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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]

Soil organic carbon (SOC) is of great importance in the global carbon cycle. Distribution patterns of SOC in various regions of China constitute a nation-wide baseline for studies on soil carbon changes. This paper presents an integrated and multi-level study on SOC stock patterns of China, and presents baseline SOC stock estimates by great administrative regions, river watersheds, soil type regions and ecosystem. The assignment is done by means of a recently completed 1: 1,000,000 scale soil database of China, which is the most detailed and reliable one in China at the present time. SOC densities of 7292 soil profiles collected across China in the middle of the 1980s were calculated and then linked to corresponding polygons in a digital soil map, resulting in a SOC Density Map of China on a 1: 1,000,000 scale, and a 1km×1km grid map. Corresponding maps of administrative regions, river watersheds, soil types (ST), and ecosystems in China were also prepared with an identical resolution and coordinate control points, allowing GIS analyses. Results show that soils in China cover an area of 9.281×106 km2 in total, with a total SOC stock of 89.14Pg (1Pg=1015 g) and a mean SOC density of 96.0tC/ha. Confidence limits of the SOC stock and density in China are estimated as [89.23Pg, 89.08Pg] and [96.143tC/ha, 95.981tC/ha] at 95% probability, respectively. The largest total SOC stock (23.60Pg) is found in South-west China while the highest mean SOC density (181.9tC/ha) is found in north-east China. The total SOC stock and the mean SOC density in the Yangtze river watershed are 21.05Pg and 120.0tC/ha, respectively, while the corresponding figures in theYellow river watershed are 8.46Pg and 104.3tC/ha, respectively. The highest total SOC stocks are found in Inceptisols (34.39Pg) with SOC density of 102.8tC/ha. The lowest and highest mean SOC densities are found on Entisols (28.1tC/ha), and on Histosols (994.728.1tC/ha), repectively. Finally, the total SOC stock in shrub and forest ecosystem classes are 25.55 and 21.50Pg, respectively; the highest mean SOC density (209.9tC/ha) was recorded in the wetland ecosystem class and the lowest (29.0tC/ha) in the desert ecosystem class. Among five forest ecosystem types, Evergreen conifer forest stores the highest SOC stock (6.81Pg), and Deciduous conifer forest shows the highest SOC density (225.9tC/ha). Figures of SOC stocks stratified by Administrative regions, river watersheds, soil types and ecosystem types presented in the study may constitute national-wide baseline for studies of SOC stock changes in various regions in the future. [Copyright &y& Elsevier]

This paper reports the annual carbon (C) balance of China''s forests during 1901–2001 estimated using the Integrated Terrestrial Ecosystem C-budget model (InTEC). Annual carbon source and sink distributions are simulated for the same period using various spatial datasets including land cover and leaf area index (LAI) obtained from remote sensing, soil texture, climate, forest age, and nitrogen deposition. During 1901–1949, China''s forests were a source of 21.0±7.8TgCyr−1 due to disturbances (human activities). Its size increased to 122.3±25.3TgCyr−1 during 1950–1987 due to intensified human activities in the late 1950s, early 1960s, 1970s and early 1980s. The forests became large sinks of 176.7±44.8TgCyr−1 during 1988–2001, owing to large-scale plantation and forest regrowth in previously disturbed areas as well as growth stimulation by nondisturbance factors such as climatic warming, atmospheric CO2 fertilization, and N deposition. From 1901 to 2001, China''s forests were a small carbon source of 3.32PgC, about 32.9±22.3TgCyr−1. The overall C balance in biomass from InTEC generally agrees with previous results derived from forest inventories of China''s forests. InTEC results also include C stock variation in soils and are therefore more comprehensive than previous results. The uncertainty in InTEC results is still large, but it can be reduced if a detailed forest age map becomes available. [Copyright &y& Elsevier]