Environmentally-extended Input-output Analysis Research Articles

Integrated assessment models and input–output analysis: bridging fields for advancing sustainability scenarios research

Technology-rich Integrated assessment models (IAMs) and Environmentally-Extended Input–Output Analysis (EEIOA) are widely employed for sustainability analysis, each offering unique strengths. IAMs focus on forward-looking scenarios, exploring technological shifts and climate change mitigation costs. EEIOA provides more comprehensive but static assessments of environmental and socio-economic impacts throughout supply chains, adopting a lifecycle perspective. I conduct a literature review to assess the current state of IAM-IO integration, paving the way for future research opportunities with advanced models. Existing studies have loosely linked IAM and IO models to improve one field or the other. This perspective highlights the potential for more advanced IAM-IO model linking and identifies three domains within sustainability scenarios research where IAM-IO integration could play a crucial role: the energy-industry nexus in decarbonization pathways, multi-dimensional sustainability impact assessment and demand-side solutions and post-growth climate mitigation scenarios. The expected research insights may be pivotal to design effective sustainable policies.

The impact of the German timber footprint on potential species loss in supply regions

Previous own assessments have shown that a) Germany has a wood consumption above global average, b) is strongly dependent on imports and c) has a domestic roundwood production that is at the limit of the sustainable harvest potential. Thereby Germany further increases the pressures on global forests which are already stressed by climate-change related impacts and a continuously growing global demand for wood. This leads to negative impacts on the biodiversity in the areas where wood is harvested. This paper aims to show the connection between Germany's timber consumption footprint and the impact on the biodiversity in the regions where the roundwood is sourced. A two-step process is used. In the first step, high-resolution land cover and land use maps are used as a basis for the countryside species-area relationship model, assessing the projected loss of the four taxa amphibians, birds, mammals and reptiles in relation to undisturbed natural ecosystems due to forests occupied for roundwood production. In the second step, roundwood equivalents consumed in Germany in 2015 are traced back to the region of origin using an environmentally-extended input-output analysis and the thereby induced potential species loss is calculated. We show that the highest impact on projected species richness loss caused by roundwood logging is taking place in Oceania (3.34E−03 species/m3), Carribean (1.56E−04 species/m3), and East Asia (1.43E−04 species/m3). German roundwood consumption has the highest projected species loss in the United States (7.4 species), followed by China (7.3 species) and Brazil (4.8 species). From a biodiversity impact perspective, Germany could theoretically reduce its impact by relocating imports to European countries. In view of the planetary boundary of sustainable roundwood consumption, which has already been exceeded, reducing consumption appears to be the only viable long-term option for high-consumption countries such as Germany to reduce negative impacts on global biodiversity.

Quantifying plastic use and waste footprints in SIDS: Application to Seychelles

Small Island Developing States (SIDS) are the most vulnerable territories to marine litter and plastic waste pollution. The magnitude of the issue and ways of action can only be known if the material flows and their origins are correctly estimated. Unfortunately, small territories are often left outside the global ecological footprint databases and models. The present research aims at quantifying the plastic footprint of Seychelles through a standard Environmentally-Extended Input-Output Analysis (EEIOA) and multi-regional input-output (MRIO) approach combining international and domestic data in the south-west Indian Ocean region. The results of several model specifications and industrial classifications are compared to the literature findings and show that SIDS may display the same level of plastic use and waste per capita as high-income countries, without the same infrastructure of waste treatment. A few services and exporting sectors concentrate the bulk of the territorial quantity of plastics used throughout the economy. The multi-regional Indian Ocean context helps to foresee potential joint actions in order to reduce the plastic footprint of SIDS.

An extended input-output analysis of links between industrial production and water pollutant discharge in the Yangtze River Economic Belt

Industrial production is key to economic development, yet it significantly influences the water environment. Recent literature has mainly focused on economic development and water pollution separately, lacking an integrated assessment. This study aims to clarify the links between industrial production and water pollution and its driving factors in the Yangtze River Economic Belt (YREB) in 2012–2017 based on environmentally-extended input-output analysis and structural decomposition analysis, thus identifying key regions and sectors for pollution reduction. The results revealed that manufacture of foods and tobacco (MFT) and chemical industry (CI) in Anhui, Jiangsu, Jiangxi, Hunan, and processing of petroleum, coking, processing of nuclear fuel (PPCN) in Chongqing were the primary sources of total chemical oxygen demand (COD), ammoniacal nitrogen (NH3–N), total nitrogen (TN), and total phosphorus (TP) discharges. The structural decomposition analysis (SDA) results demonstrated that the discharge intensity effect caused a decrease of 7.91 Mt, 0.22 Mt, 0.25 Mt, and 0.03 Mt of the indirect COD, NH3–N, TN, and TP discharge, while the scale effect led to an increase of 1.95 Mt, 0.26 Mt, 0.24 Mt and 0.03 Mt of them in 2012–2017. According to the analysis, water pollution reduction and industrial structure modernization are needed in the YREB. The technological upgrading of highly polluting industries and the structural adjustment between traditional highly polluting industries and high-tech industries were the focus for achieving green development of the YREB, especially in Anhui, Hubei, Guizhou and Yunnan. The establishment of green industrial parks, the development of environmental regulations, and the implementation of supply-side reform policies can benefit water pollution reduction and sustainable development.

Environmentally-extended input-output analyses efficiently sketch large-scale environmental transition plans: Illustration by Canada's road industry

Industries struggle to build robust environmental transition plans as they lack the tools to quantify their ecological responsibility over their value chain. Companies mostly turn to sole greenhouse gas (GHG) emissions reporting or time-intensive Life Cycle Assessment (LCA), while Environmentally-Extended Input-Output (EEIO) analysis is more efficient on a wider scale. We illustrate EEIO analysis' usefulness to sketch transition plans on the example of Canada's road industry: estimation of national environmental contributions, most important environmental issues, main potential transition levers of the sector, and metrics prioritization for green purchase plans. To do so, openIO-Canada, a new Canadian EEIO database, coupled with IMPACT World+ v1.30–1.48 characterization method, provides a multicriteria environmental diagnosis of Canada's economy. The construction sector carries the second-highest environmental impacts of Canada (8–31% depending on the indicator) after the manufacturing industry (20–54%). The road industry generates a limited impact (0.5–1.8%), and emits 1.0% of Canadians' GHGs, mainly due to asphalt mix materials (28%), bridges and engineering structures materials (24%), and direct emissions (17%). The industry must reduce the environmental burden from material purchases - mainly concrete and asphalt products - through green purchase plans and eco-design and invest in new machinery powered with cleaner energies such as low-carbon electricity or bioenergies. EEIO analysis also captures impacts often neglected in process-based pavement LCAs - amortization of capital goods, staff consumptions, and services – and shows some substantial impacts advocating for enlarging system boundaries in standard LCA. Yet, pavement construction and maintenance only explain 5% of the life cycle carbon footprint of Canada's road network, against 95% for the roads' usage (72% from vehicle tailpipes releases, 23% for manufacturing vehicles). Thereby, a carbon-neutral pathway for the road industry must first focus on reducing vehicle consumption and wear through better design and maintenance of roads. Finally, EEIO databases and analysis must be developed further as a powerful tool to fight planet degradation, and openIO-Canada must be specifically expanded and refined to allow for more robust and larger multicriteria assessments.

The carbon footprint of stone fruit production: Comparing process-based life cycle assessment and environmentally extended input-output analysis

The development of sustainable products and practices must be supported by methodologies capable of evaluating their environmental performance in an objective and systematic manner. The most popular tool for carbon footprint (CF) assessment is arguably process-based life cycle assessment (pLCA). However, interest in tools such as environmentally extended input-output analysis (EEIOA) is growing rapidly due to the convenience of using economic-based inventories rather than material/energy-based ones. The objective of this investigation is to evaluate divergences between conventional pLCA and EEIOA in the analysis of CF using the production of stone fruits as a case study. The study uses a cradle to grave approach and it is based on a detailed economic, material and energy life cycle inventory of nectarines produced in Southeast Spain. The analyses yielded 1.07 kg CO2 eq./kg for the EEIOA and 0.899 kg CO2 eq./kg for the pLCA. This difference, which might sound acceptable, is due to the compensation of larger opposing discrepancies in the various stages and processes that make up the product life cycle. Thus, pLCA yielded significantly higher total CF emissions than EEIOA (0.23 EEIOA/pLCA ratio) in the upstream stage (agricultural and packaging processes). The opposite is observed in the core stage, where EEIOA carbon emissions were significantly higher than those calculated by pLCA (4.38 EEIOA/pLCA ratio). Differences in the downstream stage (mainly distribution and storage, and EoL phase) were less notable (1.40 EEIOA/pLCA ratio). Economic-based inputs, used in EEIOA (such as labour and service costs) and unaccounted for in pLCA, may be partly responsible for such divergences, while others should be linked to differences in the impact assessment procedures followed by each of these methodologies. These results raise some doubts about the potential of EEIOA and calls for further research on the validity, complementarity and the application domains of these methodologies. In any case, both modelling approaches agree in identifying the distribution and storage life cycle stages as main contributors to carbon emissions, calling for the implementation of measures to promote the consumption of seasonal and local fruit.

Characterization of Greenhouse Gases Emissions by Economic Sectors Using Environmentally Extended Input-Output Analysis (EEIOA)

Objectives : As climate change deepened, the concept of 2050 carbon neutrality was introduced. The COP 26 Glasgow Agreement strengthened the national greenhouse gases (GHGs) target of 2030. However, there are controversies over the feasibility of these GHGs reduction goals, considering the economic sectors energy policy and the attributes of GHGs emissions. Taking this into consideration, this study aimed to formulate the 2017 Environmentally Expanded Input-output Table to analyze the characteristics of GHGs emissions in Korea's economic sectors.Methods : The carbon dioxide emission was calculated by multiplying carbon dioxide emission factors to fuel consumption in the 2017 energy balance table, while other GHGs emissions are taken from the national GHGs inventory. All the GHGs emissions calculated and taken were allocated to 381 basic sectors of the Input-Output Table to represent each sector's characteristics of GHGs emissions. Then 381 sectors are combined into a large category of 35 sectors to formulate the 2017 Republic of Korea Environmentally Extended Input-Output Table (ROKEEIOT). Using this ROKEEIOT, the emission of Scope 1. 2, and 3 by economic sectors were estimated, and the GHGs emissions and GHGs intensity by economic sectors.Results and Discussion : The carbon dioxide emissions calculated by the 2017 ROKEEIOT prepared in this study showed a difference of 2% from the 2017 national GHGs emission statistics, confirming that the 2017 ROKEEIOT is very effective. The three economic sectors with the highest direct GHGs emissions were electricity, steam, chilled or hot water, air conditioning supply (262,280 kt CO2eq.), primary metal products (117.098 kt CO2eq.), and transportation equipment (58,332 kt CO2eq.). However, the total GHGs emissions were different in the order of construction (151,476 kt CO2eq.), transportation equipment (112,168 kt CO2eq.), computer, and electronic and optical instruments (107,868 kt CO2eq.). As a result of classifying the scope of GHGs emissions, 6 industries exceeded 50% in Scope 1, and 29 sectors exceeded 50% in Scope 3, indicating that GHGs reduction measures were necessary for the supply chain in consideration of the GHGs emissions characteristics by economic sectors. In particular, 41.68% of GHGs emissions induced by final demand were generated by exports confirming, confirming the urgent need to strengthen the carbon competitiveness of export industry in preparation for the introduction of the carbon border adjustment mechanism.Conclusion : The economic contribution, direct GHGs emissions of industries, and the amount of GHGs emissions induced by supply chains and value chains show very different patterns by economic sectors. Therefore, it was confirmed that scientific policies to reduce GHGs emissions, such as net-zero and climate change measures, should reflect the characteristics of Scope 1, which is direct emission by industry, Scope 2 emissions caused by electricity and steam consumption and scope 3 emissions generated along the supply chain or value chain.

Environmentally-extended input-output analysis of circular economy scenarios in the Philippines

Conventional economic systems are based on the unsustainable use of natural resources. Circular Economy is a framework for socio-technical regime change that prioritizes material loops to improve resource efficiency. The framework promotes business activities that capitalize on material recirculation pathways and extended product life cycles. Many countries have begun adopting Circular Economy principles through policies, targets, and action plans, but research in this area has focused largely on developed countries and major emerging economies. The lack of scientific analysis of Circular Economy implementation in developing countries is a critical research gap with significant implications on global material flows. Fast-growing countries such as the Philippines will benefit from the regime change towards Circular Economy to resolve sustainability issues from economic and demographic trends. Policy interventions need to be calibrated to enable a smooth transition to circularity. To address this gap, this study uses a 16-sector Environmentally-Extended Input-Output model to simulate four scenarios on a) increasing product demand, b) implementing circular business models, c) implementing government regulations, and d) promoting service sectors. GDP growth, material intensity, and regulatory constraints of each scenario are analyzed. Results show a potential of up to 10.05% increase in GDP and 62.51% decrease in material footprint relative to business-as-usual. Policy implications on the Philippines' transition to a Circular Economy are discussed.

Estimating the energy saving potential of residential consumption in China based on decent living standards

The basic well-being of residents should be fully considered when making residential energy-saving policies. In this study, decent living standards for China were proposed. The provincial energy saving potential of Chinese residents were estimated from a lifetime perspective using environmental extended input–output analysis. The results show that, in 2017, the energy saving potential of Chinese residents constituted 32.74% of total energy consumption. The consumption categories of transportation, housing and cooking had the greatest energy saving potential of 1668.40, 3540.83 and 3229.75 trillion kJ, respectively, in which direct energy consumption accounted for 85% of total energy consumption. For food, clothing, water, health care and education, there was only energy saving potential from indirect consumption, of which food has the largest indirect energy consumption of 3159.25 trillion kJ. Moreover, the energy saving potential varied at the provincial level, coming from different consumption categories. Special attentions should be paid to the transportation in Beijing, housing in Liaoning, and cooking in Gansu, which have relatively greater energy saving potential with per capita energy saving potential of 207.38, 1002.16, and 4256.6 thousand kJ, respectively. The results verify the importance of differentiated and targeted energy policies for residential consumption in different provinces.

How do carbon footprints from LCA and EEIOA databases compare? A comparison of ecoinvent and EXIOBASE

Life cycle assessment (LCA) and environmentally extended input output analysis (EEIOA) are two widely used approaches to assess the environmental impacts of products and services with the aim of providing decision support. Here, we compare carbon footprint (CF) results for products and services in the ecoinvent 3.4 cut-off and the hybrid version of EXIOBASE. While we find that there is good agreement for certain sectors, more than half of the matched products differ by more than a factor 2. Best fits are observed in the energy, manufacturing, and agricultural sectors, although deviations are substantial for renewable energy. Poorer fits are observed for waste treatment and mining sectors. Both databases have a limited differentiation in the service sector. Differences can, to some degree, be explained by methodological differences, such as system boundaries and approaches used to resolve multi-functionality, and data differences. The common finding that, due to incomplete economic coverage (truncation error), LCA-based CFs should be lower than EEIOA-based CFs, could not be confirmed. The comparison of CFs from LCA and EEIOA databases can provide additional insights into the uncertainties of CF results, which is important knowledge when guiding decision makers. An approach that uses the coefficient of variation to identify strategic database improvement potentials is also presented and highlights several product groups that could deserve additional attention in both databases. Further strategic database improvements are crucial to reduce uncertainties and increase the robustness of decision support that the industrial ecology community can provide for the economic transformations ahead of us. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges.

Pre-construction quantification of embodied environmental impacts to promote sustainable construction projects: The case study of a diversion dam

A quantitative assessment of the embodied environmental impacts of infrastructures can provide initial guidance to industry practitioners and engineers at the outset of the construction projects. This study presents the applicability of the Environmentally Extended Input-Output Analysis as a pre-construction evaluation tool for quantifying the embodied environmental impacts of a small diversion dam in Spain. Seven impact categories are assessed from a production-based and consumption-based perspective identifying the main sectors and regions contributing to the environmental impacts. From the consumption-based perspective, Spain is the only contributor to the environmental impacts, and from the production-based perspective, Spain is the main polluting country in all the impact categories contributing on average 68.9%. The use of high quantities of construction material leads to the sectors of steel and cement to significantly increase the environmental impacts. From the production-based perspective, steel and cement contribute on average 29.5% and 17.2%, respectively. From the consumption-based perspective, both sectors account for 74% of the overall environmental impacts. As observed in this case study, the application of the EEIOA model enables engineers and designers to focus during the early design stages on decisions that achieve high embodied impact reductions, such as prioritizing recycled materials for the construction of this infrastructure and, when possible, use materials from a less polluting origin.

Capital, energy and carbon in the United States economy

Energy in economies is required both to build the stock of capital assets, and to produce goods and services from use of the stock. Decarbonization involves: changing the capital assets for producing energy; building and using capital with greater energy efficiency; and changing the distribution and characteristics of asset types in the capital stock. From 2004 to 2019, US capital assets grew by 24%, while primary energy consumption remained relatively unchanged. Here we examine the relationship between capital and energy in the US economy to understand how this growth occurred without increased energy use. The method involves mapping of energy use and greenhouse emissions onto four broad categories of capital stock, employing environmentally-extended input–output analysis and time-series data from a variety of sources. Result show that intellectual property products, with an energy intensity of 2.9 TJ / $million of investment, grew as a proportion of the capital stock relative to structures (7.0 TJ / $million) and equipment (6.9 TJ / $million). Meanwhile the energy intensity of using capital decreased in the residential sector and in all nineteen manufacturing sectors. The study connects strategies for decarbonization of the US economy in a concise and consistent framework, with turnover of the capital stock providing opportunities for both energy efficiency and decarbonization.

Macro Sustainability across Countries: Key Sector Environmentally Extended Input-Output Analysis

When formulating economic development strategies, the environment and society must be considered to preserve well-being. This paper proposes a comparative sustainability assessment method using environmentally extended input-output analysis and multi-criteria decision aid. Using symmetric input-output tables and sectoral CO2 emissions and employment data for six countries, linkage coefficients are calculated for 163 sectors in each country. Multi-criteria decision aid tool, ELECTRE III, is used to derive outranking relationships among each country’s sectors using these coefficients as criteria, resulting in a hierarchy of sectors ordered by sustainability. Sectors that frequently appear at the top of the six hierarchies included education, health care, construction, and financial intermediation. China’s results differ significantly because of its concentration of economic activity on the primary/secondary sectors. The results can enable identification of key intervention pathways along which sustainable development could be stimulated. Country-specific recommendations and reflections on economic and sustainability policy initiatives are discussed.

Structural path decomposition analysis of resource utilization in China, 1997–2017

With the ever-increasing population and rapid economic development in China, the demand for natural resources has grown substantially. To improve the efficient utilization of resources, it is necessary to know comprehensively the flow and use of natural resources among sectors. The paper uses the environmentally extended input-output analysis (EEIOA) and structural path analysis (SPA) methods to conduct a depth analysis of the flow and use paths of resource consumption in China from 1997 to 2017 in 42 sectors to determine the key supply chains and key sectors, and we also apply the structural path decomposition (SPD) method to investigate the key path changes that drive resource consumption and the key factors that lead to consumption changes in each path. The results show that the crucial supply chain path for the largest resource consumption was “Manufacture of non-metallic mineral products →Construction”, and the flow increased from 1371 million tons in 1997 to 8173 million tons in 2017, the factor production structure was the major driving factor for consumption increase on this path. In addition, the proportion of resources consumed by the agricultural sector decreased during the research period, and consumption intensity was the main driving factor for its consumption decrease. In order to reduce domestic resource consumption as much as possible, policymakers can start with the construction sector to improve the efficient utilization of resources and adjust production structure.

ENVIRONMENTALLY EXTENDED INPUT-OUTPUT ANALYSIS OF THE BURYATIA REPUBLIC ECONOMY

Environmentally Extended Input-Output Analysis (EEIOA) provides a method for assessing the relationship between economic consumption and environmental impact. EEIO is now widely used to assess environmental impacts embodied in goods and services produced and sold. In this article, environmental extensions for the generation of waste and air and water pollutants are applied based on the input-output table of Buryatia for 2016.

Dynamics in Aotearoa New Zealand’s energy consumption between 2006/2007 and 2012/2013

Contemporaneous structural changes in the New Zealand economy, growth of the services sector, and increased reliance on renewable sources of electricity, underpin changing patterns of energy consumption in Aotearoa New Zealand. The Zero Carbon Act passed in November 2019 set a pathway to transition to a net-zero carbon future. Actions aimed at reducing energy consumption, especially transport related fossil-fuel consumption, should further accelerate the transition to a low-carbon economy. However, little is known of the factors driving patterns of energy consumption. This study systematically investigates New Zealand’s energy consumption from the perspectives of production and consumption, combining environmentally-extended input-output analysis and structural decomposition analysis. Results show that at the national level, population growth was the dominant factor in promoting energy consumption. In contrast, decreasing direct energy intensity had the largest impact on limiting growth in energy consumption. Private consumption and exports were the main sources of energy consumption. Results support important policy recommendations that achieve this low-carbon transition, such as the electrification of transport and the promotion of renewable energy.

Tracking embodied water uses and GHG emissions along Chinese supply chains

China is facing both serious water scarcity and climate change challenges simultaneously. There is an urgent need to identify the synergies between water conservation and greenhouse gas (GHG) emission mitigation. This paper aims to trace the embodied water uses and GHG emissions (i.e., CO2, CH4 and N2O) via China's domestic supply chains in 2012 and to explore their common important paths for driving the water withdrawals and the emissions of GHGs using the environmentally-extended input-output analysis and the structural path analysis. The results show a significant coupling between the embodied water uses and the embodied emissions of CO2, CH4 and N2O in the supply chains on a national scale. The water-GHG nexus relationships from the consumption-side are systematically revealed in terms of industrial sectors, final demands and supply chain paths. The top 20 nexus paths ranked by water together accounted for 37.40% of the national total water withdrawals. Ranked by GHGs, the proportions were 22.46% of the total GHG emissions. Synergies in saving water resources and mitigating the emissions of CO2, CH4 and N2O can be achieved through controlling important supply chain paths and critical transmission sectors. The highly interlinked nature of water and climate change issues requires comprehensive solutions to reduce future freshwater and GHG emission needs to maintain sustained economic growth in China.

Environmentally-extended input-output and ecological network analysis for Energy-Water-CO2 metabolic system in China

Resource and environmental elements as controlling factors for ecologic and socio-economic are crucial to seek new ideas and paths for development and prosperity. In this study, environmentally-extended input-output analysis and ecological network analysis were combined to develop three ecological networks including energy ecological network, water ecological network, and carbon ecological network for searching the complex relationships among different departments for water utilization, energy consumption, and carbon emissions under considering China as a superorganism with various complex metabolic processes and the most fundamental metabolic materials. The embodied ecological elements intensity, the indirect consumption and emissions, the embodied material flows, the ecological relationships, and the dependence intensities among sectors was obtained through transforming the monetary input-output data to physical data from 2007, 2012, and 2017. The results show that the Energy Ecological Network and Water Ecological Network were in a relatively stable state with a mutualism index greater than 1, and the relationship among different sectors in the CO2 Ecological Network needs to be further adjusted. AM (Advanced Manufacture) and Agr (Agriculture) played the top exporter and importer roles with AM as the largest embodied energy consumer and CO2 emitter, and Agr as the largest embodied water user. More measures about resource conservation and emission reduction for AM and Agr are desired. Con (construction) had a strong dependence intensity on other sectors with amounts of over 90%. Resources and environmental effects on Con can be improved by increasing the utilization efficiency of intermediate products. The results could provide scientific policy implications and guidelines to promote the stable and healthy operations by revealing the dynamic change of sectors within the Energy-Water-CO2 metabolic system in China.

The influence of life cycle inventory approaches on the choice of structural systems to reduce the embodied greenhouse gas emissions of tall buildings

The construction of tall buildings generates a high spatial and temporal concentration of greenhouse gas (GHG) emissions. Research has shown that as building height increases, more resources per floor area are required to withstand the increasing effects of wind and earthquake loads. This has major implications for the environmental performance of tall buildings since the embodied GHG emissions (EGHGE) of structural systems tend to represent the greatest portion of the life cycle GHG emissions of tall buildings. In mitigating the effects of climate change, life cycle assessment (LCA) has been proposed as an early stage design tool to facilitate the choice of structural systems for tall buildings. However, international standards on LCA do not specify which of the three main life cycle inventory (LCI) approaches to use - process analysis, environmentally-extended input-output analysis or hybrid analysis. The aim of this paper is to evaluate the influence of LCI approaches on the choice of structural systems for tall buildings to minimise their embodied GHG emissions.The effects of LCI approaches on the choice of structural systems for tall buildings are evaluated using 10 tall buildings, ranging in height from 10 to 50 storeys, parametrically designed using finite element modelling. Two alternative structural systems are proposed and various LCI approaches are used to compare their EGHGE. The paper demonstrates that varying the LCI approach can significantly influence the values of EGHGE of structural systems for tall buildings by up to 116%. Notably, the paper demonstrates that, in minimising EGHGE, the adopted LCI approach can influence the choice of structural systems for tall buildings. The findings of this study confirm the need for clarity, transparency and comprehensiveness in the use of LCI approaches for comparative LCA studies, particularly in the structural design of tall buildings.

Evaluating the carbon footprint of a Spanish city through environmentally extended input output analysis and comparison with life cycle assessment

Currently, most of the greenhouse gas (GHG) emissions are attributed to cities, as they are the global centers of business, residential and cultural activity, cities are expected to play a leading role in proposing climate change mitigation actions. To do so, it is important to have tools that allow the carbon footprint of cities to be assessed as accurately as possible. This study aims to quantify the carbon footprint (CF) associated with the activities developed in a Spanish city (Cadiz, Southwest Spain) by means of two available environmental methodologies, namely Environmentally Extended Input-Output Analysis (EEIOA) and Life Cycle assessment (LCA). When EEIOA is considered, two downscaling factors were proposed for the analysis due to the nature of the data handled (monetary data), based on the incomes (DF1) and expenditures (DF2) per inhabitant at city level. Regarding LCA, the rates of consumption of goods and production of waste per inhabitant have been processed to estimate the CF. The CF scores identified were 5.25 and 3.83 tCO2-eq·inhabitant−1·year−1 for DF1 and DF2 respectively, according to EEIOA, and 5.43 tCO2-eq·inhabitant−1·year−1, considering LCA. Therefore, a similarity can be concluded between the results obtained with both methodologies despite the inherent differences. Considering the results, the downscaling procedure based on income per inhabitant should be preferred, pointing to EEIOA as a good alternative to LCA for evaluating the CF at city level, requiring less time and effort. In contrast, EEIOA reports more limitations when critical flows were identified, which LCA can solve. Finally, this study can be of great interest to policy makers and city governments to know the CF and the main flows that contribute and in this way, can develop new policies and city models for reducing GHG emission new policies and city models for reducing GHG emission and addressing climate change.