CO2 Equivalent Research Articles

The oral contraceptive cycle and its influences on maximal and submaximal endurance parameters in elite handball players.

The usage of the oral contraceptive pill is widespread among athletes of various levels. However, there is limited knowledge on how the intake of the pill alters the submaximal and maximal endurance parameters between the oral contraceptive phases. Therefore, the aim of this study was to examine potential differences between the pill intake and withdrawal phase on endurance-related parameters in first-division handball players. In total, 15 female team handball players performed two graded exercise tests until volitional exhaustion on a motorized treadmill. Tests were performed during the pill intake (days 16-17) and withdrawal phase (day 2-3). Throughout the test, respiratory gases were measured breath-by-breath, and the heart rate was measured continuously. Before and after the graded exercise test, blood samples were obtained in order to assess the blood lactate concentration. Before each test, venous blood samples were taken to determine endogenous sex hormone levels. Ventilatory parameters (O2, CO2, and E, and respiratory equivalents for O2 and CO2) were measured, and the oxidation of fat and carbohydrates was calculated. A paired-sample t-test was used to assess differences between the two time points, and the significance was accepted as p < 0.050. Significant differences with lower values during the consumption phase were found for absolute (mean difference ± SD: 88 ± 131mL∙min-1; p = 0.021) and relative O2peak (mean difference ± SD: 1 ± 2mL∙min-1∙kg-1; p = 0.012). Higher values during the consumption phase were found for submaximal respiratory equivalents for O2 (mean difference ± SD: -1.1 ± 1.7; p = 0.028) and CO2 (mean difference ± SD: -0.9 ± 1.5; p = 0.032). No differences were found for all other parameters, including differences for endogenous sex hormones (p > 0.050). The results of the current study suggest only marginal and physiologically insignificant differences in endurance-related parameters between oral contraceptive phases.

A Randomized Noninferiority Trial to Compare Enteral to Parenteral Phosphate Replacement on Biochemistry, Waste, and Environmental Impact and Healthcare Cost in Critically Ill Patients With Mild to Moderate Hypophosphatemia.

Hypophosphatemia occurs frequently. Enteral, rather than IV, phosphate replacement may reduce fluid replacement, cost, and waste. Prospective, randomized, parallel group, noninferiority clinical trial. Single center, 42-bed state trauma, medical and surgical ICUs, from April 20, 2022, to July 1, 2022. Patients with serum phosphate concentration between 0.3 and 0.75 mmol/L. We randomized patients to either enteral or IV phosphate replacement using electronic medical record-embedded program. Our primary outcome was serum phosphate at 24 hours with a noninferiority margin of 0.2 mmol/L. Secondary outcomes included cost savings and environmental waste reduction and additional IV fluid administered. The modified intention-to-treat cohort comprised 131 patients. Baseline phosphate concentrations were similar between the two groups. At 24 hours, mean ( sd ) serum phosphate concentration were enteral 0.89 mmol/L (0.24 mmol/L) and IV 0.82 mmol/L (0.28 mmol/L). This difference was noninferior at the margin of 0.2 mmol/L (difference, 0.07 mmol/L; 95% CI, -0.02 to 0.17 mmol/L). When assigned IV replacement, patients received 408 mL (372 mL) of solvent IV fluid. Compared with IV replacement, the mean cost per patient was ten-fold less with enteral replacement ($3.7 [$4.0] vs. IV: $37.7 [$31.4]; difference = $34.0 [95% CI, $26.3-$41.7]) and weight of waste was less (7.7 g [8.3 g] vs. 217 g [169 g]; difference = 209 g [95% CI, 168-250 g]). C O2 emissions were 60-fold less for comparable phosphate replacement (enteral: 2 g producing 14.2 g and 20 mmol of potassium dihydrogen phosphate producing 843 g of C O2 equivalents). Enteral phosphate replacement in ICU is noninferior to IV replacement at a margin of 0.2 mmol/L but leads to a substantial reduction in cost and waste.

The carbon footprint of epidural steroid injections: A pilot study.

Epidural steroid injections are common procedures in physical medicine and rehabilitation practice. However, their environmental impact has not been characterized. The primary aim is to estimate and compare the carbon footprint of two standard injection kits used to perform epidural steroid injections at a single academic institution. Secondary objectives were (1) to create a step-by-step guide for estimating the carbon footprint of materials and (2) to survey physicians on practice patterns and identify areas for improvement. Pilot study. Academic medical center. N/A. N/A. Carbon emissions measured in CO2 equivalents (CO2 eq). Using guidance from the Greenhouse Gas Protocol, the carbon footprint of the two kits was estimated by taking the sum of carbon emissions resulting from the production of the kit materials and the carbon emissions resulting from the waste disposal of the kit materials. The carbon footprint of the transforaminal epidural steroid injection (TFESI) kit was estimated at 1.328 kg CO2 eq. The carbon footprint of the interlaminar epidural steroid injection (ILESI) kit was estimated at 2.534 kg CO2 eq. For both kits, the carbon emissions resulting from the production of the kits were greater than the emissions resulting from disposal. The survey of interventionalists performing TFESI revealed all respondents required materials in addition to those provided in the standard epidural kit. Despite this, kit materials were typically wasted in 62% of respondents. Creating a methodology for quantifying carbon emissions is the first step to reducing carbon emissions. Once emissions are measured, the health care industry can determine the most effective strategies for reducing its impact. Our analysis has shown that it is feasible to perform emissions calculations and delineates a clear method with publicly available resources. Solutions to reduce epidural injection carbon footprint waste may include improved kit customization.

Carbon emission calculation of three biological nitrogen removal processes: A case of rare earth element tailings wastewater in Southern Jiangxi, China

Global warming has been caused by greenhouse gases (GHGs) released by human activity. Traditional sewage treatment uses much energy to achieve discharge limits in the water treatment industry, producing many GHG emissions. In this study, the emission factor approach and mass balance method are used to calculate the carbon emission equivalent of nitrification and denitrification, anaerobic ammonia oxidation, and microalgae assimilation using a rare earth tailings (REEs) wastewater example. The results show that, among the three denitrification processes, the traditional nitrification and denitrification method has the greatest carbon emission equivalent (16.23 kgCO2/kgN). Direct causes include N2O emissions, which account for 48 % of the total carbon emission equivalent. The anaerobic ammonia oxidation process produces the carbon dioxide equivalent of 0.02 kgCO2/kgN. Carbon emission comparable to microalgal assimilation is −3.23 kgCO2/kgN. The anaerobic ammonia oxidation process can thus greatly reduce carbon emissions when compared to the conventional nitrification and denitrification processes, whilst microalgae assimilation can result in negative carbon emissions.

Investigation of Woody Species Composition, Diversity, and Carbon Stock under Agroforestry Practices in Oromia National Region State, Central Ethiopia

Agroforestry is a common practice in the tropics that is characterized by various activities such as parkland on cultivated lands or home garden agroforestry around homesteads. In Ethiopia, agroforestry is an ancient land use type that is practiced by smallholder farmers. Scattered trees in cropland or parkland trees and home garden trees are old agroforestry practices, and the most dominant practices exist in different parts of Ethiopia. They cover large areas of highland, midland, and lowland agroecologies of Liban Jawi District in West Showa of Oromia National Regional State, Central Ethiopia. However, woody species particularly in parklands are declining in many agricultural landscapes due to the overuses for fuel wood, charcoal production, and expansion of agricultural lands due to the degradation of nearby forests. In the study sites, comprehensive studies in terms of their composition, diversity, structure, and carbon stocks are still not well explored. In this context, we assessed woody species composition and diversity, structure, and carbon stocks because parkland and home garden agroforestry practices in three agroecologies of highland, midland, and lowlands in the district were not quantified. About 45 parkland woody species were collected from 150 plots of 5000 m2, and 35 home garden woody species were collected from 70 plots of 400 m2. As a result, a total of 80 species belonging to 52 families and 62 genera were collected from parkland and home garden agroforestry practices. Woody species diversity was analyzed using species richness, Shannon diversity index, and Shannon evenness index. In this study, the Shannon diversity (2.8) and Shannon evenness indexes (0.54) of woody species were computed in parkland agroforestry, in the meantime the Shannon diversity index (3.30) and Shannon evenness index (0.52) for woody species of the home garden were computed. The distribution of diameter classes of 10–30 cm had the highest number of trees and shrubs followed by 31–60 cm diameter classes. However, the highest number of trees and shrubs were in 61–90 cm diameter class in the home garden. In this study, woody species, such as Citrus sinensis, Mangifera indica, Persea americana, Sesbania sesban, Vernonia amygdalina, and Azadirachta indica were the dominant species under the two agroforestry practices. The values of carbon stack for highland, midland, and lowland in parkland agroforestry were 19.8 MgCha−1, 17.6 MgCha−1, and 17.5 MgCha−1, respectively. Meanwhile, the total biomass of woody species in highland, midland, and lowland for homestead agroforestry was 32.6 MgCha−1, 34.7 MgCha−1, and 31.2 MgCha−1, respectively. These resulted in carbon dioxide sequestered of 72.59 CO2 equivalents (tha−1), 64.52 CO2 equivalents (tha−1), and 64.16 CO2 equivalents (tha−1) in highland, midland, and lowland woody species, respectively. This study holds significant inputs for policymakers, regional administrators, environmentalists, and natural resource experts by informing the farmers’ management and conservation of woody species on cultivated lands and home garden agroforestry plants around their homesteads which is serving as ecosystem services and climate mitigation response within Liban Jawi district. Under parkland and homestead agroforestry practices, communities should have know-how to predict the environmental consequences of the destruction of woody species on their farmlands.

Design of a Solar Dish Receiver and Life Cycle Assessment of a Hot Water System

The energy sector is the main source of greenhouse gases, so it has the highest potential for improvement. The improvements can be achieved by generating energy from renewable sources. It is necessary to combine production from renewable sources with storage systems. Thermal energy storage using concentrated solar power systems is a promising technology for dispatchable renewable energy that can guarantee a stable energy supply even in remote areas without contributing to greenhouse gas emissions during operation. However, it must be emphasised that greenhouse gases and other impacts can occur during the production process of concentrating solar system components. This paper analyses the receiver design to produce thermal energy for the existing CSP dish plant at the Energy Center of the Politecnico di Torino. The plant is designed to produce electrical energy in the spring and summer periods. In addition to this energy production, the CSP can be adopted to produce thermal energy, through hot water, during the less favourable periods of the year in terms of global solar radiation. The surface heat flux is calculated in the first part of the analysis to obtain the maximum internal temperature in the receiver, which is 873.7 °C. This value is a constraint for the choice of material for the solar receiver. A life cycle assessment is performed to compare the emissions generated during the production of the main components of the CSP system with the emissions generated by the methane-fuelled water heater to produce the same amount of thermal energy. It can be concluded that the production of the main components of the CSP system results in lower greenhouse gas emissions than the operational phase of a conventional system. Given the assumptions made, the utilization of methane leads to the emission of approximately 12,240 kg of CO2, whereas the production of the CSP system results in emissions totalling 5332.8 kg of CO2 equivalent

From sink to source: Dynamic of greenhouse gases emissions from beach wrack accumulations in a temperate coastal bay

Coastal ecosystems such as salt marshes, seagrass meadows, and kelp forests contribute to climate regulation as carbon sinks. However, coastal ecosystems may act as carbon sources as beach wrack accumulations may release greenhouse gases (GHG) during decomposition. The magnitude of GHG emissions of beach wrack accumulations under natural conditions are poorly understood, hampering accurate blue carbon accountings. In this study, we assessed the spatio-temporal variability and environmental factors driving CO2, CH4 and N2O emissions from beach wrack accumulations on a temperate sandy beach. Beach wrack accumulations, dominated by Zostera marina and opportunistic brown macroalgae, presented variable spatio-temporal dynamics. Annual beach wrack GHG emissions achieved up to 77,915 mg m−2 d−1 CO2e (CO2 equivalents) and varied largely throughout the study period due to interactive effects of temperature, wave exposure, beach wrack biomass moisture, abundance, and species composition. Our findings showed that methane emissions in new, freshly deposited, and in drifting wrack in the water reached up to 100 mg m−2 d−1, representing up to 57 % of annual CO2e emissions occurring throughout the year. Nitrous oxide emissions were highly variable and comprised a minor extent (i.e., up to 4 %) of annual CO2e emissions. Together, wrack CH4 and N2O emissions provided 13.69 g CO2 m−2 per year to the atmosphere. Our findings indicate that excessive opportunistic macroalgae biomass driven by eutrophication may explain increased CO2 and N2O emissions. We conclude that whilst beach wrack depositions are a natural and essential part of coastal ecosystems, they may provide an extra source of GHG to the atmosphere, potentially counteracting the role of vegetated coastal ecosystems as carbon sinks.

Integrating mobile parcel lockers into last-mile delivery networks: an operational design for home delivery, stationary, and mobile parcel lockers

PurposeThe e-commerce boom presents new challenges for last-mile delivery (LMD), which may be mitigated by new delivery technologies. This paper evaluates the impact of mobile parcel lockers (MPL) on costs and CO2 equivalent (CO2e) emissions in existing LMD networks, which include home delivery and shipments to stationary parcel lockers.Design/methodology/approachTo describe customers’ preferences, we design a multinomial logit model based on recipients’ travel distance to pick-up locations and availability at home. Based on route cost estimation, we define the operating costs for MPLs. We devise a mathematical model with binary decision variables to optimize the location of MPLs.Findings Our study demonstrates that integrating MPLs leads to additional cost savings of 8.7% and extra CO2e emissions savings of up to 5.4%. Our analysis of several regional clusters suggests that MPLs yield benefits in highly populous cities but may result in additional emissions in more rural areas where recipients drive longer distances to pick-ups.Originality/valueThis paper designs a suitable operating model for MPLs and demonstrates environmental and economic savings. Moreover, it adds recipients’ availability at home to receive parcels improving the accuracy of stochastic demand. In addition, MPLs are evaluated in the context of several regional clusters ranging from large cities to rural areas. Thus, we provide managerial guidance to logistics service providers how and where to deploy MPLs.

Policy for material efficiency in homes and cars: Enabling new climate change mitigation strategies

AbstractMaterial efficiency (ME), making products with less material or substituting with less carbon‐intensive material without a loss of functionality, can reduce greenhouse gas (GHG) emissions and complement other strategies to mitigate climate change. Seven ME strategies for cars and homes in the G7 countries were recently modeled in a study by the International Resource Panel. Modeling indicates that ME strategies focusing on construction and use of homes could lower the overall cumulative emissions in the G7 between 2016 and 2060 by 8.5 Gt CO2e (20%), while ME strategies for the production and use of cars could reduce up to 12 Gt (24%). For both homes and cars, the strategy of more intensive use—where fewer or smaller products are required to provide the same basic service—showed the greatest potential. A review of existing ME policies reveals that attention to ME in climate policy has been limited. Policy toward ME has historically focused on waste management rather than GHG reduction. Ex post evaluation of policies that do exist, especially for recycling and related waste strategies, is infrequent. Framing efficient use of materials as a measure primarily intended for climate mitigation is relatively recent and uncommon. Production‐related policy opportunities have been neglected because using ME to reduce GHGs is novel in some sectors and because increased ME faces economic and social barriers. Rebound effects where reduction of the cost of housing or transportation can increase material consumption offsetting potential gains, a problem for all efficiency‐based approaches, is understudied and not currently addressed through policy.This article is categorized under: The Carbon Economy and Climate Mitigation &gt; Policies, Instruments, Lifestyles, Behavior The Carbon Economy and Climate Mitigation &gt; Decarbonizing Energy and/or Reducing Demand

Greenhouse Gas Emissions Inventory from Roadway Construction: Case Study for the Washington State Department of Transportation

Recent emphasis on actions to reduce greenhouse gas (GHG) emissions has pushed many state departments of transportation (DOTs) to develop carbon accounting practices compatible with their current standard data collection and storage guidelines. Once accurate and reliable accounting of GHG emissions is established, strategies can be formed that could help mitigate the adverse environmental impacts of materials used by state DOTs. To date, the Washington State Department of Transportation (WSDOT) has not conducted comprehensive research on the embodied carbon within its construction material usage (i.e., upstream Scope 3 emissions inventory of procured materials) with most previous carbon accounting practices being focused on Scope 1 and Scope 2 emissions (i.e., the carbon footprint of direct and indirect energy usage). This paper summarizes the results of a life cycle assessment on the agency-wide material procurements and construction operations that emit GHGs at WSDOT as a case study. This study uses several data sources from WSDOT in conjunction with publicly available life cycle emissions factor data to estimate GHG emissions attributed to the materials used to build and maintain roadways under WSDOT’s jurisdiction. Results indicate that upstream Scope 3 emissions for WSDOT as an agency is a significant contributor to its overall GHG emissions inventory. Specifically, between 2017 and 2022, this paper estimates an average annual upstream Scope 3 emissions of 310,000 metric tons of CO2 equivalents, which translates to 56% of the total annual GHG emissions including Scope 1 and 2 emissions.

Optimized flare gas recovery technology with consideration of life cycle assessment, reliability analyses, and uncertainity of parameters

One of the most important sources of carbon dioxide emissions is gas flaring from oil wells. In addition to having an adverse effect on the environment, burning gases with a high energy value causes significant economic losses. The present work evaluated the best allocation for flare gas recovery technologies between eleven technologies considering life cycle assessment, reliability, and uncertainty analysis of some economic parameters in Iran's oil field. By choosing three objective functions, i.e., the carbon dioxide emission reduction, return payback period, and global warming by life cycle assessment analysis, the best combination of system was selected from eleven technologies using the genetic (NSGAII) algorithm and decision-making technique (TOPSIS) simultaneously. It was shown that the technology's reliability affects the best solution. Correspondingly, the integration of an enhanced oil recovery plant and a natural gas liquid at the capital investment of 120 M$ and a benefit of 263 M$ annually, with a repayment period of nine months, CO2 reduction of 1314,579 tons per year, and global warming effect of 699,820 tone CO2 equivalent was introduced as the best technology.

Think global act local: The dependency of global lithium-ion battery emissions on production location and material sources

The pursuit of low-carbon transport has significantly increased demand for lithium-ion batteries. However, the rapid increase in battery manufacturing, without adequate consideration of the carbon emissions associated with their production and material demands, poses the threat of shifting the bulk of emissions upstream. In this article, a life cycle assessment (LCA) model is developed to account for the cradle-to-gate carbon footprint of lithium-ion batteries across 26 Chinese provinces, 20 North American locations and 19 countries in Europe and Asia. Analysis of published LCA data reveals significant uncertainty associated with the carbon emissions of key battery materials; their overall contribution to the carbon footprint of a LIB varies by a factor of ca. 4 depending on production route and source. The links between production location and the gate-to-gate carbon footprint of battery manufacturing are explored, with predicted median values ranging between 0.1 and 69.5 kg CO2-eq kWh−1. Leading western-world battery manufacturing locations in the US and Europe, such as Kentucky and Poland are found to have comparable carbon emissions to Chinese rivals, even exceeding the carbon emissions of battery manufacturing in several Chinese provinces. Such resolution on material and energy contributions to the carbon footprint of LIBs is essential to inform policy- and decision-making to minimise the carbon emissions of the battery value chain. Given the current status quo, the global carbon footprint of the lithium-ion battery industry is projected to reach up to 1.0 Gt CO2-eq per year within the next decade. With material supply chain decarbonisation and energy savings in battery manufacturing, a lower estimate of 0.5 Gt CO2-eq per year is possible.

Soil Carbon: Pool, Loss, Emission and Climate Change Sources and Knowledge Level of Some Land Use Systems in Sudan Savanna, Kwara State

This research work was carried out in Sudan savanna of Kwara State to determine the effects of land use types on soil carbon pool, loss, emission and to determine the farmer’s knowledge level and sources of information on climate change. Six villages were selected randomly and in each Local Government Area, three villages were visited and three farms planted each with maize/cassava intercrop, cashew plantation and natural forest were sampled. Soil samples were collected from the farmland randomly at the depth of 0–20cm and analysed for physical and chemical properties in the laboratory. Carbon pool index was higher under cashew plantation. The mass of carbon lost recorded was higher under maize/cassava intercrop and cashew plantation recorded the lowest mass of carbon lost. Equivalent Carbon dioxide emitted recorded was lower under cashew plantation and maize/cassava intercrop recorded higher equivalent of carbon dioxide emitted. Natural forest had the highest organic carbon. Simple random sampling of 126 respondents were interviewed. Results revealed majority (71.4%) are willing to invest in residue retention and 92.9% are willing to engage in climate change mitigation practices free of charge. Maize/cassava intercrop recorded the lowest carbon pool due to burning of plant residues and the use of tillage practices. The highest carbon pool index recorded under cashew plantation was due to leaves litter decomposition. Carbon emitted was generally higher under maize/cassava intercrop as a result of continuous and vigorous cultivation leading to loss of carbon. Some farmers are not fully aware of climate change mitigation practices, therefore, more observation should be given to afforestation scheme to mitigate climate change and government and nongovernmental organization (NGOs) should educate and encourage farmers to practice crop residue retention and also minimize bush burning.

Greenhouse gas production from an intermittently dosed cold-climate wastewater treatment wetland

This study explores the greenhouse gas (GHG) fluxes of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) from a two-stage, cold-climate vertical-flow treatment wetland (TW) treating ski area wastewater at 3 °C average water temperature. The system is designed like a modified Ludzack-Ettinger process with the first stage a partially saturated, denitrifying TW followed by an unsaturated nitrifying TW and recycle of nitrified effluent. An intermittent wastewater dosing scheme was established for both stages, with alternating carbon-rich wastewater and nitrate-rich recycle to the first stage. The system has demonstrated effective chemical oxygen demand (COD) and total inorganic nitrogen (TIN) removal in high-strength wastewater over seven years of winter operation. Following two closed-loop, intensive GHG winter sampling campaigns at the TW, the magnitude of N2O flux was 2.2 times higher for denitrification than nitrification. CH4 and N2O emissions were strongly correlated with hydraulic loading, whereas CO2 was correlated with surface temperature. GHG fluxes from each stage were related to both microbial activity and off-gassing of dissolved species during wastewater dosing, thus the time of sampling relative to dosing strongly influenced observed fluxes. These results suggest that estimates of GHG fluxes from TWs may be biased if mass transfer and mechanisms of wastewater application are not considered. Emission factors for N2O and CH4 were 0.27 % as kg-N2O-N/kg-TINremoved and 0.04 % kg-CH4-C/kg-CODremoved, respectively. The system had observed seasonal emissions of 600.5 kg CO2 equivalent of GHGs estimated over 130-days of operation. These results indicate a need for wastewater treatment processes to mitigate GHGs.

Greenhouse gas emissions benefits of the lightweight vehicle fleet in China: A dynamic fleet perspective

Lightweighting is believed to be a silver bullet to reduce greenhouse gas (GHG) emissions related to the road transportation. However, the fleet-scale and long-term GHG emissions estimation on the light-duty passenger vehicle (LDPV) fleet in China is still underexplored. A dynamic fleet-based life cycle assessment (LCA) model is developed to predict the annual GHG emissions attributable to the lightweight LDPV fleet in China at provincial level. With the most aggressive implementation of lightweighting, the cumulative mitigation potential of lightweight LDPV fleet from 2021 to 2050 is 0.72 Gt CO2 eq and 0.55 Gt CO2 eq using high-strength steel (AHSS) and aluminium (Al), respectively. Sooner implementation brings a higher cumulative reduction in GHG emissions. Delaying the implementation by five years would sacrifice 0.16 Gt CO2 eq ∼0.2 Gt CO2 eq cumulative reduction, and the loss would increase to 0.31 Gt CO2 eq ∼0.41 Gt CO2 eq when postpone the lightweighting by ten years.

Experimental Global Warming Potential-Weighted Specific Stiffness Comparison among Different Natural and Synthetic Fibers in a Composite Component Manufactured by Tailored Fiber Placement.

This work aims to evaluate experimentally different fibers and resins in a topologically optimized composite component. The selected ones are made of carbon, glass, basalt, flax, hemp, and jute fibers. Tailored Fiber Placement (TFP) was used to manufacture the textile preforms, which were infused with two different epoxy resins: a partly biogenic and a fully petro-based one. The main objective is to evaluate and compare the absolute and specific mechanical performance of synthetic and natural fibers within a component framework as a base for improving assessments of sustainable endless-fiber reinforced composite material. Furthermore, manufacturing aspects regarding the different fibers are also considered in this work. In assessing the efficiency of the fiber-matrix systems, both the specific stiffness and the specific stiffness relative to carbon dioxide equivalents (CO2eq.) as measures for the global warming potential (GWP) are taken into account for comparison. The primary findings indicate that basalt and flax fibers outperform carbon fibers notably in terms of specific stiffness weighted by CO2eq.. Additionally, the selection of epoxy resin significantly influences the assessment of sustainable fiber-plastic composites.

Stock change accounting overestimates the potential climate benefit of soil carbon storage

AbstractAgriculture is being called upon to increase carbon (C) storage in soils to reduce greenhouse gas (GHG) accumulation in the atmosphere. Cropping systems research can be used to support GHG mitigation efforts, but we must quantify land management impacts using appropriate assumptions and unambiguous methods. Soil C sequestration is considered temporary because it can be re‐emitted as carbon dioxide (CO2) if the effecting practice is not maintained and/or the soil–plant system is disturbed, for example, as the result of changing climate. Because of this, the climate benefit of soil C sequestration depends on the time that C is held out of the atmosphere. When assessing the net GHG impact of management practices, soil C storage is often aggregated with non‐CO2 (N2O and CH4) emissions after converting all components to CO2 equivalents (CO2e) and assuming a given time horizon (TH), in what is known as stock change accounting. However, such analyses do not consider potential re‐emission of soil C or apply consistent assumptions about time horizons. Here, we demonstrate that tonne‐year accounting provides a more conservative estimate of the emissions offsetting potential of soil C storage compared to stock change accounting. Tonne‐year accounting can be used to reconcile differences in the context and timeframes of soil C sequestration and non‐CO2 GHG emissions. The approach can be applied post hoc to commonly observed cropping systems data to estimate GHG emissions offsets associated with agricultural land management over given THs and with more clearly defined assumptions.

Biomass and Carbon Stock of Trees in a Tropical Moist Deciduous Forest of Kamrup Metropolitan District, Assam, India

The present investigation deals with the estimation of biomass and Carbon stock potential of tree species in a tropical moist deciduous forest of Kamrup Metropolitan district of Assam, India. For vegetation sampling of trees, the stratified random method was employed and biomass and Carbon stock of trees were estimated by using an allometric equation. Altogether 39 tree species representing 34 genera and 20 families were reported. A high total density and total basal cover (TBC) were reported during the investigation (1008 stem ha⁻¹ and 71.74 m² ha⁻¹ respectively). Total biomass (TB), total Carbon stock (TCS), and CO₂ equivalent were estimated to be 985.56 Mg ha⁻¹, 492.78 Mg C ha⁻¹, and 1808.50 Mg C ha⁻¹ respectively. Among the trees, Cassia fistula exhibited the highest amount of TB, TCS, and CO₂ equivalent (131.33 Mg ha⁻¹, 65.66 Mg C ha⁻¹, and 240.99 Mg C ha⁻¹ respectively). TCS displayed a positive correlation with density, TBC, and diameter of tree species. The study provides valuable information on biomass and Carbon sequestration potential of trees in the tropical moist deciduous forest, which could be of help to forest policymakers to ensure sustainable management of Carbon stock and hence promotes mitigation of global climate change.

The carbon footprint of future engineered wood construction in Montreal

Engineered wood (EW) has the potential to reduce global carbon emissions from the building sector by substituting carbon-intensive concrete and steel for carbon-sequestering wood. However, studies accounting for material use and embodied carbon in buildings rarely analyse the city-scale or capture connections between the city and supplying hinterlands. This limits our knowledge of the effectiveness of decarbonising cities using EW and its potential adverse effects, such as deforestation. We address this gap by combining bottom-up material accounting of construction materials with life cycle assessment to analyse the carbon emissions and land occupation from future residential construction in Montreal, Canada. We compare material demand and environmental impacts of recent construction using concrete and steel to future construction using EW at the neighbourhood, urban scales under high- and low-density growth scenarios. We estimate that baseline embodied carbon per capita across the Agglomeration of Montreal is 3.2 tonnes per carbon dioxide equivalents (CO2eq.), but this ranges from 8.2 tonnes CO2eq. per capita in areas with large single-family housing to 2.0 tonnes CO2eq. per capita where smaller homes predominate. A Montreal-wide transition to EW may increase carbon footprint by up to 25% under certain scenarios, but this varies widely across the city and is tempered through urban densification. Likewise, a transition to EW results in less than 0.1% land transformation across Quebec’s timbershed. Moreover, sustainable logging practices that sequester carbon can actually produce a carbon-negative building stock in the future if carbon in the wood is not re-emitted when buildings are demolished or repurposed. To decarbonise future residential construction, Montreal should enact policies to simultaneously promote EW and denser settlement patterns in future construction and work with construction firms to ensure they source timber sustainably.

Energy audit and associated carbon footprint estimation for a Meta Abo brewery

Industrial development in Ethiopia is rapidly increasing, leading to a growing gap between energy supply and demand. To address this, efficient energy utilization in existing industries is crucial. Energy audits identify energy losses and recommend saving measures. Therefore, this study evaluates energy efficiency through an audit and estimates greenhouse gas emissions for a Meta Abo brewery. The indirect method of energy audit and the greenhouse gas protocol of carbon footprint estimation were used to evaluate the energy efficiency and carbon emissions of Meta Abo brewery. The boiler efficiency for Bono Energia and Cochran boilers was found to be 79.2% and 80.9%, respectively. Poor insulation caused an estimated annual fuel loss of 35,350 l (638,768 Ethiopian birr) for steam pipes, while steam leakage resulted in a loss of 31,614 l (571,265 Ethiopian birr). The factory's high electricity expense was attributed to a diesel generator consuming 6000 l/d. Greenhouse gas emissions raised from 9156 to 22,697 tons of CO2 equivalent between 2014 and 2018. Implementing the proposed energy-saving measures could save 20.4 TJ of thermal and electrical energy annually, costing approximately 8.5 million Ethiopian birr, and reduce boiler emissions by 455 tons of CO2 equivalent. Therefore, implementation of these measures is recommended.