTRACT FROM AUTHOR]

Straw is an important source of organic fertilizer for soil enrichment, however, the effects of different nitrogen(N) application rates and depths on straw decomposition microorganisms and carbon and nitrogen cycling under full straw return conditions in cool regions of Northeast China are not clear at this stage. In this paper, we applied macro-genome sequencing technology to investigate the effects of different N application rates (110 kg hm−2, 120 kg hm−2, 130 kg hm−2, 140 kg hm−2, 150 kg hm−2) and depths (0–15 cm, 15–30 cm) on straw decomposing microorganisms and N cycling in paddy fields in the cool zone of Northeast China. The results showed that (1) about 150 functional genes are involved in the carbon cycle process of degradation during the degradation of returned straw, of which the largest number of functional genes are involved in the methane production pathway, about 42, the highest abundance of functional genes involved in the citric acid cycle pathway. There are 22 kinds of functional genes involved in the nitrogen cycle degradation process, among which there are more kinds involved in nitrogen fixation, with 4 kinds. (2) High nitrogen application (150 kg hm−2) inhibited the carbon and nitrogen conversion processes, and the abundance of straw-degrading microorganisms and nitrogen-cycling functional genes was relatively high at a nitrogen application rate of 130 kg hm−2. (3) Depth-dependent heterogeneity of the microbial community was reduced throughout the vertical space. At 71 days of straw return, the nitrogen cycling function decreased and some carbon functional genes showed an increasing trend with the increase of straw return depth. The nitrogen cycle function decreased with the increase of straw returning depth. The microbial community structure was best and the abundance of functional genes involved in the nitrogen cycling process was higher under the conditions of 0–15 cm of returning depth and 130 kg hm−2 of nitrogen application. [ABSTRACT FROM AUTHOR]

Disposable consumer electronics become electronic waste at the end of their life, which can cause serious environmental pollution if discarded in the ground. Here, we have developed an all-wood-based flexible electronic device. The substrate is used to prepare self-densification wood-derived paper (SWP) at room temperature through the natural balsa wood (NW) self-densification process. Chemical treatment removed lignin and hemicellulose from NW, and the cell wall structure collapsed under the action of elastic capillary force generated by water evaporation. The hydrogen bonds between the cellulose fibers are further strengthened, and the arrangement of the cellulose fibers is maintained. The obtained SWP exhibits an excellent tensile strength of 229.4 ± 10.4 MPa in the fiber direction, which is 8.3–8.6 times (27.1 ± 1.7 MPa) and 4.2–4.8 times (51.2 ± 5.6 MPa) higher than NW and cellulose paper, respectively, and higher than some commercial plastics. In addition, it also exhibits excellent wetting performance and a certain degree of transparency. Finally, conductive wood carbon ink prepared from carbonized NW can be directly written on SWP using a Chinese brush to obtain customized patterns. We have demonstrated the application of an all-wood-based flexible electronic device in flexible sensors that can stably monitor finger movements. This newly developed all-wood-based composite can return to the carbon cycle of nature after its service life, providing a new way to replace traditional electronic products. [ABSTRACT FROM AUTHOR]

Blue carbon sinks (mangroves, saltmarshes, and seagrasses) are considered an effective nature-based approach for climate change mitigation. Despite growing interest, a systematic review of this topic is still scarce. This study evaluated 1348 blue carbon sink-related articles from 1990 to 2020 using bibliometric technology. The results from total of 85 countries, 1538 institutions, and 4492 authors indicated that blue carbon sink research shows the characteristics of rapid growth. The most active country, institution, and author were USA, Chinese Academy of Sciences, and Duarte C.M., respectively. Relatively close academic collaboration has formed in blue carbon science. Environmental Sciences was the most popular category with 590 papers. The percentages of articles related to mangroves, saltmarshes, and seagrasses were 63.87%, 40.36%, and 40.65%, respectively. Mangrove carbon sinks are the most popular topic, and stable isotope and remote sensing are the most researched technologies for mapping and quantifying blue carbon sinks. The threats to blue carbon sinks are complex and distinctive. Restoration, conservation, and management of blue carbon ecosystems aimed to improve their carbon sink capacity are becoming hot issues and should be further investigated in the future. These findings provide a scientific roadmap for further research in this field and will enable stakeholders to identify the research trend. [ABSTRACT FROM AUTHOR]

Guest editors: Verónica Ferreira, Luis Mauricio Bini, Katya E. Kovalenko, Andre A. Padial, Judit Padisák & María de los Ángeles González Sagrario / Aquatic Ecosystem Services Introduction to ecosystem services Millennium Ecosystem Assessment The dependency of human wellbeing from ecological systems has been long recognized. The ecosystem services approach has provided background and motivated international legislation and agreements aiming to halt and reverse ecosystem degradation and biodiversity loss, such as the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), the UN Decade on Ecosystem Restoration, and the EU Nature Restoration Law. The papers included in this Special Issue, together with reviews on ecosystem services provided by other aquatic ecosystems and organisms (e.g., Barbier et al., [2]; Macadam & Stockan, [25]; Hilt et al., [14]; Riis et al., [37]; Janssen et al., [16]), contribute to highlighting the relevance of these ecosystems and organisms to human wellbeing, and emphasizing the need for their conservation and restoration. This is followed by 6 reviews addressing ecosystem services provided by specific aquatic ecosystems and 12 reviews addressing ecosystem services provided by different groups of aquatic organisms (Table 2). [Extracted from the article]

Methodological problems, such as unwanted shifts in plant carbon allocation patterns following large isotopic labeling pulses, have hindered accurate quantification of belowground carbon movement in plant–soil systems. These problems must be addressed before we can understand the factors regulating carbon movement between plants and soils and the importance of this movement to the global carbon cycle. We studied the effects of pulse-label size on carbon allocation and transfer between ectomycorrhizal paper birch ( Betula papyrifera Marsh.) and Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) seedlings using increasing pulse levels of either 13C or 14C in two separate laboratory experiments. Our specific objectives were: (1) to determine the minimum pulse of 13CO2 or 14CO2 for detecting carbon movement between plants through belowground transfer pathways, (2) to determine whether carbon allocation patterns within these plants change when exposed to short pulses of elevated carbon dioxide and, (3) to determine whether carbon allocation patterns are similar when using two different carbon isotopes. We detected carbon movement between plants at each 13C and 14C pulse level. There was a tendency for the amount of interplant carbon transfer to increase with increasing 13C pulse level, but the same amount of transfer occurred at all 14C pulses between 0.19 and 0.56 MBq. Carbon allocation patterns did not change with pulse level but they were affected by the choice of carbon isotope. We conclude that at least 8 ml of 13C or 0.19 MBq of 14C is sufficient to detect belowground carbon transfer in small seedlings growing in close proximity. [ABSTRACT FROM AUTHOR]

Understanding the impact mechanisms of territorial space composition and landscape pattern changes on carbon storage is critical to balance the development and utilization of territorial space and the conservation of the ecosystem. Thus, taking the Fujian Delta urban agglomeration (FDUA) of China as an example, this paper analyzed the impact of the transference in territorial space composition and the change in the coupling coordination degree (CCD) of landscape patterns on carbon storage based on the urban–rural gradient and grid scales. Results illustrated that the areas of agricultural, green, and blue spaces continued to decline, while the intensity of economic space expansion increased from 20.86 to 42.45% during 2000–2020. The grids with CCD change of landscape patterns declined mainly (accounting for 64.31%) in the first decade and rose mainly (accounting for 76.79%) in the second decade. The carbon loss of each under rural gradient was gradually serious. The percentage of grids with moderate and significant decrease in carbon storage escalated from 27.83 to 70.21%. Additionally, grids experiencing high carbon loss moved from the northeast coast to the southwest inland. The response of carbon storage change showed that the expansion of agricultural space occupied by economic space played a crucial role in the carbon loss in each urban–rural gradient. The carbon loss caused by supplementing agricultural space with green space increased from the urban to the field. Enhancing the CCD of landscape patterns can boost carbon storage, and the scattering expansion of economic space needs to be avoided. This paper provides a novel perspective to explore the spatial response of carbon storage change to the territorial space composition and landscape pattern evolution, which is important to optimize the territorial space pattern and improve the regional carbon sink capacity. [ABSTRACT FROM AUTHOR]

Wetlands provide numerous ecological and economic services to mankind. The soils of wetlands are one of the largest sinks of carbon (C) among the terrestrial ecosystems and can play an important role in offsetting the emission of C as a greenhouse gas (GHG) to the atmosphere. India is bestowed with enriched wetland ecosystems that support diverse and unique habitats. The potential of the wetlands in terms of C capture and sequestration has not been quantified. Therefore, in the present paper, an assessment of C capture from different sources and its ultimate deposition in soils leading to sequestration has been done in three different types of wetlands, one created sewage-fed and two natural floodplain oxbow lakes, in the West Bengal state of India. Multiple seasonal sampling of water, macrophytes, and soil was done to assess the primary productivity, dissolved C, and deposition of C in soils of the wetlands in comparison to reference upland sites. All these wetlands are productive ecosystems as indicated by the physicochemical parameters of water and soil. The quantity of C accumulated up to 0.3 m depth in the oxbow lakes was to the tune of 144–166 Mg/ha, which was 3.43–4.78 times higher than that in the corresponding reference upland sites. In the sewage-fed wetland, the C accumulation estimated as 50 Mg/ha was 1.27 times higher than its corresponding upland site. So, the wetland ecosystems, particularly the floodplains, are highly efficient in accumulating C in their soils and thus can somewhat negate the GHG emission. [ABSTRACT FROM AUTHOR]

According to the principle of total entropy change of dissipative structure, the carbon trading market is defined as a nonlinear complex system that follows the law of entropy increase in this paper. Based on the potential function of sudden change theory, this paper studies the risk point and scale of the carbon trading market. The results show that (1) the theory of dissipative structure and catastrophe theory can be used as the theoretical basis of carbon financial market risk research, and its core technology can be used to measure and predict risks. (2) The risk mutation point measurement model based on the total entropy change principle and potential function technology effectively detected 16 major risk mutation points in the financial crisis, the European debt crisis, and the European new energy efficiency plan. The empirical test shows that the model has a good ability to capture abrupt changes and prediction accuracy. The fitting effect is very good. (3) The risk index value of the risk abrupt point can be calculated effectively by the risk scale measurement technique based on information entropy and the potential function surface equation. Furthermore, we judge the degree and grade of risk. From 2008 to 2021, amongst the 16 risk mutation points in the EU carbon trading market, there are three extremely high risk mutation points, seven high-risk mutation points, two medium-risk mutation points, two low-risk mutation points, and two very low risk mutation points. High risk or above grade accounted for 62.5%. Empirical analysis supports this conclusion. [ABSTRACT FROM AUTHOR]

The pre-industrial state of the global carbon cycle is a significant aspect of studies related to climate change. In this paper, we recall the power law kinetic representations of the pre-industrial models of Schmitz (Chem Eng Educ 36(4):296–309, 2002) and Anderies et al. (Environ Res Lett 8(4):044–048, 2013) from our earlier work. The power law kinetic representations, as uniform formalism, allow for a more extensive analysis and comparison of the different models for the same system. Using the mathematical theories of chemical reaction networks (with power-law kinetics), this work extends the analysis of the kinetic representations of the two models and assesses the similarities and differences in their structural and dynamic properties in relation to model construction assumptions. The analysis includes but is not limited to the coincidence of kinetic and stoichiometric spaces of the networks, capacity for equilibria multiplicity and co-multiplicity, and absolute concentration robustness in some species. We bring together previously published results about the power law kinetic representations of the two models and consolidate them with new observations here. We also illustrate how the pre-industrial model of Anderies et al. may serve as a building block in the analysis of a kinetic representation of a global carbon cycle with carbon dioxide removal intervention. [ABSTRACT FROM AUTHOR]

To achieve the goal of urban carbon dioxide emission reduction, how to increase carbon sequestration has become a top priority. The biological sink is mainly divided into green carbon sink and blue carbon sink. Coastal cities have two kinds of carbon sinks. There, the study of carbon sinks in coastal cities is the primary choice to cope with climate change. Therefore, this study chooses coastal cities with primary industries including agriculture, fishery, and forestry as the study subjects. The LMDI (Log-Mean Divisia Index) method and multiple regression prediction models were used to explore the low-carbon countermeasures which increase urban net carbon sink from the perspective of influencing factors and future potential. The study found that the average output value of employees in the primary industry is the main driving factor, and the change in the purchasing power of unit carbon sinks and the change in the proportion of employees in the primary industry have inhibited the increase in net carbon sinks. Projections based on the primary industry's output and afforestation area as independent variables show an overall upward trend in net carbon sinks, reaching 15.70 million tons of net carbon sinks in 2060, offsetting 10–20% of total carbon emissions in the same year. Based on the calculation results, this paper puts forward some corresponding countermeasures to increase carbon sinks. This paper provides a theoretical reference for the low-carbon development of coastal cities in China, and the strategies can be also expanded to other cities with similar resources around the world. [ABSTRACT FROM AUTHOR]

As the primary source of carbon dioxide fixation, vegetation is critical to the carbon sink process. In this paper, the Net Primary Productivity (NPP) and the Gross Primary Productivity (GPP) were simulated using the Carnegie-Ames-Stanford Approach (CASA) model and the Vegetation Photosynthesis Model (VPM), respectively, and then the Potential Gross Primary Productivity (PGPP) and the GPP affected by human activities (AGPP) were simulated by combining Potential Net Primary Productivity (PNPP), and then the impact of climate change and human activities on GPP was assessed in the Heihe River Basin (HRB). The results showed that the GPP of grassland and Bare or Sparse Vegetation (BSV) exhibited a fluctuation rise, with increases of 0.709 gCm−2 a−1 and 0.115 gCm−2 a−1, respectively, whereas the GPP of cropland showed a fluctuation reduction, with a decline rate of −0.465 gCm−2 a−1. Climate change and human activity are both positive for vegetation growth, and human activity being the primary factor influencing GPP change. Human-dominated vegetation restoration accounted for 56.1% of the overall restoration area, with grassland GPP being the most visible response to human activities. The GPP changes in crop and grassland had a positive correlation with precipitation but a negative correlation with temperature among climate change factors, whereas the GPP changes in BSV had a negative correlation with both precipitation and temperature. Quantitative analyses of climate change and human activities' dynamic contributions to vegetation can give scientific and theoretical insight for dealing with global climate change. [ABSTRACT FROM AUTHOR]

Countries have pledged to different national and international environmental agreements, most prominently the climate change mitigation targets of the Paris Agreement. Accounting for carbon stocks and flows (fluxes) is essential for countries that have recently adopted the United Nations System of Environmental-Economic Accounting - ecosystem accounting framework (UNSEEA) as a global statistical standard. In this paper, we analyze how spatial carbon fluxes can be used in support of the UNSEEA carbon accounts in five case countries with available in-situ data. Using global multi-date biomass map products and other remotely sensed data, we mapped the 2010–2018 carbon fluxes in Brazil, the Netherlands, the Philippines, Sweden and the USA using National Forest Inventory (NFI) and local biomass maps from airborne LiDAR as reference data. We identified areas that are unsupported by the reference data within environmental feature space (6–47% of vegetated country area); cross-validated an ensemble machine learning (RMSE=9–39 Mg C ha - 1 and R 2 =0.16–0.71) used to map carbon fluxes with prediction intervals; and assessed spatially correlated residuals (<5 km) before aggregating carbon fluxes from 1-ha pixels to UNSEEA forest classes. The resulting carbon accounting tables revealed the net carbon sequestration in natural broadleaved forests. Both in plantations and in other woody vegetation ecosystems, emissions exceeded sequestration. Overall, our estimates align with FAO-Forest Resource Assessment and national studies with the largest deviations in Brazil and USA. These two countries used highly clustered reference data, where clustering caused uncertainty given the need to extrapolate to under-sampled areas. We finally provide recommendations to mitigate the effect of under-sampling and to better account for the uncertainties once carbon stocks and flows need to be aggregated in relatively smaller countries. These actions are timely given the global initiatives that aim to upscale UNSEEA carbon accounting. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction into value-added multicarbon products offers a means to close the anthropogenic carbon cycle using renewable electricity. However, the unsatisfactory catalytic selectivity for multicarbon products severely hinders the practical application of this technology. In this paper, we report a cascade AgCu single-atom and nanoparticle electrocatalyst, in which Ag nanoparticles produce CO and AgCu single-atom alloys promote C-C coupling kinetics. As a result, a Faradaic efficiency (FE) of 94 ± 4% toward multicarbon products is achieved with the as-prepared AgCu single-atom and nanoparticle catalyst under ~720 mA cm−2 working current density at −0.65 V in a flow cell with alkaline electrolyte. Density functional theory calculations further demonstrate that the high multicarbon product selectivity results from cooperation between AgCu single-atom alloys and Ag nanoparticles, wherein the Ag single-atom doping of Cu nanoparticles increases the adsorption energy of *CO on Cu sites due to the asymmetric bonding of the Cu atom to the adjacent Ag atom with a compressive strain. Electrocatalytic CO2 reduction into multicarbon products offers a means to close the anthropogenic carbon cycle using renewable electricity. Here, the authors report a cascade AgCu single-atom and nanoparticle electrocatalyst with favorable properties to improve the selectivity of multicarbon products. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) emissions from aquatic ecosystems are an important component of the karst carbon cycle process and also a key indicator for assessing the effect of karst carbon sinks. This paper reviewed the CO2 partial pressure (pCO2) and its diffusion flux (FCO2) in karst surface aquatic ecosystems, mainly rivers, lakes, and reservoirs, and their influencing factors summarized the methods for monitoring CO2 emissions in karst aquatic ecosystems and discussed their adaptation conditions in karst areas. The pCO2 and FCO2 decreased in the order of rivers > reservoirs > lakes, and the values in karst lakes were eventually significantly lower than those in global lakes. The pCO2 and FCO2 of karst aquatic ecosystems had patterns of variation with diurnal, seasonal, water depth and hydrological cycles, and spatial and temporal heterogeneity. The sources of CO2 in karst waters are influenced by both internal and external sources, and the key spatial and temporal factors affecting the CO2 emissions from karst rivers, lakes, and reservoirs were determined in terms of physicochemical indicators, biological factors, and biogenic elements; additionally, the process of human activity interference on CO2 emissions was discussed. Finally, a conceptual model illustrating the impacts of urban development, agriculture, mining, and dam construction on the CO2 emissions at the karst surface aquatic ecosystem is presented. Meanwhile, based on the disadvantages existing in current research, we proposed several important research fields related to CO2 emissions from karst surface aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Half of the world population live in the cities. Cities energy consumption, environmental impact, and the opportunities they provide for our planet's sustainability make them attractive for governmental authorities. Any action taken in the cities has immediate repercussions. For this reason, many statistical data are published every year. This paper makes the best use of these data to calculate cities CO2 emissions and their thermal and electric energy consumption. The methodology applied takes into consideration each city size by number of inhabitants and gets results per inhabitant and household. This will make possible to put into practice the right actions to reduce CO2 emissions and to use alternative energy. This paper also defines an index to facilitate and simplify the analysis of results. This study was applied to the case of Spain to show the methodology here proposed. In fact, this type of study has never been carried out in Spain before. With this purpose, the 145 Spanish cities with more than 50,000 people were considered. Results show that cities with larger populations present higher consumptions per inhabitant and household. The smallest the population of a city is, the less energy the city consumes. However, electric energy consumption remains constant regardless of the population size. With regard to the CO2 emissions, results bring to light that the biggest cities produce the highest emissions. Furthermore, comparing emissions produced by electrical sources to the total emissions, it was concluded that the smallest cities produce the highest electrical emissions. [ABSTRACT FROM AUTHOR]

In the energy transition, there is an urgent need for decreasing overall carbon emissions. Against this background, the purposeful and verifiable tracing of emissions in the energy system is a crucial key element for promoting the deep decarbonization towards a net zero emission economy with a market-based approach. Such an effective tracing system requires end-to-end information flows that link carbon sources and sinks while keeping end consumers' and businesses' sensitive data confidential. In this paper, we illustrate how non-fungible tokens with fractional ownership can help to enable such a system, and how zero-knowledge proofs can address the related privacy issues associated with the fine-granular recording of stakeholders' emission data. Thus, we contribute to designing a carbon emission tracing system that satisfies verifiability, distinguishability, fractional ownership, and privacy requirements. We implement a proof-of-concept for our approach and discuss its advantages compared to alternative centralized or decentralized architectures that have been proposed in the past. Based on a technical, data privacy, and economic analysis, we conclude that our approach is a more suitable technical backbone for end-to-end digital carbon emission tracing than previously suggested solutions. [ABSTRACT FROM AUTHOR]

Wetland ecosystems have become one of the long-term solutions for mitigating global climate change due to their strong carbon sequestration potential. However, the key carbon cycle processes in wetland ecosystems still lack a systematic summary. In the context of wetland protection and restoration, there is still a lack of consensus on the technical pathways to realize carbon sink multiplication in wetland ecosystems. In this paper, the key processes of carbon cycle, such as photosynthetic carbon uptake, microbial carbon decomposition and carbon deposition and burial, are sorted out and summarized in four major wetland types, namely, swamp and peat wetlands, river and riparian wetlands, lake and lakeshore wetlands, and estuarine and coastal wetlands. Based on the key processes of carbon cycle, three technological pathways for carbon sink multiplication are proposed, including, vegetation carbon sequestration and sink enhancement technology, soil carbon emission reduction technology and carbon deposition and burial technology. The key technologies under each pathway are further refined. And the carbon sink effects of the carbon sink technologies in different wetland types are qualitatively described. Also, wetland protection and restoration methods in corresponding regions are given in the light of the regional characteristics of wetlands in China. This will provide a scientific basis for the strategy of doubling the carbon sinks of China's wetland ecosystems. [ABSTRACT FROM AUTHOR]

Rubber plantations are among the most important in the world's tropical regions. They play a positive role in carbon sequestration and in delaying climate change, supplying strategic resources of natural rubber (NR), and aiding in poverty alleviation and rural revitalisation. This paper reviews six methods of research on carbon sinks in rubber plantations: the biomass inventory method, the biomass conversion factor continuous function method, the trade potential of carbon sinks method, the calculation method for carbon storage of rubber latex, the eddy covariance method, and the remote sensing image model method. This study clarifies the carbon sink assessment and enhancement model for rubber plantations and describes the composition of the carbon pool, which includes the aboveground and belowground vegetation biomass carbon pools, litter carbon pool, latex carbon pool, and soil carbon pool. It also examines influencing factors such as tree age, global climate change, and human disturbance, as well as improvement pathways including afforestation, fertilisation, irrigation, and tapping, and evaluation methods like field surveys, positional observations, remote sensing monitoring, and model simulation. Research on carbon sequestration in rubber plantations faces challenges, including the unclear dynamics of carbon sources and sequestration, uncertain spatial and temporal patterns, and the long-term lack of accurate monitoring of carbon sinks and technologies for increasing sinks and reducing emissions. Future research should focus on the methodology of rubber plantation carbon sequestration projects, the dynamics of carbon sequestration, and the spatial allocation pattern of carbon sequestration in rubber plantations. [ABSTRACT FROM AUTHOR]

The marine MPs' hazard to ecological safety and environmental health has been confirmed. However, mangrove forests are a special land-sea interface, and their MP pollution characteristics and ecological risks have been studied more broadly. It is necessary to sort out the current status of mangrove MP research among the existing homogeneous and limited literatures, to summarize the representative views and point out the direction for future research trends. In this paper, the bibliometrics method was adopted for text mining and knowledge mapping analysis. The development process, knowledge structure, hotspots, and potential trends were discussed to provide researchers with a macro perspective. A total of 71 articles were selected from 93 articles focused on MPs in mangroves, downloaded from Science Citation Index and China Knowledge Network. The number of studies on MPs in mangroves has increased over time in which China had the most research literature (41%), followed by Brazil (7%), Indonesia (6%), and Colombia (6%). From 2019 onwards, the intensity and density of research in Chinese literature increased rapidly. The MPs' abundance in mangrove sediments was majorly attributed to their degree of self-aggregation and deposition rate. The mechanism underlying the correlation between mangrove sediment structure and volatilized characteristics of MPs remains to be further studied. Further studies should focus on the carbon sink process, ecological risk, environmental behavior, barrier mechanism, and combined pollution. [ABSTRACT FROM AUTHOR]

The Carbonate Compensation Depth (CCD) refers to the depth within the ocean where the production and dissolution rates of carbonates reach equilibrium, widely likened to the oceanic calcareous 'snowline'. The reconstruction of deep-time CCD has significant implications for understanding ocean circulation, seawater chemical conditions, sediment distribution, and the surface carbon cycle. This paper critically reviews the methods for CCD reconstruction, summarizes the driving mechanisms of the Cenozoic CCD evolution and its association with the carbon cycle, and offers insights into future directions for CCD research. CCD reconstruction has evolved over the past half century from early qualitative to quantitative methods. These methodological improvements have markedly improved the accuracy and resolution of CCD. Existing studies have indicated a general trend of the CCD deepening across major ocean basins since the Cenozoic, interspersed with a minor shallowing phase during the mid-Miocene. The variations in the CCD are primarily influenced by factors such as ocean productivity, weathering, and shelf-basin partitioning. During climate events such as the Paleocene-Eocene Thermal Maximum, the CCD exhibits pulselike fluctuations. Future research should focus on precision and quantification while integrating model simulations to further explore the correlations and response mechanisms between the CCD and the paleoclimate as well as the carbon cycle. [ABSTRACT FROM AUTHOR]

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]

To achieve carbon peak targets, realize carbon neutrality vision, and tackle global climate change, China must improve the carbon emission performance at the city level. Based on the carbon emission performance of 191 prefecture-level cities in China from 1997 to 2017, this paper analyses the evolution characteristics of urban carbon emission performance from three aspects: the overall spatial and temporal evolution, the differences according to both region and city size, and the differences among clusters categorized by carbon emission performance at the city level. This paper also reveals the impact of the social and economic transition on China's carbon emission performance. The results show that: (1) The overall level of carbon emission performance of Chinese cities is low, and there is a downward trend during the study period. The differences in carbon emission performance among cities are convergent, but there is a wide gap between high and low values. (2) The carbon emission performance of cities in eastern coastal areas is higher than that in non-coastal areas cities. Large urban agglomerations and economically developed regions, such as provincial capitals, are the agglomeration areas of high urban carbon emission performance values. (3) The carbon emission performance level of cities with similar sizes will converge. At the same time, such changes will enhance the differences among carbon emission performances at the city level within the same region. (4) Cities that belong to high urban carbon emission performance clusters are mainly distributed in the eastern region. Such cities are classified into large cities, supercities, and megacities. Compared with low urban carbon emission performance clusters, cities in high urban carbon emission performance clusters show a higher proportion in the medium-high level and high level of carbon emission performance. Moreover, cities in high urban carbon emission performance clusters are more likely to improve theirurban carbon emission performance. (5) The economic agglomeration effect, industrial structure adjustment and carbon intensity reduction have a significant impact on improving urban carbon emission performance. Population agglomeration has an incremental effect, and the anticipated benefits of environmental regulation have yet to be fully realized. The impacts of different clusters and different regions are variable. Finally, this paper advances policy enlightenment according to its research findings. [ABSTRACT FROM AUTHOR]

Global warming attributed to the emission of greenhouse gases has caused unprecedented extreme weather events, such as excessive heatwave and rainfall, posing enormous threats to human life and sustainable development. China, as the toppest CO2 emitter in the world, has promised to achieve carbon emission peak by 2030. However, it is difficult to estimate county-level carbon emissions in China because of the lack of statistical data. Previous studies have established relationship between carbon emission and nighttime light; however, using only nighttime light for carbon emission modeling ignores the impact of natural or other socioeconomic factors on emissions. In this paper, we adopted the back propagation neural network to estimate carbon emissions at county level in Shaanxi, China, using nighttime light, Normalized Difference Vegetation Index, precipitation, land surface temperature, elevation, and population density. Trend analysis, spatial autocorrelation, and standard deviation ellipse were employed to analyze the spatiotemporal distributions of carbon emission during 2012–2019. Three metrics (R2, root mean square error, and mean absolute error) were adopted to validate the accuracy of the proposed model, with the values of 0.95, 1.30, and 0.58 million tons, respectively, demonstrating a comparable estimation performance. The results present that carbon emissions in Shaanxi Province rise from 256.73 in 2012 to 305.87 million tons in 2019, formatting two hotspots in Xi'an and Yulin city. The proposed model can estimate carbon emissions of Shaanxi Province at a finer scale with an acceptable accuracy, which can be efficiently applied in other spatial or temporal domains after being localized, providing technical supports for carbon reduction. [ABSTRACT FROM AUTHOR]

Low carbon research has currently become the most discussed environmental issue. Current comprehensive evaluation methods for low carbon consider carbon emission, cost, process parameters, and resource utilization, but the realization of low carbon may lead to cost fluctuations and functional changes and lack consideration of product functional requirements. Hence, this paper developed a multidimensional evaluation method for low-carbon research based on the association among three dimensions, namely, carbon emission, cost, and function. This multidimensional evaluation method was named life cycle carbon efficiency (LCCE), which is defined as the ratio between the value in the life cycle and the carbon emissions generated. The LCCE model was established, and then carbon emission calculation, cost assessment, and function quantification of the life cycle were performed according to the three dimensions. Case study and sensitivity analysis verified the feasibility of the proposed method. The method had comprehensive and accurate evaluation results, which provided theoretical support and optimized the low-carbon design. [ABSTRACT FROM AUTHOR]

In recent years, climate change and carbon sinks have been widely studied by the academic community, and relevant research results have emerged in abundance. In this paper, a scientometric analysis of 747 academic works published between 1991 and 2018 related to climate change and carbon sinks is presented to characterize the intellectual landscape by identifying and revealing the basic characteristics, research power, intellectual base, research topic evolution, and research hotspots in this field. The results show that ① the number of publications in this field has increased rapidly and the field has become increasingly interdisciplinary; ② the most productive authors and institutions in this subject area are in the USA, China, Canada, Australia, and European countries, and the cooperation between these researchers is closer than other researchers in the field; ③ 11 of the 747 papers analyzed in this study have played a key role in the evolution of the field; and ④ in this paper, we divide research hotspots into three decade-long phases (1991–1999, 2000–2010, and 2011–present). Drought problems have attracted more and more attention from scholars. In the end, given the current trend of the studies, we conclude a list of research potentials of climate change and carbon sinks in the future. This paper presents an in-depth analysis of climate change and carbon sink research to better understand the global trends and directions that have emerged in this field over the past 28 years, which can also provide reference for future research in this field. [ABSTRACT FROM AUTHOR]

Since the first issue of JSS in March 2001, the journal has developed into one of the largest (in terms of the number of papers published) and most respected (as indicated by its journal impact factor) journals in its subject area. The journal was established, in part, because of a recognition that soils and sediments had to date been treated as individual environmental compartments, and there was a lack of journals - and thus publications - that looked at the link between the two. 15 Li Y, Yu S, Strong J, Wang H. Are the biogeochemical cycles of carbon, nitrogen, sulfur, and phosphorus driven by the Fe-III-Fe-II redox wheel in dynamic redox environments? 27 Zhang Z, Solaiman ZM, Meney K, Murphy DV, Rengel Z. Biochars immobilize soil cadmium, but do not improve growth of emergent wetland species Juncus subsecundus in cadmium-contaminated soil. [Extracted from the article]

This study explores a bibliometric approach to quantitatively review carbon cycling research and statistically assess its developments and trends during 1993-2013. Articles referencing carbon cycling from the Science Citation Index Expanded (SCI-EXPANDED) database were analyzed by accessing the following: publication pattern by year, publication performance by country and institution, publication performance by journal, linguistic diversity, publication type, and keyword analysis. Results show USA was the leading country in carbon cycling research (contributing 47 % to worldwide publication) while China showed a marked increase in past 10 years. Europe has the most countries that are actively involved in carbon cycling research. The Chinese Academy of Sciences was the No. 1 most productive institution in the world and contributed 51 % to papers accomplished by China. Topics identified in this study, such as climate change, soil respiration, Arctic region, increased in popularity during the past 20 years. Research techniques such as remote sensing, eddy covariance, and radiocarbon are more frequently used in carbon cycling research in recent times. Although topics such as carbon dioxide and methane are still vital to climate change research, their relative popularities (compared to other topics) declined over the past two decades, indicating more diverse topics (such as decomposition, respiration, Arctic, fire, etc.) will be investigated in the coming decade. Uncertainty assessment achieved an overall 80 % similarity in keywords analysis and demonstrated that within a given research field (carbon cycling in this case), the bibliometric analysis is mostly robust to the uncertainty in choosing keywords. [ABSTRACT FROM AUTHOR]

Nature-based Solutions (NbS) are integral to efforts to keep global warming below 2°C in accordance with the United Nations' 2015 Paris Agreement on Climate Change. Yet the transboundary governance dimensions of NbS remain unclear and largely undocumented. In Southeast Asia, NbS have emphasised the conservation and/ or sustainable commodification of carbon sinks found in terrestrial and mangrove forests, seagrass meadows, peatlands and agricultural soils. Mostly project-driven and fixed-term, these "solutions" have often failed to meet their social and ecological objectives. Increasingly, they have added to cross-border problems of: (1) displaced carbon emissions; and (2) economic migration and societal dispossession. This perspective paper delineates a transboundary governance research agenda to mitigate these trade-offs and enhance the co-benefits of NbS in carbon sinks. Building on NbS literature, it identifies cross-sector, multi-scalar and interdisciplinary pathways to improve transboundary cooperation, inclusion and equity in carbon sink governance in varying Southeast Asian contexts. [ABSTRACT FROM AUTHOR]

This study investigates the degree of spatial correlation between carbon emissions and ecological support coefficients among cities in the middle reaches of Yangtze River (MRYR) region by using social network analysis method and spatial autocorrelation analysis. The actual carbon compensation quota (ACCQ) of each city in MRYR is also calculated based on the carbon revenue and expenditure method, and the theoretical carbon compensation quota (TCCQ) is obtained by introducing technology level and ecological value factors. The results show that (1) carbon sinks in the MRYR region increased very little, while carbon emissions increased significantly during the study period, resulting in an overall carbon deficit in 2015. (2) Wuhan and Changsha, as regional economic centers, are at the center of the carbon emission spatial network, with significant carbon emission spillover. (3) The ecological carrying capacity of the MRYR region showed a spatial and temporal pattern of decline at the center and stability at the periphery. (4) The TCCQ is more convergent in revenues and expenditures than the ACCQ and is more suitable for government policymaking. Based on these findings, we recommend that governments establish regional carbon emission quota systems and horizontal carbon compensation mechanisms based on carbon budget accounting. [ABSTRACT FROM AUTHOR]

Carbon emissions from land use change have become one of the main sources of regional carbon emissions. In order to explore the changes, 87 districts and counties in Gansu Province are taken as research objects. Based on the remote sensing data and statistical data of land use, the carbon emission coefficient method was used to investigate the spatial characteristics of land use carbon emission of each district and county in Gansu Province in recent 20 years from the perspective of carbon ecological support coefficient and per capita carbon footprint. The main results are as follows: (1) the growth of land use carbon emissions in Gansu Province from 2000 to 2020 was significant, but the growth of carbon emissions after 2010 was fast, and the growth of carbon sinks was relatively slow. (2) The ecological support coefficient of carbon emissions at county level in Gansu Province showed a trend of high in the south and low in the north, high in the east and low in the west, and this trend became more and more obvious with the passage of time. (3) Based on carbon emission, county population, and carbon ecological support capacity, the per capita carbon footprint of each county in Gansu Province was analyzed. The results showed that the per capita carbon footprint in Gansu Province was increasing, indicating that the gap between carbon emission and carbon absorption in each county was widening. By the above result, the author divides the counties of Gansu Province into three regions, low-carbon maintenance area, green development area, and ecological optimization area, and puts forward development suggestions for different regions, respectively. Therefore, this paper can also provide a theoretical reference for the formulation of carbon neutral planning measures in inland northwest China. [ABSTRACT FROM AUTHOR]

Mineral extraction in resource-based cities has caused serious damage to the original ecology, resulting in poor regional vegetation growth, reduced carbon sequestration capacity, and reduced ecosystem resilience. Especially in resource-based cities with fragile ecology, the overall anti-interference ability of the environment is relatively worse. Seeking ecological network optimization solutions that can improve vegetation growth conditions on a large scale is an effective way to enhance the resilience of regional ecosystems. This paper introduces carbon sequestration indicators and designs a differential ecological networks (ENs) optimization model (FTCC model) to achieve the goal of improving ecosystem resilience. The model identifies the patches that need to be optimized and their optimization directions based on the differences in ecological function-topology-connectivity-carbon sequestration of the patches. Finally, the resilience of the ecological network before and after optimization was compared, proving that the model is effective. The results show that the sources in the Yulin ENs form three main clusters, with connectivity between clusters relying on only a few patches. The patches in the northeastern and southwest clusters are large but their ecological functions need to be improved. After optimization, 16 new stepping stones were added, 38 new corridors were added, and the ecological function of 39 patches was enhanced. The optimized ecological network resilience was improved in terms of structure, function, and carbon sinks, and carbon sinks increased by 6364.5 tons. This study provides a reference for measures to optimize landscape space and manage ecosystem resilience enhancement in resource-based cities. [ABSTRACT FROM AUTHOR]

Plant-atmosphere exchange fluxes of CO2 measured with the Eddy covariance method are used extensively for the assessment of ecosystem carbon budgets worldwide. The present paper describes eddy flux measurements for a managed upland grassland in Central France studied over two decades (2003–2021). We present the site meteorological data for this measurement period, and we describe the pre-processing and post-processing approaches used to overcome issues of data gaps, commonly associated with long-term EC datasets. Recent progress in eddy flux technology and machine learning now paves the way to produce robust long-term datasets, based on normalised data processing techniques, but such reference datasets remain rare for grasslands. Here, we combined two gap-filling techniques, Marginal Distribution Sampling (short gaps) and Random Forest (long gaps), to complete two reference flux datasets at the half-hour and daily-scales respectively. The resulting datasets are valuable for assessing the response of grassland ecosystems to (past) climate change, but also for model evaluation and validation with respect to future global change research with the carbon-cycle community. [ABSTRACT FROM AUTHOR]

Urban land change plays an essential role in the development of country's economy. Rapid and unplanned urban growth increases land surface temperature (LST) and reduces carbon storage (CS) by replacing the natural land use/land cover (LULC). This paper aims to monitor and predict the changes in urban growth patterns on LST and CS for the winter season in Guangzhou from 1989 to 2021. The integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model is used to assess the existing (1989-2021) scenario of CS. The Cellular Automata-Artificial Neural Network (CA-ANN) and Long Short Term Memory (LSTM) based Whale Optimization Algorithm (WOA) are used to predict the future LULC, CS and LST scenarios. The results indicate that an increase in urban areas by 63% causes an upsurge of high LST (≥34 °C) areas by 652 km2 and a decrease in carbon storage by 56,943.607 t from 1989 to 2021. In addition, the results demonstrate that 93% of lower temperature areas have higher CS capacity (65%), whereas 80% of higher temperature areas demonstrate a low CS capacity (89%). This study can provide effective mitigating measures for designing smart cities and valuable guidelines for ensuring environmental-friendly green cities. [ABSTRACT FROM AUTHOR]

Purpose: Organic carbon (OC) plays an important role in the multimedium transport of pollutants and the carbon cycle. However, the distribution and fate of OC in coastal areas with multiple sedimentary environments, especially in underdeveloped coastal areas, have been underappreciated and lacked sufficient understanding. Materials and methods: In this paper, the characteristics and fate of OC in four sedimentary environments (mangrove, sandy coast, bay, and estuary) in a coastal area in Guangdong, China, were compared. Dissolved organic carbon (DOC) and suspended sediment (SPS) concentrations in water phases as well as total organic carbon (TOC) content and grain size distribution in sediments were determined. Results and discussion: The DOC concentrations and TOC contents were 0.006–13.66 mg L−1 and 0.04–9.51%, respectively, indicating a large spatial heterogeneity. The DOC levels showed an increasing trend into the bays and a decreasing trend along the estuaries, relating to hydrodynamic conditions for OC transport. The SPS concentrations were positively correlated with the TOC/DOC ratios in estuaries, confirming the carrier role of SPS in water–sediment systems. No significant differences in DOC concentrations were found under different water column depths, inferring that water–sediment ratios were not a limiting factor for DOC levels. The actual OC storage of the whole mangrove sedimentary environment was underestimated by 18.2% when calculated using the OC levels of the largest mangrove. Conclusion: Our results suggest that the OC storage estimation in multiple sedimentary environments could be underestimated. This study provides new insight for management and protection of coastline eco-environments and the estimation of carbon stock in the hopes of adapting to climate change. [ABSTRACT FROM AUTHOR]

Abundant unminable coal in deep strata and abandoned mines are also precious sources of clean gas energy, under which biotransformation is a potential path. In recent years, substantial progress has been made in laboratory research on coal degradation to produce methane by microbial metabolism. This paper systematically reviews the research progress of microbial enhancement and microbial stimulation of coal, physicochemical pretreatments of coal, and environmental factors affecting coal biotransformation. The research idea of coal biotransformation should aim at field production increase and gradually clarify the microbial mechanism of coal degradation and the regional distribution and functional composition of microbial communities on the block scale. The research on coal biotransformation helps improve the development level of coalbed methane and the sustainable development of unconventional natural gas resources. [ABSTRACT FROM AUTHOR]

In this paper, a new integrated system is proposed consisting of four subsystems, including a Cu–Cl cycle, a carbon capture cycle (sodium-based sorbent), an ammonia production unit, and a methanation unit. Carbon capturing cycle with sodium-based sorbent could adsorb 1.5 times more than other sorbents such as amine-based sorbent. Moreover, Cu–Cl cycle is one of the promising cycles in terms of economic and low temperature. Therefore, integrating these two cycles with ammonia and methane production unit is the novelty for this paper. Also, Aspen plus software was used to simulate the developed system to evaluate the process of the system. Moreover, sensitivity analysis and mass/energy balance are performed for the developed systems through the simulation. The energy required to capture carbon dioxide was found to be 6.313 MW per kg of CO2, and the overall efficiency of the system is equal to 19.6%. [ABSTRACT FROM AUTHOR]

Poly- and perfluoroalkyl substances (PFAS) and global climate change have attracted worldwide attention. PFAS have been found all across the planet, from the polar regions to the global ocean. Global oceans have emerged as a substantial sink for the carbon in the environment due to their remarkable capacity to absorb atmospheric carbon. Oceans absorb around 24% of the world's CO2 emissions. Thus, the ocean plays a prominent role in the earth's carbon cycle. However, the widespread application of PFAS in a wide range of products and the inefficient management of PFAS-containing wastes made them ubiquitous pollutants, which are increasingly getting as a pollutant of emerging concern. Marine PFAS pollutants can produce harmful effects on gas exchange and the ocean's carbon cycle. Thus, it leads to an increase in greenhouse gas emissions, which eventually adversely affects global warming and climate change. Consequently, threats of marine PFAS to oceans carbon sequestration are discussed in this paper. Marine PFAS pollutants adversely affect the following sectors: (1) The growth and photosynthesis of phytoplankton, (2) development and reproduction of zooplankton by causing toxicity in zooplankton, (3) marine biological pomp, and (4) carbon stock of oceans. In this way, marine PFAS can pose a threat to ocean carbon sequestration. It is expected that this study can develop knowledge about the potential impact of PFAS on ocean carbon sequestration. However, the need for further research to investigate the hidden dimensions of this issue, including the potential scope and scale of this impact, should not be overlooked. [ABSTRACT FROM AUTHOR]

Wetlands provide a great ecological service by accumulating and sequestering carbon in their soils and thus help in mitigating climate change caused due to global warming. However, the capacity and efficiency of different types of wetlands vary considerably depending upon the nature of the wetland, hydrology, biogeochemistry, climatic condition, and many other factors. In the present paper, we have studied the carbon accumulation and sequestration in three different wetlands, one sewage fed, and two floodplain oxbow lakes in the West Bengal state of India. The selected wetlands vary in terms of ecological regimes such as water volume, depth, link channel, agricultural runoffs, primary productivity, macrophyte coverage, and fishery. The carbon accumulation in the wetlands, which varied from 48.53 to 143.17 Mg/ha up to 30-cm depth of soil, was much higher than that in the corresponding upland sites. The difference was much higher in the floodplain wetlands. So the study revealed that wetlands are better carbon sinks than the corresponding reference sites and the carbon sequestration potential varies according to the type of wetlands. A positive correlation was also observed between macrophyte coverage and the amount of C stored in the wetlands. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) plays an important role in the global carbon cycle, and an in-depth analysis of its chemical composition is fundamental to the study of its environmental and biogeochemical behavior and significance. DOM is a complex mixture of organic substances, and determining its molecular composition is a long-standing challenge in the field of analytical chemistry. The development and application of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has enabled the identification of the chemical composition of DOM at the molecular level. This paper summarizes progress made in the molecular characterization of DOM based on the FT-ICR MS technique, including DOM sample pretreatment methods, mass spectrometry ionization techniques, data acquisition, data processing and presentation, and molecular structure characterization. Focusing on the work done by the instrument at the State Key Laboratory of Heavy Oil Processing in the China University of Petroleum, Beijing, we introduce applications of FT-ICR MS in the fields of earth science, environmental science and engineering, and look ahead to further research directions in the future. [ABSTRACT FROM AUTHOR]

Facing the dual pressure of economic development and ecological environmental protection, it is undoubtedly a good strategy to strengthen energy conservation and emission reduction while further increasing carbon sink. The contribution of forest carbon sink is well-known, but the carbon sink function of mariculture is rarely known. Based on the statistics of China's fishery department and the quality assessment method, this paper constructed a preliminary accounting system for the removable carbon sink of mariculture shellfish and algae, and estimated its capacity in China from 2005 to 2017. On this basis, the logarithmic mean Divisia index was used to analyze the effects of structure and scale factors on the removable carbon sink of mariculture shellfish and algae. The results showed that the annual average removable carbon sink of shellfish and algae in China's mariculture reached 92.7 ten thousand tons, and the overall trend was upward. The total removable carbon sink of shellfish was greater than that of algae. Among them, Grassastrea gigas was the main source of removable carbon sink in China's mariculture, followed by Ruditapes philippinarum. The economic value of annual removable carbon sink of mariculture shellfish and algae in China was equivalent to 139–556 million dollars. Furthermore, the scale factor plays a leading role in the removable carbon sink capacity of mariculture in China, while the structure factor plays a minor role. [ABSTRACT FROM AUTHOR]

Land use and land cover (LULC) will cause large flows of carbon sources and sinks. As the world's largest carbon emitter with a complicated LULC, China's carbon emissions have profound implications for its ecological environment and future development. In this paper, we account for the land-use changes and carbon emissions of 30 Chinese provinces and cities in China from 2000 to 2020. Furthermore, the spatial correlation of carbon emissions among the study areas is explored. Four typical regions with spatial association (Beijing, Hebei, Sichuan, and Anhui) are selected, and their land-use change trends in 2025 and 2030 are simulated to predict the total carbon emissions in the future. The results show that the distribution of land-use in China is mainly cultivated and woodland, but the growth of urban built-up (UBL) land area indirectly leads to the continuous increase of carbon emissions. Total carbon emissions have increased over the past two decades, albeit at a slower growth rate, with some provinces experiencing no further growth. In the typical regional carbon emission simulation, it is found that the carbon emissions of the four provinces would show a downward trend in the future. The main reason is the reduction in indirect carbon emissions from fossil energy in UBL, while the other part is the influx of carbon sinks due to grassland, woodland, etc. We recommended that future carbon reduction measures should focus and prioritize controlling fossil energy and mitigating carbon emissions from UBL. Simultaneously, the significant contribution of forests and other land types as carbon sinks should be acknowledged to better implement China's carbon neutral commitment. [ABSTRACT FROM AUTHOR]