Carbon Sink Capacity Research Articles

The spatial response of carbon storage to territorial space composition and landscape pattern changes: A case study of the Fujian Delta urban agglomeration, China.

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.

Research on Constraints and Countermeasures of Forest Carbon Sink Economic Development in Sichuan Province

In response to global climate change, China has made a solemn commitment to achieve carbon peak by 2030 and carbon neutrality by 2060, with the development of carbon sink economy being an important approach to fulfill the dual carbon goals. Sichuan Province, with its abundant forest resources and vast territory, possesses a strong carbon sink capacity, which naturally lends itself to the development of a carbon sink economy. Based on Sichuan Province, this paper analyzes the current situation and challenges of carbon sink economic development, explores the ecological compensation mechanism for carbon sink economy under the dual drivers of ecological protection and economic development, harnesses the ecological functions of carbon sink economy, and contributes to the realization of the dual carbon goals, in line with the concept of “Clear waters and green mountains are invaluable assets”.

Effect of Land Use on the Stability of Soil Organic Carbon in a Karst Region

The composition of soil organic carbon and its stability mechanism are the key to understanding the terrestrial carbon sink capacity. The stability of soil organic carbon in a karst ecosystem greatly affects the soil carbon fixation capacity. In order to understand the impact of human activities on the stability of soil organic carbon in karst areas, the karst valley area of Zhongliang Mountain in Chongqing was selected as an example, and soil samples of four typical land use modes (mixed forest, bamboo forest, grassland, and cultivated land) were collected in layers to analyze the total organic carbon (TOC) and heavy fraction organic carbon (HFOC). The distribution characteristics of light fraction organic carbon (LFOC), labile organic carbon (LOC), and recalcitrant organic carbon (ROC) were analyzed quantitatively by using a structural equation model to provide basic data for soil carbon sink assessment and soil quality protection in karst areas. The results showed that the organic carbon components under different land use patterns in karst areas had obvious surface accumulation, and the content of organic carbon components in the surface layer was 1.2 times that in the bottom layer. Except for LFOC, the content of other organic carbon components was the highest in the mixed forest, followed by that in the bamboo forest and wasteland, with the lowest in cultivated land. Mixed forest ω(TOC) content was the highest, 42.5 g·kg-1, followed by that of bamboo forest (36.6 g·kg-1) and grassland (18.7 g·kg-1), and cultivated land content was the lowest, 13.4 g·kg-1. The soil organic carbon content of cultivated land was 68.5%, 63.5%, and 28.3% lower than that of mixed forest, bamboo forest, and grassland, respectively. Mixed forest had the highest content of ω(HFOC), 21 g·kg-1, followed by those of bamboo forest (20.9 g·kg-1), grassland (18.2 g·kg-1), and cultivated land (13.5 g·kg-1). The mixed forest ω(LOC) content was the highest, 16.3 g·kg-1, followed by those of bamboo forest (14.9 g·kg-1), grassland (11.5 g·kg-1), and cultivated land (5.3 g·kg-1). Mixed forest ω (ROC) content was the highest, 25.7 g·kg-1, followed by those of bamboo forest (21.6 g·kg-1), grassland (15.9 g·kg-1), and cultivated land (10.3 g·kg-1). The bamboo forest land ω(LFOC) content was 15.9 g·kg-1, followed by those of mixed forest (13.9 g·kg-1), grassland (7.3 g·kg-1), and cultivated land (4.9 g·kg-1). The recalcitrant organic carbon index (ROCI) was used to indicate the stability of soil organic carbon. The variation range of ROCI was 33.9%-64.5%, of which the highest was mixed forest (64.5%-66.3%), and the lowest was cultivated land (33.8%-39.6%). The ROCI of mixed forest, bamboo forest, and grassland were 1.8 times, 1.6 times, and 1.4 times that of cultivated land, respectively. Karst area ω (inert organic carbon) content and ROCI showed that human agricultural activities caused the reduction in soil organic carbon content and the destruction of soil physical structure, resulting in the accelerated decomposition and turnover rate of soil organic matter. The most important factor affecting soil stability in karst areas was soil pH. Tillage activities caused soil pH to rise, reduced soil microbial activity, and were not conducive to the accumulation of the inert organic carbon and soil organic carbon pool in the soil.

Tea Gardens, A Potential Carbon-sink for Climate Change Mitigation

The necessity to identify ecosystems with high carbon sink capacity as an alternative mitigation approach to terrestrial carbon sequestration has increased due to hazards such as global warming from emissions of Green House Gases mainly due to anthropogenic activities. Tea is an intensively managed perennial cash crop planted beneath a canopy of shade trees. They provide a prospect for the reduction of climate change while providing economic incentives so much so that some states and the country are dependent on the plantations and the revenue generated out of the tea gardens. Tea and shade trees together can store a significant quantity of atmospheric CO2 in the plants and the soil .The area of the gardens and the shade trees that grow in them makes it very necessary to estimate the amount of carbon sequestered in tea agroforestry systems and define their role as carbon sinks countering the climatic changes and the mitigation of the same.

Analysis of Agricultural Carbon Emissions and Carbon Sinks in the Yellow River Basin Based on LMDI and Tapio Decoupling Models

In addition to creating economic value, crops also serve important ecological functions. Especially their carbon sink function, which plays a key role in mitigating climate change. In this study, the LMDI and the Tapio model were innovatively combined to quantitatively evaluate the carbon emissions and sinks in the Yellow River basin (YRB). It shows that the average annual growth rate of the YRB was −0.1344% during 2002–2020. Carbon emissions show a negative trend due to the transformation and upgrading of agriculture from traditional to modern and the implementation of policies related to China’s agricultural benefits. Agricultural production efficiency is a major factor in inhibiting agricultural carbon emissions, reducing carbon emissions by an average of approximately 8.07 million tons per year. High-carbon emission and high-sink areas in agriculture are mainly concentrated in the southeast of the YRB, where livestock and poultry farming is the principal source of carbon emissions, with rice, wheat, and corn being the principal contributors to the carbon sink. Moreover, there are significant differences in the carbon sink capacity of crops in the YRB. Optimizing crop selection and area distribution can enhance the carbon sink capacity in different regions, contributing to more effective carbon emission control. This study combines agricultural carbon emissions with the carbon sequestration capacity of crops, providing data support and a theoretical basis for the policy formulation and planning of low-carbon agriculture in China. It is of great significance for promoting sustainable agricultural development and mitigating climate change.

Universal microbial reworking of dissolved organic matter along environmental gradients.

Soils are losing increasing amounts of carbon annually to freshwaters as dissolved organic matter (DOM), which, if degraded, can offset their carbon sink capacity. However, the processes underlying DOM degradation across environments are poorly understood. Here we show DOM changes similarly along soil-aquatic gradients irrespective of environmental differences. Using ultrahigh-resolution mass spectrometry, we track DOM along soil depths and hillslope positions in forest catchments and relate its composition to soil microbiomes and physico-chemical conditions. Along depths and hillslopes, we find carbohydrate-like and unsaturated hydrocarbon-like compounds increase in abundance-weighted mass, and the expression of genes essential for degrading plant-derived carbohydrates explains >50% of the variation in abundance of these compounds. These results suggest that microbes transform plant-derived compounds, leaving DOM to become increasingly dominated by the same (i.e., universal), difficult-to-degrade compounds as degradation proceeds. By synthesising data from the land-to-ocean continuum, we suggest these processes generalise across ecosystems and spatiotemporal scales. Such general degradation patterns can help predict DOM composition and reactivity along environmental gradients to inform management of soil-to-stream carbon losses.

Assessment of carrying capacity and carbon sink capacity of Argopecten irradians: taking Qinhuangdao as an example

Assessment of carrying capacity and carbon sink capacity of Argopecten irradians: taking Qinhuangdao as an example

Effects of Spartina alterniflora control on soil carbon and nitrogen in coastal wetlands

The invasive species Spartina alterniflora has significantly disrupted the ecological stability of coastal wetland ecosystems. Consequently, its control has become an important aspect of coastal wetland conservation. When controlling S. alterniflora, it is imperative to assess the ecological impacts of control methods. In this study, the effects of different control methods, i.e. “mowing + flooding” (MF) and “mowing + plowing” (MP), on the soil carbon and nitrogen contents in coastal wetlands were investigated in the Yellow River Delta, China. The results showed that the contents of soil organic carbon, inorganic carbon, and total nitrogen in the MF area within 2 years after treatment were 2.03–3.93 g/kg, 13.74–16.06 g/kg, and 0.24–0.47 g/kg, respectively, which were 36.33 %–-199 %, 2.91 %–36.71 % and 115.42 %–212.09 % higher than that those in the CK area, respectively. The C/N ratio in the MF treatment was 6.98–8.54, which was 5.42 %–40.30 % lower than that in the CK treatment. The contents of soil organic carbon, inorganic carbon, and total nitrogen in the MP area were 1.52–2.3 g/kg, 13.07–14.94 g/kg, and 0.2–0.32 g/kg, respectively, which were 15.91 %–54.18 %, 0.97 %–15.56 % and 35.19 %–182.26 % higher than those in the CK area. The C/N ratio in the MP area was 14.72 %–46.79 % lower than that in the CK area. Correlation analysis revealed that the soil carbon and nitrogen contents in the MF area were significantly positively correlated with the soil water content and electrical conductivity, and the C/N ratio was significantly negatively correlated with the soil sand content. In the MP area, the soil carbon and nitrogen contents were affected by the soil water content and electrical conductivity. The soil organic carbon content was also significantly negatively correlated with soil pH and significantly positively correlated with soil clay content. The C/N ratio was significantly negatively correlated with the total nitrogen content. Overall, the effects of MF on the soil carbon and nitrogen content in coastal wetlands were greater than those of MP. Future studies need to pay attention to the changes in tidal hydrological processes to more accurately assess the impacts of the control of S. alterniflora on the overall carbon sink capacity of the intertidal zone.

Harvested Spartina area performs better than native Scirpus in sedimentation and carbon preservation under storm surge

Typhoons pose threats to coastal wetlands, but the impacts on carbon stocks remain unclear. This study investigated typhoon effects on salt marsh carbon pools with different vegetation covers (harvested Spartina alterniflora, native Scirpusmariqueter, bare mudflat) in the Yangtze River estuary.During Typhoon Muifa (September 2022), significant erosion occurred in the Scirpus area while the harvested Spartina area experienced sediment deposition, indicating its stronger coastal protection capacity. Grain size analysis validated the geomorphic changes. The harvested Spartina area also captured coarser sediments from the mudflat. Wave data showed the amplified hydrodynamics during typhoons can transport more sediment into marshes.In the Scirpus area, surface sediments (0–15 cm) lost 43% organic carbon and 73% belowground biomass due to erosion. The deposited sediments after typhoons lacked the original high carbon content. In contrast, harvested Spartina areas maintained carbon levels despite intense hydrodynamics. The bare mudflat lost 43% total carbon after experiencing substantial erosion.This study demonstrates harvested Spartina areas effectively mitigated carbon loss and even facilitated carbon sequestration through enhanced sediment trapping during typhoons. With intensifying storm surges, seasonal harvesting of Spartina could balance coastal protection and ecological functions better than complete removal. The carbon sink capacity of sediments with native vegetation is vulnerable to typhoons due to limited resilience. Harnessing bio-geomorphic feedbacks is crucial for preserving blue carbon storage facing climate change.

Exploring the optimization of spatial patterns for carbon sequestration services based on multi-scenario land use/cover changes in the changchun-Jilin-Tumen region, China

Optimizing the spatial pattern of carbon sequestration services is essential for enhancing regional ecosystem carbon sink capacity and promoting carbon budget equilibrium. This study leveraged land use/cover changes (LUCC), meteorological, ecological, and socio-economic data, integrating the InVEST and PLUS models to quantitatively evaluate changes in carbon sequestration services within three 2035 scenarios: economic development (ED), ecological protection (EP), and natural development (ND). Furthermore, it incorporated a Bayesian belief network (BBN) with decision-making optimization capabilities to pinpoint areas necessitating the optimization of spatial patterns for carbon sequestration services. The research findings reveal: (1) Substantial impacts of land use/cover changes on carbon sequestration services, with the spatial distribution of carbon sequestration capacity closely linked to land use patterns. (2) Considerable variation in carbon storage levels across different Changchun-Jilin-Tumen scenarios, while their spatial distribution patterns remain generally consistent. Over time, a notable declining trend in carbon storage levels by 2035 compared to previous years is observed. Spatially, the eastern and central regions of the study area emerge as high-value carbon storage zones, with the northwestern region exhibiting lower carbon storage values. (3) The three scenarios categorize CSS into ecological conservation zones, ecological buffer zones, construction development zones, and arable land protection areas. Notably, the construction development zones in the western and northwestern parts of the study area urgently require optimization management. Undertaking spatial pattern optimization studies based on the current state of CSS will sustain their sustainable development and assist in future spatial planning, carbon neutrality goals, and ecological restoration in the Changchun-Jilin-Tumen region.

Evolution of spatial network structure for land-use carbon emissions and carbon balance zoning in Jiangxi Province: A social network analysis perspective

Exploring the spatial network structure of land-use carbon emissions (LUCE) and the carbon balance in developing regions is pivotal for climate change mitigation in these areas. Using socio-economic and land-use data from 2000 to 2020, this study focused on Jiangxi Province as a representative case to elucidate the spatial network structure of LUCE and conduct carbon balance zoning. The primary findings were as follows: (1) The LUCE distribution in Jiangxi Province demonstrated a spatial pattern with high values in the northwest and low values in the southeast. An increasing trend was observed in the total amount of LUCE. Furthermore, there were evident regional differences in the Ecological Support Coefficient (ESC), indicating a weakening regional carbon sink capacity. (2) The spatial network structure of LUCE was intricate but stable. Although the gravitational interactions of LUCE between cities have intensified, overall network connectivity remained moderately correlated, indicating a prominent regional development imbalance. (3) There was a pronounced “core-periphery” structure in the LUCE spatial correlation network. Northern Jiangxi was the “core” of the network, taking an “initiator” role, whereas most cities in southern Jiangxi played a “passive” role, and resided at the “periphery” of the network. The inter-regional LUCE network exhibited pronounced spatial spillover, with inter-block correlations surpassing those within blocks. (4) By leveraging empirical data and spatial metrics, we categorized Jiangxi Province into five distinct carbon balance zoning types and subsequently proposed land-use optimization strategies. From the perspective of social network analysis (SNA), this study offers methodological insights into low-carbon development and synergistic emission reduction in developing regions.

Cost Valuation and Climate Mitigation Impacts of Forest Management: A Case Study from Piatra Craiului National Park, Romania

With the intensification of the effects of climate change, the urgent need to address their drivers, especially greenhouse gas emissions, has become essential. In this context, forests offer a robust solution, with their potential to store and mitigate carbon emissions. However, striking a balance is critical given the significant economic contribution of the forestry and wood-based industries, which account for about 5% of Romania’s GDP and employ 6% (around 300 thousand) of its active workforce. This study, conducted in the Piatra Craiului National Park located in Romania’s Southern Carpathians, we utilize the EFISCEN application to generate three distinct 50-year forest evolution scenarios based on harvest intensity, namely Business As Usual (BAU), Maximum Intensity (MAX), and No Harvest (MIN), on two historical different managed forests, i.e., conservation and production. The study aims to guide forest owners in decision making with scenario modeling tools, with the objectives of assessing the forest carbon sequestration potential and evaluating the economic feasibility. In the most probable scenario, the BAU scenario, the growing stock increases from 2.6 million m3 to 3.8 million m3 over 50 years, with a more than 40% increase. Comparing the carbon stock change for all tree harvest scenario types indicates that the MIN scenario has the highest carbon sink capacity in the next 50 years; the BAU scenario is a well-balanced option between carbon sink and wood provision and has an optimal EUR 3.7 million in annual revenue. The MAX scenario can boost the growth and increase the annual revenue from wood by 35% but is effective only for a short time and thus has the smallest calculated revenue in time. Achieving a win–win relationship between carbon sequestration and wood supply is imperative, as well as good planning and scenarios to contribute to climate mitigation and also as provisions for local communities and to sustain the local economy.

Growing-season carbon budget of alpine meadow ecosystem in the Qinghai Lake Basin: a continued carbon sink through this century according to the Biome-BGC model

BackgroundThe alpine meadow is one of the most important ecosystems in the Qinghai-Tibet Plateau (QTP), and critically sensitive to climate change and human activities. Thus, it is crucial to precisely reveal the current state and predict future trends in the carbon budget of the alpine meadow ecosystem. The objective of this study was to explore the applicability of the Biome-BGC model (BBGC) in the Qinghai Lake Basin (QLB), identify the key parameters affecting the variation of net ecosystem exchange (NEE), and further predict the future trends in carbon budget in the QLB.ResultsThe alpine meadow mainly acted as carbon sink during the growing season. For the eco-physiological factors, the YEL (Yearday to end litterfall), YSNG (Yearday to start new growth), CLEC (Canopy light extinction coefficient), FRC:LC (New fine root C: new leaf C), SLA (Canopy average specific leaf area), C:Nleaf (C:N of leaves), and FLNR (Fraction of leaf N in Rubisco) were confirmed to be the top seven parameters affecting carbon budget of the alpine meadow. For the meteorological factors, the sensitivity of NEE to precipitation was greater than that to vapor pressure deficit (VPD), and it was greater to radiation than to air temperature. Moreover, the combined effect of two different meteorological factors on NEE was higher than the individual effect of each one. In the future, warming and wetting would enhance the carbon sink capacity of the alpine meadow during the growing season, but extreme warming (over 3.84 ℃) would reduce NEE (about 2.9%) in the SSP5-8.5 scenario.ConclusionOverall, the alpine meadow ecosystem in the QLB generally performs as a carbon sink at present and in the future. It is of great significance for the achievement of the goal of carbon neutrality and the management of alpine ecosystems.

Research ReportDiurnal global ocean surface pCO2 and air-sea CO2 flux reconstructed from spaceborne LiDAR data.

The ocean absorbs a significant amount of carbon dioxide (CO2) from the atmosphere, helping regulate Earth's climate. However, our knowledge of ocean CO2 sink levels remains limited. This research focused on assessing daily changes in ocean CO2 sink levels and air-sea CO2 exchange, using a new technique. We used LiDAR technology, which provides continuous measurements during day and night, to estimate global ocean CO2 absorption over 23 years. Our model successfully reproduced sea surface partial pressure of CO2 data. The results suggest the total amount of CO2 absorbed by oceans is higher at night than during the day. This difference arises from a combination of factors like temperatures, winds, photosynthesis, and respiration. Understanding these daily fluctuations can improve predictions of ocean CO2 uptake. It may also help explain why current carbon budget calculations are not fully balanced-an issue scientists have grappled with. Overall, this pioneering study highlights the value of LiDAR's unique day-night ocean data coverage. The findings advance knowledge of ocean carbon cycles and their role in climate regulation. They underscore the need to incorporate day-night variability when assessing the ocean's carbon sink capacity.

Ecosystem carbon exchange across China's coastal wetlands: Spatial patterns, mechanisms, and magnitudes

Coastal wetlands are of great importance for global carbon cycle and climate mitigation because of their strong carbon uptake capacity. However, the national-scale ecosystem carbon exchange dynamics in coastal wetlands, including magnitudes, spatial patterns, and controlling mechanisms, remains poorly understood. In this study, we utilized eddy covariance measurements from China's coastal wetlands to quantify carbon fluxes, assess their spatial patterns, and explore the controlling mechanisms. Integrating climate, vegetation, and soil factors, we constructed a cascaded relationship network to reveal the potential controlling mechanisms of spatial variations in carbon fluxes. The results revealed that gross primary production (GPP) and ecosystem respiration (ER) were 1405 ± 656 (mean ± sd) gC m−2 yr−1and 893 ± 465, respectively. Net ecosystem production (NEP) in coastal wetlands (567 ± 348 gC m−2 yr−1) exceeded China's terrestrial and marine ecosystems by 2–8 times, highlighting their significant carbon sink capacity. The carbon sink capacity in mangroves was significantly higher than salt marsh, exhibiting a twofold difference in NEP. Spatially, carbon fluxes displayed negative correlations with latitude, indicating the influence of climate features. Although tropical climate zone exhibited significantly higher carbon fluxes than temperate zone, no differences were observed between subtropics zone with others due to the distribution of mixed plants and largest area. The structural equation model (SEM) showed that the climate factors, including temperature, precipitation, and net radiation indirectly promoted GPP and ER through regulating the physiological process of mangrove and salt marsh, as well as soil carbon production and consumption. The cascaded relationship of climate-vegetation-soil showed in SEM explained 71–85 % of the spatial variations in GPP and ER, and ultimately accounted for 85 % of NEP. The carbon consumption efficiency (ER/GPP) in coastal vegetations was of 0.6, lower than that of global and China's terrestrial ecosystems, suggesting their strong efficiency in carbon fixation in coastal wetlands. Lastly, the scenario simulation results implied the importance of coastal vegetation restoration on enhancing blue carbon benefits.

High-Resolution Mapping of Mangrove Species Height in Fujian Zhangjiangkou National Mangrove Nature Reserve Combined GF-2, GF-3, and UAV-LiDAR

Mangroves as an important blue carbon ecosystem have a unique ability to sequester and store large amounts of carbon. The height of mangrove forest is considered to be a critical factor in evaluating carbon sink capacity. However, considering the highly complicated nature of the mangrove system, accurate estimation of mangrove species height is challenging. Gaofen-2 (GF-2) panchromatic and multispectral sensor (PMS), Gaofen-3 (GF-3) SAR images, and unmanned aerial vehicle-light detection and ranging (UAV-LiDAR) data have the capability to capture detailed information about both the horizontal and vertical structures of mangrove forests, which offer a cost-effective and reliable approach to predict mangrove species height. To accurately estimate mangrove species height, this study obtained a variety of characteristic parameters from GF-2 PMS and GF-3 SAR data and utilized the canopy height model (CHM) derived from UAV-LiDAR data as the observed data of mangrove forest height. Based on these parameters and the random forest (RF) regression algorithm, the mangrove species height result had a root-mean-square error (RMSE) of 0.91 m and an R2 of 0.71. The Kandelia obovate (KO) exhibited the tallest tree height, reaching a maximum of 9.6 m. The polarization features, HH, VV, and texture feature, mean_1 (calculated based on the mean value of blue band in GF-2 image), had a reasonable correlation with canopy height. Among them, the most significant factor in determining the height of mangrove forest was HH. In areas where it is difficult to conduct field surveys, the results provided an opportunity to update access to acquire forest structural attributes.

The Chemical Weathering of Rocks and Its Carbon Sink Effect in the Naqu River Basin of the Nujiang River Source Area, Southwest China

Carbon plays an important role in global climate change. The mechanisms of carbon sources and carbon sinks have also received wide attention from society, and the physical and chemical characteristics of riverine ions can reflect the chemical weathering of rocks and carbon sink capacity of river basins. Based on the data on river, rainwater, and rock samples from 2019, this study used various methods, such as ion ratio diagrams and ternary diagrams, to analyze the chemical characteristics of water; the chemical weathering and carbon sink effects of rocks were also calculated while assuming three scenarios based on the main sources of ions in the Naqu River. The results showed that for the whole catchment, the main ion sources in the river were: carbonate rock chemical weathering > silicate rock chemical weathering > evaporite dissolution > atmospheric precipitation input. According to the calculations, in the three scenarios, the carbonate weathering rates were 16.84, 11.32, and 14.08 t/km2/yr, and the carbon sink capacities were 66.47, 121.13, and 93.80 mol/km2/yr, respectively; the evaporite weathering rates were 2.20, 9.63, and 5.92 t/km2/yr, respectively. The silicate chemical weathering rate and carbon sink capacity did not change significantly in either scenario, with 6.82 t/km2/yr and 248.6 mol/km2/yr, respectively. This study quantified the ion sources in the Naqu River basin and accurately analyzed their chemical genesis, which helps in understanding the role of the rivers of the Qinghai–Tibet Plateau in the global carbon cycle and global climate change, in addition to providing a reference for the scientific development of the Nujing River.

A new index integrating forestry and ecology models for quantitatively characterizing forest carbon sequestration potential ability in a subtropical region

Due to the important role of forests in carbon neutrality, it is a big task in accurately calculating and predicting forest carbon storage and carbon sink capacity in recent years. However, considering the factors on the capacity of forest carbon sequestration, ecologists and foresters consider different models to evaluate the forest carbon sink ability at different scales, with foresters focusing more on forest growth models, while ecologists adding more climate and environmental factors, which may result in inconsistent results in carbon storage. Therefore, constructing an integrated model by combining the forestry and ecology models is essential for accurately quantifying and characterizing the forest carbon sink potential at the regional scale. Here, we proposed a new forest carbon sink potential index (FCSPI), which is defined as fractional deficiency of the current forest carbon to its maximum level, based on forest permanent plots, climate, and edaphic data to evaluate the forest sink potential ability from stand level to zonal scale across the northern subtropical zone in Hubei province, China, which coupled the stand growth model and climate-productivity model. The results at stand level showed that the R2 and RMSE of FCSPI were 0.78 and 0.072 respectively, which indicated that the FCSPI is an intuitive, highly practical, straightforward, easy, and rapid to implement methodology for forest carbon sequestration assessment. Moreover, FCSPI can conveniently extended from stand scale to zonal scale based on the site quality index for carbon sink (SIC) and stand age variables, which were derived from the opened climate, edaphic, and topographic data. The results of wall-to-wall FCSPI across the subtropical forest in Hubei province reveal the current and future carbon potential sequestration, which can help managers to focus on forest management for climate-smart actions and planning in forest ecosystem services framework.

Understanding ecological restoration potential: The role of water resources and slope gradient limits

Ecological restoration is one of the most feasible ways to mitigate climate change and conserve ecosystems. However, the scope, intensity, effectiveness, and future potential of ecological restoration are restricted by unfavorable environmental conditions, especially limited water resources and complex topography. This paper proposes an assessment framework of ecological restoration potential under the coupled limits of water resources and slope gradient to quantitatively assess ecological restoration potential (ERP) under these two limiting factors. Results indicate that the current vegetation plantation in 20%, 0.19% and 32% areas of China's 31 provinces are larger, equal, and lower than the vegetation threshold permitted by local water resources respectively, which represents about 0.299 billion ha potential for additional restoration area. The ecological restoration potential under the integrated water resources and slope gradient constraints is 0.4 Pg C, less than half (47%) of the potential under the single limit of water resources (0.856 Pg C). However, this potential and China's existing carbon sink capacity related to terrestrial ecosystems is estimated to offset up to 8% of its current carbon dioxide emissions. Ecological restoration programs in areas with slope >5° will require additional economic investment to support Soil and Water Conservation programs, estimated to average about 212 trillion yuan. Succinctly, it is critical to integrate field investigations, process-based assessments and landscape design for sustainable ecological restoration. This work can provide techniques support for quantitative measurement of ecological restoration potential considering multiple limiting factors and guidance for sustainable implementation of ecological restoration programs.

Enhancing the ocean carbon sink capacity of Shandong province, China, under the “dual carbon” goal

The ocean is a key component of the global carbon cycle. As climate change becomes increasingly severe, enhancing the ocean’s carbon sink capacity is of great significance to achieving the “dual carbon” goal for China. As a major maritime province, Shandong is in an advantageous position to utilize the ocean to respond to climate change and achieve the national goals of carbon peaking and carbon neutrality. Focusing on consolidating and enhancing ocean carbon sink capabilities, Shandong needs to formulate a clear timetable and roadmap to promote blue carbon technology research and development, actively cultivate a blue carbon trading market, and tap the inner potential of ocean carbon sink. Shandong should also strengthen international cooperation to jointly construct a carbon-neutral global community.