Double‐Counting in Life Cycle Calculations

Many popular frameworks apply life cycle calculations to examine environmental burdens occurring throughout the life cycle of products and services that are either purchased by final consumers or demanded as inputs by producers. Accounting for the full supply chain of producer items can lead to double‐counting effects when results of separate studies are added up and referenced or compared to totals. If, for instance, energy life cycle inventories were prepared for all consumer and producer items in an economy and added up, the resulting total amount of energy would be greater than national energy consumption. Although this double‐counting is inconsequential if analyses are appraised in isolation without reference to national totals, it leads to serious errors when large interconnected systems are analyzed or when results are placed into wider (e.g., regional, national, or global) contexts. The article lists a number of prominent policy and decision‐making frameworks that make use of life cycle techniques, where this double‐counting error is highly undesirable. It proposes a solution to the double‐counting problem in which supply chains in the product life cycle are split and burdens shared between the supplying and demanding sides of every transaction in the economy.     

Water Consumption Based on a Disaggregated Social Accounting Matrix of Huesca (Spain)

Making use of the social accounting matrix (SAM) of the Spanish province of Huesca in 2002, updated following Junius and Oosterhaven's GRAS method and work by Lenzen and colleagues, we have estimated the water footprint of the region. The water footprint is defined as the volume of water needed for the production of the goods and services consumed by the inhabitants plus the direct consumption in the households. We built an open Leontief model, which gives us the water embodied in the production of goods. The valuations concern the industrial, service, and domestic sectors’ water consumption, the embodied water imported from and exported to other countries, and the agrarian water use. This agrarian sector, clearly the sector that shows the greatest water consumption, is carefully examined, so it is disaggregated for the calculations into 31 irrigation land products, dry land, and 9 livestock classifications. As a consequence, the framework enables the observation of the relationships and flows of water taking place among all the sectors and activities in the economy. Finally, we also make use of the per capita water footprint estimations to get a clear picture of how the responsibility for water use is distributed once foreign trade is taken into account.     

A Material History of Australia

This article presents an analysis of the material history of Australia in the period 1975–2005. The values of economy‐wide indicators of material flow roughly trebled since 1975, and we identify the drivers of this change through structural decomposition analysis. The purpose of this work is to delve beneath the top‐level trends in material flow growth to investigate the structural changes in the economy that have been driving this growth. The major positive drivers of this change were the level of exports, export mix, industrial structure, affluence, and population. Only improvements in material intensity offered retardation of growth in material flow. Other structural components had only small effects at the aggregate level. At a more detailed level, however, the importance of the mineral sectors became apparent. Improvements in mining techniques have reduced material requirements, but increased consumption within the economy and increased exports have offset these reductions. The full roll out of material flow accounting through Australian society and business and a systematic response to its implications will require change in the national growth focus of the last two generations, with serious consideration needed to reverse the current volume‐focused growth of the economy and also to recast neoliberal and globalized trade policies that have dominated the globe for the past decades.     

Hybrid Framework for Managing Uncertainty in Life Cycle Inventories

Life cycle assessment (LCA) is increasingly being used to inform decisions related to environmental technologies and polices, such as carbon footprinting and labeling, national emission inventories, and appliance standards. However, LCA studies of the same product or service often yield very different results, affecting the perception of LCA as a reliable decision tool. This does not imply that LCA is intrinsically unreliable; we argue instead that future development of LCA requires that much more attention be paid to assessing and managing uncertainties. In this article we review past efforts to manage uncertainty and propose a hybrid approach combining process and economic input–output (I‐O) approaches to uncertainty analysis of life cycle inventories (LCI). Different categories of uncertainty are sometimes not tractable to analysis within a given model framework but can be estimated from another perspective. For instance, cutoff or truncation error induced by some processes not being included in a bottom‐up process model can be estimated via a top‐down approach such as the economic I‐O model. A categorization of uncertainty types is presented (data, cutoff, aggregation, temporal, geographic) with a quantitative discussion of methods for evaluation, particularly for assessing temporal uncertainty. A long‐term vision for LCI is proposed in which hybrid methods are employed to quantitatively estimate different uncertainty types, which are then reduced through an iterative refinement of the hybrid LCI method.     

The United Kingdom's Fossil Resource Consumption Between 1968 and 2000

This article presents the trends of two indicators measuring fossil resource consumption in the United Kingdom (UK). First, a domestic material consumption (DMC) indicator for fossil resources (DMC_fossil) in the mass unit million tonnes is calculated. DMC_fossil shows that between 1970 and 2000 UK fossil resource consumption decreased by 10%, which suggests absolute dematerialization for this resource. Investigation into the mix of fossil resources during this period highlighted the shift from the heavy fossil resource coal to the lighter, more energy‐dense natural gas, which resulted in decreased mass of resource required. Second, an alternative indicator, resource consumption by a nation (RCN) for fossil resources (RCN_fossil) was calculated, which includes the indirect fossil resources attributable to traded goods and is measured in million tonnes of oil equivalent. RCN_fossil shows that between 1970 and 2000 United Kingdom's fossil resource consumption increased by 14%, which emphasizes that even though there has been a decrease in the mass of fossil resources demanded, it has been accompanied by an increase in the volume of resource consumed. Additionally, deconstruction of RCN_fossil shows that indirectly used resources attributable to exports and imports for the United Kingdom are significant. RCN_fossil indicates that on the basis of past trends, fossil resources attributable to UK imports will overtake fossil resources attributable to its exports, which will make it dependent on imported resources. We conclude that further debate on appropriate aggregate and complementary indicators is needed.     

The Raw Material Equivalents of International Trade

This article aims at estimating the raw material equivalents (RMEs)—the upstream used material flows required along the production chain—of imports and exports for some Latin American countries: Brazil, Chile, Colombia, Ecuador, and Mexico. Furthermore, the United States is included in the analysis as a reference for a high‐income economy. The RME concept and the empirical evidence are articulated by use of an input?output methodology. Results are set out for the year 2003 for each of the countries and in time series for the years 1977, 1986, 1996, and 2003 in the case of Chile. The findings show not only the physical dimensions behind direct material traded but also how the previous exporter (importer) position of a country (based on standard material flow analysis indicators) deteriorates, alleviates, or changes. Implications for material consumption indicators, such as direct material consumption (DMC) and raw material consumption (RMC), are also drawn. The results suggest basing the discussion of material flows on a broader set of indicators to obtain a more comprehensive picture of the implications of international trade and its impacts on the environment.     

Development of a Consumer Environmental Index and Results for Washington State Consumers

Consumer choices affect sustainability of societal systems, and state governments increasingly are interested in environmental impacts of consumption. This article describes a Consumer Environmental Index (CEI) to track the impacts of product purchase, use, and disposal and applies this initial CEI to Washington State in the United States. CEI has modules for product and service use, upstream resource extraction and manufacturing, and downstream disposal. CEI uses hybrid life cycle assessment (LCA) methods, combined with purchasing data from the Bureau of Labor Statistics (BLS) Consumer Expenditure Survey. For Washington State, when human health and ecosystem toxicity impact was assessed with the TRACI/CalTOX methods, weighted aggregate and per consumer impacts in all categories increased during the 6 years from 2000 to 2005. For impacts per real dollar spent, only the CEI's climate change component declined, falling nearly 7% between 2000 and 2005. Purchasing details in the BLS expenditure surveys enable the CEI to track environmental impact details on 700 individual categories of products and services. For example, sugar, motor oil, and wood heat appear to have serious environmental impacts, whereas recycling of paper, cardboard, and food and beverage container discards can be as effective at reducing greenhouse gas emissions as cutting vehicle fuel usage nearly in half. Such results may serve to increase understanding of environmentally effective actions to reduce climate, human health, and ecosystem impacts of consumption.     

Generalized Make and Use Framework for Allocation in Life Cycle Assessment

Allocation in life cycle inventory (LCI) analysis is one of the long‐standing methodological issues in life cycle assessment (LCA). Discussion on allocation among LCA researchers has taken place almost in complete isolation from the series of closely related discussions from the 1960s in the field of input?output economics, regarding the supply and use framework. This article aims at developing a coherent mathematical framework for allocation in LCA by connecting the parallel developments of the LCA and the input?output communities. In doing so, the article shows that the partitioning method in LCA is equivalent to the industry‐technology model in input?output economics, and system expansion in LCA is equivalent to the by‐product‐technology model in input?output output economics. Furthermore, we argue that the commodity‐technology model and the by‐product‐technology model, which have been considered as two different models in input?output economics for more than 40 years, are essentially equivalent when it comes to practical applications. It is shown that the matrix‐based approach used for system expansion successfully solves the endless regression problem that has been raised in LCA literature. A numerical example is introduced to demonstrate the use of allocation models. The relationship of these approaches with consequential and attributional LCA models is also discussed.     

Energy Intensities and Carbon Dioxide Emissions in a Social Accounting Matrix Model of the Andalusian Economy

The aim of this article is to calculate energy intensity and carbon dioxide (CO₂) emissions in Andalusia, the largest and most populated region of Spain. Energy intensities for five energy commodities used in production activities are calculated using a social accounting matrix (SAM) model with three alternative scenarios, each utilizing differing closure rules. More interestingly, by using 2005 data and updating the values of exogenous accounts, the article also provides estimates of CO₂ emissions ten years out from the 1995 base year. Finally, counterfactual experiments are performed to quantify the overall reduction in direct energy coefficients that would have made it possible to maintain constant production‐sector emissions from 1995 to 2005. The results indicate that there is a strong interdependence among energy sectors and the most intensive energy users; they also indicate the importance of induced effects when factor accounts and private consumption are endogenous. The estimates obtained concerning CO₂ emissions are close to official estimates, both from 1995 and 2005. The counterfactual experiments indicate that a 26.5% cut in the size of direct energy requirements would have made it possible to maintain constant emissions. They also indicate that efforts to curtail emissions should be focused on improving efficiency in coal extraction and combustion and oil refining.     

Is energy intensity a driver of structural change? Empirical evidence from the global economy

Input–output tables (IOTs) provide a relevant picture of economic structure as they represent the composition and interindustry relationships of an economy. The technical coefficients matrix (A matrix) is considered to capture the technological status of an economy; so, it is of special relevance for the evaluation of long-term, structural transformations, such as sustainability transitions in integrated assessment models (IAMs). The A matrix has typically been considered either static or exogenous. Endogenous structural change has rarely been applied to models. The objective of this paper is to analyze energy intensity, a widely used variable in IAMs, and its role as a driver of structural change. We therefore identify the most relevant technical coefficients in the IOTs time series and estimate an econometric model based on the energy intensity of five different final end-use energy sources. The results of this analysis show that energy intensity has a significant influence on the evolution of the A matrix and should therefore be taken into consideration when analyzing endogenous structural change in models.