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Concept: Carbon footprint


Galicia is an Autonomous Community located in the north-west of Spain. As a starting point to implement mitigation and adaptation measures to climate change, a regional greenhouse gas (GHG) inventory is needed. So far, the only regional GHG inventories available are limited to the territorial emissions of those production activities which are expected to cause major environmental degradation. An alternative approach has been followed here to quantify all the on-site (direct) and embodied (indirect) GHG emissions related to all Galician production and consumption activities. The carbon footprint (CF) was calculated following the territorial life cycle assessment (LCA) methodology for data collection, that combines bottom-up and top-down approaches. The most up-to-date statistical data and life cycle inventories available were used to compute all GHG emissions. This case study represents a leap of scale when compared to existing studies, thus addressing the issue of double counting, which arises when considering all the production activities of a large region. The CF of the consumption activities in Galicia is 17.8 ktCO2e/year, with 88% allocated to Galician inhabitants and 12% to tourist consumption. The proposed methodology also identifies the main important contributors to GHG emissions and shows where regional reduction efforts should be made. The major contributor to the CF of inhabitants is housing (32%), followed by food consumption (29%). Within the CF of tourist consumption, the share of transport is highest (59%), followed by housing (26%). The CF of Galician production reaches 34.9 MtCO2e/y, and its major contributor is electricity production (21%), followed by food manufacturing (19%). Our results have been compared to those reported for other regions, actions aimed at reducing GHG emissions have been proposed, and data gaps and limitations identified.

Concepts: Carbon dioxide, Climate change, Spain, Natural gas, Galicia, Greenhouse gas, Life cycle assessment, Carbon footprint


Life cycle thinking asks companies and consumers to take responsibility for emissions along their entire supply chain. As the world economy becomes more complex it is increasingly difficult to connect consumers and other downstream users to the origins of their greenhouse gas (GHG) emissions. Given the important role of subnational entities - cities, states, and companies - in GHG abatement efforts, it would be advantageous to better link downstream users to facilities and regulators who control primary emissions. We present a new spatially explicit carbon footprint method for establishing such connections. We find that for most developed countries the carbon footprint has diluted and spread: for example, since 1970 the US carbon footprint has grown 23% territorially, and 38% in consumption-based terms, but nearly 200% in spatial extent (i.e. the minimum area needed to contain 90% of emissions). The rapidly growing carbon footprints of China and India, however, do not show such a spatial expansion of their consumption footprints in spite of their increasing participation in the world economy. In their case, urbanization concentrates domestic pollution and this offsets the increasing importance of imports.

Concepts: Carbon dioxide, Developed country, Natural gas, Greenhouse gas, Ecological footprint, Footprint, Carbon footprint, Administrative division


To examine the environmental life cycle from poppy farming through to production of 100 mg in 100 mL of intravenous morphine (standard infusion bag).

Concepts: Opioid, Morphine, Sustainability, Opium, Opium poppy, Carbon footprint, Poppy seed, Poppy straw


In this study, the carbon footprint of introducing a food waste disposer (FWD) policy was examined in the context of its implications on solid waste and wastewater management with economic assessment of environmental externalities emphasizing potential carbon credit and increased sludge generation. For this purpose, a model adopting a life cycle inventory approach was developed to integrate solid waste and wastewater management processes under a single framework and test scenarios for a waste with high organic food content typical of developing economies. For such a waste composition, the results show that a FWD policy can reduce emissions by nearly ∼42% depending on market penetration, fraction of food waste ground, as well as solid waste and wastewater management schemes, including potential energy recovery. In comparison to baseline, equivalent economic gains can reach ∼28% when environmental externalities including sludge management and emissions variations are considered. The sensitivity analyses on processes with a wide range in costs showed an equivalent economic impact thus emphasizing the viability of a FWD policy although the variation in the cost of sludge management exhibited a significant impact on savings.

Concepts: Energy, Atom, Economics, Recycling, Waste, Life cycle assessment, Garbage disposal, Carbon footprint


Energy neutrality and reduction of carbon emissions are significant challenges to the enhanced sustainability of wastewater treatment plants (WWTPs). Harvesting energy from wastewater carbonaceous substrates can offset energy demands and enable net power generation; yet, there is limited research about how carbonaceous substrates influence energy and carbon implications of WWTPs with integrated energy recovery at systems-level. Consequently, this research uses biokinetics modelling and life cycle assessment philology to explore this notion, by tracing and assessing the quantitative flows of energy embodied or captured, and by exploring the carbon footprint throughout an energy-intensive activated sludge process with integrated energy recovery facilities. The results indicate that energy use and carbon footprint per cubic meter of wastewater treated, varies markedly with the carbon substrate. Compared with systems driven with proteins, carbohydrates or other short-chain fatty acids, systems fed with acetic acid realized energy neutrality with maximal net gain of power from methane combustion (0.198 kWh) and incineration of residual biosolids (0.153 kWh); and also achieved a negative carbon footprint (72.6 g CO2). The findings from this work help us to better understand and develop new technical schemes for improving the energy efficiency of WWTPs by repurposing the stream of carbon substrates across systems.

Concepts: Oxygen, Carbon dioxide, Sewage treatment, Carbon monoxide, Methane, Activated sludge, Life cycle assessment, Carbon footprint


Carbon footprint (CF) is nowadays one of the most widely used environmental indicators. The scope of the CF assessment could be corporate (when all production processes of a company are evaluated, together with upstream and downstream processes following a life cycle approach) or product (when one of the products is evaluated throughout its life cycle). Our hypothesis was that usually product CF studies (PCF) collect corporate data, because it is easier for companies to obtain them than product data. Six main methodological issues to take into account when collecting corporate data to be used for PCF studies were postulated and discussed in the present paper: fugitive emissions, credits from waste recycling, use of “equivalent factors”, reference flow definition, accumulation and allocation of corporate values to minor products. A big project with 18 wineries, being wine one of the most important agri-food products assessed through CF methodologies, was used to study and to exemplify these 6 methodological issues. One of the main conclusions was that indeed, it is possible to collect corporate inventory data in a per year basis to perform a PCF, but having in mind the 6 methodological issues described here. In the literature, most of the papers are presenting their results as a PCF, while they collected company data and obtained, in fact, a “key performance indicator” (ie., CO2eq emissions per unit of product produced), which is then used as a product environmental impact figure. The methodology discussed in this paper for the wine case study is widely applicable to any other product or industrial activity.

Concepts: Present, Scientific method, Case study, Methodology, Recycling, Indicator, Life cycle assessment, Carbon footprint


Negative outcomes such as noise and vibration generated by railways have become a challenge for both industry and academia in order to guarantee that the railway system can accomplish its purposes and at the same time provide comfort for users and people living in the neighbourhood along the railway corridor. The research interest on this field has been increasing and the advancement in noise and vibration mitigation methodologies can be observed using various engineering techniques that are constantly put into test to solve such effects. In contrast, the life cycle analysis of the mitigation measures has not been thoroughly carried out. There is also a lack of detailed evaluation in the efficiency of various mechanisms for controlling rolling noise and ground-borne vibration. This research is thus focussed on the evaluation of materials used, the total cost associated with the maintenance of such the measures and the carbon footprint left for each type of mechanism. The insight into carbon footprint together with life cycle cost will benefit decision making process for the industry in the selection of optimal and suitable mechanism since the environmental impact is a growing concern around the world.

Concepts: Scientific method, Decision making, Cognition, Decision theory, Decision making software, Life cycle assessment, Rail transport, Carbon footprint


Irrigation increases yields and allows several crops to be produced in regions where it would be naturally impossible due to limited rainfall. However, irrigation can cause several negative environmental impacts, and it is important to understand these in depth for the correct application of mitigation measures. The life cycle assessment methodology was applied herein to compare the main irrigated and non-irrigated crops in Northeast Spain (corn and wheat, respectively), identifying those processes with greater contribution to environmental impacts (carbon and water footprint categories) and providing scientifically-sound information to facilitate government decisions. Due to concerns about climate change and water availability, the methods selected for evaluation of environmental impacts were IPCC 2013 GWP (carbon footprint) and water scarcity indicator (water footprint). The area studied, a 7.38-km(2) basin, was monitored for 12 years, including the period before, during, and after the implementation of irrigation. The functional unit, to which all material and energy flows were associated with, was the cultivation of 1 ha, throughout 1 year. The overall carbon footprint for irrigated corn was higher, but when considering the higher productivity achieved with irrigation, the emissions per kilogram of corn decrease and finally favor this irrigated crop. When considering the water footprint, the volumes of irrigation water applied were so high that productivity could not compensate for the negative impacts associated with water use in the case of corn. Nevertheless, consideration of productivities and gross incomes brings the results closer. Fertilizer use (carbon footprint) and irrigation water (water footprint) were the main contributors to the negative impacts detected.

Concepts: Agriculture, Water, Irrigation, Ecological footprint, Life cycle assessment, Water footprint, Deficit irrigation, Carbon footprint


Environmental or ‘ecological’ footprints have been widely used in recent years as indicators of resource consumption and waste absorption presented in terms of biologically productive land area [in global hectares (gha)] required per capita with prevailing technology. In contrast, ‘carbon footprints’ are the amount of carbon (or carbon dioxide equivalent) emissions for such activities in units of mass or weight (like kilograms per functional unit), but can be translated into a component of the environmental footprint (on a gha basis). The carbon and environmental footprints associated with the world production of liquid biofuels have been computed for the period 2010-2050. Estimates of future global biofuel production were adopted from the 2011 International Energy Agency (IEA) ‘technology roadmap’ for transport biofuels. This suggests that, although first generation biofuels will dominate the market up to 2020, advanced or second generation biofuels might constitute some 75% of biofuel production by 2050. The overall environmental footprint was estimated to be 0.29 billion (bn) gha in 2010 and is likely to grow to around 2.57 bn gha by 2050. It was then disaggregated into various components: bioproductive land, built land, carbon emissions, embodied energy, materials and waste, transport, and water consumption. This component-based approach has enabled the examination of the Manufactured and Natural Capital elements of the ‘four capitals’ model of sustainability quite broadly, along with specific issues (such as the linkages associated with the so-called energy-land-water nexus). Bioproductive land use was found to exhibit the largest footprint component (a 48% share in 2050), followed by the carbon footprint (23%), embodied energy (16%), and then the water footprint (9%). Footprint components related to built land, transport and waste arisings were all found to account for an insignificant proportion to the overall environmental footprint, together amounting to only about 2.

Concepts: Carbon dioxide, Petroleum, Mass, Biofuel, Global warming potential, Ecological footprint, Life cycle assessment, Carbon footprint


This study includes an environmental analysis of a membrane bioreactor (MBR), the objective being to quantitatively define the inventory of the resources consumed and estimate the emissions produced during its construction, operation and end-of-life deconstruction. The environmental analysis was done by the life cycle assessment (LCA) methodology, in order to establish with a broad perspective and in a rigorous and objective way the environmental footprint and the main environmental hotspots of the examined technology. Raw materials, equipment, transportation, energy use, as well as air- and waterborne emissions were quantified using as a functional unit, 1m(3) of urban wastewater. SimaPro was used as the LCA analysis tool, and two impact assessment methods, i.e. IPCC 2013 version 1.00 and ReCiPe version 1.10, were employed. The main environmental hotspots of the MBR pilot unit were identified to be the following: (i) the energy demand, which is by far the most crucial parameter that affects the sustainability of the whole process, and (ii) the material of the membrane units. Overall, the MBR technology was found to be a sustainable solution for urban wastewater treatment, with the construction phase having a minimal environmental impact, compared to the operational phase. Moreover, several alternative scenarios and areas of potential improvement, such as the diversification of the electricity mix and the material of the membrane units, were examined, in order to minimize as much as possible the overall environmental footprint of this MBR system. It was shown that the energy mix can significantly affect the overall sustainability of the MBR pilot unit (i.e. up to 95% reduction of the total greenhouse gas emissions was achieved with the use of an environmentally friendly energy mix), and the contribution of the construction and operational phase to the overall environmental footprint of the system.

Concepts: Environment, Sustainability, Impact assessment, Greenhouse gas, Life cycle assessment, Industrial ecology, Design for Environment, Carbon footprint