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The land use, land-use change and forestry (LULUCF) sector, as a source and a sink of greenhouse gas (GHG) emissions, is critical for achieving carbon neutrality. Many academic journals have published papers on land use carbon emission or sink (LUCES), but LUCES reviews are relatively rare, which poses great challenges in accurately understanding the research progress and future prospects. This work analyzes the research characteristics, hotspots and future perspectives of LUCES research by using a bibliometric analysis (such as DDA, VOSviewer, CiteSpace software) and a review based on the data (6115 scientific papers) during 1991–2023 from the Web of Science (WoS) platform. We found that (1) over the past 33 years, it first presented a steady growth, then fluctuating growth, and finally a rapid growth trend in the yearly number of publications in LUCES research. The USA (17.31%), China (14.96%), and the UK (7.37%) occupy a dominant position in this research field. (2) The related LUCES research is interdisciplinary, which mainly cover science and technology, meteorology and atmospheric sciences, geology, and environmental sciences and ecology disciplines. (3) The research hotspot analysis on LUCES shows that these articles mostly covered the follow three aspects: ecosystem services, climate change, and carbon neutrality. (4) A review of the past LUCES literature suggests that it is mainly focused on exploring the forefront issues in terms of the definition and boundaries, evaluation method and influencing factors, etc. This work suggests that further research could explore the main scientific problems on quantification of land-based carbon neutrality, quantitative analysis of the impact mechanisms, as well as interdisciplinary research and collaborative governance needed for carbon neutrality. [ABSTRACT FROM AUTHOR]

Based on panel data from 30 provinces from 2001 to 2018 in China, this paper explores the effects and mechanisms of green urbanization on the forestry green total factor productivity (FGTFP) in the context of carbon neutral strategy using a two-way fixed effects model and instrumental variables. The results show that: Firstly, as a sector with ecological and economic benefits, ignoring carbon sink output tends to make FGTFP overestimated. Secondly, green urbanization has a significant positive contribution effect on FGTFP, and this finding still holds after a series of robustness tests including instrumental variables. Thirdly, green urbanization can indirectly promote FGTFP by stimulating the integration of forestry and tourism and strengthening environmental regulations. Fourthly, there is regional heterogeneity in the impact of green urbanization on FGTFP, i.e., the promotion effect of green urbanization on FGTFP is more significant in non-state forest areas compared with state-owned forest areas. Based on the above conclusions, the following countermeasures are proposed: firstly, attaching importance to green urbanization and strengthening environmental constraints; secondly, relying on green urbanization to drive the integration of forestry and tourism; thirdly, actively promoting the construction of green urbanization and green development of forestry in non-state forest areas, while vigorously developing the carbon sink economy to crack the transformation dilemma of backward state forest areas. [ABSTRACT FROM AUTHOR]

Accurate measurement of agricultural total factor productivity (AGTFP) is crucial to measure the level of sustainable agricultural development, and agricultural carbon sink is an important element to leverage the development of green transformation. Few studies have incorporated agricultural carbon sink into the measurement framework of AGTFP, and the evolutionary dynamics and related spatial effects of Chinese AGTFP from the perspective of carbon sinks are unclear. On this basis, the paper used a provincial-level agricultural panel data set of China from 2000 to 2019 to measure the provincial indicators of agricultural carbon sinks, CO2 emissions and agricultural non-point source pollution. Then, we incorporated these environmental factors into the measurement framework of AGTFP and used the SBM-DEA model to calculate the Chinese AGTFP from the perspective of carbon sinks. We further analyzed the spatial and temporal divergence and convergence of AGTFP in China using Moran'I and spatial econometric models. We found that after measuring AGTFP, including agricultural carbon sinks, 28 out of 30 Chinese provinces showed an increased trend, but the development gap between regions was obvious. The spatial econometric model showed a significantly positive spatial correlation between the AGTFP of each province and did not have absolute α-convergence and absolute β-convergence characteristics. After adding the control variables of resource endowment of each province, it showed conditional β-convergence characteristics, and the spatial spillover effect of China's AGTFP was increasing. Finally, the paper proposed policy recommendations for the sustainable and coordinated development of China's agricultural regions in response to the research findings. [ABSTRACT FROM AUTHOR]

Achieving carbon neutrality is an important initiative to cope with global warming. Most studies on the role of tourism towards carbon neutrality were based on the carbon emission reduction (CER) perspective while the carbon sink (CS) perspective was lacking. Based on the quasi-natural experiment of high-standard scenic spots, this paper aimed to examine the effect of tourism resources development on regional CS with high-precision multi-source datasets of 2601 Chinese county units. According to the results of the time-varying difference-in-difference (DID) model regression, CNSA significantly deteriorated CS, but the findings of the rolling regression test confirmed that the adverse effect diminished over time. [ABSTRACT FROM AUTHOR]

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

Carbon sink is the process of absorbing CO2 from the atmosphere, through forests, wetlands, grasslands, and oceans. Through this process, greenhouse gases can be absorbed from the atmosphere. In order to analyze the contribution of carbon sinks to carbon neutrality, three parts of works were carried out on carbon sinks in Beijing-Tianjin-Hebei. Firstly, the regional carbon sinks were calculated based on actual data. Secondly, the macro-factors were selected related to carbon sinks, on which the econometric analysis was carried out. Finally, a carbon sink prediction model was constructed based on partial least squares regression. After that, three carbon sink development scenarios with different intensities were set up. Under these three scenarios, the carbon sink potential of the Beijing-Tianjin-Hebei region was forecasted from 2020 to 2030. The results show that under the strong carbon sink scenario, the carbon sink in Beijing-Tianjin-Hebei can neutralize 388.6901 million tons/a of carbon emissions by 2030, whose contribution rate to China's carbon emission reduction can reach 10.48%. Compared with the baseline scenario and weak carbon sink scenario, the strong carbon sink scenario can achieve greater carbon sink potential and contribute more to China's carbon neutrality. As a conclusion, the target of carbon neutrality of China can be easier to achieve under the strong carbon sink scenario. [ABSTRACT FROM AUTHOR]

Climate change is currently the biggest environmental challenge facing sustainable development in human society, and it is an inherent requirement for achieving sustainable development by actively addressing climate change. Under the increasingly strict constraints of climate governance, developed countries such as the United States, European Union countries, and Japan have responded and actively formulated low-carbon development goals and policy measures that are in line with their national conditions. These policies mainly involve various fields such as low-carbon technology, energy conservation and emission reduction, and circular development, with clear policy guidance. In this paper, the evolution of policies on marine carbon sink and carbon trading in China is summarized, providing support for better understanding the background of formulating relevant international and domestic policies. [ABSTRACT FROM AUTHOR]

Net ecosystem productivity (NEP) plays an important role in understanding ecosystem function and the global carbon cycle. In this paper, the key parameters of the Carnegie Ames Stanford Approach (CASA) model, maximum light use efficiency (εmax), was optimized by using vegetation classification data. Then, the NEP was estimated by coupling the optimized CASA model, geostatistical model of soil respiration (GSMSR) and the soil respiration–soil heterotrophic respiration (Rs-Rh) relationship model. The ground observations from ChinaFLUX were used to verify the NEP estimation accuracy. The results showed that the R2 of the optimized CASA model increased from 0.411 to 0.774, and RMSE decreased from 21.425 gC·m−2·month−1 to 12.045 gC·m−2·month−1, indicating that optimizing CASA model by vegetation classification data was an effective method to improve the estimation accuracy of NEP. On this basis, the spatial and temporal distribution of NEP in China was analyzed. The research indicated that the monthly variation of NEP in China was a single peak curve with summer as the peak, which generally presented the pattern of southern region > northern region > Qinghai–Tibet region > northwest region. Furthermore, from 2001 to 2016, most regions of China showed a non-significant level upward trend, but main cropland (e.g., North China Plain and Northeast Plain) and some grassland (e.g., Ngari in Qinghai–Tibet Plateau and Xilin Gol League in Inner Mongolia) showed a non-significant-level downward trend. The study can deepen the understanding of the distribution of carbon sources/sinks in China, and provide a reference for regional carbon cycle research. [ABSTRACT FROM AUTHOR]

Negative emission technologies driven by nature with less energy input, lower costs, and long carbon storage capacities are essential for meeting ambitious global carbon mitigation goals. This paper evaluates the carbon sequestration potential of bivalve shellfish farming because its sequestration process is driven by nature, and it is cost-effective and energy efficient. The carbon in shells and the carbon that enters sediments via bio-deposition are long-lived forms of carbon. Using China as a case study, a preliminary estimation suggests that the carbon sequestration efficiency and intensity of cultivated shellfishes are much higher than those of artificial forests. In China, approximately 6.23 Mt CO 2 -eq a−1 was fixed via net carbon sequestration during shellfish growth from 2015 to 2019. In addition, the farmed shellfishes provided 0.37 Mt of harvested protein, and approximately 37.39 Mt CO2-eq a-1 were reduced compared to the same amount of protein provided by beef, and thus, shellfish farming has the win-win benefits of carbon sequestration and high-quality food provision. More importantly, a total of 5.64 Gt CO 2 -eq, accounting for 17.63% of the total emissions in 2020, can be potentially sequestrated at the global scale under the world's largest farming area scenario. • A Negative Emission Technology via shellfish farming was introduced. • Carbon sequestration function and efficiency of shellfish farming were investigated. • Carbon sequestration potential for bivalve shellfish farming was evaluated globally. • Life cycle GHG emissions of shellfish farming in China was assessed. [ABSTRACT FROM AUTHOR]

Forests and grasslands play an important role in carbon cycling. They not only absorb CO2 from the air through vegetation biomass and soil carbon sinks, but also reduce and control the horizontal transport of soil carbon (i.e., reinforcing soil carbon storage via soil conservation), thus avoiding erosion-induced CO2 emissions. In this study, vegetation biomass and soil carbon sinks, soil carbon reinforcement and reduced carbon emissions via soil conservation by forests and grasslands were quantified on the scale of the whole of China. The analysis was based on the distribution of biomass and the soil carbon pool and soil erosion rates derived from national surveys, as well as carbon density values from field surveys and literature. In 2021, forests and grasslands in China generated 394.18 Mt C/year (y) of steady-state carbon sinks through vertical biomass and soil absorption. The biomass carbon sinks of grasslands, and those of leaves, twigs, flowers and fruits of the forests, were not taken into account when quantifying the stable biomass sink, because they can become net producers of CO2 due to seasonal withering and carryover, or they can form soil organic carbon as potential soil carbon sinks. The amount of horizontal soil carbon reinforcement in China's forests and grasslands in 2021 was 20.31 Mt C/y, which was positively correlated with the reduction in the water erosion area; consequently, vertical emissions of approximately 14.89–29.78 Mt of CO2 into the atmosphere were avoided. Overall, in 2021, China's forests and grasslands absorbed atmospheric CO2 and reduced emissions by 1.46–1.47 Gt CO2/y, equivalent to approximately 13% of China's annual fossil CO2 emissions. This study demonstrates the fact that the adoption of forest and grassland measures sequesters carbon in soil and biota and reduces the risks of CO2 emissions by both vertical and horizontal paths, which is important for achieving carbon neutrality and mitigating climate change. [ABSTRACT FROM AUTHOR]

Quantifying carbon neutrality and its spatial range on the Loess Plateau of China is crucial for effective carbon planning. By utilizing advanced systems like the (Intelligent Urban Ecosystem Management System, IUEMS) and satellite data, we estimated carbon sequestration and emissions. Spatial carbon neutrality was determined, projecting distributions using the (Patch-generating Land Use Simulation Model, PLUS). Results show increasing carbon sequestration from 2000 to 2020, particularly in central and western regions. Topographical factors like altitude and slopes significantly influence sequestration. Carbon emissions are low overall, concentrated in urban areas on the northern slope, with an initial increase followed by a decline. The carbon neutrality service range from 2000 to 2050 spans 174-262.63 km, gradually expanding in space, albeit slightly decreasing after 2030. [ABSTRACT FROM AUTHOR]

In a speech at the UN General Assembly on September 22, 2020, President Xi Jinping announced that China would peak carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060. China has issued a series of documents on the carbon peaking and neutrality goals, which have become hot issues in society. The concept of carbon peaking is relatively easy to understand, but for that of carbon neutrality, there are some misunderstandings, such as mixed use of different terms and ambiguous scope, classification, and relationships between related concepts, which not only directly affect the implementation of the 'dual carbon' goals in China, but also impede China􀆳s participation in global climate governance and international climate cooperation towards the goal of carbon neutrality. This paper attempts to trace the origin and evolution of the concept of carbon neutrality. It sorts out the different expressions of the carbon neutrality goal, compares the differences and correlations between related concepts, and discusses the key elements and implications of the concept of carbon neutrality. The discussion leads to the following conclusions: ① The concept of carbon neutrality was introduced to the field of global climate governance after carbon trading and carbon offsetting had been proposed in the Kyoto Protocol in 1997. ② The concept of carbon neutrality has both narrow and broad senses. Narrowly speaking, it refers to carbon dioxide neutrality, while in a broad sense, it is a collective term for related concepts such as carbon dioxide neutrality, greenhouse gas neutrality, climate neutrality, net zero carbon dioxide emissions, and net zero greenhouse gas emissions. In the international community, the expression 'net zero' is more widely used. ③ To understand the concept of carbon neutrality, four elements need to be grasped: the balance between the source and removal of anthropogenic emissions; multiple implementation entities and their carbon accounting boundaries; the scope of emissions (covering merely carbon dioxide or all greenhouse gases); and carbon neutralization paths including carbon emission reduction, carbon removal, carbon offsets, etc. ④ Clarifying the concept of carbon neutrality is the basis for efficiently implementing the 'dual carbon' goals and promoting international cooperation. The terms used in the legal documents and IPCC guidelines and reports approved in the UNFCCC negotiations are internationally accepted concepts and norms. They are recognized by various governments and serve as an important foundation for scientific research as well as the cognitive basis for international negotiations and actions. The definition and interpretation of the concept of carbon neutrality should be consistent with the international community as much as possible to form a unified understanding that is not only conducive to promoting international cooperation towards carbon neutrality, but also to China' s implementation of the Paris Agreement and advancement of work towards the 'dual carbon' goals. [ABSTRACT FROM AUTHOR]

Shallow lake sediments have huge potential for carbon storage, but they are vulnerable to various environmental changes and are highly susceptible to becoming a source of carbon emissions. Understanding the amount of sediment carbon storage can provide information about the potential of shallow lakes in mitigating climate change. In this study, sediment sampling was conducted at 12 study sites in Chaohu Lake, China, and sediment water content, grain size, bulk density, and sediments organic carbon (SOC) content were examined in five layers along the vertical direction, respectively, and the distribution and storage of SOC were estimated. The results showed that the surface sediments in the west lake area of Chaohu Lake would release 66,300 t of SOC to the overlying water body in the future. The sediments in the middle lake area and the east lake area will absorb another 15,900 t and 17,300 t of TOC from the water body in the future, respectively. Overall, the lake-wide sediments will release 33,100 t of SOC into the water body in the future. In addition, the results of the study also indicate that human activities are another major influence on the change in organic carbon stocks in lake sediments, and therefore, proactive measures for the restoration and protection of lake sediments are essential because increasing the SOC stocks in the sediments and maintaining the lakes in a sustainable manner can contribute to the crucial role they play in mitigating climate change. [ABSTRACT FROM AUTHOR]

Lake wetlands play a crucial role in mitigating climate change. Human activities and climate change impact the carbon sequestration capacity of lake wetlands. However, this process is intricate. Clarifying the decisive factors that affect carbon sequestration is crucial for preserving, utilizing, and enhancing the carbon sequestration capacity of plateau lake wetlands. Here we analyzed the regulatory role of land use under policy guidance on the carbon sequestration capacity of the plateau lake wetland of Caohai (CHLW), SW China. The results show that: (1) The cumulative carbon sequestration varied significantly from 1990 to 2020, with the highest carbon sequestration of 15.80 × 105 t C in 1995 and the lowest of 3.18 × 105 t C in 2020, mainly originating from endogenous carbon sequestration within the plateau lake wetlands. (2) As of 2020, the carbon stock of CHLW was approximately 2.54 × 108 t C. (3) The carbon sequestration in CHLW experienced a dynamic change process of decrease-increase-decrease over 30 years, mainly influenced by land use changes under policy regulation, with human and natural factors accounting for 91% and 9%, respectively. (4) Under three simulated scenarios (Q1, Q2, and Q3), the ecological priority scenario exhibited positive regulation on the carbon sequestration of CHLW and the entire protected area in 2030 and 2060, with the highest increase in carbon sequestration. This scenario is consistent with the current conservation policy, indicating that the current protection policy for CHLW is scientifically reasonable. This research demonstrates how land use and climate changes impact carbon storage in wetlands, with consideration of policy guidance. It provides references for utilizing and conserving lake wetlands worldwide, ultimately achieving the dual goals of wetland conservation and carbon neutrality. [ABSTRACT FROM AUTHOR]

The economic and ecological effects of three shrimp farming models commonly adopted in China, including the indoor super-intensive culture model (ISIC), the pond integrated multi-trophic aquaculture model (PIMTA), and the pond mono-culture model (PMC) were evaluated in this study. The economic and ecological effects of the three models were quantitatively estimated using a series of statistical analyses. The break-even analysis of the three models indicated that the unit output of ISIC and PMC was comparatively higher than others. Meanwhile, the variable cost of ISIC and PMC was much higher than the fixed cost, while PIMTA presented the opposite result. However, the cost-benefit study showed that PIMTA had the greatest profit margin. Regarding ecological effects, the comparison of water quality factors and pollutant emissions indicated that the PIMTA model could comparatively decrease the nitrogen and phosphorus discharge from aquaculture sewage and prevent water eutrophication. Moreover, PIMTA led to a higher bacterial diversity than ISIC. Furthermore, the analysis of the carbon sink capacity of the three cultivation modes showed that the PIMTA model had the highest carbon sink capacity of 812.21 g kg−1. When PIMTA shrimp production is 0.72 times higher than the total production of ISIC and PMC, the goal of zero CO2 emissions can be achieved. By combining ISIC high-density farming with PIMTA ecological farming, companies can effectively balance the ecological damage caused by shrimp farming by adjusting the ratio of ISIC and PIMTA while addressing the market demand for shrimp. [ABSTRACT FROM AUTHOR]

Initiatives to mitigate climate change have recently aroused great interest in the role of natural carbon sinks in coastal ecosystems. Seaweeds are widely distributed in the world and represent a large biomass. Since they are part of the global carbon reserves, they remove carbon dioxide and influence climate change. Using the recent 20 years of seaweed mariculture in China's coastal areas as a case, this paper quantifies the carbon storage in cultivated seaweed biomass, and evaluates the carbon sink potential, the remediation ability of nitrogen and phosphorus and other environmental benefits. The carbon sink potential of cultivated seaweeds exhibits a rising trend from 2000 to 2019. The total carbon, nitrogen, and phosphorus removal amount of seaweed were 3,551,754.9 ± 177,587.75, 297,772.25 ± 14,888.61, 39,967.15 ± 1998.36 tons according to the seaweed cultivation yield in China coast. The total benefit of carbon sequestration was 22,405.67 ± 259.59 million CNY, and the average benefit was 1120.28 ± 263.27 million CNY, with the average annual growth rate of 4.00%. The total environmental benefit was 1,962,020.88 ± 22,747.42 million CNY, and the average benefit was 98,103.04 ± 23,073.08 million CNY, with the average annual growth rate of 4.00%. The present study illustrates distinctly the ecological value of large-scale cultivated seaweeds in increasing marine carbon sequestration and resolving offshore environmental issues, which is an efficient approach and comparable to other key marine ecosystems. Based on the carbon sink role of seaweed mariculture, and with the goal of global carbon neutrality, more attention should be paid to the carbon sink capacity of large-scale seaweed cultivation industry and be vigorously developed worldwide. • Seaweed has an active effect in N, P remediation and quantities of CO 2 accumulation. • Seaweed has a strong carbon sequestration capacity and is a key part of carbon sink. • Carbon sequestration benefit of seaweed cultivation is 22,405.67 ± 259.59 millions CNY. • Suggesting to pay more attention to the seaweed carbon sink on a global scale. • Suggesting to vigorously develop and promote seaweed cultivation industry worldwide. [ABSTRACT FROM AUTHOR]

Given the increasing attention to climate change and rising CO2 (CCRC) in the global carbon cycle, we remain unclear about how China's unprecedented land use/cover change (LUCC) in the carbon budget has been affected by CCRC in recent decades. Here, we combined remotely sensed land use/cover (LUC) datasets and the Biome‐BGCMuSo model to address this issue by setting different scenarios. We found that LUCC led the carbon sink to increase by approximately 104.24 ± 46.52 Tg C without considering CCRC during 1990–2020. Carbon sinks contributed by afforestation (374.97 ± 36.50 Tg C) and grassland planting (15.75 ± 9.11 Tg C) offset other LUC trajectories caused carbon loss (286.47 ± 32.18 Tg C, 87.33% owing to agricultural reclamation). LUCC contributed carbon sinks were amplified by ∼20% under CCRC at the national scale. This rate increased to 106.03% in northeast China but decreased to −26.68% in southern China. CCRC led carbon sink contributed by afforestation amplified by 85.11% in northeastern China but was only 26.35% in southern China. CCRC amplified carbon emissions due to agricultural reclamation by 103.20% in northeastern China and by 25.09% in southern China. Our results demonstrated that ecological restoration projects are efficient in enhancing carbon sinks and mitigating emissions. Divergent amplifying/reducing effect of CCRC across different geographic regions implied the sensitivity of different LUC trajectories to CCRC varied with different climate backgrounds. Land management strategies should be implemented with spatial heterogeneity to amplify afforestation and grassland planting contributed carbon sinks and decrease other LUC trajectories caused carbon loss under the global change environment. Plain Language Summary: It is undoubted that climate change and rising CO2 (CCRC) would alter the effect of land use/cover change (LUCC) on the carbon budget. However, to what extent CCRC will influence the effect of LUCC on the carbon budget remains unclear. In this work, we evaluated the impact of CCRC on the carbon budget change caused by LUCC. We found that CCRC would amplify or dampen the impact of LUCC on the carbon budget. Meanwhile, this amplifying or dampening rate was divergent in different geographic regions. Our work provides new insights for making climate change mitigation targeted land decisions to increase carbon sinks with ecological restoration and construction and reduce emissions through protection. Key Points: Afforestation and grassland planting offset other land use/cover change (LUCC) caused carbon loss and continue to increase carbon sinkClimate change and rising CO2 (CCRC) amplified China's LUCC contributed carbon sinks by approximately 20%CCRC amplified carbon sink induced by LUCC in northeastern China, reduced it in southern China [ABSTRACT FROM AUTHOR]

Lakes are hot spots of carbon cycles in inland aquatic systems. As a vital factor, meteorology, including air temperature, precipitation, wind speed and evapotranspiration, is profoundly affecting or even regulating the wetland-air CO2 exchanges. Compared with some other similar lakes in China, the largest shallow grass-type Baiyangdian Lake (BYDL) acts as a vital CO2 sink on the North China Plain. The purpose of this study is to reveal the effects of meteorology on the process of CO2 flux variation. Based on the method of the eddy covariance, the daily average wetland-air CO2 flux at the BYDL over the monitoring period from April 2019 to November 2020, reached −0.63 μmol m−2 s−1, and the annual average reached −0.71 μmol m−2 s−1 from 12 April 2019 to 12 April 2020. The CO2 sink fluxes varied with the seasons and reached the maximum in summer. Temperature and evapotranspiration are two major driving factors, whose higher values can positively improve the wetland CO2 sinks. Precipitation generally coincides with the CO2 sinks, but the relatively larger summertime precipitation (0.39 m in 2020, compared with that of 0.17 m in 2019) inhibits the CO2 uptakes on longer timescales. A moderate wind speed in the range of 1.6~3.3 m s−1, promoted the CO2 sinks for the shallow grass-type lake. Compared with previous studies at the same or similar wetlands, consistent CO2 sink fluxes are found. Further in this study, the variation trends of CO2 sinks with the changing meteorological factors are revealed for the first time in this type of wetland. Once meteorology is determined under both the anthropogenic and climatic impacts, the evaluation and prediction of the lacustrine carbon cycling could be more precise. Generally, this study will serve as an important data point into the global understanding of lake carbon fluxes. [ABSTRACT FROM AUTHOR]

Aims: Mangrove ecosystems can help mitigate climate change by sequestering significant amounts of carbon (C) from the atmosphere and ocean, contributing to regional "blue carbon" stocks. However, it is unclear whether non-native species introduced in coastal wetlands can function as a more efficient carbon sink. Methods: By examining two dominant mangrove species, native Kandelia obovata (KO) and exotic Sonneratia apetala Buch.-Ham. (SA), at the Qi'ao Island, China, we quantified and compared ecosystem C storage, C sequestration rate, source and stability of soil organic carbon (SOC) under different vegetation covers. Results & conclusion: Our results showed that both species acted as strong carbon sinks relative to mudflat reference, with overall ecosystem C storage being comparable under KO (410 Mg C ha−1) and SA with different stand ages (224–452 Mg C ha−1), but a few times higher than corresponding unvegetated mudflat. However, by excluding SOC accumulation from prior land use (i.e., unvegetated mudflat), non-native species (i.e., SA) showed a significantly higher ecosystem carbon sequestration rate (8.2–16.4 Mg C ha−1 yr−1) than native KO (4.5 Mg C ha−1 yr−1), owing largely to fast biomass carbon sequestration in SA ecosystem. Relative to mudflat reference, the input of autochthonous source (mangrove tissues) contributed substantially to additional carbon sequestration under mangroves. It should be noted that the relative size of carbon sequestration in non-native mangroves is also affected by factors related to ecosystem, climate, soil properties and land use, the differences still exist among locations, and ecosystem modeling with field validation is desirable for regional estimation of carbon stocks and sequestration rates. [ABSTRACT FROM AUTHOR]

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

Phytolith carbon (C) sequestration plays a key role in mitigating global climate change at a centennial to millennial time scale. However, previous estimates of phytolith‐occluded carbon (PhytOC) storage and potential in China's grasslands have large uncertainties mainly due to multiple data sources. This contributes to the uncertainty in predicting long‐term C sequestration in terrestrial ecosystems using Earth System Models. In this study, we carried out an intensive field investigation (79 sites, 237 soil profiles [0–100 cm], and 61 vegetation assessments) to quantify PhytOC storage in China's grasslands and to better explore the biogeographical patterns and influencing factors. Generally, PhytOC production flux and soil PhytOC density in both the Tibetan Plateau and the Inner Mongolian Plateau had a decreasing trend from the Northeast to the Southwest. The aboveground PhytOC production rate in China's grassland was 0.48 × 106 t CO2 a–1, and the soil PhytOC storage was 383 × 106 t CO2. About 45% of soil PhytOC was stored in the deep soil layers (50–100 cm), highlighting the importance of deep soil layers for C stock assessments. Importantly, the Tibetan Plateau had the greatest contribution (more than 70%) to the PhytOC storage in China's grasslands. The results of multiple regression analysis indicated that altitude and soil texture significantly influenced the spatial distribution of soil PhytOC, explaining 78.1% of the total variation. Soil phytolith turnover time in China's grasslands was mainly controlled by climatic conditions, with the turnover time on the Tibetan Plateau being significantly longer than that on the Inner Mongolian Plateau. Our results offer more accurate estimates of the potential for phytolith C sequestration from ecological restoration projects in degraded grassland ecosystems. These estimates are essential to parameterizing and validating global C models. [ABSTRACT FROM AUTHOR]

China announced its national goal to reach the peak of carbon emission by 2030 and achieve carbon neutrality by 2060, during the General Assembly of the United Nations in September 2020. In this context, the potential of the carbon sink in China's terrestrial ecosystems to mitigate anthropogenic carbon emissions has attracted unprecedented attention from scientific communities, policy makers and the public. Here, we reviewed the assessments on China's terrestrial ecosystem carbon sink, with focus on the principles, frameworks and methods of terrestrial ecosystem carbon sink estimates, as well as the recent progress and existing problems. Looking forward, we identified critical issues for improving the accuracy and precision of China's terrestrial ecosystem carbon sink, in order to serve the more realistic policy making in pathways to achieve carbon neutrality for China. [ABSTRACT FROM AUTHOR]

Net ecosystem gas exchange (NEE), a balance between gross ecosystem primary productivity (GPP) and ecosystem respiration (ER), is an important indicator of terrestrial ecosystem CO2 sink or source. Increasing frequency in droughts during different periods of the growing season may affect terrestrial ecosystem carbon (C) balance. However, detecting how drought timing controls ecosystem C processes is insufficiently explored because it is a challenge to accurately monitor and forecast drought dynamics.In a 5‐year (2015–2019) precipitation manipulation experiment in a temperate steppe in northern China, we imposed a 60% decrease in precipitation in the early (April–June, DEP) and late (July–September, DLP) growing seasons in plots under rainout shelters to simulate drought occurrence timing. The responses of GPP, ER and NEE to DEP and DLP were examined to determine how the timing of decreased precipitation affects CO2 fluxes.Both DEP and DLP reduced GPP and ER. Decreased precipitation in the late growing season reduced NEE due to a greater decline in GPP than ER. In contrast, the lack of an effect of DEP on NEE can be attributed to a proportional decline in GPP and ER. Reduced normalized difference vegetation index (NDVI) and GPP induced by decreased precipitation explained the decline in GPP and ER respectively. Drought in the late growing season weakened the ecosystem C sink. The result indicates a low resistance in net C uptake to DLP. However, we did not find evidence that previous precipitation decreases resulted in a lower overall rate of ecosystem C exchange, indicating a high resilience in C processes in this semi‐arid grassland.Synthesis and applications. Our study provides solid evidence that drought in the late growing season weakens ecosystem C sink in the semi‐arid grassland. The findings suggest that management practices aimed at enhancing water availability during the late growing season should be preferred for increasing C sequestration. [ABSTRACT FROM AUTHOR]

The current study aims to analyze the regional differences and spatiotemporal dynamic evolution of carbon emission intensity (CEI) and carbon emission per capita (CEPC) of planting industry with consideration of carbon sink effect. The results indicate that: (i) The CEI and CEPC of China's planting industry present significant non-equilibrium distribution characteristic during the investigate period, provinces with high CEI are mainly distributed in major agricultural provinces, while high CEPC provinces are mainly located in northeast and individual central provinces with large planting industry. (ii) Inter-regional difference is the principal course of the total differences, the CEI Theil index demonstrates gradient decreasing pattern of "western > central > eastern > northeast," the contribution rate of CEI Theil index shows "northeast > eastern > central > western," the CEPC Theil index shows the spatial pattern of "northeast > central > western > eastern," and the contribution rate of CEPC Theil index presents the spatial pattern of "eastern > central > western > northeast." (iii) The dynamic evolution of CEI and CEPC curve presents polarization or multipolar differential phenomenon accompanies with distinct gradient characteristics, the regional difference of agglomeration level in CEI is gradually narrowing, while the CEPC gradually expanding and the dispersion level is increasing, which implies the "intra-regional convergence and inter-regional divergence." Consequently, differential carbon reduction policies have been put forward according to the study findings. [ABSTRACT FROM AUTHOR]

Forest aboveground biomass (AGB) is of great significance since it represents large carbon storage and may reduce global climate change. However, there are still considerable uncertainties in forest AGB estimates, especially in rugged regions, due to the lack of effective algorithms to remove the effects of topography and the lack of comprehensive comparisons of methods used for estimation. Here, we systematically compare the performance of three sources of remote sensing data used in forest AGB estimation, along with three machine-learning algorithms using extensive field measurements (N = 1058) made in the Khingan Mountains of north-eastern China in 2008. The datasets used were obtained from the LiDAR-based Geoscience Laser Altimeter System onboard the Ice, Cloud, and land Elevation satellite (ICESat/GLAS), the optical-based Moderate Resolution Imaging Spectroradiometer (MODIS), and the SAR-based Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR). We show that terrain correction is effective for this mountainous study region and that the combination of terrain-corrected GLAS and PALSAR features with Random Forest regression produces the best results at the plot scale. Including further MODIS-based features added little power for prediction. Based upon the parsimonious data source combination, we created a map of AGB circa 2008 and its uncertainty, which yields a coefficient of determination (R2) of 0.82 and a root mean squared error of 16.84 Mg ha−1 when validated with field data. Forest AGB values in our study area were within the range 79.81 ± 16.00 Mg ha−1, ~25% larger than a previous, SAR-based, analysis. Our result provides a historic benchmark for regional carbon budget estimation. [ABSTRACT FROM AUTHOR]