Total Annual Greenhouse Gas Emissions Research Articles

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.

Persistent use of nitrous oxide for anaesthesia in European hospitals despite its harmfulness to the climate – how emission taxation can achieve the coupling of cost-effectiveness and climate protection: observational study

BackgroundHealth care has the intrinsic obligation to preserve health. This concept is also applicable to planetary health. Nitrous oxide (N2O) lacks clinical indications in modern anaesthesia, while it is a high-potential greenhouse gas. Its seemingly low cost contrasts with the consequential externalised socio-economic costs due to its contribution to the climate crisis, which is approximately €698 per emitted ton of CO2 equivalent. This difference can be internalised through emission taxation. In this study, we aim to evaluate how much N2O – total amount and converted to CO2 equivalent – is used at a German university hospital and compare this amount to that used at European hospitals. Furthermore, how the cost of N2O usage changes under different emission taxation scenarios is calculated.MethodsThis trial was a retrospective observational study at a German university hospital with approximately 1,250 beds between 2016 and 2020. Additionally, five European hospitals from the Health Care Without Harm Network were used for comparison from a European perspective. The main outcome parameters were the amount of N2O used, in total and converted to CO2 equivalent, and the total cost at emission taxation of €0, €25, €55 and €698 per ton CO2 equivalent.ResultsAt the peak, 2,104 tCO2 equivalent in N2O was emitted in 2019. The actual cost was €14,040 in this year, while the corresponding socio-economic damage due to the climate crisis was almost €1.5 million. Other European hospitals showed comparable amounts of emissions.ConclusionsThe annual peak amount of emitted N2O corresponded to the total annual greenhouse gas emission of 188 people in Germany. To achieve a drastic reduction in use, the abandonment of recommendations by anaesthesiologic societies appears necessary, in addition to an internalisation of future costs via emission taxation, which will cause inadequate cost for a medication without relevant benefit or indication. To that end, the inclusion of health sector emissions within national or international greenhouse gas taxation, for example, the European Union Emissions Trading System, appears necessary and expedient in view of the urgent need to address the ecological transformation.Trial registrationThe trial was registered with the German Clinical Trials Register, identifier DRKS00024973 on 12/04/2021.

A comprehensive continental-scale analysis of carbon footprint of food production: Comparing continents around the world

Food production is an important source of anthropogenic greenhouse gas (GHG) emissions. Quantifying the carbon footprint of all the major food categories in different continents is critical for accurately evaluating various aspects of GHG emissions from food production on a continental and global scale. Such information, however, is lacking. Thus, we conducted a meta-analysis of plant-based and animal-based food production in all continents comprehensively using 5353 carbon footprint values from 524 published papers and calculated GHG emissions from food production (system boundary is from cradle to farm gate) at the continental and global scale. Our results indicate that the average carbon footprint of plant-based foods amounts to 0.66 kg CO2-eq kg−1, which is only 10.7% of animal-based foods (6.15 kg CO2-eq kg−1). The carbon footprint of plant-based food in Asia and Europe is 8.9%–184% higher than that of other continents. Africa has the lowest carbon footprint for plant-based foods, owing to its low agricultural input and limited crop management. However, the carbon footprint of animal-based foods in Africa and Asia is 2.5%–150% higher than that of other continents, with North America and Oceania recording the lowest. Total annual GHG emission from global food production reached 8125 Mt CO2-eq, with grains, meat, and milk together accounting for 70.8%. Asia, owing to its large production, emerged as the largest emitter, accounting for 55.4% of global GHG emissions. It was followed by Europe (16.3%) and North America (10.5%), while Africa, South America and Oceania together emit 17.8%. In summary, our study presents the most comprehensive account of the carbon footprint of food production at the continental and global scale to-date, which will help develop strategies and policies to reduce GHG emissions at various levels such as geographical regions, food and nutrition security, resource availability and resource use.

Private Vehicles Greenhouse Gas Emission Estimation at Street Level for Berlin Based on Open Data

As one of the major greenhouse gas (GHG) emitters that has not seen significant emission reductions in the previous decades, the transportation sector requires special attention from policymakers. Policy decisions, thereby need to be supported by traffic emission assessments. Estimations of traffic emissions often rely on huge amounts of actual traffic data whose availability is limited, hampering the transferability of the estimation approaches in time and space. Here, we propose a high-resolution estimation of traffic emissions, which is based entirely on open data, such as the road network and points of interest derived from OpenStreetMap (OSM). We estimated the annual average daily GHG emissions from individual motor traffic for the OSM road network in Berlin by combining the estimated Annual Average Daily Traffic Volume (AADTV) with respective emission factors. The AADTV was calculated by simulating car trips with the open routing engine Openrouteservice, weighted by activity functions based on statistics of the German Mobility Panel. Our estimated total annual GHG emissions were 7.3 million t CO2 equivalent. The highest emissions were estimated for the motorways and major roads connecting the city center with the outskirts. The application of the approach to Berlin showed that the method could reflect the traffic pattern. As the input data is freely available, the approach can be applied to other study areas within Germany with little additional effort.

Implementation of the energy efficiency existing ship index and carbon intensity indicator on domestic ship for marine environmental protection

The International Maritime Organization has set a goal to achieve a 50% reduction of total annual greenhouse gas emission related to the international shipping by 2050 compared to the 2008 baseline emissions. Malaysia government has taken an initiative to investigate the assessment (cost-effectiveness) of this International Maritime Organization's short-term measure on Malaysian-registered domestic ships although this measure is only for international merchant ship. To achieve this, this paper collected the ship's data from the shipowners from 25 sample ships. Engine power limitation is the most cost-effective option, but low power limits can lead to substantially increased sailing times. Based on cost-efficiency analysis, it creates for the purpose of compliance with the operational carbon intensity indicator. It found that even if it is possible to bring an asset back into service, it may not be possible to do so in a manner that generates a profit or complies with applicable regulations. In these situations, it may be more prudent to scrap the asset rather than run the risk of having it become a stranded asset. This is especially true for older tankers. Alternatives with lengthy payback periods are not desirable for the domestic tanker fleet that is already in operation.

Fuel use in small-scale fishing vessels along the southeast coast of India: a comparative study to ascertain possible reasons and potential recommendations for effective management

Regulating the fuel consumption of small-scale fishing vessels could help to keep global warming well below 1.5°C and lead to effective management in small-scale fisheries (SSF) of developing countries like India. In this regard, a bottom-up approach was carried out to collect the requisite data to explore the fuel consumption of small-scale fishing vessels along India's southeast coast. Consequently, twenty-four fishing vessels (type A to type X) were grouped into seven categories based on fishing methods. The estimated numerical value of fuel use intensity (FUI) ranging from 0.08 to 0.80 was used to examine the fuel-efficient fishing vessel and engine type. In addition, the estimated revenue on fuel ranging from ₹5625.06/l to ₹218.07/l and annual greenhouse gas (GHG) emissions using the Tier 1 method were used to understand the economic efficiency and GHG emission trend, respectively. The total annual GHG emissions from all the fishing vessels at the selected sites were about 1.25E + 08 t CO2-eq year-1. The result shows that longline-cum-gillnetters, seine-netters, longliners and drift-gillnetters largely contributed to 65% of the annual GHG emissions. By recognizing the factors influencing the fuel consumption of fishing vessels in SSF, this sector could be understood, effectively managed, and performed well. Therefore, the possible reasons were extensively discussed through a comparative approach, and potential recommendations for effective management were made.

Initial effects of post-harvest ditch cleaning on greenhouse gas fluxes in a hemiboreal peatland forest

Ditch cleaning (DC) is a well-established forestry practice across Fennoscandia to lower water table levels (WTL) and thereby facilitate the establishment of tree seedlings following clear-cutting. However, the implications from these activities for ecosystem-atmosphere greenhouse gas (GHG) exchanges are poorly understood at present. We assessed the initial DC effects on the GHG fluxes in a forest clear-cut on a drained fertile peatland in hemiboreal Sweden, by comparing chamber measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes from soil and ditches in DC and uncleaned (UC) areas over the first two post-harvest years. We also evaluated spatial effects by comparing fluxes at 4 m and 40 m from ditches. We found that 2 years after DC, mean (±standard error) WTL of −65 ± 2 cm was significantly lower in the DC area compared to −56 ± 2 cm in the UC area. We further observed lower gross primary production and ecosystem respiration in the first year after DC which coincided with delayed development of herbaceous ground vegetation. We also found higher CH4 uptake but no difference in N2O fluxes after DC. Greater CH4 uptake occurred at 4 m compared to 40 m away from both cleaned and uncleaned ditches. Model extrapolation suggests that total annual GHG emissions in the second year were reduced from 49.4 ± 17.0 t-CO2-eq-ha−1-year−1 in the UC area to 27.8 ± 10.3 t-CO2-eq-ha−1-year−1 in the DC area. A flux partitioning approach suggested that this was likely caused by decreased heterotrophic respiration, possibly because of enhanced soil dryness following DC during the dry meteorological conditions. CH4 and N2O fluxes from clear-cut areas contributed <2 % to the total (soil, ditches) GHG budget. Similarly the area-weighted contributions by CO2 and CH4 emissions from both cleaned and uncleaned ditches were <2 %. Thus, our study highlights that DC may considerably alter the post-harvest GHG fluxes of drained peatland forests. However, long-term observations under various site conditions and forest rotation stages are warranted to better understand DC effects on the forest GHG balance.

Environmental and socio-economic benefits of circularity in real estate management

The environmental potential of reusing interior and building products (notably furniture, lighting, doors, windows, flooring and ceilings) has been calculated by a rather basic model based on life cycle approach. By making a calculation model available to housing and renovation companies in Sweden, a total of over 43000 items have been included in calculations as objects for reuse, stemming from about 130 renovation projects with a total waste saving of 800 tonnes of waste in the renovation stage. The first calculations of the corresponding avoided climate impact, from avoided waste management and avoided new product extraction and manufacturing, corresponds to around 1600 tonnes of CO2-equivalents. Translating this and other environmental aspects to monetary values with the EPS system, socio-economic savings is around 2.3 million Euro. Assuming the same composition of items for potential reuse from all renovation activities in Sweden and extrapolating to the total annual amount of building waste, the potential annual savings on the national scale is estimated to be 900000 tons of building waste and 1.3 million tons of CO2 equivalents, corresponding to around 7% of the total annual greenhouse gas emissions of the Swedish building sector. With the EPS evaluation, the total annual environmental benefit adds up to 600 million Euro. The calculation model is currently being refined to include a better coverage of logistics and refurbishment activities.

A research agenda for circular food waste management in Bavaria

It is no exaggeration to say that food waste along the supply chain is becoming a significant problem for humanity. Food waste is expensive and damaging to the environment and climate e.g. Accorsi and Manzini (2019), Dani (2019), Dora et al. (2020). In Germany alone, food waste generates about 4 percent of the country's total annual greenhouse gas emissions (BMEL, 2022). Entrepreneurs are often perceived as the world's problem solvers. By offering innovative new products and services they are providing pathways to overcome some of the pressing global issues, including climate change. And more specifically innovative entrepreneurs, startups as well as established companies are actively seeking to tackle the problem of food waste using innovative business models and linking agile supply chains and production systems to these business models (Dora et al., 2020, Rogers and Srivastava, 2021). In Germany, for example, companies such as “Rettergut”, Knödelkult”, “Etepete” or “TooGoodToGo”, approach the problem of food waste with completely different business models. This ranges from saving “ugly” fruit and vegetables, to redistributing production surplus, as well as up-cycling food and creating (digital) platforms, to ensure surplus meets demand (Deutsche Umwelthilfe, 2021, Janssen, 2018).Other innovative business models (Baierl and Behrens, 2019), whereby imperfect produce, by-products of agriculture, waste and overproduction are efficiently used are part of this exploratory research. The authors create an overview of the status quo of the markets using the example of Germany's B2B food supply chain, covering market players, their transport-, sourcing and production strategies and business model applications. Many questions still need to be addressed, including the following: Can innovative business models from different industries be applied to food? Is the platform business model suitable for the reduction of food waste? Is it necessary for retailers - as the final (downstream) tier in the supply chain before the customer - to become more flexible regarding a varying supply of products? How can the sharing economy and regional or local sourcing add to a sustainable food supply chain/network? These and other pertinent questions will the addressed in this exploratory research, for which the answers will be sought by conducting interviews with key stakeholders within our network and examining use cases.

The cost-effectiveness of CO2 mitigation measures for the decarbonisation of shipping. The case study of a globally operating ship-management company

The International Maritime Organisation has set a goal to achieve a 50% reduction of the total annual greenhouse gas emissions related to the international shipping by 2050 compared to the 2008 baseline emissions. Thus, companies are looking for solutions and measures to align with the Organisation's goal. Marginal Abatement Cost Curves have been extensively used in the literature to rank several Greenhouse Gas mitigation measures based on their costs of reducing an additional unit of pollution. In this paper an expert-based, bottom-up approach was employed to construct Marginal Abatement Cost Curves for a globally operating ship-management company. Several mitigation measures were examined for the following vessel categories (a) Containerships 8000+ TEU, (b) Containerships 2000–2999 TEU, (c) Bulkers 35000–59999 DWT, and (d) Gas Tankers <49999 CBM. Furthermore, the fuel price fluctuation and carbon taxation were used to investigate the sensitivity of baseline Marginal Abatement Cost Curves. The measures, which remain cost-effective under all sensitivity analyses, undergo a Pareto Analysis and a Marginal Cost-Effectiveness Analysis. The results suggest that most of the recommended mitigation measures are of an operational and technical nature, with exception the burning of Liquified Natural Gas and the installation of Flettner Rotors for the Gas Tankers. The company could save up to 17% CO2 emissions and approximately 2 million dollars per year compared to the 2019 baseline by employing all recommended mitigation measures to all vessel categories. In addition, Carbon Storage and Capture could become a cost-effective solution with appropriate carbon taxation, but it is not the ultimate solution since it does not lead to independence from fossil fuels. The study also reveals that depending on the operating condition, even within the same vessel category, different mitigation measures should be employed.

Sustainability initiative for a Malaysian university campus: living laboratories and the reduction of greenhouse gas emissions

Urban university campuses may be a substantial producer of greenhouse gas (GHG) emissions into the environment, through either campus operations or research activities. To date, there is little research on GHG emission reduction in higher education institutions—particularly in developing countries—so this work presents such an initiative from an urban university located in Kuala Lumpur, Malaysia. Higher education institutions in Malaysia are progressively integrating similar strategies to apply the United Nations’ Sustainable Development Goals (SDG) to education-translational research activities. The paper presents the GHG emission reduction data from campus activities and a living laboratory project conducted within Universiti Malaya (UM) main campus. Emissions reduction was categorised based on the standard GHG Protocol from the Kyoto Protocol into Scope 1, 2 and 3. GHG Scope 1 contributes the most activities and yielded the main GHG emission reductions in electricity consumption (in kg CO2-eq/kWh) with a 90.72% decline for the year 2016–2017. The highest reduction for total annual GHG emissions was found for the year 2017–2018, with a reduction of 6,590,000 kg CO2-eq/year. Most of the living laboratory research activities in that year were categorised in the change management core area. These activities benefitted from continuous funding and were more successful when the research was in mature phase, regardless of research constraints and difficulties.

A study on the necessity of integrated evaluation of alternative marine fuels

ABSTRACT On 13 April 2018, the International Maritime Organization (IMO) published an initial strategy on reduction of greenhouse gas (GHG) emissions from ships. The ambitious vision of this strategy is to reduce the total annual GHG emissions from international shipping by at least 50% by 2050 compared to 2008. One of the solutions to achieve this vision is to operate vessels on alternative marine fuels that generate less or no GHG emissions, like liquefied natural gas (LNG), hydrogen, ammonia, methanol, ethanol, biofuel, synthetic fuel, electricity (produced by battery), and so on. The challenge is that each alternative fuel has its own characteristic on various aspects. For instance, some alternative fuels may generate no GHG emission but can have higher risk than conventional marine fuel. Other alternative fuels may generate no GHG emission with relatively low risk, but the capital and/or operational expenditure can be significantly higher than other fuels. The main objective of this paper is to explore the properties of selected alternative marine fuels and to emphasize the necessity of integrated evaluation of them. It is concluded that the alternative marine fuels need to be comprehensively evaluated with respect to environmental impact, risk to human, and business value.

The Role of Slower Vessel Speeds in Reducing Greenhouse Gas Emissions, Underwater Noise and Collision Risk to Whales

Reducing speeds across shipping fleets has been shown to make a substantial contribution to effective short term measures for reducing greenhouse gas (GHG) emissions, working towards the goal adopted by IMO in April 2018 to reduce the total annual GHG emission by at least 50% by 2050 compared to 2008. I review modelling work on GHG emissions and also on the relationships between underwater noise, whale collision risk and speed. I examine different speed reduction scenarios that would contribute to GHG reduction targets, and the other environmental benefits of reduced underwater noise and risk of collisions with marine life. A modest 10% speed reduction across the global fleet has been estimated to reduce overall GHG emissions by around 13% (Faber et al. 2017) and improve the probability of meeting GHG targets by 23% (Comer et al. 2018). I conclude that such a 10% could reduce the total sound energy from shipping by around 40%. The associated reduction in overall ship strike risk has higher uncertainty but could be around 50%. This would benefit whale populations globally and complement current efforts to reduce collision risk in identified high risk areas through small changes in routing.

Soil C Storage Potential of Exogenous Organic Matter at Regional Level (Italy) Under Climate Change Simulated by RothC Model Modified for Amended Soils

Soil amendment with exogenous organic matter (EOM) represents an effective option for sustainable management of organic residues and enhancement of soil organic C (SOC) content. Optimization of soil amendment is hampered by the high variability in EOM quality and pedoclimatic conditions. A possible solution to this problem could be represented by spatially explicit soil C modelling. The aim of this study was the evaluation at regional level of the long term C storage potential of EOM added to the soil under climate change by using a modified version of the RothC specifically developed for C simulation in amended soil. To achieve this goal a spatially explicit version of the modified RothC model was deployed to assess at a national scale the potential for C storage of agricultural soils amended with different EOMs. Long term model simulations of continuous amendment (100 years) indicated that EOMs greatly differ for their soil C sequestration potential (range 0.110 - 0.385 t C ha-1 y-1), mainly depending to their degree of stabilization. Spatial explicit modelling of amended soil, taking into account the different combinations of EOMs and application sites, indicated a high variability in the potential of SOC accumulation at the national level (range: 0.06 - 0.62 t C ha-1 y-1). EOM quality showed a larger impact on long term SOC accumulation than variability in pedoclimatic conditions. Model simulations predicted that the contribution of soil amendment in tackling greenhouse gas (GHG) emissions is limited: soil C sequestration potential of compost applied to all Italian agricultural land corresponded to 5.3% of the total annual GHG emissions in Italy. Large scale modelling enables areas with the largest potential for EOM accumulation to be identified, therefore suggesting ways for optimizing resources. Result suggests that reliable C modelling in amended soil requires modification and optimization of actual models to accommodate the different quality of EOMs applied to the soil. The spatially explicit version of the modified RothC model improves the predictive power of SOC modelling at regional scale in amended soils, because it takes into account, besides variability in pedoclimatic conditions, the large differences in EOMs quality.

Evaluation of greenhouse gas emissions from waste management approaches in the islands.

Concerns about waste generation and climate change have attracted worldwide attention. Small islands, which account for more than one-sixth of the global land area, are facing problems caused by global climate change. This study evaluated the greenhouse gas emissions from five small islands surrounding Taiwan. These islands - Penghu County, Liuqui Island, Kinmen County, Matsu Island and Green Island - have their own waste management approaches that can serve as a guideline for waste management with greenhouse gas mitigation. The findings indicate that the total annual greenhouse gas emissions of the islands ranged from 292.1 to 29,096.2 [metric] tonne CO2-equivalent. The loading waste volumes and shipping distances were positively related to greenhouse gas emissions from transportation. The greenhouse gas emissions from waste-to-energy plants, mainly carbon dioxide and nitrous oxide, can be offset by energy recovery (approximately 38.6% of greenhouse gas emissions from incineration). In addition, about 34% and 11% of waste generated on the islands was successfully recycled and composted, respectively. This study provides valuable insights into the applicability of a policy framework for waste management approaches for greenhouse gas mitigation.

Valuing Ecosystem Services and Disservices across Heterogeneous Green Spaces

This study investigates small-scale variability in ecosystem services and disservices that is important for sustainable planning in urban areas (including suburbs surrounding the urban core). We quantified and valued natural capital (tree and soil carbon stocks) ecosystem services (annual tree carbon sequestration and pollutant uptake, and stormwater runoff reduction) and disservices (greenhouse gas emissions and soil soluble reactive phosphorus) within a 30-hectare heterogeneous green space that included approximately 13% wetland, 13% prairie, 16% forest, and 55% subdivision. We found similar soil organic carbon across green space types, but spatial heterogeneity in other ecosystem services and disservices. The value of forest tree carbon stock was estimated at approximately $10,000 per hectare. Tree carbon sequestration, and pollutant uptake added benefits of $1000+ per hectare per year. Annual per hectare benefits from tree carbon stock and ecosystem services in the subdivision were each 63% of forest values. Total annual greenhouse gas emissions had significant spatial and temporal variation. Soil soluble reactive phosphorus was significantly higher in the wetland than in forest and prairie. Our results have implications for urban planning. Adding or improving ecosystem service provision on small (private or public) urban or suburban lots may benefit from careful consideration of small-scale variability.

Influence of climate variability and stocking strategies on greenhouse gas emissions (GHGE), production and profit of a northern Queensland beef cattle herd

Previous studies of greenhouse gas emissions (GHGE) from beef production systems in northern Australia have been based on models of ‘steady-state’ herd structures that do not take into account the considerable inter-annual variation in liveweight gain, reproduction and mortality rates that occurs due to seasonal conditions. Nor do they consider the implications of flexible stocking strategies designed to adapt these production systems to the highly variable climate. The aim of the present study was to quantify the variation in total GHGE (t CO2e) and GHGE intensity (t CO2e/t liveweight sold) for the beef industry in northern Australia when variability in these factors was considered. A combined GRASP–Enterprise modelling platform was used to simulate a breeding–finishing beef cattle property in the Burdekin River region of northern Queensland, using historical climate data from 1982–2011. GHGE was calculated using the method of Australian National Greenhouse Gas Inventory. Five different stocking-rate strategies were simulated with fixed stocking strategies at moderate and high rates, and three flexible stocking strategies where the stocking rate was adjusted annually by up to 5%, 10% or 20%, according to pasture available at the end of the growing season. Variation in total annual GHGE was lowest in the ‘fixed moderate’ (~9.5 ha/adult equivalent (AE)) stocking strategy, ranging from 3799 to 4471 t CO2e, and highest in the ‘fixed high’ strategy (~5.9 ha/AE), which ranged from 3771 to 7636 t CO2e. The ‘fixed moderate’ strategy had the least variation in GHGE intensity (15.7–19.4 t CO2e/t liveweight sold), while the ‘flexible 20’ strategy (up to 20% annual change in AE) had the largest range (10.5–40.8 t CO2e/t liveweight sold). Across the five stocking strategies, the ‘fixed moderate’ stocking-rate strategy had the highest simulated perennial grass percentage and pasture growth, highest average rate of liveweight gain (121 kg/steer), highest average branding percentage (74%) and lowest average breeding-cow mortality rate (3.9%), resulting in the lowest average GHGE intensity (16.9 t CO2e/t liveweight sold). The ‘fixed high’ stocking rate strategy (~5.9 ha/AE) performed the poorest in each of these measures, while the three flexible stocking strategies were intermediate. The ‘fixed moderate’ stocking strategy also yielded the highest average gross margin per AE carried and per hectare. These results highlight the importance of considering the influence of climate variability on stocking-rate management strategies and herd performance when estimating GHGE. The results also support a body of previous work that has recommended the adoption of moderate stocking strategies to enhance the profitability and ecological stability of beef production systems in northern Australia.

Network Theory Integrated Life Cycle Assessment for an Electric Power System

In this study, we allocate Greenhouse gas (GHG) emissions of electricity transmission to the consumers. As an allocation basis, we introduce energy distance. Energy distance takes the transmission load on the electricity energy system into account in addition to the amount of electricity consumption. As a case study, we estimate regional GHG emissions of electricity transmission loss in Chile. Life cycle assessment (LCA) is used to estimate the total GHG emissions of the Chilean electric power system. The regional GHG emission of transmission loss is calculated from the total GHG emissions. We construct the network model of Chilean electric power grid as an undirected network with 466 nodes and 543 edges holding the topology of the power grid based on the statistical record. We analyze the total annual GHG emissions of the Chilean electricity energy system as 23.07 Mt CO2-eq. and 1.61 Mt CO2-eq. for the transmission loss, respectively. The total energy distance for the electricity transmission accounts for 12,842.10 TWh km based on network analysis. We argue that when the GHG emission of electricity transmission loss is estimated, the electricity transmission load should be separately considered. We propose network theory as a useful complement to LCA analysis for the complex allocation. Energy distance is especially useful on a very large-scale electric power grid such as an intercontinental transmission network.

Greenhouse gas emissions of an on-farm swine manure treatment plant – comparison with conventional storage in anaerobic tanks

This study aims to estimate greenhouse gas (GHG) emission reduction over a five-month period due to the implementation of a swine manure treatment plant, installed as an alternative to conventional manure storage in anaerobic tanks. The treatment plant, located in Segovia (Spain), was installed in a farrow-to-finish farm with approximately 300 sows, and was based on solid–liquid separation using screw pressing followed by coagulation-flocculation and nitrification-denitrification of the liquid fraction. Information collected during the study of the on-farm treatment plant together with the guidelines proposed by the Intergovernmental Panel on Climate Change (IPCC) was used to quantify GHG emissions for each scenario. Implementing the manure treatment plant led to a total annual GHG emission reduction of 62% (from 1204 t CO2-equiv to 456 t CO2-equiv). CO2 and CH4 emissions fell by 72% and 69%, respectively, whereas N2O emissions were similar in the two scenarios studied. It should be pointed out that only CO2 emissions from fossil fuel use were considered in the estimation. In addition, the contribution made by each of the treatment plant units to GHG emission was calculated. Carbon credit exchange might translate to a direct benefit of 0.21 € per m3 of treated manure. Reducing GHG emissions should thus be considered as a complementary factor in the development of cleaner systems for manure management, yielding both environmental as well as financial advantages.

Defining sustainable diets by comparing greenhouse gas emissions from different food groups: a systematic review

BackgroundMany physical and biological systems are changing because of anthropogenic global warming, but many effects of climate change can be avoided, reduced, or delayed by mitigation. The UK Climate Change Act 2008 sets a target to cut the total annual greenhouse gas emissions (GHGE) by 80% by 2050, with an interim target of a reduction of 34% by 2020, compared with 1990 levels. UK food production and consumption is responsible for up to 18–30% of the total GHGE. Therefore, defining sustainable healthy diets is important to cut down GHGE from food. We have adequate information on nutrients in food, but we do not have robust data on GHGEs of individual food groups. MethodsThis systematic review estimated GHGE values (mean and range) for all the food groups in a commonly used food frequency questionnaire (FFQ). Eight medical and geographical databases were searched from 1995 to 2012 to identify lifecycle assessment (LCA) studies of food. Full papers or reports of selected studies were obtained. If they estimated the GHGE (individual gases or the total global warming potential [GWP]) per functional unit (eg, kilogram or tonne of meat, litre of milk) of any food group by LCA they were included. If studies assessed only emissions per land area or per farm they were excluded. We selected studies that described these components and authors were contacted if these components were not explained in the full report. Studies were not excluded if authors did not respond or were not available in English language. GWP per kg of food, in kg of carbon dioxide equivalence over 100 years (KgCO2e), was recorded from each study with details about farming methods, location, and the boundaries of lifecycle. The initial search identified 14 096 hits. 126 were selected after screening titles and abstracts and a further 42 papers were added by searching organisational websites and databases. Quality assessors were masked. FindingsBeef (mean 28·00, range 8·10–156·00) and lamb (15·52, 0·67–56·70) had the highest GWP values per kg and bread (–0·56, 0·25–0·93), fruits (–0·53, 0·06–1·37), and potatoes (–0·21, 0·13–0·48) were among the lowest values. The mean GWP for 1 kg of fruit juice was 2·92 KgCO2e. Whether organically and locally produced foods always have less GWP than non-organic foods and imported foods, respectively, is unclear. The GHGE values for organic products such as pork, chicken, eggs, potatoes, and tomatoes were higher than those for these foods when non-organically produced. The boundary of the LCA considered by the authors contributed substantially to variance in the results. Variation in results is due to a wide range of production systems, locations, and different system boundaries used in LCA studies. Therefore, the final estimates are not directly comparable and ranges overlap between food groups. GHGE is not the only indicator to measure the sustainability of food. However, GHGE was used in this study because it is the most commonly used indicator and government targets are set to measure the reduction in GHGE. InterpretationOrganic foods and locally produced foods do not always produce fewer GHGEs. Little consistency in LCA methods makes direct comparisons of estimates difficult. Future LCA food studies should make efforts to follow a uniform approach, to include common definition of stages in the lifecycle and inclusion of similar activities always under each category of food. These GHGE estimates are for common food groups in a FFQ and could be combined with existing nutrition databases to address questions around sustainable healthy diets. These findings will be used to quantify the GHGE changes of different dietary scenarios in the UK to achieve GHGE reduction targets. FundingBritish Heart Foundation.