Life Cycle Inventories of Transport Services: Background Data for Freight Transport (10 pp)

Background, Goal and Scope The ecoinvent database is a reference work for life cycle inventory data covering the areas of energy, building materials, metals, chemicals, paper and cardboard, forestry, agriculture, detergents, transport services and waste treatment. Generic inventories are available for freight and passenger transport including air, rail, road, and water transport. The goal of freight transport modelling is to provide background data for transport services, which occur between nearly any two process steps of a product system. This paper presents and discusses the model structure, basic assumptions and results for selected freight transport services.Main Features Transport services are divided into several datasets referred to as transport components. In addition to vehicle operation (comprising vehicle travel and pre-combustion), infrastructure processes such as vehicle maintenance, manufacturing and disposal, as well as transport infrastructure construction, operation and disposal, are also modelled. In order to link the various transport components to the functional unit of one tonne kilometre (tkm), so-called demand factors are determined. In the case of transport infrastructure that is not exclusively used by freight transport, allocation is essential. The respective allocation parameters employed for line infrastructure construction/disposal and operation datasets (including land use) are yearly Gross-tonne kilometre performance (Gtkm) and kilometric vehicle/train performance. Results are presented for selected environmental exchanges related to gaseous emissions (climate change gases, nitrogen oxides, and hydrocarbons), heavy metal (zinc and cadmium) emissions to soil and air, as well as BOD (Biological Oxygen Demand), and land use. Particle emissions are further distinguished into fine (PM2.5) and coarse (diameter between 2.5 and 10 µm) particles. The results presented comprise both an intra- and inter-modal comparison.Results and Discussions A comparison of Swiss and European rail transport reveals considerably lower emissions from Swiss rail transport due to the almost exclusive use of hydropower as traction energy. For gaseous emissions, freight transport by water or rail exhibits considerably better performance than road transport (65-92% less gaseous emissions). As far as zinc and cadmium emissions to soil are concerned, water and rail transport produce less than 1% of the emissions resulting from road transport for either pollutant. For zinc and cadmium emissions to air, road transport has the highest emissions; however, the emissions due to water and rail transport range from 2 to 18% of the emission levels arising from road transport. Particle emissions show a more diverse pattern. Whilst fine particle emissions due to water and rail transport are considerably lower than road transport, rail transport with respect to coarse particles performs worse than road transport. Dominance analysis reveals the importance of infrastructure processes. For instance, the NMHC-emissions of infrastructure processes account for 40%, 30% and 50% of emissions for road, rail and barge transport, respectively. For the demand factor of infrastructure operation, a sensitivity analysis of the employed allocation factor was performed, revealing no sensitivity for gaseous emissions and particles. On the other hand, considerable changes in both emission levels and in the ranking of transport modes is observed for land occupation. Finally, we varied selected operation parameters for road transport, resulting in considerable reductions of CO2 and NOX emissions of up to 60%. In one extreme case (load factor: 100%), NOx emissions for vehicle operation of a lorry are lower than for inland water transport. Only as a result of the considerably higher NOx emissions occurring in infrastructure processes does road transport score worse than water transport, with the ranking remaining the same as for the generic data presented in ecoinvent 2000.Conclusions and Perspectives The provided datasets allow for a preliminary screening of the importance of transport processes within a product life cycle. In the cases for which transport processes are identified as sensitive for the overall outcome of certain product life cycle or for transport specific comparisons, the modular structure and transparent documentation of demand factors allows for an easy and transparent integration of more case-specific data for selected transport components.     

中国铁路机车牵引能耗的生态足迹变化

基于我国机车能耗统计资料、电力年度统计数据,首次计算了1975 2007年我国铁路机车牵引能耗的生态足迹及其强度变化。结果表明:(1)从1975年至2001年,我国铁路蒸汽机车牵引能耗生态足迹年均减少9.59万hm²,年均降低3.6%。从1975年至2007年,内燃机车牵引能耗生态足迹年均增加3.41万hm²;电力机车的火电生态足迹年均增加3.99万hm²,电力机车的水电生态足迹年均增加215.14 hm²可耕地。我国铁路机车牵引能耗生态足迹总量呈波动态势。(2)从1975年到2007年,我国铁路机车牵引能耗的生态足迹强度呈逐年降低态势,其值从1975年的528.79 m²/万换算吨公里降至2007年的85.54 m²/万换算吨公里,年均降低13.85 m²/万换算吨公里。(3)我国铁路机车牵引能耗的生态足迹强度远远低于民航飞机的能耗生态足迹强度,1991 2007年前者的均值只有后者的12.3%。     

Dependency of the O2 consumption/O2 transport relationship on amino acid supply in sepsis

Summary In sepsis tissue O₂ uptake may be abnormally limited because of a depressed O₂ consumption/O₂ transport relationship. This study has been performed to assess patterns of O₂ consumption, CO₂ production and O₂ transport in septic patients undergoing total parenteral nutrition; more in particular, this study has investigated the interdependence between the patterns of blood O₂ uptake and simultaneous CO₂ release, and the availability of substrates (amino acids, glucose and fat). It has been shown that the O₂ consumption/O₂ transport relationship is significantly influenced by the exogenous amino acid load, which tends to increase O₂ uptake and O₂ consumption at any given O₂ transport, thus suggesting a favourable effect of amino acid administration on energy metabolism. The data on CO₂ production and CO₂ release, in addition to reconfirming the results of previous studies, have shown that the changes in O₂ uptake and in CO₂ production mediated by substrate doses have a quantifiable impact on blood O₂-CO₂ exchange interactions.     

Material and Energy Flows and Environmental Impacts of the Internet in Switzerland

The Internet leads to material and energy consumption as well as various environmental impacts on both the regional and global scale. Yet, assessments of the Internet's energy consumption and resulting greenhouse gas emissions are still rare, and assessments of material flows and further environmental impacts are virtually non‐existent. This article investigates material flows, the direct energy consumption during the use phase, as well as environmental impacts linked to the service, “Internet in Switzerland.” In our model, the service, Internet in Switzerland, is divided into various Internet participant categories. All devices used to access or provide Internet services are merged in a limited number of equipment families and, as such, included in an inventory of the existing infrastructure (stock). Based on this inventory, a material flow analysis (MFA) is performed, which includes the current stock as well as flows resulting from growth and disposal. The direct energy consumption for the operation of the infrastructure is quantified. Environmental impacts are calculated with a life cycle assessment approach, using the ecoinvent database and the software, SimaPro, applying four different methods. The MFA results in a 2009 stock of 98,100 tonnes. Approximately 4,130 gigawatt hours per year, or 7% of the total Swiss electricity consumption, were used in 2009 to operate the Swiss infrastructure. The environmental impacts caused during the production and use phases vary significantly depending on the assessment method chosen. The disposal phase had mainly positive impacts as a result of material recovery.     

Economic and environmental assessment of automotive plastic waste end-of-life options: Energy recovery versus chemical recycling

Most automotive plastic waste (APW) is landfilled or used in energy recovery as it is unsuitable for high-quality product mechanical recycling. Chemical recycling via pyrolysis offers a pathway toward closing the material loop by handling this heterogeneous waste and providing feedstock for producing virgin plastics. This study compares chemical recycling and energy recovery scenarios for APW regarding climate change impact and cumulative energy demand (CED), assessing potential environmental advantages. In addition, an economic assessment is conducted. In contrast to other studies, the assessments are based on pyrolysis experiments conducted with an actual waste fraction. Mass balances and product composition are reported. The experimental data is combined with literature data for up- and downstream processes for the assessment. Chemical recycling shows a lower net climate change impact (0.57 to 0.64 kg CO₂e/kg waste input) and CED (3.38 to 4.41 MJ/kg waste input) than energy recovery (climate change impact: 1.17 to 1.25 kg CO₂e/kg waste input; CED: 6.94 to 7.97 MJ/kg waste input), while energy recovery performs better economically (net processing cost of −0.05 to −0.02€/kg waste input) compared to chemical recycling (0.05 to 0.08€/kg waste input). However, chemical recycling keeps carbon in the material cycle contributing to a circular economy and reducing the dependence on fossil feedstocks. Therefore, an increasing circularity of APW through chemical recycling shows a conflict between economic and environmental objectives.     

Uncovering urban transportation infrastructure expansion and sustainability challenge in Bangkok: Insights from a material stock perspective

Development of transportation infrastructure that extends roads and railways in Bangkok has overlooked the negative environmental impact of construction material accumulation. To analyze the extent of this impact, we originally established road and railway's material intensity coefficients and investigated spatially explicit roadway and railway material stock (MS) for the years of 2004, 2009, 2014, 2019, and 2037, based upon the master plans’ target year. We further analyzed how MS evolution relates to the city's socio-economic indicators and CO₂ emission. Significant growth is found in transportation MS during 2004–2019, and roadways particularly increased from 122 to 164 million metric tons (Mt). The master plans would require 43 and 6.55 Mt construction materials for roadway and railway extension, respectively, by 2037. More material-intensive roads (cross-provincial highways and major local roads) built to the suburbs of the cities and underground/elevated structures of the mass rapid transit system in dense urban areas will require three times the annual cement and steel consumption of that in the 2004–2019 period. Furthermore, a 2–3 fold increase in the number of registered vehicles and associated CO₂ emissions during the study period have brought questions to the transportation infrastructure MS efficiency. The findings of this study will enable informed decision-making regarding the concern of resource consumption and for considering environmentally friendly approaches in urban transportation planning for Bangkok and other developing cities.     

The Dematerialization Potential of the Australian Economy

In this article we test the long‐term dematerialization potential for Australia in terms of materials, energy, and water use as well as CO₂ emissions by introducing concrete targets for major sectors. Major improvements in the construction and housing, transport and mobility, and food and nutrition sectors in the Australian economy, if coupled with significant reductions in the resource export sectors, would substantially improve the current material, energy, and emission intensive pattern of Australia's production and consumption system. Using the Australian Stocks and Flows Framework we model all system interactions to understand the contributions of large‐scale changes in technology, infrastructure, and lifestyle to decoupling the economy from the environment. The modeling shows a considerable reduction in natural resource use, while energy and water use decrease to a much lesser extent because a reduction in natural resource consumption creates a trade‐off in energy use. It also shows that trade and economic growth may continue, but at a reduced rate compared with a business‐as‐usual scenario. The findings of our modeling are discussed in light of the large body of literature on dematerialization, eco‐efficiency, and rebound effects that may occur when efficiency is increased. We argue that Australia cannot rely on incremental efficiency gains but has to undergo a sustainability transition to achieve a low carbon future to keep in line with the international effort to avoid climate change and resource use conflicts. We touch upon the institutional changes that would be required to guide a sustainability transition in the Australian economy, such as an emission trading scheme.     

Applying cumulative exergy demand (CExD) indicators to the ecoinvent database

Goal, Scope and Background Exergy has been put forward as an indicator for the energetic quality of resources. The exergy of a resource accounts for the minimal work necessary to form the resource or for the maximally obtainable amount of work when bringing the resource’s components to their most common state in the natural environment. Exergy measures are traditionally applied to assess energy efficiency, regarding the exergy losses in a process system. However, the measure can be utilised as an indicator of resource quality demand when considering the specific resources that contain the exergy. Such an exergy measure indicates the required resources and assesses the total exergy removal from nature in order to provide a product, process or service. In the current work, the exergy concept is combined with a large number of life cycle inventory datasets available with ecoinvent data v1.2. The goal was, first, to provide an additional impact category indicator to Life-Cycle Assessment practitioners. Second, this work aims at making a large source of exergy scores available to scientific communities that apply exergy as a primary indicator for energy efficiency and resource quality demand. Methods The indicator Cumulative Exergy Demand (CExD) is introduced to depict total exergy removal from nature to provide a product, summing up the exergy of all resources required. CExD assesses the quality of energy demand and includes the exergy of energy carriers as well as of non-energetic materials. In the current paper, the exergy concept was applied to the resources contained in the ecoinvent database, considering chemical, kinetic, hydro-potential, nuclear, solar-radiative and thermal exergies. The impact category indicator is grouped into the eight resource categories fossil, nuclear, hydropower, biomass, other renewables, water, minerals, and metals. Exergy characterization factors for 112 different resources were included in the calculations. Results CExD was calculated for 2630 ecoinvent product and process systems. The results are presented as average values and for 26 specific groups containing 1197 products, processes and infrastructure units. Depending on the process/product group considered, energetic resources make up between 9% and 100% of the total CExD, with an average contribution of 88%. The exergy of water contributes on the average to 8% the total exergy demand, but to more than 90% in specific process groups. The average contribution of minerals and metal ores is 4%, but shows an average value as high as 38% and 13%, in metallic products and in building materials, respectively. Looking at individual processes, the contribution of the resource categories varies substantially from these average product group values. In comparison to Cumulative Energy Demand (CED) and the abiotic-resource-depletion category of CML 2001 (CML’01), non-energetic resources tend to be weighted more strongly by the CExD method. Discussion Energy and matter used in a society are not destroyed but only transformed. What is consumed and eventually depleted is usable energy and usable matter. Exergy is a measure of such useful energy. Therefore, CExD is a suitable energy based indicator for the quality of resources that are removed from nature. Similar to CED, CExD assesses energy use, but regards the quality of the energy and incorporates non-energetic materials like minerals and metals. However, it can be observed for non-renewable energy-intensive products that CExD is very similar to CED. Since CExD considers energetic and non-energetic resources on the basis of exhaustible exergy, the measure is comparable to resource indicators like the resource use category of Eco-indicator 99 and the resource depletion category of CML 2001. An advantage of CExD in comparison to these methods is that exergy is an inherent property of the resource. Therefore less assumptions and subjective choices need to be made in setting up characterization factors. However, CExD does not coversocietal demand (distinguishing between basic demand and luxury), availability or scarcity of the resource. As a consequence of the different weighting approach, CExD may differ considerably from the resource category indicators in Eco-indicator 99 and CML 2001. Conclusions The current work shows that the exergy concept can be operationalised in product life cycle assessments. CExD is a suitable indicator to assess energy and resource demand. Due to the consideration of the quality of energy and the integration of non-energetic resources, CExD is a more comprehensive indicator than the widely used CED. All of the eight CExD categories proposed are significant contributors to Cumulative Exergy Demand in at least one of the product groups analysed. In product or service assessments and comparative assertions, a careful and concious selection of the appropriate CExD-categories is required based on the energy and resource quality demand concept to be expressed by CExD. Recommendations and Perspectives A differentiation between the exergy of fossil, nuclear, hydro-potential, biomass, other renewables, water and mineral/metal resources is recommended in order to obtain a more detailed picture of resource quality demand and to recognise trade-offs between resource use, for instance energetic and non-energetic raw materials, or nonrenewable and renewable energies. ESS-Submission Editor: Dr. Gerald Rebitzer (Gerald.Rebitzer@alcan.com)     

The use of steel in the United Kingdom's transport sector: A stock–flow–service nexus case study

Energy and material flows and material stocks are key requirements for the supply of goods and services, which in turn support societal development. However, most resource accounting methods restrict the analysis to resource flows, which fails to acknowledge the increasing role of in‐use stocks in service provision. Using the UK transport sector as a case study, we undertook a material flow analysis through the lens of the stock–flow–service (SFS) nexus. We used the latter to identify how steel consumption and accumulation in vehicles contributed to passenger mobility between 1960 and 2015. Our results show that the efficiency of the steel stock contained in cars and motorcycles decreased from 37.5 to 28.0 passenger‐km (pkm)/kg‐year. The steel service for buses decreased from 63.6 to 32.1 pkm/kg‐year, while that of the national railway increased from 23.8 to 70.3 pkm/kg‐year steel. London Underground steel stock–service efficiency improved from 31.5 to 57.0 pkm/kg‐year steel. The annual fraction of flows that maintained the steel stock varied according to vehicle category and was between 3.4% and 8.2%. In terms of the stock expansion rate, the greatest change (on average, an annual increase of 3%) was that of “cars and motorcycles.” This reflects the demographic transitions and the growing consumer demand for car‐based mobility. We discussed how the SFS nexus contributes to a more comprehensive form of resource accounting and reflect upon some of its limitations and how they might be addressed.     

A spatially explicit life cycle inventory of the global textile chain

Background, aim, and scope  Life cycle analyses (LCA) approaches require adaptation to reflect the increasing delocalization of production to emerging countries. This work addresses this challenge by establishing a country-level, spatially explicit life cycle inventory (LCI). This study comprises three separate dimensions. The first dimension is spatial: processes and emissions are allocated to the country in which they take place and modeled to take into account local factors. Emerging economies China and India are the location of production, the consumption occurs in Germany, an Organisation for Economic Cooperation and Development country. The second dimension is the product level: we consider two distinct textile garments, a cotton T-shirt and a polyester jacket, in order to highlight potential differences in the production and use phases. The third dimension is the inventory composition: we track CO₂, SO₂, NO _x , and particulates, four major atmospheric pollutants, as well as energy use. This third dimension enriches the analysis of the spatial differentiation (first dimension) and distinct products (second dimension). Materials and methods  We describe the textile production and use processes and define a functional unit for a garment. We then model important processes using a hierarchy of preferential data sources. We place special emphasis on the modeling of the principal local energy processes: electricity and transport in emerging countries. Results  The spatially explicit inventory is disaggregated by country of location of the emissions and analyzed according to the dimensions of the study: location, product, and pollutant. The inventory shows striking differences between the two products considered as well as between the different pollutants considered. For the T-shirt, over 70% of the energy use and CO₂ emissions occur in the consuming country, whereas for the jacket, more than 70% occur in the producing country. This reversal of proportions is due to differences in the use phase of the garments. For SO₂, in contrast, over two thirds of the emissions occur in the country of production for both T-shirt and jacket. The difference in emission patterns between CO₂ and SO₂ is due to local electricity processes, justifying our emphasis on local energy infrastructure. Discussion  The complexity of considering differences in location, product, and pollutant is rewarded by a much richer understanding of a global production–consumption chain. The inclusion of two different products in the LCI highlights the importance of the definition of a product's functional unit in the analysis and implications of results. Several use-phase scenarios demonstrate the importance of consumer behavior over equipment efficiency. The spatial emission patterns of the different pollutants allow us to understand the role of various energy infrastructure elements. The emission patterns furthermore inform the debate on the Environmental Kuznets Curve, which applies only to pollutants which can be easily filtered and does not take into account the effects of production displacement. We also discuss the appropriateness and limitations of applying the LCA methodology in a global context, especially in developing countries. Conclusions  Our spatial LCI method yields important insights in the quantity and pattern of emissions due to different product life cycle stages, dependent on the local technology, emphasizing the importance of consumer behavior. From a life cycle perspective, consumer education promoting air-drying and cool washing is more important than efficient appliances. Recommendations and perspectives  Spatial LCI with country-specific data is a promising method, necessary for the challenges of globalized production–consumption chains. We recommend inventory reporting of final energy forms, such as electricity, and modular LCA databases, which would allow the easy modification of underlying energy infrastructure. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Environmental impacts and limitations of third‐generation biobutanol: Life cycle assessment of n‐butanol produced by genetically engineered cyanobacteria

Photosynthetic cyanobacteria have attracted interest as production organisms for third‐generation biofuels, where sunlight and CO₂ are used by microbes directly to synthesize fuel molecules. A particularly suitable biofuel is n‐butanol, and there have been several laboratory reports of genetically engineered photosynthetic cyanobacteria capable of synthesizing and secreting n‐butanol. This work evaluates the environmental impacts and cumulative energy demand (CED) of cyanobacteria‐produced n‐butanol through a cradle‐to‐grave consequential life cycle assessment (LCA). A hypothetical production plant in northern Sweden (area 1 ha, producing 5–85 m³ n‐butanol per year) was considered, and a range of cultivation formats and cellular productivity scenarios assessed. Depending on the scenario, greenhouse gas emissions (GHGe) ranged from 16.9 to 58.6 gCO₂eq/MJ_BuOH and the CED from 3.8 to 13 MJ/MJ_BuOH. Only with the assumption of a nearby paper mill to supply waste sources for heat and CO₂ was the sustainability requirement of at least 60% GHGe savings compared to fossil fuels reached, though placement in northern Sweden reduced energy needed for reactor cooling. A high CED in all scenarios shows that significant metabolic engineering is necessary, such as a carbon partitioning of >90% to n‐butanol, as well as improved light utilization, to begin to displace fossil fuels or even first‐ and second‐generation bioethanol.     

Accounting for transportation impacts in the environmental assessment of waste management plans

Background, aim, and scope  Many recent studies on waste management have described in detail the potential impacts of recycling and final treatment of municipal waste. In public debates, the attention has also been focused on the choice of final disposal technologies (e.g. landfilling vs. incineration). However, a comprehensive assessment of the impacts of waste collection and transport was still lacking. In the present study, we use LCA to evaluate the potential impact of the provincial waste management plan of Varese (northern Italy). Particular attention is devoted to the estimation of environmental impacts generated during waste transport. Materials and methods  A detailed Life Cycle Inventory was built for the transportation phase, based on primary data collected by interviewing the agencies involved in waste collection. To model the recycling and final disposal phase we relied on the BUWAL 250 database. Impacts were evaluated with the Eco-Indicator 99 method in its egalitarian formulation. Results  The results of our analysis reveal that the major potential impacts of the plan are associated with waste collection and transport. These impacts are partially compensated by reduced resource consumption through recycling and energy recovery through incineration. Discussion  The outputs of the LCIA were compared with those obtained by using other ecoindicators (Eco-Indicator 99 hierarchist and individualist, CML2, EPS2000). Although not comparable on a quantitative basis, they are qualitatively consistent. Conclusions  Neglecting the effects of collection and transport might result in a severe underestimation of the environmental impacts of a waste management system, especially as refers to depletion of fossil fuels, emission of respiratory inorganics and climate change. To reduce the environmental impact of waste management systems, an accurate optimisation of waste transport is required. Recommendations and perspectives  Effective waste management planning requires the explicit inclusion of waste collection and transport when comparing alternative management policies.     

Efficient BiVO4 Photoanode with an Excellent Hole Transport Layer of CuSCN for Solar Water Oxidation

Bismuth vanadate (BiVO₄) is reported as a key material in photoelectrocatalysis owing to high theoretical efficiency, relatively narrow band gap of 2.4 eV, and favorable conduction band edge position for hydrogen evolution. However, the sluggish hole transport dynamics lead to slow photogenerated charge separation and transport efficiencies, which result in charge recombination due to aggregation. Herein, a novel hole transport layer of copper(I) thiocyanate (CuSCN) with the aim of significantly enhancing the efficiency of charge transport and stability of BiVO₄ photoanodes is reported. The introduction of the hole transport layer could provide an appropriate intermediate energy level for photogenerated hole transfer and avoid charge recombination and trapping. After a photoassisted electrodeposition process of NiCoFe-B_i catalysis, the obtained photoanode achieves a photocurrent density of 5.6 mA cm⁻² at 1.23 V versus reversible hydrogen electrode under AM 1.5 G simulated solar radiation, and an applied bias photon to current efficiency of 2.31%. With the CuSCN layer, BiVO₄ photoanode presented impressive stable photocurrent during 50 h continuous illumination. Meanwhile, the unbiased tandem device of the NiCoFe-B_i/CuSCN/BiVO₄ photoanode and the Si solar cell exhibit a solar-to-hydrogen efficiency of 5.75% and excellent stability for 14 h.     

基于替代式自下而上法的区域旅游交通碳排放测度

区域旅游交通碳排放测度是分解旅游业减碳任务的一个难题。在剖析替代式自下而上法机理的基础上,以长三角为例,依托归纳法和变异系数法,尝试从人均GDP、人均消费水平和人均运输线路长度三方面测算出游距离,采取以实地调研数据为主、辅之以Mus TT模型法拟定各旅游交通方式的距离比例,立足区情确定碳排放系数,并以区域输入和输出的双向旅游流的人次比值法则对替代结果进行还原调整。研究表明:(1)2011年,长三角旅游交通碳排放总量为8.32 Mt,其中江苏省、浙江省和上海市分别为3.23、2.98 Mt和2.11 Mt;(2)飞机和自驾车共占排放量的71.64%,较明显低于世界平均比例,二者是降低旅游交通碳排放的关键;旅游公共交通的碳排放比例具有远高于发达国家甚至全球平均水平的"中国式"烙印;由高碳排放系数的旅游交通方式向低碳排放系数甚至零碳排放系数的转变,是旅游交通减排的基本方向。     

Land use planning in Ireland—a life cycle energy analysis of recent residential development in the Greater Dublin Area

Background, aim, and scope  One third of the total housing stock in the Republic of Ireland has been built in 10 years up to and including 2006 and of this approximately 34% was built in the Greater Dublin Area (GDA). Much of the housing was low-density with poor public transport links leading to doubts over its sustainability—particularly in terms of energy use. Although the country is committed to reducing greenhouse gas emissions to 13% above 1990 levels by the period 2008–2012, by 2005, emissions were already 25.4% higher than the baseline and current projections are that this figure will rise to 37% over the period. The residential sector is estimated to contribute to approximately 24.5% of energy-related CO₂ emissions. This paper estimates total emissions from residential developments in the GDA constructed between 1997 and 2006. Materials and methods  Carbon dioxide equivalent (CO₂) emissions are estimated using a life cycle assessment approach over a 100-year building lifespan and employing process, input–output and hybrid energy techniques. Life cycle stages include: construction, operation, transport, maintenance and demolition. The main data sources include: national population and industry census data, household travel survey data, residential energy performance surveys and national accounts. The GDA was split into four zones each encompassing development at increasing radii from Dublin’s city centre, namely: city centre, suburbs, exurbs and commuter towns. Results  Per capita CO₂ life cycle emissions in the GDA were found to be approximately 50–55% greater in the exurbs and commuter towns than in the city centre. Of the five life cycle stages studied, operational energy requirements (predominantly space heating and hot water, but including power) contributed most significantly to emissions (68%), followed by transport (17%), construction (9%) and maintenance/renovation (6%). Discussion  Operating emissions from dwellings in the commuter town and extra-urban zones were almost twice those in the city centre both due to larger dwelling sizes and the predominance of detached and semi-detached dwellings (with large amounts of exposed walls) in the former and the prevalence of smaller apartments in the latter. Car use was most pronounced in the zones furthest from the city centre where per capita emissions were almost twice those of residents in the city centre. Despite their smaller size, the per capita construction CO₂ emissions of apartments were approximately one third greater than for low-rise dwellings due to the greater energy intensity of the structure. However, this difference was more than compensated for by the significantly lower operational emissions referred to above. Conclusions  In 2006, recurrent CO₂ emissions (operational, transport and maintenance) from dwellings built in the GDA over the ten preceding years were 2,108 kt while construction-related emissions in that year were 1,325 kt giving a total contribution from the residential sector of 3,434 kt CO₂/annum—representing 4.9% of national emissions for that year. Had the development policy prescribed ‘city centre’-type development and transport modes, then emissions for the year 2006 would have been 2,892 kt CO₂—a reduction of almost 16% over the actual figure. However, in this scenario recurrent emissions would have been reduced to 1,417 kt CO₂—a reduction of 33% over actual levels. Recommendations and perspectives  This study supports Irish and international governments’ policies aimed at curbing CO₂ emissions from the domestic sector which focus primarily on reducing operational emissions from new and existing housing through design and construction improvements. However, it demonstrates that significant reductions in operational emissions are associated with high-density residential development with modest floor areas. Furthermore, it highlights the scope for transport emissions’ reductions through better spatial planning leading to reduced car travel.     

Spatiotemporal railway use by grizzly bears in Canada's Rocky Mountains

Railway networks contribute to the direct mortality of wildlife through collisions with trains, which can threaten vulnerable wildlife populations even in protected areas, including grizzly bears (Ursus arctos) in Banff and Yoho National Parks, Canada. Mitigation to reduce bear-train collisions requires information about how grizzly bears use the railway spatially and temporally and how particular types of use might increase collision vulnerability. We used data from 27 grizzly bears fitted with global positioning system (GPS) collars between 2000 and 2016 to relate railway use by bears via resource selection functions to variables that described land cover, human use, and topography. We used the same suite of explanatory variables to distinguish pairs of 4 types of steps, in which 3 successive GPS points (with 2-hr fix rates) included ≥1 within 30 m of the rail (hereafter on) and 2 others that defined locations where bears effectively entered the railway (first fix off rail, next 2 on), crossed it (only the middle fix on the rail), continued along the railway (all 3 fixes on), or exited the railway corridor (first 2 on, last off). We compared both sites of higher use and each of these 4 step types to the relative frequency of bear-train collisions, predicting a positive correlation for continue step types. Relative to available locations, bears were more likely to use the railway close to railroad sidings (sections of twinned track where trains sometimes stop), at intermediate distances from human-use features (e.g., town sites, highways, trails), in areas with lower values of the compound topographic index (a proxy for wetness; within 500 m), and within 90 m of rugged terrain. Seasonally, bears made greater use of the railway in spring and fall. Among 1,515 sequences of 3 steps, crossing locations comprised >50% and were most distinct from continue locations (about 20%), which occurred in areas with more rugged terrain (within 300 m), closer to railway sidings, in spring and fall, and with steps that were 60% shorter. Contrary to our prediction, past reports of bear-train collisions were negatively correlated with continue locations and unrelated to overall use or any other movement type. Our results suggest that railway use by bears increased where it provided increased forage or easier travel, particularly in spring and fall, but more work will be needed to determine the mechanistic basis of bear-train collisions. Meanwhile, mitigation efforts such as habitat alteration or warning systems might target locations where past strikes are concentrated for grizzly bears or other sensitive populations. © 2019 The Wildlife Society.     

Reducing CO<Subscript>2</Subscript> Emissions from Domestic Travel: Exploring the Social and Health Impacts

The importance and meaning of social and recreational travel for a diverse group of Auckland residents is explored in this article. Study participants identified a range of social and health benefits, including maintaining social connections with family and friends, opportunities to participate in physical activity, and reducing stress. However, many of these trips are by car. New Zealand has one of the highest rates of private car ownership internationally, low-density urban development, and a poor public transport infrastructure. Social and recreational trips make up a sizeable proportion of domestic travel and are contributing to New Zealand’s increasing rate of CO₂ emissions. There is an obvious need to address the negative ecological impacts of human activity. Our findings suggest that alongside strategies to reduce CO₂ emissions, it also is important to introduce measures to maintain the benefits from social and recreational travel. Suggestions are made for further areas of research.     

Life cycle assessment of cane-sugar on the island of mauritius

Goal, Scope and Background  Agricultural production includes not only crop production, but also food processing, transport, distribution, preparation, and disposal. The effects of all these must be considered and controlled if the food chain is to be made sustainable. The goal of this case study was to identify and review the significant areas of potential environmental impacts across the whole life cycle of cane sugar on the island of Mauritius. Methods  The functional unit was one tonne of exported raw sugar from the island. The life cycle investigated includes the stage of cane cultivation and harvest, cane burning, transport, fertilizer and herbicide manufacture, cane sugar manufacture and electricity generation from bagasse. Data was gathered from companies, factories, sugar statistics, databases and literature. Energy depletion, climate change, acidification, oxidant formation, nutrification, aquatic ecotoxicity and human toxicity were assessed. Results and Discussion  The inventory of the current sugar production system revealed that the production of one tonne of sugar requires, on average, a land area of 0.12 ha, the application of 0.84 kg of herbicides and 16.5 kg of N-fertilizer, use of 553 tons of water and 170 tonne-km of transport services. The total energy consumption is about 14235 MJ per tonne of sugar, of which fossil fuel consumption accounts for 1995 MJ and the rest is from renewable bagasse. 160 kg of CO₂ per tonne of sugar is released from fossil fuel energy use and the net avoided emissions of CO₂ on the island due to the use of bagasse as an energy source is 932,000 tonnes. 1.7 kg TSP, 1.21 kg SO₂,1.26 kgNO_xand 1.26 kg CO are emitted to the air per tonne of sugar produced. 1.7 kg N, 0.002 kg herbicide, 19.1 kg COD, 13.1 kgTSS and 0.37 kg PO₄ ^3- are emitted to water per tonne of sugar produced. Cane cultivation and harvest accounts for the largest environmental impact (44%) followed by fertilizer and herbicide manufacture (22%), sugar processing and electricity generation (20%), transportation (13%) and cane burning (1%). Nutrification is the main impact followed by acidification and energy depletion. Conclusions  There are a number of options for improvement of the environmental performance of the cane-sugar production chain. Cane cultivation, and fertilizer and herbicide manufacture, were hotspots for most of the impact categories investigated. Better irrigation systems, precision farming, optimal use of herbicides, centralisation of sugar factories, implementation of co-generation projects and pollution control during manufacturing and bagasse burning are measures that would considerably decrease resource use and environmental impacts. Recommendation and Outlook  LCA was shown to be a valuable tool to assess the environmental impacts throughout the food production chain and to evaluate government policies on agricultural production systems.     

Life cycle assessment-based selection of a sustainable lightweight automotive engine hood design

Purpose

This study presents a life cycle assessment (LCA)-based sustainable and lightweight automotive engine hood design and compares the life cycle energy consumption and potential environmental impacts of a steel (baseline) automotive engine hood with three types of lightweight design: advanced high strength steel (AHSS), aluminum, and carbon fiber.

Methods

A “cradle-to-grave” LCA including the production, use, and end-of-life stages is conducted in accordance with the ISO 14040/14044 standards. Onsite data collected by Chinese automotive companies in 2015 are used in the assessment. The Cumulative Energy Demand v1.09 method is applied to evaluate cumulative energy demand (CED), and the International Panel on Climate Change 2013 100a method is used to estimate global warming potential (GWP 100a).

Results and discussion

Among the different lightweight designs for the engine hood, the aluminum design is the most sustainable and has the lowest CED and GWP (100a) from a life cycle perspective, which is based on a lifetime driving distance of approximately 150,000 km. In addition, the AHSS design is also sustainable and lightweight. The carbon fiber design results in higher CED and GWP (100a) values than the steel (baseline) design during the life cycle but results in the largest CED and GWP (100a) savings through waste material recycling. The AHSS design exhibits the best break-even distance based on CED and GWP (100a) within 150,000 km.

Conclusions

Sensitivity analysis results show that the lifetime driving distance and material recycling rate have the largest impacts on the overall CEDs and GWPs of the three lightweight designs.

     

基于多角度基尼系数的江西省资源环境公平性研究

资源环境基尼系数是衡量和评价资源消耗、污染物排放在各个城市或地区间的公平性与合理性的有效途径。对基于GDP(gross domestic product)、人口、国土面积等角度推算的资源环境基尼系数方法的优劣性进行了评价,提出了"生态负荷系数"的概念,界定了"生态容量"的概念与内容,并从GDP、人口和生态容量的角度出发,以江西省11地市作为评价对象,选取2009年能源消耗、水资源消耗、COD(chemical oxygen demand)排放及SO2排放等4个评价因子,构建了江西省资源环境基尼系数、生态负荷系数的计算与评价方法,并对计算结果进行了对比分析。结果表明:(1)不同角度计算的基尼系数不尽相同,从生态负荷系数来看,在江西11个城市中,南昌、鹰潭、萍乡、景德镇、新余等经济发达城市是引起能源消耗、SO2排放主要的不公平因子,是需要转变经济发展模式的城市,更须注重经济与环境的协调发展;(2)从生态容量的角度推算的资源环境基尼系数普遍高于从GDP和人口角度推算的资源环境基尼系数,且都高于"警戒线";(3)从理论上看,基于生态容量角度的资源环境基尼系数比基于GDP和人口角度的资源环境基尼系数更为科学与合理。文章最后讨论了不同角度的资源环境基尼系数及生态负荷系数的科学性与合理性的问题。