SETAC Globe - Environmental Quality Through Science
 
  21 July 2011
Volume 12 Issue 7
 

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Life Cycle Assessment and Sustainability

Annette Köhler, PE INTERNATIONAL

Life cycle assessment (LCA) is a holistic methodology used to assess environmental performance of a product over its entire life. The science underlying LCA needs to advance to tackle the challenges of ecosystem protection and assessment of impacts. There are many new developments in LCA methodologies, life cycle management, and sustainability in SETAC. Seven different sessions were devoted to developments in life cycle impact assessment (new pathways and toxicity models), life cycle sustainability assessment (incorporating life cycle costing and social impacts), increasing the robustness of LCA methodologies (dynamic LCA, spatially and temporally defined life cycle inventory models, and database designs to simplify LCA), life cycle inventory (LCI) modeling (including attributional versus consequential issues) and life cycle management approaches for different industrial sectors.

Life Cycle Inventory Modeling

One of the most discussed topics in LCA was how to model the inventory phase. The session on this topic introduced many new tools, models, and computations, but the core focus was to answer specific questions on performance in a decision-making context.

There are two different modeling types (with variants):

  • Attributional: existing supply, use and end-of-life of product systems
  • Consequential: aiming at capturing the consequences of decision made in the system on other parts of the economy

graph Frischknecht et al.

Frischknecht et al. (2011). Figure used with permission from presenter.


Within these models there are a number of different approaches:

  • Scenario analysis of method assumptions
  • Expanding classical process-based modeling with simulation model (e.g. general equilibrium models)
  • Extension from single marginal processes to mix of marginal processes
    • To better capture real-world situation
    • Increase robustness

Among the authors there was agreement on the goal- and scope-dependent modeling but not on the best approach to take in each decision context. The scientific challenge is to define good practice that effectively supports the use of LCA in policy and business decisions.

Life Cycle Impact Assessment

The life cycle impact assessment session was dedicated to toxicity modeling of both organic chemicals and metals and emerging new pathways. A broad portfolio of topics were presented:

  • Fate modeling with incomplete data (empirical simplification of fate model)
  • Variability and spatial distribution of chemical removal rates
  • Fate and effects modeling of metals (e.g. free ion concentration as sufficient descriptor for aquatic and terrestrial toxic impacts )
  • Eco-toxic impacts on warm-blooded predators
  • Energy, water use, noise, and biome-specific acidification modeling

A number of solutions were presented:

  • Mechanistic simplification with regression model to close data gaps (applicable for fate, exposure, and effects)
  • Broader coverage of environmental mechanisms and species (e.g. warm-blooded predators, different types of noise emissions)
  • Different approaches for geographical differentiation
  • Use of generic or standardised characteristics for archetypes, biomes, watersheds
  • Moving towards global coverage!

Overall, there was broadened applicability of LCIA models by empirical simplification of characterization models and extention to more chemicals; however, the new approaches pose higher demands on computation structures of databases and tools.

A new framework for fate and effect modeling of metals in LCIA was also presented. Available fate and effect models were mainly developed for organic chemicals. Currently there are methodological deficits for evaluating the impact of metals. An international working group, with the support of the metals industry, has made significant strides in closing this substantial gap in LCIA practice such that a more meaningful evaluation of metals is now possible.

New framework for LCIA

Gandhi et al. 2011 Figure used with permission from presenter.

The Clearwater consensus (Diamond et al. 2010 [IN] Gandhi et al. 2011): Free metal ion, not soluble fraction, is the toxicological relevant fraction!

Increasing Robustness of LCA Methodology

There is an increased complexity in modeling due to spatial and temporal issues in the links between technical systems and impacts on the environment. Approaches for dynamic/time-resolved LCA and spatiotemporally defined LCIs were presented, with time resolution of climate gas emissions and carbon sequestration used as an example of dynamic LCA.

graph Annie Levasseur et al.

Levasseur et al. (2011). Figure used with permission from presenter.

There is growing global demand for life cycle thinking and LCA to be incorporated into decision-making at policy level and in businesses. LCA models and methods are increasingly complex; however, practitioners need practical, simple tools. In order for LCA to be more widely used, more robust and useable approaches are needed for both regulatory and business applications within input across sectors.

Developments in Life Cycle Sustainability Assessment (LCSA), Life Cycle Management (LCM) Approaches for Different Industrial Sectors

There is a strong need to incorporate economic and social impacts into LCA. Different concepts for integrating environmental, social and economic assessments were presented in other LCA sessions, including:

  • Frameworks for LCSA and LCM capabilty for sustainable value chains
  • Life Cycle Costing as the second pillar of LCSA
  • Application of LCA in environmental product declarations
  • Development of product category rules for sector-specific environmental product declarations
  • Barriers to reliable LCA of biofuels (e.g. predicting production technologies, characterizing tailpipe emissions, accurate emission factors for future fleet, incoporating spatial heterogenicity)
  • Extension to new areas of protection in LCSA: economic material availability

More case studies demonstrating the effective use of sustainability and management approaches are needed. One example of effective implementation of LCA results in business decision making was based on the climate change impacts of decisions regarding sources of fruits and vegetables for sale to the consumer (see Food miles in retailers decision making” (Stoessel et al. 2011). In this example the impact of food consumption on greenhouse gas (GHG) emissions was reduced by optimizing the source and method of transport of different types of fruits and vegetables, in collaboration with retailers.

The reduction occurred by retailers refraining from purchasing selected vegetables from overseas and removing discounts on selected vegetables transported by air. Declaration of all products transported by air and carbon compensation were also identified for various food products.

Outlook for LCA

The next World Congress 2012 in Berlin and the theme will be securing a sustainable future by integrating science, policy, and people. This will require focusing on integration of different disciplines, balance of conflicting stakeholder interests and addressing societal needs.

A broader approach to sustainability needs cross-fertilization between environmental, economic, and social sciences. The SETAC LCA community needs to drill down into the tools being applied or developed to ensure that the methods are robust, accurate, and support decision-making. For those of us who are involved in the details of the assessments, we need to evaluate how our work relates to questions of sustainability.

To secure a sustainable future, we need to make sure we are looking at the right issues.

Author contact information: a.koehler@pe-international.com

References:

Frischknecht, R. and M. Stucki.  2011.  Scope dependent inventory models: a proposal for choice between attributional and consequential models.  LC04-2 session presentation at the 2011 SETAC Europe Annual Meeting in Milan

Gandhi, N. et al. 2011.  Development of a new modelling framework to address issues of metal fate and effects in LCIA.  LC01A-3 session presentation at the 2011 SETAC Europe Annual Meeting in Milan

Levasseur, A. et al. 2011. Assessing temporary carbon sequestration and storage with dynamic LCA. LC03-2 session presentation at the 2011 SETAC Europe Annual Meeting in Milan

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