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The persistence of dissolved organic matter (DOM) plays a crucial role in the cycling and distribution of carbon and nutrients. Nonetheless, our understanding of how environmental alterations affect the persistence of sedimentary DOM remains incomplete. Excitation Emission Fluorescence Matrix-Parallel Factor Analysis (EEM-PARAFAC) was used to examine the fluorescence and compositional characteristics of hydrophilic and hydrophobic DOM (separated using XAD-8 resin) within sediments from twelve lakes and reservoirs. Fluorescence analysis indicated that DOM persistence is dependent on the proportions of the three components derived from PARAFAC. The Mantel test showed that climatic factors had the most significant impact on DOM persistence (Mantel's r = 0.46-0.54, Mantel's p = 0.001-0.007), while anthropogenic (Mantel's r = 0.24-0.32, Mantel's p = 0.03-0.05) and hydrological factors (Mantel's r = 0.03-0.22, Mantel's p = 0.06-0.40) had a somewhat lesser influence. Environmental changes resulted in a consistent decline in DOM persistence from Northeast to Southwest China, accompanied by an increase in gross primary productivity (GPP). Reduced DOM persistence due to climate, hydrological, and anthropogenic factors may lead to elevated concentrations of total phosphorus (TP), contributing to deteriorating water quality and events such as algal blooms. The decline in water quality due to reduced DOM persistence in lakes with high GPP can exacerbate the transition from carbon sinks to carbon sources. Consequently, the persistence of sedimentary DOM significantly influences nutrient and carbon cycling in lakes. Investigating DOM persistence in lakes across diverse geographic locations offers a new perspective on lake eutrophication and carbon emissions. Furthermore, it is crucial to develop targeted recommendations for lake restoration and management., 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.)

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

Process-related carbon emissions, which cannot be completely eliminated by the improvement of processes and energy structure, are recognized as an enormous challenge for in-depth decarbonization. To accelerate the achievement of carbon neutrality, the concept of 'artificial carbon cycle' is proposed based on the integrated system of process-related carbon emissions from high-emitting industries and CCU technology as a potential pathway towards a sustainable future. This paper conducts a systematic review on the integrated system with the case of China, which is the largest carbon-emitting and manufacturing country, to provide a clearer and more meaningful analysis. Multi-index assessment was used to organize the literature and draw the useful conclusion. Based on literature review, the high-quality carbon sources, reasonable carbon capture approaches and promising chemical products were identified and analyzed. Then the potential and practicability of the integrated system was further summarized and analyzed. Finally, key factors of future development including technology improvement, green hydrogen, clean energy and industrial cooperation were stressed to provide a theoretical reference for future researchers and policy makers. • Demonstration on the rationality and importance of applying CCU technology on process-based carbon emissions. • Multi-index assessment on adoptable carbon sources, possible pathways of carbon capture and carbon conversion. • Analysis on the potential and practicability of the integrated system to accelerate carbon neutrality. [ABSTRACT FROM AUTHOR]

The carbon trading policy seeks to control carbon emissions by putting a price on carbon emissions and establishing a corresponding carbon market for trading. It is a significant move by China to address climate issues and achieve its Carbon Neutrality target. Therefore, assessing the policy effects of carbon trading is fundamental to its implementation nationwide. Based on the panel data of 30 provinces and cities in China from 2008 to 2018, this paper uses the Synthetic Control Method and Differences-in-Differences method to assess the effects of carbon trading policy on achieving Carbon Neutrality. By measuring the net carbon emissions, this research explores the level of Carbon Neutrality in each region. Based on the Five-sphere Integrated Plan (which covers the economy, politics, culture, social and ecological civilization), this research further verifies the impact paths of carbon trading policy on Carbon Neutrality. The results show that: First, carbon trading policy has a significant and sustainable effect on Carbon Neutrality. Second, from the perspective of the Five-sphere Integrated Plan, the carbon trading policy can help to reduce carbon sources and increase carbon sinks by adjusting the industrial structure, coordinating low-carbon policies, promoting cultural dissemination, increasing green space construction, and reducing energy intensity to achieve Carbon Neutrality. Third, cultural construction plays the most significant role in mediating carbon trading and Carbon Neutrality, followed by political construction. • This paper examines the effectiveness of carbon trading policy for Carbon Neutrality. • We use the Synthetic Control Method and Difference-in-Differences method. • The impact paths of carbon trading policy are examined from the Five-sphere Integrated Plan perspective. • Carbon Neutrality should be incorporated into the Five-sphere Integrated Plan. • A cross-perspective study of the Five-sphere Integrated Plan, carbon trading with Chinese characteristics has been formed. [ABSTRACT FROM AUTHOR]

Massive production and spread application of plastics have led to the accumulation of numerous plastics in the global environment so that the proportion of carbon storage in these polymers also increases. Carbon cycle is of fundamental significance to global climate change and human survival and development. With the continuous increase of microplastics, undoubtedly, there carbons will continue to be introduced into the global carbon cycle. In this paper, the impact of microplastics on microorganisms involved in carbon transformation is reviewed. Micro/nanoplastics affect carbon conversion and carbon cycle by interfering with biological fixation of CO 2 , microbial structure and community, functional enzymes activity, the expression of related genes, and the change of local environment. Micro/nanoplastic abundance, concentration and size could significantly lead to difference in carbon conversion. In addition, plastic pollution can further affect the blue carbon ecosystem reduce its ability to store CO 2 and marine carbon fixation capacity. Nevertheless, problematically, limited information is seriously insufficient in understanding the relevant mechanisms. Accordingly, it is required to further explore the effect of micro/nanoplastics and derived organic carbon on carbon cycle under multiple impacts. Under the influence of global change, migration and transformation of these carbon substances may cause new ecological and environmental problems. Additionally, the relationship between plastic pollution and blue carbon ecosystem and global climate change should be timely established. This work provides a better perspective for the follow-up study of the impact of micro/nanoplastics on carbon cycle. [Display omitted] • Research progress on impact of micro/nanoplastics on carbon cycle is reviewed. • Mechanisms of MPs affecting carbon cycle were systematically reviewed. • Impact of MPs on blue carbon ecosystem reduce its ability to store CO 2. • Plastic pollution affect marine carbon fixation capacity and global carbon cycle. • Knowledge gaps and challenges of relevant research are proposed. [ABSTRACT FROM AUTHOR]

Significant climate finance gaps exist for small islands in transitioning to net zero, as climate commitments far outweigh the government budget and international financing. To create alignment between resource allocation and climate commitments, a roadmap for strategic and cost-effective decarbonization is of supreme importance. This paper presents a geographic carbon accounting model which incorporates emissions from electricity, transportation, food systems, and human respiration, whilst accounting for the carbon uptake by the terrestrial biosphere in view of identifying high-intensity aggregated emissions estimated in the range of 200–215 ktCO 2e in the coastal and inland urban regions of the remote island of Mauritius. An estimated 4641 ktCO 2e , representing 79.4% of overall emissions, has been observed to originate from buildings, food, and waste systems. About 1150 ktCO 2e , accounting for a share of 19.7%, is derived from transport systems. The study advocates for the enhanced participation of local authorities to better contribute to climate governance, whilst supporting legislative, financial, technological, and behavioural reforms. Despite the relatively low sequestration potential of forests replacing all non-habitable lands, which is estimated at 1002 ktCO 2e and representing about 17.1% of annual net emissions, afforestation programmes are encouraged owing to multiple ecosystem services provided by trees. • A GIS-based Carbon Accounting framework is developed for a remote island. • High-intensity emission hotspots are identified for strategic management responses. • Enhanced participation of local authorities in climate governance is encouraged. • Legislative, financial, technological, and behavioural reforms are proposed. [ABSTRACT FROM AUTHOR]

The Chinese government has made great efforts in air pollutant reduction and carried out strict regulation policies. Since numerous air pollutants and CO 2 tend to have the same root, source, and process, recent studies argue that environmental regulation may also contribute to reducing carbon emissions. To investigate how various types of environmental regulations affect carbon emissions reduction, this paper constructs the spatial Durbin model and panel threshold model based on provincial panel data in China during 2003–2019. The main findings are as follows: First, China's net carbon emissions show a decreasing trend from east to west, displaying significant spatial agglomeration characteristics. Then, formal and informal environmental regulations have inverted U-shaped impacts on net carbon emissions. The "green paradox" and "reverse emission reduction" effects come into play at different stages. Finally, the threshold model reveals that with the improvement of regional technological innovation levels, the carbon-reducing effect of environmental regulation will increasingly come to the fore. These research findings are conducive to providing theoretical guidance for government to formulate and implement environmental regulation policies rationally. • Carbon sink effect is considered in the carbon emissions assessment framework. • The spatial spillover and threshold effects of environmental regulation is studied. • Environmental regulation has an inverted U-shaped impact on net carbon emissions. • Technological innovation level exerts a threshold effect between them. [ABSTRACT FROM AUTHOR]

As a major component of temperate steppes in the Eurasian continent, the Mongolian Plateau (MP) plays a pivotal role in the East Asian and global carbon cycles. This paper describes the use of five remote sensing indices derived from satellite data to characterize vegetation cover on MP, namely: gross primary production (GPP), net primary production (NPP), normalized difference vegetation index (NDVI), leaf area index (LAI) and fractional vegetation cover (FVC). It is found that GPP, NPP, and NDVI exhibit increasing trends, whereas LAI and FVC present decreasing trends on the MP since 1982. The different indices highlight discrepancies in the spatial pattern of vegetation growth, with the greatest increase in the southeast of MP. Only 3.4% of the total land area of MP exhibited consistent trends in the indices (0.1% degradation and 3.3% growth, P < 0.01), with the synchronous change of both LAI and NPP exhibiting higher consistency than that of raw NDVI and NPP. Understanding of the characteristics and status of vegetation change on the MP has far-reaching implications for its ecological protection management, and climate change mitigation. • Five indices were used to quantitatively analyze the vegetation changes on the MP since 1982. • An increasing trend of GPP, NPP and NDVI, and a decreasing trend of LAI and FVC were observed. • Only 3.4% of the MP's area showed consistent trends (0.1% degradation and 3.3% growth, P < 0.01). • The synchronous change of LAI and NPP exhibited higher consistency than that of LAI and NPP. [ABSTRACT FROM AUTHOR]

Panting protected forests to increase soil carbon sequestration is an effective means of reducing carbon emissions. Soil organic carbon (SOC) decomposition is one of the main indicators of soil carbon sequestration. However, SOC decomposition and its influencing factors in protected forests have not been fully characterized, especially in coastal zones. In this paper, coastal zone protected forest stands composed of Quercus acutissima Carruth (QAC), Pinus thunbergii Parl (PTP) and mixed PTP and QAC (MF) were selected as the research objects. The trends of the SOC decomposition rate were characterized by the beta (β) value, and the influencing factors were further explored with structural equation models. The results were as follows: The SOC content decreased from leaf to litter and then to the soil profile at all sites, while the δ13C value increased. The β value ranged from −3.12 to −5.76, with an average of −3.81. The β value was positively correlated with the diversity and richness of soil bacteria, supporting the hypothesis that the increase in δ13C with depth was mainly caused by isotope fractionation in the process of microbial SOC decomposition. The structural equation model showed that nitrogen and the availability of nitrogen have a strong ability to explain the value of β, which indicates that nitrogen-based edaphic variables play an important role in affecting SOC decomposition. The SOC decomposition rate in PTP was higher than that in QAC and MF. The results of this study indicate that the prediction of SOC decomposition based on the β value is suitable for coastal zone protected forests. The incorporation of edaphic variables into global carbon cycle models may enhance the predictions of SOC dynamics in coastal zone protected forests. [Display omitted] • δ13C enrichment along the soil depth profile was mainly due to selective utilization of carbon by bacteria. • Nitrogen availability and C:N have a strong ability to explain the SOC decomposition. • Tree species composition caused the significant change of SOC decomposition rate. • β value can be regarded as a good indicator of SOC decomposition in coastal zone. [ABSTRACT FROM AUTHOR]