Showing papers by "Markus Berger published in 2013"

Review of methods addressing freshwater use in life cycle inventory and impact assessment

Abstract: In recent years, several methods have been developed which propose different freshwater use inventory schemes and impact assessment characterization models considering various cause–effect chain relationships. This work reviewed a multitude of methods and indicators for freshwater use potentially applicable in life cycle assessment (LCA). This review is used as a basis to identify the key elements to build a scientific consensus for operational characterization methods for LCA. This evaluation builds on the criteria and procedure developed within the International Reference Life Cycle Data System Handbook and has been adapted for the purpose of this project. It therefore includes (1) description of relevant cause–effect chains, (2) definition of criteria to evaluate the existing methods, (3) development of sub-criteria specific to freshwater use, and (4) description and review of existing methods addressing freshwater in LCA. No single method is available which comprehensively describes all potential impacts derived from freshwater use. However, this review highlights several key findings to design a characterization method encompassing all the impact pathways of the assessment of freshwater use and consumption in life cycle assessment framework as the following: (1) in most of databases and methods, consistent freshwater balances are not reported either because output is not considered or because polluted freshwater is recalculated based on a critical dilution approach; (2) at the midpoint level, most methods are related to water scarcity index and correspond to the methodological choice of an indicator simplified in terms of the number of parameters (scarcity) and freshwater uses (freshwater consumption or freshwater withdrawal) considered. More comprehensive scarcity indices distinguish different freshwater types and functionalities. (3) At the endpoint level, several methods already exist which report results in units compatible with traditional human health and ecosystem quality damage and cover various cause–effect chains, e.g., the decrease of terrestrial biodiversity due to freshwater consumption. (4) Midpoint and endpoint indicators have various levels of spatial differentiation, i.e., generic factors with no differentiation at all, or country, watershed, and grid cell differentiation. Existing databases should be (1) completed with input and output freshwater flow differentiated according to water types based on its origin (surface water, groundwater, and precipitation water stored as soil moisture), (2) regionalized, and (3) if possible, characterized with a set of quality parameters. The assessment of impacts related to freshwater use is possible by assembling methods in a comprehensive methodology to characterize each use adequately.

Methodological Challenges in Volumetric and Impact‐Oriented Water Footprints

Abstract: Summary This work identifies shortcomings in water footprinting and discusses whether the water footprint should be a volumetric or impact-oriented index A key challenge is the current definition of water consumption according to which evaporated water is regarded as lost for the originating watershed per se Continental evaporation recycling rates of up to 100% within short time and length scales show that this definition is not generally valid Also, the inclusion of land use effects on the hydrological balance is questionable, as land transformation often leads to higher water availability due to locally increased runoff Unless potentially negative consequences, such as flooding or waterlogging, and adverse effects on the global water cycle are considered, water credits from land transformation seem unjustified Most impact assessment methods use ratios of annual withdrawal or consumption to renewability rates to denote local water scarcity As these ratios are influenced by two metrics—withdrawal and availability—arid regions can be regarded as uncritical if only small fractions of the limited renewable supplies are used Besides neglecting sensitivities to additional water uses, such indicators consider neither ground nor surface water stocks, which can buffer water shortages temporally Authors favoring volumetric indicators claim that global freshwater appropriation is more important than local impacts, easier to determine, and less error prone than putting complex ecological interaction into mathematical models As shown in an example, volumetric water footprints can be misleading without additional interpretation because numerically smaller footprints can cause higher impacts

Carbon footprint of recycled biogenic products: the challenge of modelling CO2 removal credits

Abstract: Current carbon footprinting (CF) and life cycle assessment (LCA) methods do not treat recycled biogenic carbon adequately, because the calculation rules for recycled products and biogenic carbon stored in products are defined independently from each other. Therefore, an improved and consistent calculation rule for the CF of product systems containing both recycling processes and carbon stored in products is proposed. The methodological approach consists of the application of the same allocation principles for both greenhouse gas (GHG) releases and GHG removals: (1) explicit accounting of inputs (GHG removals) and outputs (GHG releases) of biogenic carbon flows instead of assuming carbon neutrality per se; (2) consistent application of allocation rules for environmental benefits and environmental burdens. It is shown that the different modelling approaches (e.g. polluter pays, conservative or partitioning) lead to different results in LCA and CF calculations, e.g. the GHG emissions of first life cycle of t...