Manfred Lenzen

Errors in Conventional and Input‐Output—based Life—Cycle Inventories

Conventional process‐analysis‐type techniques for compiling life‐cycle inventories suffer from a truncation error, which is caused by the omission of resource requirements or pollutant releases of higher‐order upstream stages of the production process. The magnitude of this truncation error varies with the type of product or process considered, but can be on the order of 50%. One way to avoid such significant errors is to incorporate input‐output analysis into the assessment framework, resulting in a hybrid life‐cycle inventory method. Using Monte‐Carlo simulations, it can be shown that uncertainties of input‐output– based life‐cycle assessments are often lower than truncation errors in even extensive, third‐order process analyses.

The material footprint of nations

Significance This original research paper addresses a key issue in sustainability science: How many and which natural resources are needed to sustain modern economies? Simple as it may seem, this question is far from trivial to answer and has indeed not been addressed satisfactorily in the scholarly literature. We use the most comprehensive and most highly resolved economic input–output framework of the world economy together with a detailed database of global material flows to calculate the full material requirements of all countries covering a period of two decades. Called the “material footprint,” this indicator provides a consumption perspective of resource use and new insights into the actual resource productivity of nations. Metrics on resource productivity currently used by governments suggest that some developed countries have increased the use of natural resources at a slower rate than economic growth (relative decoupling) or have even managed to use fewer resources over time (absolute decoupling). Using the material footprint (MF), a consumption-based indicator of resource use, we find the contrary: Achievements in decoupling in advanced economies are smaller than reported or even nonexistent. We present a time series analysis of the MF of 186 countries and identify material flows associated with global production and consumption networks in unprecedented specificity. By calculating raw material equivalents of international trade, we demonstrate that countries’ use of nondomestic resources is, on average, about threefold larger than the physical quantity of traded goods. As wealth grows, countries tend to reduce their domestic portion of materials extraction through international trade, whereas the overall mass of material consumption generally increases. With every 10% increase in gross domestic product, the average national MF increases by 6%. Our findings call into question the sole use of current resource productivity indicators in policy making and suggest the necessity of an additional focus on consumption-based accounting for natural resource use.

International trade drives biodiversity threats in developing nations.

Human activities are causing Earth’s sixth major extinction event—an accelerating decline of the world’s stocks of biological diversity at rates 100 to 1,000 times pre-human levels. Historically, low-impact intrusion into species habitats arose from local demands for food, fuel and living space. However, in today’s increasingly globalized economy, international trade chains accelerate habitat degradation far removed from the place of consumption. Although adverse effects of economic prosperity and economic inequality have been confirmed, the importance of international trade as a driver of threats to species is poorly understood. Here we show that a significant number of species are threatened as a result of international trade along complex routes, and that, in particular, consumers in developed countries cause threats to species through their demand of commodities that are ultimately produced in developing countries. We linked 25,000 Animalia species threat records from the International Union for Conservation of Nature Red List to more than 15,000 commodities produced in 187 countries and evaluated more than 5 billion supply chains in terms of their biodiversity impacts. Excluding invasive species, we found that 30% of global species threats are due to international trade. In many developed countries, the consumption of imported coffee, tea, sugar, textiles, fish and other manufactured items causes a biodiversity footprint that is larger abroad than at home. Our results emphasize the importance of examining biodiversity loss as a global systemic phenomenon, instead of looking at the degrading or polluting producers in isolation. We anticipate that our findings will facilitate better regulation, sustainable supply-chain certification and consumer product labelling.

BUILDING EORA: A GLOBAL MULTI-REGION INPUT–OUTPUT DATABASE AT HIGH COUNTRY AND SECTOR RESOLUTION

There are a number of initiatives aimed at compiling large-scale global multi-region input–output (MRIO) tables complemented with non-monetary information such as on resource flows and environmental burdens. Depending on purpose or application, MRIO construction and usage has been hampered by a lack of geographical and sectoral detail; at the time of writing, the most advanced initiatives opt for a breakdown into at most 129 regions and 120 sectors. Not all existing global MRIO frameworks feature continuous time series, margins and tax sheets, and information on reliability and uncertainty. Despite these potential limitations, constructing a large MRIO requires significant manual labour and many years of time. This paper describes the results from a project aimed at creating an MRIO account that represents all countries at a detailed sectoral level, allows continuous updating, provides information on data reliability, contains table sheets expressed in basic prices as well as all margins and taxes, and contains a historical time series. We achieve these goals through a high level of procedural standardisation, automation, and data organisation.

Primary energy and greenhouse gases embodied in Australian final consumption: an input–output analysis

Input–output modeling of primary energy and greenhouse gas embodiments in goods and services is a useful technique for designing greenhouse gas abatement policies. The present paper describes direct and indirect primary energy and greenhouse gas requirements for a given set of Australian final consumption. It considers sectoral disparities in energy prices, capital formation and international trade flows and it accounts for embodiments in the Gross National Expenditure as well as the Gross Domestic Product. Primary energy and greenhouse gas intensities in terms of MJ/

A modified ecological footprint method and its application to Australia

and kg CO2-e/

Mapping the Structure of the World Economy

are reported, as well as national balances of primary energy consumption and greenhouse gas emissions.

INPUT–OUTPUT ANALYSIS AND CARBON FOOTPRINTING: AN OVERVIEW OF APPLICATIONS

We present a new calculation of Australias ecological footprint. Modifications have been made to the concept as originally proposed, in response to its perceived shortcomings: rather than characterising the consumption of the Australian population in terms of appropriated ‘bioproduction’ at world-average productivity, a regional, disturbance-based approach is taken, including actual Australian land use and emissions data. We consider greenhouse gases other than CO2 and emission sources other than energy use. We re-classify land use and introduce a weighting system to describe the degree of land disturbance. For our calculations, we employ a single-region, static, partially closed input–output framework. Australias ecological footprint is determined based on actual land use as well as on land disturbance. We set up National Greenhouse Gas and Ecological Footprint Accounts distinguishing imports, domestic consumption, and exports. We investigate variations of the ecological footprint with demographic factors such as income, expenditure, size, and location of households, and draw some policy implications from our results. When determined based on actual land use on all types of land, Australias ecological footprint is about 13.6 hectares per capita (ha/cap), which is considerably larger than results obtained in previous studies. After weighting, a land disturbance of 7.2 ha/cap is obtained. The per-capita ecological footprint shows a correlation with household expenditure, which can be described by an elasticity ηE=0.64. Furthermore, the per-capita ecological footprint decreases noticeably with household size.

A CARBON FOOTPRINT TIME SERIES OF THE UK – RESULTS FROM A MULTI-REGION INPUT–OUTPUT MODEL

We have developed a new series of environmentally extended multi-region input-output (MRIO) tables with applications in carbon, water, and ecological footprinting, and Life-Cycle Assessment, as well as trend and key driver analyses. Such applications have recently been at the forefront of global policy debates, such as about assigning responsibility for emissions embodied in internationally traded products. The new time series was constructed using advanced parallelized supercomputing resources, and significantly advances the previous state of art because of four innovations. First, it is available as a continuous 20-year time series of MRIO tables. Second, it distinguishes 187 individual countries comprising more than 15,000 industry sectors, and hence offers unsurpassed detail. Third, it provides information just 1-3 years delayed therefore significantly improving timeliness. Fourth, it presents MRIO elements with accompanying standard deviations in order to allow users to understand the reliability of data. These advances will lead to material improvements in the capability of applications that rely on input-output tables. The timeliness of information means that analyses are more relevant to current policy questions. The continuity of the time series enables the robust identification of key trends and drivers of global environmental change. The high country and sector detail drastically improves the resolution of Life-Cycle Assessments. Finally, the availability of information on uncertainty allows policy-makers to quantitatively judge the level of confidence that can be placed in the results of analyses.

Environmentally important paths, linkages and key sectors in the Australian economy

This article provides an overview of how generalised multi-regional input–output models can be used for carbon footprint applications. We focus on the relevance and suitability of such evidence to inform decision making. Such an overview is currently missing. Drawing on UK results, we cover carbon footprint applications in seven areas: national emissions inventories and trade, emission drivers, economic sectors, supply chains, organisations, household consumption and lifestyles as well as sub-national emission inventories. The article highlights the multiple uses of generalised multi-regional input–output models for carbon footprinting and concludes by highlighting important avenues for future research.