Search Results (304)

Reasonable nitrogen fertilizer management and cultivation methods can enhance the nitrogen supply and carbon sequestration capabilities of soil, which is beneficial for meeting the growth requirements of crops and alleviating environmental issues. However, the existing research on optimizing nitrogen use efficiency and soil carbon sequestration in organic systems remains limited. Therefore, a field trial was conducted to elucidate the impacts of different cultivation patterns and nitrogen application rates on soil carbon and nitrogen pools, especially on how these factors affect the components of soil organic carbon. The treatments included conventional cultivation with low nitrogen treatment (CFN12), conventional cultivation with high nitrogen treatment (CFN18), organic cultivation with low nitrogen treatment (OFN12), and organic cultivation with high nitrogen treatment (OFN18). The results demonstrated that, relative to CFN18, OFN12 significantly increased the accumulation amounts of organic carbon and nitrogen in paddy soil. This was evident under multiple classifications of organic carbon, while it showed no advantage in the accumulation of mineral nitrogen. Notably, the organic cultivation mode increased the activities of enzymes involved in the carbon–nitrogen cycle in the cultivated layer and optimized the structure of humus, which gave the proportion of aggregates with a particle size greater than 0.5 mm more advantages. Correlation analysis demonstrated that the pertinent indices associated with soil carbon and nitrogen pools exhibited a highly significant positive correlation in the topsoil layer, accompanied by pronounced synergistic interactions among them. The PCA comprehensive scoring results indicate that OFN12 has the highest total score, indicating that it is beneficial for the improvement of soil fertility. This study offers practical insights for improving soil health, boosting plant growth, and enhancing climate mitigation through soil carbon storage, contributing to more sustainable agricultural practices. Full article

Urban green spaces (UGS) supply a wide range of ecosystem services (ESs), which are key to mitigation and adaptation to climate changes. In this study, we focus on two ESs, i.e., greenhouse gas sequestration by terrestrial ecosystems and mitigating the heat island effect through vegetation, as defined by the Common International Classification of Ecosystem Services. The purpose is to support municipalities with characteristics similar to those of the municipality investigated in this study with a rough assessment of ESs through freely available data. The ES delivery capacity assessment relies on the adoption of two indicators: (i) increased carbon storage in forests and (ii) the Heat Island Mitigation Index (HIMI). We applied the method to the UGS of the municipality of Sassari (Italy) and found that the potential amount of carbon storage is 42,052.7 t, while the value of HIMI provided by the green spaces in the homogeneous territorial areas is 67.73%. The methodological approach adopted in this study is potentially applicable in Italian as well as Mediterranean small to medium municipalities to integrate the quantitative assessment of ESs in local planning tools. The novelty of this study lies in the applied practical approach, which is implementable by public bodies lacking data and resources, to assessing prima facie the need for operational climate adaptation and mitigation strategies. Full article

The building sector significantly contributes to global energy consumption and carbon emissions, primarily due to the extensive use of carbon-intensive materials such as concrete and steel. Mass timber construction, particularly using cross-laminated timber (CLT), offers a promising low-carbon alternative. This study aims to calculate the embodied carbon emissions and biogenic carbon storage of a CLT-based affordable housing project, 340+ Dixwell in New Haven, Connecticut. This project was designed using a honeycomb structural system, where mass timber floors and roofs are supported by mass timber-bearing walls. The authors are not aware of a prior study that has evaluated the life cycle impacts of honeycomb mass timber construction while considering Timber Use Intensity (TUI). Unlike traditional post-and-beam systems, the honeycomb design uses nearly twice the amount of timber, resulting in higher carbon sequestration. This makes the study significant from a sustainability perspective. This study follows International Standard Organization (ISO) standards 14044, 21930, and 21931 and reports the results for both lifecycle stages A1–A3 and A1–A5. The analysis covers key building components, including the substructure, superstructure, and enclosure, with timber, concrete, metals, glass, and insulation as the materials assessed. Material quantities were extracted using Autodesk Revit^®, and the life cycle assessment (LCA) was evaluated using One Click LCA (2015)^®. The A1 to A3 stage results of this honeycomb building revealed that, compared to conventional mass timber housing structures such as Adohi Hall and Heartwood, it demonstrates the lowest embodiedf carbon emissions and the highest biogenic carbon storage per square foot. This outcome is largely influenced by its higher Timber Use Intensity (TUI). Similarly, the A1-A5 findings indicate that the embodied carbon emissions of this honeycomb construction are 40% lower than the median value for other multi-family residential buildings, as assessed using the Carbon Leadership Forum (CLF) Embodied Carbon Emissions Benchmark Study of various buildings. Moreover, the biogenic carbon storage per square foot of this building is 60% higher than the average biogenic carbon storage of reference mass timber construction types. Full article

To explore the impact of different agroforestry systems on carbon sequestration, the carbon management index, and carbon fractions, a long-term (37 years) field trial was conducted using three tree-based agroforestry systems consisting of tree species, namely Acacia tortilis, Hardwickia binata, and Tecomella undulata, along with fallow land in a semi-arid region of India. The soil samples were taken at four distinct depths (0–15, 15–30, 30–60, and 60–90 cm) with eight replications and analyzed for soil total organic carbon (TOC), soil organic carbon fractions, soil carbon stocks, and the carbon management index (CMI). In the topsoil layer (0–30 cm), the Acacia tortilis-based agroforestry system recorded a total organic carbon (TOC) content of 4.09%, which was 42.5% higher than that of fallow land. In this layer, the active carbon pool (ACP) was more prominent than the passive carbon pool (PCP). Compared to fallow land, the ACP increased by 68.3%, 59%, and 53.6% for the Acacia tortilis-, Hardwickia binata-, and Tecomella undulata-based systems, respectively. Similarly, the PCP increased by 18.4%, 11.8%, and 8.2% for the same respective systems in the topsoil layer. For the 0–90 cm soil layer, the Acacia tortilis-based agroforestry system sequestered the highest amount of total organic carbon (39.34 Mg C ha⁻¹), followed by agroforestry systems based on Hardwickia binata (37.86 Mg C ha⁻¹), Tecomella undulata (36.99 Mg C ha⁻¹), and fallow land (30.65 Mg C ha⁻¹). Carbon sequestration is higher in the subsurface soil layers (30–90 cm) than in the surface layers. This trend is observed across all agroforestry systems. The carbon management index registered higher for the Acacia tortilis-based agroforestry system (166.58) at the top soil layer than others. Hence, long-term agroforestry systems could improve soil carbon storage and the carbon management index as compared to fallow land. A 37-year field study in a semi-arid region of India revealed that Acacia tortilis-based agroforestry significantly enhances soil carbon sequestration, active carbon pools, and the carbon management index, especially in deeper soil layers, compared to fallow land. Full article

The carbon emissions from the cement industry account for approximately 8% of global carbon emissions, which exerts significant pressure on the environment. In this paper, the microbial-induced calcium carbonate precipitation (MICP) technology was introduced into the carbonization modification research of recycled hardened cement powder (RHCP), and the carbon sequestration performance of RHCP under different pressures was studied. The physicochemical properties of the carbonated products were characterized by microscopic testing methods, and the carbon sequestration mechanism under different pressures was obtained. Subsequently, carbonated RHCP (C-RHCP) was tested as a partial cement substitute for solidified sludge to evaluate its mechanical and durability properties. The results show that when the pressures were 0.3 and 0.5 MPa, the carbon sequestration capacity of RHCP was relatively good, reaching 59.14 and 59.82 g/kg, respectively. Since the carbon sequestration amounts under the two pressures were similar, and considering the energy consumption, in this study, a reaction pressure of 0.3 MPa was selected to prepare C-RHCP. Compared with pure cement, the 28-day unconfined compressive strength (UCS) of the sludge cured with 30% C-RHCP increased by 12.08%. The water stability coefficient of the solidified sludge in the C-RHCP group was greater than 1 after soaking for 7, 14, and 21 days, while the water stability coefficient of the cement group decreased to 0.92 at 14 days. After 20 freeze–thaw cycles, the mass losses of the cement group, the RHCP group, and the C-RHCP group were 31.43%, 38.99%, and 33.09%, respectively. This research not only provides an environmentally friendly strategy for the resource utilization of RHCP but also pioneers a new synergistic model that combines microbial mineralization with the modification of industrial solid waste. It demonstrated significant scientific value and engineering application prospects in reducing carbon emissions in the cement industry and promoted sustainable geotechnical engineering practices based on the “waste–waste” principle. Full article

Biochar can be regarded as a high-energy type of solid fuel produced via pyrolysis, which is the thermal modification of biomass of plant or animal origins. The biggest advantage of biomass relative to classic fossil fuels is the significant reduction in carbon dioxide emissions in the combustion process. Biochar is also considered a natural soil additive for improving soil parameters, increasing crop yields, remediating pollutants, and reducing emissions of methane, among other things. Over the past few years, the range of biochar applications has expanded significantly, as reflected in the number of scientific articles on the topic. Pyrolysates are used in the production of cosmetics, pharmaceuticals, building materials, animal feed, sorbents, and water filters, as well as in the field of modern energy storage and conversion, such as supercapacitors. The key importance of this material is attributed to its ability to sequestrate carbon and reduce greenhouse gas emissions. The relentless growth of the global economy and the high demand for energy generate large amounts of CO₂ in the atmosphere. Solving the carbon balance problem and the low-carbon energy transition toward carbon neutrality is very challenging. Biochar therefore appears to be an excellent tool for creating systems that can play an important role in mitigating climate change. The purpose of this review is to consolidate the existing knowledge and assess the potential of biochar in carbon neutrality based on the application sector. Full article

This paper explores the role of agroforestry in sequestering atmospheric carbon in the tropics and subtropics, specifically in the Madhupur Sal forest of Bangladesh. Agroforestry, combining trees with crops on agricultural lands, is recognized for its potential to act as a carbon sink and enhance productivity. The study assesses various agroforestry practices, including acacia–pineapple–turmeric–papaya, acacia–pineapple–ginger–banana, and sal–pineapple–aroid combinations. This study innovatively assessed both the carbon sequestration and economic viability of agroforestry in the Madhupur Sal forest, presenting a sustainable land-use model that balances environmental benefits and farm profitability. The research reveals improved farm productivity in these agroforestry systems, with different tree species sequestering varying amounts of carbon. Acacia species, ranging from 12 to 25 ft in height, sequestered an average of 23.35 lbs/year, while sal species (Shorea robusta), with trees 45 to 61 ft tall, sequestered 49.80 lbs/year on average. Factors such as tree height, diameter at breast height (DBH), number of leaves, and branches influence carbon sequestration. The paper suggests that the carbon sequestration (CS) potential of agroforestry results in greenhouse gas emission reduction in Bangladesh. By emphasizing the profitability of these practices alongside carbon sequestration, the study encourages the adoption of agroforestry as a sustainable and economically viable strategy. Full article

The adverse effects of climate change, which are associated with the rise in greenhouse gases, impact all nations worldwide. In this context, tropical forests play a critical role in carbon sequestration. However, the significant anthropogenic pressure on these forests contributes to accelerated deforestation and a decrease in their capacity to regulate the climate. This study uses a comprehensive review of 176 published scientific articles and reports to assess the carbon sequestration capacity of rubber plantations, comparing their effectiveness with that of natural tropical forests. The findings are largely consistent and indicate that agricultural systems, such as rubber plantations, which were not traditionally associated with carbon sequestration, play a significant role in this area. Rubber plantations present a complementary alternative to the rapid deforestation of tropical forests, with the capacity to sequester substantial amounts of carbon. The range of carbon storage potential for rubber plantations, spanning from 30 to over 100 tons per hectare, rivals that of natural tropical forests, which can store over 300 tons per hectare. Furthermore, rubber plantations are notable for their indirect carbon sequestration potential. By providing a sustainable source of latex and wood, and thus income, they can reduce the pressure on natural tropical forests. However, challenges remain, particularly concerning sustainable management and the integration of rubber plantations into sustainable tropical forest management strategies. This analysis focuses on the opportunities and challenges of rubber plantations as an offset solution for carbon sequestration. It highlights the prospects for effectively integrating these plantations into sustainable tropical forest management policies. Full article

The study represents an innovative method to utilize the strong computational power of CMG-GEM, a numerical reservoir simulator coupled with artificial neural networks (ANNs) to predict carbon storage capacity in saline aquifers. The key parameters in geological storage formations are identified by generating a diverse dataset from CMG-GEM simulation runs by varying the different geological and operational parameters. Robust data analysis was performed to understand the effects of these parameters and access the different CO₂ trapping mechanisms. One of the significant novelties of this model is its ability to incorporate additional inputs not previously considered in similar studies. This enhancement allows the model to predict all CO₂ trapping mechanisms, rather than being limited to just one or two, providing a more holistic and accurate assessment of carbon sequestration potential. The generated dataset was used in MATLAB to develop an ANN model for CO₂ storage prediction across various trapping mechanisms. Rigorous testing and validation are performed to optimize the model, resulting in an accuracy of 98% using the best algorithm, which reflects the model’s reliability in evaluating the CO₂ storage. Therefore, the number of simulation runs was significantly reduced, which saves great amounts of computational power and simulation running time. The integration of machine learning and numerical simulations in this study represents a significant advancement in sustainable CO₂ storage assessment, providing a reliable tool for long-term carbon sequestration strategies. Full article

The utilization of fossil fuels releases a large amount of carbon dioxide (CO₂) gas, leading to global temperature changes and climate warming. Carbon dioxide geological sequestration (CCS) is an effective solution, including the use of shallow seabed hydrate reservoirs as a geological sink. However, the sealing and strength of the caprock affect the sequestration effectiveness. Therefore, this study assessed the strength and sealing properties of a shallow seabed layer reinforced with Microbial-induced Carbonate Precipitation (MICP) technology through a combination of triaxial tests and X-ray CT. In addition, carbon dioxide sequestration experiments were conducted to investigate the factors influencing the ability of MICP technology to accelerate the mineralization and sequestration of carbon dioxide. The results demonstrate that MICP technology can enhance the sealing capacity of caprock by increasing its strength, reducing its porosity, and accelerating CO₂ mineralization. After 120 h of treatment, the CO₂ concentration in the air decreased from 887 ppm to 310 ppm, showing a significant mineralization effect. The bacteria used, Bacillus megaterium, can simultaneously secrete urease and carbonic anhydrase (CA). During the urease hydrolysis of urea, this not only increases the rate of calcium carbonate formation and improves the sealing performance but also accelerates the catalytic mineralization of CO₂ by carbonic anhydrase by creating an alkaline environment. Full article

In this study, the carbon emissions of Jilin University of Architecture and Technology were comprehensively calculated using the “Guidelines for accounting of carbon emissions of university campuses” issued by the China Association for Energy Conservation in Buildings. The total emissions for 2023 amounted to 13,571.85 tonnes of CO₂ equivalents, with a per person emission of 0.93 tonnes. Incorporating carbon offsets like green plant sequestration, renewable energy, and waste recycling reduced emissions by 9007.68 tonnes, resulting in a net emission of 4564.17 tonnes and a per person net emission of 0.31 tonnes. To further cut emissions, the university implemented strategies such as nearly zero-energy buildings, clean energy heating, energy monitoring, and green courses. Despite these efforts, achieving carbon neutrality remains challenging. The university could explore opportunities to increase renewable energy use or procure green electricity. Its adoption of clean electricity for heating in the severe cold zones not only supports carbon neutrality but also serves as a model for similar campuses. Full article

Terrestrial Storage of Biomass (TSB) is a Negative Emission Technology for removing CO₂ already in the atmosphere. TSB is compared to other NETs and is shown to be a natural, carbon-efficient, and low-cost option. Nature performs the work of removal by growing biomass via photosynthesis. The key to permanent sequestration is to bury the biomass in pits designed to minimize the decomposition. The chemistry of biomass formation and decomposition is reviewed to provide best practices for the TSB burial pit design. Methane formation from even a small amount of decomposition has been raised as a concern. This concern is shown to be unfounded due to a great difference in time constants for methane formation and its removal from the air by ozone oxidation. Methane has a short lifetime in air of only about 12 years. Woody biomass decomposition undergoes exponential decay spread over hundreds to thousands of years. It is inherently slow due to the cross-linking and dense packing of cellulose, which means that the attack can only occur at the surface. A model that couples the slow and exponential decay of the rate of methane formation with the fast removal by oxidation shows that methane will peak at a very small fraction of the buried biomass carbon within about 10 years and then rapidly decline towards zero. The implication is that no additional equipment needs to be added to TSB to collect and burn the methane. Certified carbon credits are listed on various exchanges. The US DOE has recently issued grants for TSB development. Full article

Loblolly pine plantations have long been cultivated primarily for timber production due to their rapid growth and economic value. However, these forests are now increasingly acknowledged for their important role in mitigating climate change. Their dense canopies and fast growth rates enable them to absorb and store substantial amounts of atmospheric carbon dioxide. By integrating sustainable management practices, these plantations can maximize both timber yield and carbon sequestration, contributing to global efforts to reduce greenhouse gas emissions. Balancing timber production with vital ecosystem services, such as carbon storage, demands carefully tailored management strategies. This study examined how the timing of thinning—specifically early thinning at 17 years and late thinning at 32 years—impacts biomass accumulation, carbon storage capacity, and carbon sequestration rates in loblolly pine plantations located in northern Iran. Two thinning intensities were evaluated: normal thinning (removal of 15% basal area) and heavy thinning (removal of 35% basal area). The results demonstrated that thinning significantly improved biomass, sequestration rates and carbon storage compared to unthinned stands. Early thinning proved more effective than late thinning in enhancing these metrics. Additionally, heavy thinning had a greater impact than normal thinning on increasing biomass, carbon storage, and sequestration rates. In early heavy-thinned stands, carbon storage reached 95.8 Mg C/ha, which was 63.0% higher than the 58.8 Mg C/ha observed in unthinned 32-year-old stands. In comparison, early normal thinning increased carbon storage by 41.3%. In late heavy-thinned stands, carbon storage reached 199.4 Mg C/ha, which was 29.0% higher than in unthinned stands of the same age (154.6 Mg C/ha at 52 years). In contrast, late normal thinning increased carbon storage by 13.3%. Similarly, carbon sequestration rates in unthinned stands were 1.84 Mg C/ha/yr at 32 years and 2.97 Mg C/ha/yr at 52 years. In comparison, 32-year-old stands subjected to normal and heavy thinning had sequestration rates of 2.60 and 2.99 Mg C/ha/yr, respectively, while 54-year-old normally and heavily thinned stands reached 3.37 and 3.83 Mg C/ha/yr, respectively. The highest carbon storage was concentrated in the stems for 52–58% of the total. Greater thinning intensity increased the proportion of carbon stored in stems while decreasing the contribution from foliage. These results indicate that heavy early thinning is the most effective strategy for maximizing both timber production and carbon sequestration in loblolly pine plantations. Full article

Water use efficiency (WUE) plays a pivotal role in connecting the carbon and water cycles and represents the amount of water used by plants or ecosystems to achieve carbon sequestration. The response of WUE to climate warming and its underlying mechanisms remain unclear. Here, we examined the effects of varying levels of warming on carbon fluxes, water fluxes, and WUE in an alpine peatland, with Blysmus sinocompressus and Carex secbrirostris as dominant species. Open-top chambers were utilized to simulate two levels of warming: low-level warming (TL) and high-level warming (TH). The carbon dioxide and water fluxes were monitored over a growing season (June to September). Gradient warming significantly decreased both gross primary productivity (GPP) and net ecosystem carbon exchange (NEE); GPP was 10.05% and 13.31% lower and NEE was 21.00% and 30.00% lower in the TL and TH treatments, respectively, than in the control. Warming had no significant effect on soil evaporation, and plant transpiration and evapotranspiration were 36.98% and 23.71% higher in the TL treatment than in the control, respectively; this led to decreases of 31.38% and 28.17% in canopy water use efficiency (WUEc) and ecosystem water use efficiency (WUEe), respectively. Plant transpiration was the main factor affecting both WUEe and WUEc in response to warming. The findings underscore the essential function of water fluxes in regulating WUE and enhance our understanding of carbon–water coupling mechanisms under climate change. Full article

With the exploitation of oilfields, the oil production efficiency of traditional water flooding has been very low, and CO₂-enhanced oil recovery (EOR) has become an inevitable trend of development. CO₂-EOR is affected by many factors, among which the heterogeneity of reservoirs is one of the main influencing factors. In order to understand the impact of different reservoir conditions on the production of oil from CO₂ and the reasons behind it, and on the basis of researching the heterogeneity of reservoir porosity and permeability and its influence on the CO₂-enhanced oil recovery process, this study has altogether established three different reservoir characteristics for comparative analysis. Under the homogeneous and heterogeneous porosity and permeability conditions of a reservoir, the displacement characteristics during a CO₂–oil displacement process were analyzed. The layered heterogenous model had the best oil displacement effect, with its oil displacement amount reaching 8.46 × 10⁴ kg, while the homogeneous model and the spatially heterogenous model had lower values; they were 1.51 × 10⁴ and 1.42 × 10⁴, respectively. The results indicate that the heterogeneous conditions overall improved the flooding effect of CO₂. Under the same injection volume and other reservoir conditions, the cumulative oil flooding effect of the layered heterogenous model was the best compared to the homogeneous and spatially heterogeneous models. Good permeability promotes the accumulation of oil, leading to a higher saturation of the oleic phase. This work provides an in-depth analysis of the effect of the non-uniform distribution of formation permeability on CO₂-enhanced oil recovery and can help to improve carbon sequestration efficiency and oil recovery in CO₂–oil recovery projects. Full article