Jannick Højrup Schmidt

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 inputoutput 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 inputoutput communities. In doing so, the article shows that the partitioning method in LCA is equivalent to the industry-technology model in inputoutput economics, and system expansion in LCA is equivalent to the by-product-technology model in inputoutput 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 inputoutput 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.

Assessing the land use implications of biodiesel use from an LCA perspective

The land use required in order to meet the increasing demand for biodiesel has significant impacts. New methodological developments within environmental life cycle assessment (LCA) establish a cause–effect relationship between the demand for biodiesel and its impacts on biodiversity. The objective of this article is to assess and compare the impacts of rapeseed oil (RSO) production in the EU and palm oil (PO) production in Southeast Asia. The functional unit of the LCA is 20.8 Mtoe (million tons oil equivalents) biodiesel equalling the EU25 goals for biodiesel in 2020. Land occupation and transformation are quantified for the two alternative vegetable oils, and losses throughout the product chain from cultivation over crushing to refining are inventoried. Market mechanisms and land which is indirectly affected by product substitutions from co-products are included in the modelling. Land occupation and transformation are evaluated by the use of life cycle impact assessment (LCIA) models on land use and biodiversity. Three basic scenarios are evaluated: (1) RSO-based biodiesel is produced from rapeseed grown on fields which were previously grown by other crops (barley, BL) – the displaced BL is imported from abroad; (2) RSO-based biodiesel is produced from rapeseed grown on former set-aside land in the EU; and (3) PO-based biodiesel produced in Southeast Asia is imported to the EU. It is concluded that the new EU policies on using set-aside land for energy crops cannot cover the European demand for biodiesel and crops must thus be imported from outside the EU. This means that land use outside the EU is affected. The modelling shows that the use of PO affects the land use in Malaysia or Indonesia and that Canadian land use for BL cultivation is affected when rapeseed is produced in the EU. The impacts on land use and biodiversity are presented for all three scenarios. Finally, it is discussed how an LCA perspective like the one applied here can contribute to the assessment of environmental impacts within land use science.

Solid Waste and the Circular Economy: A Global Analysis of Waste Treatment and Waste Footprints

Summary Detailed and comprehensive accounts of waste generation and treatment form the quantitative basis of designing and assessing policy instruments for a circular economy (CE). We present a harmonized multiregional solid waste account, covering 48 world regions, 11 types of solid waste, and 12 waste treatment processes for the year 2007. The account is part of the physical layer of EXIOBASE v2, a multiregional supply and use table. EXIOBASE v2 was used to build a waste-input-output model of the world economy to quantify the solid waste footprint of national consumption. The global amount of recorded solid waste generated in 2007 was approximately 3.2 Gt (gigatonnes1), of which 1 Gt was recycled or reused, 0.7 Gt was incinerated, gasified, composted, or used as aggregates, and 1.5 Gt was landfilled. Patterns of waste generation differ across countries, but a significant potential for closing material cycles exists in both high- and low-income countries. The European Union (EU), for example, needs to increase recycling by approximately 100 megatonnes per year (Mt/yr) and reduce landfilling by approximately 35 Mt/yr by 2030 to meet the targets set by the Action Plan for the Circular Economy. Solid waste footprints are strongly coupled with affluence, with income elasticities of around 1.3 for recycled waste, 2.2 for recovery waste, and 1.5 for landfilled waste, respectively. The EXIOBASE v2 solid waste account is based on statistics of recorded waste flows and therefore likely to underestimate actual waste flows.

EXIOBASE 3: Developing a Time Series of Detailed Environmentally Extended Multi‐Regional Input‐Output Tables

Environmentally extended multiregional input-output (EE MRIO) tables have emerged as a key framework to provide a comprehensive description of the global economy and analyze its effects on the environment. Of the available EE MRIO databases, EXIOBASE stands out as a database compatible with the System of Environmental-Economic Accounting (SEEA) with a high sectorial detail matched with multiple social and environmental satellite accounts. In this paper, we present the latest developments realized with EXIOBASE 3-a time series of EE MRIO tables ranging from 1995 to 2011 for 44 countries (28 EU member plus 16 major economies) and five rest of the world regions. EXIOBASE 3 builds upon the previous versions of EXIOBASE by using rectangular supply-use tables (SUTs) in a 163 industry by 200 products classification as the main building locks. In order to capture structural changes, economic developments, as reported by national statistical agencies, were imposed on the available, disaggregated SUTs from EXIOBASE 2. These initial estimates were further refined by incorporating detailed data on energy, agricultural production, resource extraction, and bilateral trade. EXIOBASE 3 inherits the high level of environmental stressor detail from its precursor, with further improvement in the level of detail for resource xtraction. To account for the expansion of the European Union (EU), EXIOBASE 3 was developed with the full EU28 country set (including the new member state Croatia). EXIOBASE 3 provides a unique tool for analyzing the dynamics of environmental pressures of economic activities over time.

A historical perspective of Global Warming Potential from Municipal Solid Waste Management

The Municipal Solid Waste Management (MSWM) sector has developed considerably during the past century, paving the way for maximum resource (materials and energy) recovery and minimising environmental impacts such as global warming associated with it. The current study is assessing the historical development of MSWM in the municipality of Aalborg, Denmark throughout the period of 1970 to 2010, and its implications regarding Global Warming Potential (GWP(100)), using the Life Cycle Assessment (LCA) approach. Historical data regarding MSW composition, and different treatment technologies such as incineration, recycling and composting has been used in order to perform the analysis. The LCA results show a continuous improvement in environmental performance of MSWM from 1970 to 2010 mainly due to the changes in treatment options, improved efficiency of various treatment technologies and increasing focus on recycling, resulting in a shift from net emission of 618 kg CO(2)-eq.tonne(-1) to net saving of 670 kg CO(2)-eq.tonne(-1) of MSWM.

A flexible parametric model for a balanced account of forest carbon fluxes in LCA

PurposeDespite a mature debate on the importance of a time-dependent account of carbon fluxes in life cycle assessments (LCA) of forestry products, static accounts of fluxes are still common. Time-explicit inventory of carbon fluxes is not available to LCA practitioners, since the most commonly used life cycle inventory (LCI) databases use a static approach. Existing forest models are typically applied to specific study fields for which the detailed input parameters required are available. This paper presents a simplified parametric model to obtain a time-explicit balanced account of the carbon fluxes in a forest for use in LCA. The model was applied to the case of spruce as an example.MethodsThe model calculated endogenous and exogenous carbon fluxes in tons of carbon per hectare. It was designed to allow users to choose (a) the carbon pools to be included in the analysis (aboveground and belowground carbon pools, only aboveground carbon or only carbon in stem); (b) a linear or sigmoidal dynamic function describing biomass growth; (c) a sigmoidal, negative exponential or linear dynamic function describing independently the decomposition of aboveground and belowground biomass; and (d) the forest management features such as stand type, rotation time, thinning frequency and intensity.Results and discussionThe parametric model provides a time-dependent LCI of forest carbon fluxes per unit of product, taking into account the typically limited data available to LCA practitioners, while providing consistent and robust outcomes. The results obtained for the case study were validated with the more complex CO2FIX. The model ensures carbon balance within spatial and time delimitation defined by the user by accounting for the annual biomass degradation and production in each carbon pool. The inventory can be used in LCA studies and coupled with classic indicators (e.g. global warming potential) to accurately determine the climate impacts over time. The model is applicable globally and to any forest management practice.ConclusionsThis paper proposes a simplified and flexible forest model, which facilitates the implementation in LCA of time-dependent assessments of bio-based products.

Methodology for the Construction of Global Multi-Regional Hybrid Supply and Use Tables for the EXIOBASE v3 Database

Summary This article describes the algorithm that has been developed within the European Union (EU) FP7 project DESIRE for the construction of the EXIOBASE multiregional hybrid supply and use tables (MR-HSUTs) version 3. The tables include 43 countries plus five rest-of-the-world regions and are built for the period 2000–2011. MR-HSUTs are compiled in mixed units, that is, tangible goods in mass units, intangible energy flows in terajoules, and, finally, services in euros. The article summarizes the various steps of the developed procedure, from data collection until the final supply and use tables. It will be shown how several disconnected data sets with varying quality are harmonized so as to build an effective analytical database that can be used for several types of analyses, such as life cycle assessment, total material requirement, material intensity per product service, carbon footprint, and so on.

Challenges relating to data and system delimitation in Life Cycle Assessments of food products

: This chapter describes the major challenges relating to LCA data and system delimitation when carrying out LCAs on products from the food industry. Food is characterised as a product where emissions related to the feedstock (agriculture) and electricity in the use (and processing) stage can be identified as hotspots. Calculation of environmental impacts from agricultural products and electricity are highly sensitive to the applied approach for modelling; consequential versus attributional. Both consequential and attributional modelling are demonstrated in different situations, and pros and cons of the two approaches are discussed. Based on this, consequential modelling is proposed as the preferable option because it takes into account cause–effect relationships, it does not ignore the effects of co-products and it maintains mass- and substance-balance of processes. Since consequential modelling seeks to be more accurate, the risk of misleading decision support is minimised in consequential modelling. The disadvantage of consequential modelling is that no commonly accepted marginal supplies of products for different countries/regions exist. The same applies for attributional modelling, but national/regional market averages are more fixed and less sensitive to assumptions introduced by the individual LCA practitioner.

Trade and the role of non-food commodities for global eutrophication

The oversupply of nutrients (phosphorous and nitrogen) in fresh and marine water bodies presents a serious ecosystem threat due to impacts on water quality through eutrophication. With agriculture characterized as a primary driver of eutrophication, the role of food consumption and trade has been the focus of recent phosphorus and nitrogen impact studies. However, the environmental impacts associated with non-food commodities are significant and yet to be characterized. Here, we link a spatially explicit treatment of phosphorous and nitrogen eutrophication potentials to a multi-regional input–output approach to characterize the importance of overall consumption for marine and freshwater eutrophication across 44 countries and 5 rest-of-world regions over the period 2000–2011. We find that clothing, goods for shelter, services and other manufactured products account for 35% of global marine eutrophication and 38% of the global freshwater eutrophication footprints in 2011, up from 31 and 33%, respectively, in 2000. Relative to food consumption, non-food consumption is also significantly more income elastic and shaped by trade. As economies develop, this points to the need for trade agreements and policies to consider the displacement of ecosystem impacts.As agriculture is the primary driver of eutrophication resulting from the oversupply of nitrogen and phosphorus to water bodies, much attention has been paid to the environmental impacts of food consumption. Little is known about the impacts of consuming other goods. This study shows that in 2011 the final demand for non-food products accounted for over one-third of the global marine and freshwater eutrophication impacts—a 28% increase since 2000.

On the boundary between economy and environment in life cycle assessment

PurposeWe investigate how the boundary between product systems and their environment has been delineated in life cycle assessment and question the usefulness and ontological relevance of a strict division between the two.MethodsWe consider flows, activities and impacts as general terms applicable to both product systems and their environment and propose that the ontologically relevant boundary is between the flows that are modelled as inputs to other activities (economic or environmental)—and the flows that—in a specific study—are regarded as final impacts, in the sense that no further feedback into the product system is considered before these impacts are applied in decision-making. Using this conceptual model, we contrast the traditional mathematical calculation of the life cycle impacts with a new, simpler computational structure where the life cycle impacts are calculated directly as part of the Leontief inverse, treating product flows and environmental flows in parallel, without the need to consider any boundary between economic and environmental activities.Results and discussionOur theoretical outline and the numerical example demonstrate that the distinctions and boundaries between product systems and their environment are unnecessary and in some cases obstructive from the perspective of impact assessment, and can therefore be ignored or chosen freely to reflect meaningful distinctions of specific life cycle assessment (LCA) studies. We show that our proposed computational structure is backwards compatible with the current practice of LCA modelling, while allowing inclusion of feedback loops both from the environment to the economy and internally between different impact categories in the impact assessment.ConclusionsOur proposed computational structure for LCA facilitates consistent, explicit and transparent modelling of the feedback loops between environment and the economy and between different environmental mechanisms. The explicit and transparent modelling, combining economic and environmental information in a common computational structure, facilitates data exchange and re-use between different academic fields.