Carbon Sequestration Change Research Articles

Benthic remineralization under future Arctic conditions and evaluating the potential for changes in carbon sequestration in warming sediments

Benthic (seafloor) remineralization of organic material determines the fate of carbon in the ocean and its sequestration. Bottom water temperature and labile carbon supply to the seafloor are expected to increase in a warming Arctic and correspondingly, benthic remineralization rates. We provide some of the first experimental data on the response of sediment oxygen demand (SOD), an established proxy for benthic remineralization, to increased temperature and/or food supply across a range of Arctic conditions and regimes. Each factor significantly increased SOD rates (with different degrees of variability); however the largest increases were seen with both factors combined (50% to ten-fold increases), consistently across the four seasons and the spatial gradient covering shelf to deep basin included in our study. This ability of the Arctic benthos to process increased pulses of carbon suggests that increased sedimented carbon under warming conditions is likely to be utilized and processed, not accumulated, impacting carbon storage and decreasing the Arctic’s role as a global carbon sink.

Land Use Intensity Alters Ecosystem Service Supply and Demand as Well as Their Interaction: A Spatial Zoning Perspective

Clarifying the interaction between ecosystem service supply (ESS) and demand (ESD) and its response to land use change is essential for achieving ecological security. Previous research mainly focused on how land use change affects ESS, ignoring its impact on the interaction between ESS and ESD, making it difficult to guide regional sustainability in social–ecological coupled systems. Taking the Yangtze River Delta as the study area, after evaluating five types of ESS and ESD during 2000–2020, this study analyzed the interaction between changes in ESS and ESD using Geodetector from a spatial zoning perspective and subsequently explored the impact of land use intensity on ESS, ESD, and their interaction using Spearman correlation analysis and regression analysis. The results showed that there was obvious spatial–temporal heterogeneity in ESS and ESD. Different ecosystem services varied in their interaction between ESS and ESD, and the demand changes in water conservation and soil retention significantly influenced their supply changes, while supply changes in carbon sequestration were not influenced by its demand changes. The effect of ESD changes on ESS changes also showed spatial heterogeneity. All interactions between ESS changes and ESD changes, except carbon sequestration, were significant in the Supply Increases–Demand Increases zone. Soil retention and water conservation showed a significant supply–demand interaction in the Supply Decreases–Demand Decreases zone and the Supply Decreases–Demand Increases zone, respectively, while no ecosystem service showed significant supply–demand interaction in the Supply Increases–Demand Decreases zone. Land use intensity had linear and nonlinear effects on different ESS and ESD, and it was also found that the effect of ESD changes on corresponding ESS changes was relatively obvious in regions with dramatic land use change. Finally, this paper incorporated the changes in ESS and ESD, as well as their interaction, into land use management, which can provide implications for regional sustainability.

Estimation of changes in carbon sequestration and its economic value with various stand density and rotation age of Pinus massoniana plantations in China

Plantations actively participate in the global carbon cycle and play a significant role in mitigating global climate change. However, the influence of forest management strategies, especially planting density management, on the biomass carbon storage and production value of plantations for ensuring carbon sink benefits is still unclear. In this study, we estimated the carbon sequestration and economic value of Pinus massoniana plantations with various stand densities and rotation ages using a growth model method. The results revealed that with increasing stand age, low-density plantations at 2000 trees·ha−1 (358.80 m3·ha−1), as well as high-density plantations at 4500 trees·ha−1 (359.10 m3·ha−1), exhibited nearly identical standing volumes, which indicated that reduced inter-tree competition intensity favors the growth of larger trees during later stages of development. Furthermore, an increase in planting density led to a decrease in the average carbon sequestration rate, carbon sink, and number of trees during the rapid growth period, indicating that broader spacing between trees is favorable for biomass carbon accumulation. Further, extending the rotation period from 15 to 20 years or 25 years and reducing the optimal planting density from 3000 to 2000 trees·ha−1 increased the overall benefits of combined timber and carbon sink income by 2.14 and 3.13 times, respectively. The results highlighted that optimizing the planting density positively impacts the timber productivity and carbon sink storage of Pinus massoniana plantations and boosts the expected profits of forest managers. Thus, future afforestation initiatives must consider stand age and planting density management to shift from a scale-speed pattern to a quality-benefit design.

Assessing the Impacts of land Use Change on Carbon Sequestration: A Comprehensive Analysis for Kochi City, India

Land use typologies play a pivotal role in determining the carbon sequestration capacity of urban ecosystems. Ashuman activities continue to reshape landscapes, understanding the impact of different land uses on carbon storageis crucial for developing effective climate change mitigation strategies for cities. This paper aims to analyse therelationship between land use typologies and carbon sequestration. Carbon sequestered in the selected city i.e., Kochiis quantified using the InVEST Carbon Storage and Sequestration model (Integrated Valuation of Ecosystem Servicesand Tradeoffs), coupled with remote sensing. The model uses input data on carbon pools including above-ground,below-ground, soil biomass, and dead carbon matter. The change in carbon sequestration with change in land usebetween 2003 and 2023 is calculated. The study reveals that there has been a reduction in wetland areas by 59 %which leads to 63% less sequestration of carbon highlighting the implication of land use on carbon sequestration.

Response of ecosystem services and environmental dynamics in large open-pit coal mines: A case study in semi-arid areas

Surface coal mining in semi-arid regions has detrimental impacts on the structure and function of surface ecosystems, thereby impeding the attainment of regional sustainable development goals. Moreover, the impact of climate change on ecological restoration in semi-arid mining areas is an inevitable consideration. To elucidate the response of ecosystem services in mining areas to regional climate change, topography, soil, vegetation and socioeconomic development, this study selected six large-scale surface coal mines located in semi-arid regions of China as research objects. In this study, we aimed to assess the main ecosystem services (carbon sequestration, soil conservation, and flow regulation) provided by these mines. In addition, we analysed the spatial and temporal evolution and interrelationships of these ecosystem services. Furthermore, we explored the underlying mechanisms between ecosystem services and environmental factors. The results showed the following: (1) Geospatially, there was a gradual decrease in carbon sequestration and flow regulation from northeast to southwest in the mining areas. However, the soil conservation exhibited an upward trend. Throughout the research period, the carbon sequestration change rate in the six mining areas displayed an initial downward and subsequent upward trend, the rate of soil conservation exhibited a gradual upward trend, and the flow regulation decline rate followed a downward trend. (2) Change rate of carbon sequestration and soil conservation in the six mining areas showed a significant positive correlation (r = 0.51, p < 0.001), with the strongest correlation observed in the Shengli Mining Area (r = 0.64, p < 0.001). (3) Ecosystem service changes in the mining areas were primarily driven by initial conditions (95.0%), followed by meteorological factors (4.2%). Three ecological restoration models were proposed for the different regions based on driver analyses. The findings of this study offer scientific evidence that can be used to inform ecological management, enhance ecological security, and promote regional sustainable development in mining areas.

Integrating Remote Sensing (RS) and Geographic Information System (GIS) for Carbon Sequestration Monitoring in Tropical Watershed

The watershed has many functions related to ecosystem protection. The existence of vegetation in the watershed can absorb some carbon from the atmosphere through photosynthesis. In fact, this carbon sequestration potential is declining due to vegetated land conversion phenomena. Therefore, monitoring carbon sequestration in this area needs to be done. However, it faces a problem due to the large size of the watershed area in a tropical region, so carbon sequestration cannot be measured by field-measurement. By combining RS and GIS, the carbon sequestration in a large watershed can be measured frequently to solve the problem. This research aims to analyze the dynamic change of carbon sequestration in Upper Bengawan Solo from 2000 until 2020. In this research, carbon sequestration was modelled using the Net Primary Productivity (NPP). NPP was measured by using the CASA method used Landsat Imagery and Meteorological Data from Meteorological Agency of Indonesia (BMKG). The results show that the carbon sequestration in Upper Bengawan Solo over 20 years decreased. The most significant decrease happens in the sub-urban area surrounding the urban area in Surakarta city. It indicates an environmental change in this watershed due to physical or human interference during this period. Meanwhile, by using RS and GIS, the spatial distribution of carbon sequestration change can be known, so it can be used to pinpoint the location which needs prior attention based on the higher level of these changes. This research implies that combining RS and GIS can help carbon sequestration monitoring be quicker and cost-limited.

Carbon Sequestration Dynamics in Urban-Adjacent Forests: A 50-Year Analysis

Achieving carbon neutrality is crucial for urban ecosystems. Forests growing near cities largely determine the state of the environment in urban areas. The aim of the present research is to assess the carbon productivity dynamics in forests near Krasnoyarsk (a large industrial center) over a 50-year period in terms of carbon sequestration and conservation. The study was based on forest inventory conducted in Karaul'noe Forestry in 1972, 1982, and 2002 and forest inventory covering six forest compartments in 2022. The forest covers 3980 ha and consists of 52 forest compartments. The analysis was based on the assessment of carbon productivity dynamics and followed four levels of principles: forestry, structure, forest compartment, and forest stand. The research was based on forest fund dynamics, analyzing methods, long-term forest inventory, assessing carbon stock, and growing stock dynamics. Pine is the dominant forest-forming species that absorbs the most carbon in the study area. Pine is long-lived, covers a vast area, and has the highest carbon sequestration potential. At the forest structure level, the predominant carbon pools are mid-late successional and late successional stands dominated by pine, birch, and aspen. Forest compartment-level analysis revealed three trends in carbon sequestration: carbon balance, a decrease in carbon sequestration, and an increase in carbon sequestration. Notably, the prevailing trend is determined by changes in carbon sequestration by dominant forest-forming species (pine). Forest stand-level analysis showed that stands have become more and more uneven-aged. About 65% of total carbon stock is concentrated in mid successional, mid-late successional and late-successional stands, and 35% in young stands. The carbon sequestration rate decreases in forests with age. However, pine forests increase biological productivity and continue to successfully sequester carbon. Deciduous forests have lost their carbon sequestration potential, and the area they occupy is currently decreasing in the study area. The development of the young generation in pine stands suggests that the carbon sequestration potential in forests growing near the city will not decrease and may even increase due to climate change. Doi: 10.28991/CEJ-2023-09-09-08 Full Text: PDF

APPLICATION OF REMOTE SENSING FOR MONITORING CARBON FARMING: A REVIEW

This research article presents an overview of the role of carbon farming in mitigating climate change by sequestering carbon in soil and vegetation. The article highlights the potential of remote sensing technology for monitoring carbon farming practices and CO2 absorption. Carbon farming practices, such as conservation tillage, cover cropping, crop rotation, and agroforestry, are discussed. The article explains the application of remote sensing technology, including satellite-based remote sensing, aerial photography, and ground-based sensors, in monitoring changes in carbon sequestration and CO2 absorption. The article concludes that remote sensing technology provides a powerful tool for monitoring carbon farming and CO2 absorption and is likely to become even more effective in the future as technology continues to advance.

Improving food security and farmland carbon sequestration in China through enhanced rock weathering: Field evidence and potential assessment in different humid regions

Enhanced rock weathering (ERW) in farmland is an emerging carbon dioxide removal technology with crushed silicate rocks for soil improvement. However, due to climatic variability and field data limitations, uncertainties remain regarding the influence of ERW on food security and soil carbon pools in temperate regions. This study focused to evaluate the crop productivity and carbon sequestration potential of farmland ERW in China by conducting field monitoring in different humid regions and ERW performance model. Additionally, the contribution of climate, soil, and management factors to ERW-mediated yield and carbon sequestration changes was explored using random forest and correlation networks. Field monitoring indicated that farmland ERW significantly improved crop yield in humid region (13.5 ± 5.2 %), along with notable improvements in soil pH and available nutrients. Precipitation (10.4–16.7 %) and soil pH (9.7–16.8 %) had the highest contribution on ERW mediated yield and carbon sequestration changes, but the contribution of management factors (24–26.2 %), especially N input (2.7–7.0 %), should not be disregarded. The model evaluation demonstrated that the carbon sequestration rate of farmland ERW in China can reach 0.28–0.40 Gt yr−1, thereby presenting an opportunity to expand and accelerate the nationally determined contributions of China. The mean sequestration cost of farmland ERW was 633 ± 161 CNY ¥ t-CO2−1, which was an attractive sequestration price considering the positive benefits of rock powder on soil pH and nutrients. Deploying ERW in acidified and mineral nutrient deficient regions was able to serve as an alternative to lime and part chemical fertilizers to improve yield and maximize agricultural sustainability and resource co-benefits. Farmland ERW also has the potential to resource silicate waste to assist traditional, difficult-to-decarbonize industries to reduce carbon emissions. As a result, a comprehensive assessment of existing artificial silicate waste materials could further expand the application of farmland ERW.

Shifting of nutrient limitation dominates the recovery of aboveground net primary productivity of mixed forests in northeastern China after selective logging

The primary productivity of temperate forests is commonly limited by nitrogen (N) supply, which may be aggravated by the removal of trees. After selective logging, whether and the mechanism by which the N limitation can be alleviated by the rapidly increasing nutrient turnover during the recovery processes, which is important for improving carbon sequestration in temperate forests, remain unclear. We investigated the effect of nutrient limitation (leaf N:Pcom: the leaf N:P ratio at the community level) on plant community productivity by selecting 28 forest plots including seven forest recovery periods (at the sites logged 6, 14, 25, 36, 45, 55, and 100 years ago) following low-intensity selective logging (13–14 m3/ha) and one unlogged treatment by measuring the soil N concentration, soil phosphorus (P) concentration, leaf N concentration, leaf P concentration, and the aboveground net primary productivity (ANPP) of 234 plant species. The plant growth in temperate forests was limited by N, but the P limitation was observed at the sites logged 36 years ago, which showed a transition pattern of plant growth from N limitation to P limitation during the forest recovery process. Meanwhile, a robust linear trend in the community ANPP was observed with the increase in the community leaf N:P ratio, which suggests the enhancement in community ANPP with the release of N limitation after selective logging. Nutrient limitation (leaf N:Pcom) had a significant direct effect (56.0 %) on the community ANPP and showed a higher independent contribution (25.6 %) to the variation in the community ANPP than the soil nutrient supply and even the changes in species richness. Our results suggested that selective logging alleviated the N limitation, but a shift toward P limitation should also be highly regarded in learning the changes in carbon sequestration during the recovery processes.

Effects of climate and afforestation on carbon sequestration change in northern China

AbstractIn recent decades, carbon sequestration (CS) capacity in Northern China has changed significantly, but the main factors leading to the spatial heterogeneity of CS change were still unclear. In this study, we analyzed the spatio‐temporal characteristics of CS change from 2000 to 2020 in Northern China, and further used correlation analysis and multiple linear regression model (MLR) to identify the main factors leading to the spatial differentiation of CS change. Furthermore, we adopted random forest model (RF) to compare the importance of these factors and geographically weighted regression (GWR) to spatially illustrate the heterogeneity of their influence on CS change. Our results showed that the most obvious increases of CS were concentrated in the Loess Plateau, Yanshan Mountains and Taihang Mountains. After eliminating redundant and low‐impact variables, we screened six factors that can well predict the spatial differentiation of CS change in Northern China. Based on the selected predictors, the MLR could explain 62.9% of the spatial variation of CS change, while the RF and GWR could explain 82.2% and 65.7% under the same predictors, respectively. Meanwhile, the spatial feature of each predictor's influence on CS change showed obvious differences. Among all predictors, afforestation was the most important factor leading to the spatial variation of CS change, and aridity index had the largest contribution among the climatic factors. In addition, we found that aridity index and potential evapotranspiration could explain better than commonly used precipitation and temperature. This study deepens the understanding of the spatial heterogeneity of CS change in Northern China and provides further suggestions for improving regional CS capacity.

Carbon Sequestration Characteristics Under Natural Vegetation Restoration in Ziwuling Area of the Loess Plateau

The aim of this study was to analyze the carbon sink effect under natural vegetation restoration and the influence of changes in vegetation community characteristics on ecosystem carbon density in ecologically fragile areas of the Loess Plateau. In this study, the changes in carbon sequestration of a vegetation-soil system under eight successional stages[slope cropland, abandoned cropland for 10 years, abandoned cropland for 20 years, Sophora davidii (Franch.) Skeels., Betula platyphylla Suk., Pinus tabulaeformis Carr., Quercus wutaishanic Mary+P. tabulaeformis Carr mixed forests, and Q. wutaishanic Mary] in Ziwuling area over 150 restoration periods were investigated using the common method of spatial and temporal substitution. This study also discussed the relationship between changes in vegetation community characteristics and vegetation-soil system carbon density. The results showed that the community coverage of the investigated vegetation fluctuated from 85% in the slope cropland stage to 100% in the arbor stage. The number of species, Margalef index, Shannon-Wiener index, Pielou index, and Simpson index initially increased rapidly, then declined slowly until becoming stable, and reached a peak in the middle of the succession (B. platyphylla Suk.). The biomass and carbon density of vegetation components (above-ground biomass, below-ground roots, and litter) increased exponentially during the succession, i.e., increased slowly before B. platyphylla Suk. but increased significantly in B. platyphylla Suk. and P. tabulaeformis Carr.(P<0.05). The biomass and carbon density reached the maximum values of 27858.08 g·m-2 and 13232.51 g·m-2, respectively, in Q. wutaishanic Mary+P. tabulaeformis Carr mixed forests and tended to be stable in the late succession stage. Soil organic carbon density showed a power function relationship with vegetation restoration, with the greatest increase in the stages of abandoned cropland for 10 years and B. platyphylla, but no significant changes in the subsequent stages (P>0.05). In the early succession stage, the carbon density of the farmland ecosystem was the lowest (4395.70 g·m-2), whereas the other seven stages increased by 55.54%, 40.37%, 69.96%, 202.48%, 326.35%, 357.43%, and 351.07%, respectively, compared with the farmland ecosystem. Community coverage, Margalef index, Shannon-Wiener index, above-ground biomass, root biomass, and litter biomass were significantly positively correlated with vegetation-soil system carbon density (P<0.05). The carbon sink effect of long-term natural restoration in Ziwuling Region was significant, and the carbon density of the vegetation-soil system under interspecific competition tended to be stable in the late succession stage. Dynamic changes in the vegetation community structure and plant diversity during the succession process increased vegetation carbon density and soil carbon density. This study helps to clarify the carbon sink effect of natural vegetation restoration in ecologically fragile areas of the Loess Plateau and provides a theoretical basis for promoting natural forest conservation and achieving carbon neutrality.

Spatio-Temporal Analysis of Carbon Sequestration in Different Ecosystems of Iran and Its Relationship with Agricultural Droughts

The increase in environmental and human-related changes (e.g., increase in the carbon cycle flux of plants) has increased the dynamism of ecosystems. Examining fluctuations in net primary production (NPP) is very important in adopting correct strategies for ecosystem management. The current study explores the spatiotemporal variations in NPP and its association with agricultural droughts in Iran’s ecosystems over 20 years (2000–2020). Mann–Kendall and Sen’s slope methods in each pixel were used to track changes in trends. Drought upsets the terrestrial carbon cycle balance. In this study, Vegetation Health Index (VHI) used to assess drought that extracted from different bands of images satellite. Then, the relationship between NPP rates and agricultural droughts was investigated through running Pearson correlation. The results demonstrated that Iran’s annual share of carbon sequestration is 1.38 kg*C/m2/year. The highest carbon sequestration rate was recorded in Caspian Hyrcanian forests. In contrast, the lowest rate was observed in the Arabian Desert and East Sahero-Arabian xeric shrublands in southwestern Iran. Moreover, the highest photosynthesis variations were recorded in Arabian Desert and East Sahero-Arabian xeric shrublands and Tigris–Euphrates alluvial salt marsh, while the lowest changes were registered in Badghyz and Karabil. In total, 34.2% of the studied pixels showed a statistically significant rising or falling trend. Sen’s slope estimator demonstrated that the sharpest negative trend in carbon sequestration belonged to Caspian Hyrcanian mixed forests (−12.24 g*C/m2/year), while the sharpest positive trend was observed in Azerbaijan shrub desert and steppe (12.29 g*C/m2/year). The results of the Pearson correlation revealed significant correlations between NPP and VHI in different ecosystems with coefficients ranging from −0.93 to 0.95. The largest area with a positive correlation (33.97%) belonged to the Zagros Mountains forest steppe. Identification of areas with the greatest carbon sequestration changes could result in prioritizing varied ecosystems management for carbon sequestering. It can be also utilized in environmental planning such as scaling up ecosystem values or estimating current and past ecological capacity.

Assessing spatiotemporal variations of forest carbon density using bi-temporal discrete aerial laser scanning data in Chinese boreal forests

Assessing the changes in forest carbon stocks over time is critical for monitoring carbon dynamics, estimating the balance between carbon uptake and release from forests, and providing key insights into climate change mitigation. In this study, we quantitatively characterized spatiotemporal variations in aboveground carbon density (ACD) in boreal natural forests in the Greater Khingan Mountains (GKM) region using bi-temporal discrete aerial laser scanning (ALS) data acquired in 2012 and 2016. Moreover, we evaluated the transferability of the proposed design model using forest field plot data and produced a wall-to-wall map of ACD changes for the entire study area from 2012 to 2016 ​at a grid size of 30 ​m. In addition, we investigated the relationships between carbon dynamics and the dominant tree species, age groups, and topography of undisturbed forested areas to better understand ACD variations by employing heterogeneous forest canopy structural characteristics. The results showed that the performance of the temporally transferable model (R2 ​= ​0.87, rRMSE ​= ​18.25%), which included stable variables, was statistically equivalent to that obtained from the model fitted directly by the 2016 field plots (R2 ​= ​0.87, rRMSE ​= ​17.47%). The average rate of change in carbon sequestration across the entire study region was 1.35 ​Mg·ha−1·year−1 based on the changes in ALS-based ACD values over the course of four years. The relative change rates of ACD decreased as the elevation increased, with the highest and lowest ACD growth rates occurring in the middle-aged and mature forest stands, respectively. The Gini coefficient, which represents forest canopy surface structure heterogeneity, is sensitive to carbon dynamics and is a reliable predictor of the relative change rate of ACD. This study demonstrated the applicability of bi-temporal ALS for predicting forest carbon dynamics and fine-scale spatial change patterns. Our research contributed to a better understanding of the influence of remote sensing-derived environmental variables on forest carbon dynamic patterns and the development of context-specific management approaches to increase forest carbon stocks.

Research on Promoting Carbon Sequestration of Urban Green Space Distribution Characteristics and Planting Design Models in Xi’an

Urban green space is considered to reduce the concentration of forcing factors of climate change such as the carbon dioxide in the atmosphere. Promoting carbon sequestration efficiency within a limited urban green space has become a practical challenge that must be faced in urban sustainability. This study proposed three design models and a list of high carbon sequestration plants. Based on the research on the distribution and change in carbon sequestration in urban green spaces, combined with field surveys and remote sensing images, this study analyzed the main factors affecting carbon sequestration. The results showed that the carbon sequestration capacity in urban green space tends to decrease gradually along with the change in forest structure in a time series of the years 2000, 2007, 2014, and 2019, and this trend was mainly related to the characteristic factors of plant communities in urban green spaces: the carbon sequestration of plants was significantly positively correlated with DBH (diameter at breast height) and community density; positively correlated with hierarchical structure. In addition, we put forward a list of plants with high carbon sequestration, including Styphnolobium japonicum, Salix babylonica, Pittosporum tobira, Spiraea salicifolia, and Iris pseudacorus, proposed three planting design models for different green spaces and habitats to improve the efficiency of carbon sequestration in urban green spaces, and established the community structure models of high carbon-fixing plants which can be directly applied to practical projects. It also explored the sustainable design approach of ecological processes in low-carbon cities.

The governance of community gardens as commons and its role in the socio-ecological outcomes of gardening in Austin, Texas, USA.

Community gardens represent vacant lots in urban areas with public or private land ownership that community members use primarily for urban agriculture. This research studies community gardens in Austin, Texas (USA), with the focus on: (1) approaches taken to govern community gardens and (2) socio-ecological outcomes of gardening associated with the implemented models of governance. Social outcomes are represented by the level of gardeners' satisfaction and perceptions of their success. Environmental outcomes represent ecological services provided by gardens as green spaces and expressed through net primary productivity (NPP), which measures carbon sequestration. This paper argues that these types of outcomes in community gardens are codependent and affect each other, and the governance approach determines what forms this interdependence takes. This study employs Ostrom's socio-ecological systems (SES) framework that reflects both social and natural aspects of community gardening and explains the connection between the governance approaches, gardeners' perception of their success, and changes in carbon sequestration. This paper uses a mixed-methods approach with key informant interviews with managers of community gardens yielding both qualitative and quantitative data. Remote sensing analysis is applied to calculate the amount of biomass for the carbon sequestration model using remote sensing imagery from the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) and Planet Inc. The analysis reveals that the highest measurements of the social and ecological performance in community gardens in Austin are associated with 'bottom-up' governance structures where community members are in charge of decision-making and management.

Feasibility of enhancing carbon sequestration and stock capacity in temperate and boreal European forests via changes to management regimes

Forest management practices might act as nature-based methods to remove CO2 from the atmosphere and slow anthropogenic climate change and thus support an EU forest-based climate change mitigation strategy. However, the extent to which diversified management actions could lead to quantitatively important changes in carbon sequestration and stocking capacity at the tree level remains to be thoroughly assessed. To that end, we used a state-of-the-science bio-geochemically based forest growth model to simulate effects of multiple forest management scenarios on net primary productivity (NPP) and potential carbon woody stocks (pCWS) under twenty scenarios of climate change in a suite of observed and virtual forest stands in temperate and boreal European forests. Previous modelling experiments indicated that the capacity of forests to assimilate and store atmospheric CO2 in woody biomass is already being attained under business-as-usual forest management practices across a range of climate change scenarios. Nevertheless, we find that on the long-term, with increasing atmospheric CO2 concentration and warming, managed forests show both higher productivity capacity and a larger potential pool size of stored carbon than unmanaged forests as long as thinning and tree harvesting are of moderate intensity.

Vegetation coverage and carbon sequestration changes in China’s forest projects area

To achieve the ultimate goal of carbon neutralization by 2060 in China, increasing carbon sequestration has become more important. Based on satellite images, field observations and spatial econometric models, this study examined vegetation coverage and carbon sequestration changes during the period 2000–2020 in China’s eight forestry engineering projects area, analysed their correlation, and compared their response to climate change. The results show that there was a significant turning green trend in all regions. The NDVI with an increasing trend accounted for 68.5 % of the whole study area, which were widely distributed and especially significant in the south. The NDVI with a decreasing trend were more concentrated in the north. For NEP, 31.44 % of the total study area showed decreasing trend, which had a wide distribution and more concentrated in the south and the coastal regions of China. NEP under increasing trend were more obvious in the centre and north of China. In time series, 77.85 % of NDVI in the total study area positively correlated with NEP, with the average correlation coefficient of R = 0.51 (P > 0.05), and the higher positive correlations were more concentrated in the centre and north of China. For precipitation, 83.32 % and 65.31 % of the total area can promote the increase in NDVI and NEP, with the effect more obvious in the north. For temperature, about half of the total area showed a positive correlation, more obvious in the north, for both NDVI and NEP. Spatially, NDVI changes corresponded well with NEP for most vegetation types, for both precipitation and temperature. The few differences only appeared for broad-leaved forest and coniferous forest changes with average precipitation higher than 50 mm between 2000 and 2020. We draw the conclusion that turning green will increase carbon sequestration, the effect is more obvious in northern China.

Modelling spatial-temporal changes in carbon sequestration by mangroves in an urban coastal landscape

Mangrove deforestation by land use conversions is the greatest threat to the conservation of coastal ecosystems, ranking Brazil as a country with high gross annual CO2 emissions. Despite the recognized socio-ecological importance in providing essential ecosystem services (e.g., erosion prevention, protection against extreme weather events, provision of habitats for estuarine species, and blue carbon storage), mangroves have been converted from blue carbon sinks to sources. Here, we modelled and evaluated the spatial-temporal changes in blue carbon stocks and net sequestration potential in mangrove forests in Santos and São Vicente, Brazil, from 1988 to 2050. We used classified images obtained from MapBiomas and the InVEST Coastal Blue Carbon model, which quantifies the potential carbon sequestered in the study area based on changes in the land use and land cover over the determined study period. We found an increased trend in carbon stocks and net sequestration of mangroves in both municipalities. Over the analysis period, carbon stocks in the mangroves of the city of Santos increased 29% in total, while we found a smaller rise (14%) in São Vicente. We found that land use changed substantially during 1988 until 2018, with mangrove extent varying in the region from 3,375 ha in 1988 to 3,764 ha in 2018 within the entire study region. Overall, the net carbon sequestration was approximately 925,393 Mg CO2e and 287,130 Mg CO2e, in Santos and São Vicente, respectively, over a period from 1988 to 2050. To our knowledge, this study is the first to quantify soil carbon stock and accumulation in mangroves along an urban coastal landscape in Brazil and emphasizes the current and future role of mangroves in climate change mitigation. Our findings can support the development of public policies for mangrove conservation and restoration actions to mitigate climate impacts.

Abruptly attenuated carbon sequestration with Weddell Sea dense waters by 2100

Antarctic Bottom Water formation, such as in the Weddell Sea, is an efficient vector for carbon sequestration on time scales of centuries. Possible changes in carbon sequestration under changing environmental conditions are unquantified to date, mainly due to difficulties in simulating the relevant processes on high-latitude continental shelves. Here, we use a model setup including both ice-shelf cavities and oceanic carbon cycling and demonstrate that by 2100, deep-ocean carbon accumulation in the southern Weddell Sea is abruptly attenuated to only 40% of the 1990s rate in a high-emission scenario, while the rate in the 2050s and 2080s is still 2.5-fold and 4-fold higher, respectively, than in the 1990s. Assessing deep-ocean carbon budgets and water mass transformations, we attribute this decline to an increased presence of modified Warm Deep Water on the southern Weddell Sea continental shelf, a 16% reduction in sea-ice formation, and a 79% increase in ice-shelf basal melt. Altogether, these changes lower the density and volume of newly formed bottom waters and reduce the associated carbon transport to the abyss.