Greenhouse Gas Mitigation Research Articles

Systematic investigation on the rational design and optimization of bi-based metal oxide semiconductors in photocatalytic applications

To address the global energy shortage and mitigate greenhouse gas emissions on a massive scale, it is critical to explore novel and efficient photocatalysts for the utilization of renewable resources. Bi-based metal oxide (Bi x MO y ) semiconductors composed of bismuth, transition metal, and oxygen atoms have demonstrated improved photocatalytic activity and product selectivity. The vast number of element combinations available for Bi x MO y materials provides a huge compositional space for the rational design and isolation of promising photocatalysts for specific applications. In this study, we have systematically investigated the electronic and optical properties over Bi2O3 and a series of selected Bi x MO y group materials (BiVO4, BiFeO3, BiCoO3, and BiCrO3) by calculating band structure, basic optical property features, mobility and separation of charge carriers. It is clearly noted that the band gap and band edge position of the Bi x MO y group materials can be tuned in a wide range in comparison to Bi2O3. Similarly, the light response of Bi x MO y also can be broadened from the ultraviolet to the visible light region by adjusting the selection of transition metals. Additionally, the analysis of the effective mass of charge carriers of these materials further confirms their possibility in photocatalytic reaction applications because of the appropriate separation efficiency and mobility of carriers. A selection of experimental investigations on the crystal structure, composition, and optical properties of Bi2O3, BiVO4, and BiFeO3 as well as their catalytic performance in the degradation of methylene blue over was also conducted, which agree well with the theoretical predictions.

Opportunities beyond net-zero CO2 for cost-effective greenhouse gas mitigation in China

Achieving net-zero CO2 emissions is the current main focus of China’s carbon neutrality goal. However, non-CO2 greenhouse gases (GHGs) are more powerful climate forcers, making their emission reduction an opportunity to rapidly mitigate future warming. Here, we evaluate non-CO2 mitigation potentials, costs and climate benefits in the context of China’s carbon neutrality goals. The assessment is conducted by coupling the integrated assessment model GCAM with a climate emulator. The findings indicate that mitigation technologies can largely reduce fluorinated gas emissions from industrial sectors, but long-term non-CO2 reductions of energy sector activities rely heavily on fuel switching. Furthermore, the cumulative costs of deploying non-CO2 mitigation technologies are projected to be less than 10% of the total costs of achieving carbon neutrality from 2020 to 2060. If non-CO2 mitigation measures are included in the overall mitigation portfolio, the benefits of avoided warming would by far outweigh the total mitigation cost increase. Our results thus highlight that incorporating a wider suite of GHGs into climate change mitigation strategies can enhance the cost-effectiveness of mitigation efforts.

Vegetation Change Detection Analysis Using Multi-sensor Hyperspectral Imagery

Vegetation is a fundamental component of ecosystems that maintains carbon levels, hydrological cycles, mitigating greenhouse gases, and ensures climate stability. In recent years, the impacts of global climate change have led to changes in vegetation cover at various levels. Efforts to monitor changes in vegetation are important and beneficial for various fields such as forest monitoring, agriculture, and plantations, among others. The main objective of this research is to detect changes both increase and decrease in vegetation using multi-sensor hyperspectral imagery. The hyperspectral images used in this study are Hyperion 2014 and PRISMA 2021. The method involves creating different levels of spectral resolution simulations from hyperspectral images to detect vegetation changes. Meanwhile, the vegetation change Clustering method employs unsupervised (k-means) techniques. The cluster results can indicate vegetation changes such as vegetation degradation, vegetation, devegetation, or no change, though they currently have low accuracy. The highest accuracy is by Simulated RapidEye image simulations, is 33.5%. The low accuracy results attributed insufficient preprocessing, particularly in topographic correction. Additionally, this research indicates that the spectral resolution levels do not have a significant impact on vegetation change detection, as the differences in change classes at each level are very small.

The Role of Plant-Mycorrhizal-Fungal Interactions in Soil Health and Carbon Sequestration in Agroecosystems

Abstract: Understanding the intricate interactions between plants, mycorrhizal fungi, and soil health is crucial for sustainable agriculture and climate change mitigation. This review synthesizes current research to elucidate the multifaceted role of plantmycorrhizal-fungal interactions in soil health and carbon sequestration in agroecosystems. A meta-analysis of 75 studies spanning diverse ecosystems and plant species reveals a significant positive correlation between mycorrhizal colonization and soil organic carbon content, with an average increase of 25% compared to non-mycorrhizal systems. Furthermore, mycorrhizal symbiosis enhances soil structure and aggregation, promoting water retention and nutrient cycling, which are essential for maintaining soil fertility and resilience to environmental stressors. The contributions of different mycorrhizal types (arbuscular, ectomycorrhizal, and ericoid) to soil carbon dynamics are also examined, highlighting their unique roles in carbon allocation and stabilization. Additionally, the review discusses the potential implications of plant-mycorrhizal-fungal interactions for mitigating greenhouse gas emissions through enhanced carbon sequestration in agricultural soils. Insights into the mechanisms underlying these interactions, including mycorrhizal-mediated changes in root exudates, microbial communities, and soil enzymatic activities, are discussed. Overall, this review underscores the importance of integrating mycorrhizal symbiosis into agroecosystem management practices to enhance soil health, carbon sequestration, and climate resilience.

Investigation of the mechanical, microstructure, and durability properties of concrete with fine uniform and non-uniform polyethylene terephthalate (PET) aggregates

Concrete manufacturing is highly resource-intensive and is a major source of greenhouse gas emission. Accelerating depletion of natural resources such as sand, which is the primary material for aggregate in concrete manufacture is a growing problem. At the same time, the disposal of vast volumes of non-biodegradable plastic waste poses a global environmental challenge. The incorporation of aggregates derived from municipal plastic waste to substitute for sand has the potential to help address both issues, while at the same time mitigating greenhouse gas emission. This study examines the potential of municipal polyethylene terephthalate (PET) plastic waste as a fine aggregate in concrete manufacturing. The primary focus was on PET aggregates with non-uniform and uniform shapes ranging in size from 2.36 to 4.75 mm. In the concrete mixtures, 0 %, 30 %, and 50 % of the fine natural aggregate by volume were replaced with fine PET aggregate with a water to cement ratio of 0.40. The obtained results showed a reduction in compressive and splitting tensile strength when compared to control specimens. However, replacing 30 % of fine natural aggregate with PET (both uniform and non-uniform shapes) significantly improved chloride resistance by 13 % and 12 %, respectively, while also enhancing the bond between cement paste and PET particles. This study characterizes the material properties of PET concrete, which represents a promising method for reusing municipal plastic waste and mitigating environmental concerns in concrete production.

Development of climate smart agriculture based on empowering farmers around forests through triple-helix collaboration

Background: The agricultural sector policy in Indonesia in facing climate change is to increase agricultural productivity and reduce GHG emissions through the development of Climate Smart Agriculture based on empowering farmers around forests. Methods: Qualitative methods produced descriptive data in the form of written or spoken words from people, and observable behaviour. Findings: Synergy and collaboration between the Government, Universities and the Community in the form of triple-helix collaboration through Climate Smart Agriculture activities, which are carried out through the following activity stages: 1) Technology Transfer Stage, including activities for making corn planting demonstration plots under coconut stands, making planting demonstration plots taro under cocoa stands, creation of Moringa plantation management demonstration plots on dry land; 2) Training Stage, activities are carried out to process agricultural products into secondary products, namely: Corn Flour, Corn Analog Rice, Taro Flour, Taro Analog Rice, Moringa Leaf Powder, and Moringa Leaf Tea; 3) Packaging and e-marketplace initiation stage, through packaging design, labeling, marketing via digital platforms and assistance; 4) Empowerment activities and strengthening the institutional capacity of agricultural extension workers and farmer groups are urgently needed to support the development of climate-smart agriculture. Conclusion: Innovations to support the development of Climate Smart Agriculture based on empowerment around forests through triple-helix collaboration will improve farming management through activities. Novelty/Originality of this Study: The research presents a novel triple-helix collaboration model for developing Climate Smart Agriculture, integrating government, university, and community efforts to enhance agricultural productivity while mitigating greenhouse gas emissions.

Deciphering the role of Moringa oleifera seeds and probiotic bacteria on mitigation of biogas production from ruminants

Maintaining cleaner and more sustainable ecosystems by mitigating greenhouse gas (GHG) emissions from livestock through dietary manipulation is in demand. This study was aimed to assess the effect of Moringa oleifera seeds and probiotics (Pediococcus acidilactici BX-B122 and Bacillus coagulans BX-B118) as feed supplements on GHG production and fermentation profile from steers and sheep. The treatments included diets containing 0, 6, 12, and 18% of M. oleifera seeds meal and a mixture of probiotic bacteria (0.2 ml/g of diet). Total biogas production, CH4, CO, and H2S emission from animals (up to 48 h), rumen fermentation profile, and CH4 conversion efficiency were recorded using standard protocols. Results showed interaction among M. oleifera seeds and probiotics on asymptotic biogas production and total biogas production up to 48 h (P < 0.05). The rate of CH4 emission in steers was reduced from 0.1694 to 0.0447 ml/h using 6 and 18% of M. oleifera seeds (P < 0.05). Asymptotic CO and the rate of CO production were increased (P < 0.05) by supplementing different doses of M. oleifera seeds and probiotics. Adding 12% of M. oleifera seeds and probiotics reduced H2S production from 0.0675 to 0.0112 ml H2S/g DM (at 48 h of fermentation) in steers. In sheep, the additives mitigated H2S production from 0.0364 to 0.0029 ml H2S/g DM (at 48 h of fermentation), however there were not interaction (P = 0.7744). In addition, M. oleifera seeds and probiotics reduced the pH level and dry matter degradability (DMD) in steers and sheep (P < 0.0001) showing a positive impact on CH4:ME and CH4:OM (in steers) and CH4:SCFA (in sheep), while the interaction was not significant (P > 0.05) for CH4:SCFA (in steers) and CH4:ME and CH4:OM (in sheep). In conclusion, the interaction of M. oleifera seeds and probiotics in the feeding diet reduced GHG emissions and affected the fermentation profile of steers and sheep.

Mitigating greenhouse gas emissions from the cattle sector: Land‐use regulation as an alternative to emissions pricing

AbstractReducing animal‐based food production would not only reduce agricultural greenhouse gas emissions but also free land that could sequester carbon. We examine the efficiency of a subsidy to cattle farmers for setting aside land for natural ecosystem regeneration. We develop a partial equilibrium model of the cattle sector that integrates land use, greenhouse gas emissions, and animal feeding. We compare the subsidy to alternative policies: a meat tax and a standard on animal feeding. We identify the conditions under which the subsidy is the best alternative to these other second‐best policies. The efficiency of the subsidy lies in its effects on both the extensive margin (reduced quantity of meat) and the intensive margin (production intensification, which reduces both the emission and land‐use intensities of meat). An empirical application to France, where spontaneous regeneration corresponds mostly to forest regrowth, shows that the subsidy dominates the other alternative policies considered for a wide range of parameter values but is sensitive to carbon leakage when the economy is open to trade.

Potential contribution of water management practices under intensive crop production to climate-change-associated global warming

Optimizing water management practices to mitigate greenhouse gas (GHG) emissions in agroecosystems is of increasing interest under climate change. However, previous studies have focused more on paddy fields, little is known as to how water table management in subsurface drained fields or how irrigation practices in humid areas might affect the global warming potential (GWP). Drawing upon experimental data from four intensive crop production sites in Eastern Canada operating under different water management practices, the DeNitrification-DeComposition (DNDC) biogeochemical model was used to assess potential GHG emissions under twelve different sets of General Circulation Models coupled with Regional Climate Models (GCM-RCM) climate projections (2046–2075). Simulations showed that water table control/sub-irrigation and sprinkler irrigation might decrease GWP by allowing greater soil organic carbon (SOC) sequestration, despite increased N2O and CO2 emissions than non-irrigated systems. While drip irrigation marginally increased the SOC sequestration, GWP still increased because the C gains from the residues generated by the greater crop biomass were offset by increased CO2 and N2O emissions. Compared with surface drip irrigation, subsurface drip irrigation reduced the GWP by reducing N2O emissions, as well as increasing crop yield and SOC stock. Although greater crop biomass was expected to return to soil under projected climate change, simulations showed a consistent increase in the GWP of tomato cropping system alone under climate change.

Methane production from the energy valorization of biomass and agro-industrial waste: an experimental approach for the bioenergy development in Rio Grande do Sul, Brazil

This research evaluates methane production in the co-digestion process using anaerobic sludge and effluent from parboiled rice industries in southern Brazil, as well as canned peach waste employing a 22-factorial design. As main results, the highest biogas generation index was equal to 97.6 mLCH4 in the reactor with a 1.35 S/I ratio, during the initial 12 h of the experiment. R2 reactor produced 88.5 mLCH4, with an S/I ratio of 1.7. Therefore, canned peach waste presents significant opportunities for the implementation of circular economy practices and the utilization of waste for energy production. By converting peach waste into bioenergy and biofuels through processes such as anaerobic digestion, industries can contribute to the decarbonization efforts and mitigate greenhouse gas emissions. Moreover, canned peach and rice industries can not only enhance their environmental performance but also contribute to the transition toward a more sustainable and energy-efficient future.

A Financial Analysis and Valuation of Tesla

The pressing issue of global warming, fueled by excessive carbon dioxide emissions, has spurred global concern. Researchers highlight the potential of new energy vehicles, particularly electric cars, in significantly mitigating greenhouse gas emissions. As demand for electric vehicles rises, attention turns to companies like Tesla, spearheading this transformative industry. This study delves into Tesla's financial landscape in 2023, juxtaposing it against other electric vehicle manufacturers, aiming to unveil Tesla's comparative advantages. Leveraging data sourced from Yahoo Finance, the study employs a comprehensive financial analysis, focusing on liquidity, solvency, profitability, and investment metrics. Results underscore Tesla's remarkable performance across these dimensions, showcasing its impressive profitability, operational prowess, financial stability, and investment appeal relative to its competitors. This report stands poised to guide investors intrigued by Tesla's potential, offering valuable insights into the company's financial health and positioning within the burgeoning electric vehicle sector. Through such analysis, stakeholders can make informed decisions in navigating the dynamic landscape of sustainable transportation investments.

ENVIRONMENTAL AND ECONOMIC ASSESSMENT OF COMPOST BARN SYSTEM IN MILK PRODUCTION IN BRAZIL

Intensifying animal productivity in specific areas is recommended to reduce or mitigate greenhouse gas emissions associated with these production systems. This study evaluates the environmental and economic impacts of six dairy farm using an intensive Compost Bedding Pack Barns system in Minas Gerais, Brazil. A Life Cycle Assessment grounded in the IPCC 2006 guidelines, was conducted as a valuable tool in environmental management, providing a comprehensive understanding of the environmental costs from feed cultivation to milk distribution. The Life Cycle Assessment results showed an average carbon footprint of 1.48 kg of CO2 eq. per liter of fat- and protein-corrected milk. Alongside this, an economic and financial viability assessment using investment analysis tools indicated that, despite initial investments and high fixed and variable costs, the system presents strong economic results. These findings support the premise that intensifying productive systems can mitigate environmental impacts while ensuring financial profitability, enhancing the sustainability and competitiveness of Brazil's dairy industry.

Changes in microbial dynamics and fermentation characteristics of alfalfa silage: A potent approach to mitigate greenhouse gas emission through high-quality forage silage

Feeding ruminants with high-quality forage can enhance digestibility and reduce methane production. Development of high-quality silage from leguminous plants with lactic acid bacteria can improve digestibility and it mitigate the greenhouse gas emissions. In this study, we developed a high-quality alfalfa silage with improved fermentation index and microbial dynamics using Levilactobacillus brevis-KCC-44 at low or high moisture (LM/HM) conditions and preserved it for 75 or 150 days. Alfalfa fermentation with L. brevis enhances acidification and fermentation characteristics primarily due to the dominance of lactic acid bacteria (LAB) L. brevis (>95%) compared to alfalfa fermented with epiphytic LAB. The inoculant L. brevis improved the anaerobic fermentation indexes resulting in a higher level of lactic acid in both high (10.0 ± 0.12 & 8.90 ± 0.31%DM) and low moisture (0.55 ± 0.08 & 0.39 ± 0.0 %DM) in 75 and 150 days respectively, compared to control silage. In addition, the marginal amount of acetic acid (range from 0.23 ± 0.07 to 2.04 ± 0.27 %DM) and a reduced level of butyric acid (range between 0.03 ± 0.0 to 0.13 ± 02 %DM) was noted in silage treated with LAB than the control. The LAB count and abundance of Levilactobacillus were higher in alfalfa silage fermented with L. brevis. Microbial richness and diversity were reduced in alfalfa silage treated with L. brevis which prompted lactic acid production at a higher level even for a prolonged period of time. Therefore, this L.brevis is an effective inoculant for producing high-quality alfalfa silage since it improves fermentation indexes and provides reproducible ensiling properties.

Layered double hydroxides and metal-organic frameworks for electrocatalytic CO2 reduction: A comprehensive review

Electrocatalytic carbon dioxide (CO2) reduction has emerged as a promising approach for converting CO2 into value-added products and mitigating greenhouse gas emissions. Layered double hydroxides (LDHs) and metal-organic frameworks (MOFs) have attracted significant attention as potential electrocatalysts for CO2 reduction due to their unique structural properties and tunable chemical compositions. In this review, we provide a comprehensive overview of recent advances in the utilization of LDHs and MOFs as electrocatalysts for CO2 reduction. Scrutiny on various catalysts, along with their general design ways for CO2 reduction is presented. This review will provide insight into the up-to-date research progress in MOF-based materials for CO2 conversion. Furthermore, we highlight opportunities in this field and propose future research directions aimed at optimizing the performance of LDHs and MOFs for CO2 reduction applications.

Absolute permeability estimation from microtomography rock images through deep learning super-resolution and adversarial fine tuning

The carbon capture and storage (CCS) process has become one of the main technologies used for mitigating greenhouse gas emissions. The success of CCS projects relies on accurate subsurface reservoir petrophysical characterization, enabling efficient storage and captured CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extrm{CO}_2$$\\end{document} containment. In digital rock physics, X-ray microtomography (μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu $$\\end{document}-CT) is applied to characterize reservoir rocks, allowing a more assertive analysis of physical properties such as porosity and permeability, enabling better simulations of porous media flow. Estimating petrophysical properties through numeric simulations usually requires high-resolution images, which are expensive and time-inefficient to obtain with μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu $$\\end{document}-CT. To address this, we propose using two deep learning models: a super-resolution model to enhance the quality of low-resolution images and a surrogate model that acts as a substitute for numerical simulations to estimate the petrophysical property of interest. A correction process inspired by generative adversarial network (GAN) adversarial training is applied. In this approach, the super-resolution model acts as a generator, creating high-resolution images, and the surrogate network acts as a discriminator. By adjusting the generator, images that correct the errors in the surrogate’s estimations are produced. The proposed method was applied to the DeePore dataset. The results shows the proposed approach improved permeability estimation overall.

Research on the Influencing Factors of Pulsed Hydraulic Fracturing Effects in Hot Dry Rock Based on Numerical Simulation

Geothermal energy, representing one of the five principal non-carbon-based renewable resources, is crucial in the global energy transition and in mitigating greenhouse gas emissions. Hot Dry Rock (HDR) reservoirs, rich in geothermal resources, predominantly utilize hydraulic fracturing, the most extensively researched and applied technology. However, fracturing these robust HDR formations poses significant challenges compared to traditional hydraulic fracturing in sedimentary rocks in the oil and gas industry. Cyclic pulse fracturing, an innovative mode of fracturing, has received limited academic attention, particularly regarding its permeability enhancement mechanism under varying thermal and pressure conditions, which remains largely unexplored. Building on prior laboratory experiments, this study employs the pore pressure cohesive zone model within ABAQUS software to elucidate the initiation and expansion of hydraulic fractures. Numerical simulations investigated the influence of critical parameters such as pulse pattern, temperature, geostress differential, and confining pressure on fracture propagation. The findings indicate that cyclic pulse hydraulic fracturing can significantly reduce the breakdown pressure in HDR, with reductions up to 37.68% under certain conditions. Notably, at constant amplitude, increased frequency exacerbates damage to hot dry rocks; conversely, at constant frequency, higher amplitudes result in greater damage. Additionally, pulse hydraulic fracturing improves the fracturing process, yielding a more intricate fracture network. In HDR pulse hydraulic fracturing, the temperature disparity between the fracturing fluid and the rock markedly impacts the breakdown pressure. Cold water interacting with a high-temperature geo-thermal reservoir triggers a thermal shock effect, diminishing initiation pressure and expediting fracture development and expansion. The impact of geostress differential and confining pressure on pulse hydraulic fracturing is complex, influencing not only the breakdown pressure but also the direction and extent of fracture expansion.

Cross-sectional analysis of socioeconomic drivers of PM2.5 pollution in emerging SAARC economies

Within the intricate interplay of socio-economic, natural and anthropogenic factors, haze pollution stands as a stark emblem of environmental degradation, particularly in the South Asian Association for Regional Cooperation (SAARC) region. Despite significant efforts to mitigate greenhouse gas emissions, several SAARC nations consistently rank among the world’s most polluted. Addressing this critical research gap, this study employs robust econometric methodologies to elucidate the dynamics of haze pollution across SAARC countries from 1998 to 2020. These methodologies include the Pooled Mean Group (PMG) and Augmented Mean Group (AMG) estimator, Panel two-stage least squares (TSLS), Feasible Generalized Least Squares (FGLS) and Dumitrescu–Hurlin (D–H) causality test. The analysis reveals a statistically significant cointegrating relationship between PM2.5 and economic indicators, with economic development and consumption expenditure exhibiting positive associations and rainfall demonstrating a mitigating effect. Furthermore, a bidirectional causality is established between temperature and economic growth, both influencing PM2.5 concentrations. These findings emphasize the crucial role of evidence-based policy strategies in curbing air pollution. Based on these insights, recommendations focus on prioritizing green economic paradigms, intensifying forest conservation efforts, fostering the adoption of eco-friendly energy technologies in manufacturing and proactively implementing climate-sensitive policies. By embracing these recommendations, SAARC nations can formulate comprehensive and sustainable approaches to combat air pollution, paving the way for a healthier atmospheric environment for their citizens.

Influence of Ultrasonic Cavitation on Botryococcus Braunii Growth

This study investigates ultrasonic energy’s impact on enhancing the growth of Botryococcus braunii (B. braunii) microalgae. Microalgae, known for their advantages in greenhouse gas mitigation and biomass conversion, were subjected to various stressors, including ultrasonic waves, to optimize productivity. Ultrasonic waves induce acoustic cavitation, increasing membrane permeability and substrate conversion. The study examined the impact of energy and maximum pressure resulting from bubble collapse on the relative specific growth rate of B. braunii microalgae. It was observed that reproduction showed a promotive trend until the energy surpassed 30 kJ. However, when ultrasonic energy reached 18.2 kJ, reproduction was inhibited due to the maximum pressure generated during bubble bursting, which reached 5.7 µN/µm2, leading to the suppression of reproduction upon encountering bubble collapse events. Under specific ultrasonic conditions (15.1 kJ energy, maximum pressure of 45.5 × 105 Pa), a maximum specific growth rate of 0.329 ± 0.020 day−1 in a two-day interval boosted B. braunii microalgae biomass productivity. These findings advance our understanding of ultrasonic wave effects on microalgae reproduction and underscore the potential for optimizing ultrasonic parameters to enhance biomass production.

Climate impacts of alternative beef production systems depend on the functional unit used: Weight or monetary value

Beef production has been identified as a significant source of anthropogenic greenhouse gas (GHG) emissions in the agricultural sector. United States and Canada account for about a quarter of the world's beef supply. To compare the GHG emission contributions of alternative beef production systems, we conducted a meta-analysis of 32 studies that were conducted between 2001 and 2023. Results indicated that GHG emissions from beef production in North America varied almost fourfold from 10.2 to 37.6 with an average of 21.4 kg CO2e/kg carcass weight (CW). Studies that considered soil C sequestration (C-seq) reported the highest mitigation potential in GHG emissions (80%), followed by growth enhancement technology (16%), diet modification (6%), and grazing management improvement (7%). Our study highlights the implications of using carbon intensity per economic activity (i.e., GHG emissions per monetary unit), compared to the more common metric of intensity on per weight of product basis (GHG emissions per kg CW) for comparisons across differentiated beef cattle products. While a positive association was found between the proportion of lifespan on grassland and the conventional weight-based indicator, grass-finished beef was found to have lower carbon intensity per economic activity than feedlot-finished beef. Our study emphasizes the need to incorporate land use and management effects and soil C-seq as fundamental aspects of beef GHG emissions and mitigation assessments.

Production of Biofuels from Agricultural Waste

Agricultural waste represents a largely untapped resource that could be utilized for the production of biofuels through various conversion pathways. As the global demand for renewable and sustainable energy grows, biofuels offer solutions to mitigate climate change impacts while improving waste management. This review analyzes using agricultural residues and by-products as feedstocks for biofuel production through biological, thermochemical and chemical conversion processes. The different types of lignocellulosic biomass available from agricultural activities are discussed, along with their compositions. While agricultural waste has advantages like wide availability and low cost, challenges relating to heterogeneous composition, pre-existing contamination and seasonal availability must be addressed. Fermentation, anaerobic digestion, pyrolysis and gasification are examined as established routes for converting agricultural waste into liquid biofuels and biogas. Pretreatment methods, enzyme production pathways and synthesis of fuels like ethanol, butanol and diesel substitutes are outlined. Environmental benefits of biofuels from waste, including greenhouse gas mitigation and recycling of soil nutrients, are evaluated against fossil fuel alternatives. Case studies on operational plants and feasibility studies provide insights into technical and economic viability at scale. Challenges regarding feedstock logistics, conversion efficiency, commercial scale-up and sustainability assessment are identified for future research focus. In conclusion, the review finds that agricultural waste is a promising renewable resource for biofuel production when integrated with appropriate thermochemical, biochemical or anaerobic digestion technologies. While the field is advancing, further improvements in areas such as feedstock supply, pretreatment technologies, and demonstration of sustainability will be critical to realize the full potential of this emerging bioeconomy sector. The review recommends steps to accelerate commercialization and policy frameworks to incentivize waste-to-energy solutions.