Proposing a life cycle land use impact calculation methodology

Wouter Achten,Bart Muys,Pieter Vandenbempt,Erik Mathijs,Patrick Lemaître

doi:10.1038/npre.2008.2340.1

Abstract

AbstractThe Life Cycle Assessment (LCA) community is yet to come to a consensus on a methodology to incorporate land use in LCA. Earlier our research group presented a methodology based on the ecosystem exergy concept. The ecosystem exergy concept suggests that ecosystems develop towards more effective degradation of energy fluxes passing through the system. The concept is argued to be derivable from two axioms: the principles of (i) maximum exergy storage and the (ii) maximum exergy dissipation. In this paper we present a methodology to assess impacts of human induced land use occupation, in which we make a difference between functional and structural land use impacts. The methodology follows a dynamic multi-indicator approach looking at mid-point impacts on soil fertility, soil structure, biomass production, vegetation structure, on-site water balance and biodiversity. The impact scores are calculated as a relative difference with a reference system. We propose to calculate the impact by calculating the land quality change between the former and the actual land use relative to the quality of the potential natural vegetation. Impact scores are then aggregated, as endpoint impacts, in (i) structural land use impact (exergy storage capacity) and (ii) functional land use impact (exergy dissipation capacity). For aggregation of the relative mid-point impact scores no characterization factor is used. In order to fit this impact calculation in the LCA framework the end-point impact scores are multiplied by a LCA component, a component that enables us to report the impact per functional unit.

Highlights

IntroductionHuman activities have spatial needs for extraction of resources,forestry and agriculture,infrastructure and dwellings,industrial production processes and landfill.The use of land will often make the land unavailable for other uses,butmay change the quality of the land in terms of life supportor potentiality for other land use (Heijungs etal.1997;Lindeijer 2000;Lindeijer etal.2002).In an LCA contextland use was defined (Lindeijer etal.2002)as intensive human activities,aiming at exclusive use of land for certain purposes and adapting the properties of land areas in view of these purposes.Land use and land use change are considered by the international community as a significantaspectof global change, which may induce climate change (Kalnay & Cai 2003; Lavy et al 2004), desertification (Lavy etal.2004;Asner & Heidebrecht2005)and loss of biodiversity and life support functions (Lindeijer 2000;Lindeijer etal.2002;M iles etal.2004;M ilài Canals etal.2007).Several methods have been developed for the assessmentof environmental impacts generated by land use and land use change (e.g.monitoring procedures,standards withprinciples,criteria and indicators (PC&I),environmental impactassessment(EIA)and life cycle assessment(LCA)(Baelemans & M uys 1998)).These methods and tools still face specific and shared problems regarding the land use impactassessment.Among these problems the selection and definition of relevantand measurable indicators seems one of the mostpersistent(Baelemans & M uys 1998).Discussions on land use impactin LCA community seem to reveal a lack of consensus on whatexactly has to be assessed (M ilài Canals etal.2006;Udo de Haes 2006;Baitz2007;M ilài Canals etal.2007;M ilài Canals 2007;M ilài Canals etal.2007a).According to the authors the reason for these problems lies in theProc.of the 6thInt.Conf.on LCA in the Agri-Food Sector,Zurich,November 12–14,2008 page 22 of 414Proposing a life cycle land use impact calculation methodology lack of a solid theoretical concept which can serve as paradigm in which land use and land use change impacts can be evaluated and assessed.In this paper we propose a method to assess land use impact on the natural environment and life support functions (areas of protection)
Several methods have been developed for the assessmentof environmental impacts generated by land use and land use change (e.g.monitoring procedures,standards withprinciples,criteria and indicators (PC&I),environmental impactassessment(EIA)and life cycle assessment(LCA)(Baelemans & M uys 1998)).These methods and tools still face specific and shared problems regarding the land use impactassessment.Among these problems the selection and definition of relevantand measurable indicators seems one of the mostpersistent(Baelemans & M uys 1998).Discussions on land use impactin LCA community seem to reveal a lack of consensus on whatexactly has to be assessed (M ilài Canals etal.2006;Udo de Haes 2006;Baitz2007;M ilài Canals etal.2007;M ilài Canals 2007;M ilài Canals etal.2007a).According to the authors the reason for these problems lies in the
We propose to do this assessment from an ecosystem perspective, using a theoretical concept describing how ecosystems are structured and how they function

Summary

Introduction

Human activities have spatial needs for extraction of resources,forestry and agriculture,infrastructure and dwellings,industrial production processes and landfill.The use of land will often make the land unavailable for other uses,butmay change the quality of the land in terms of life supportor potentiality for other land use (Heijungs etal.1997;Lindeijer 2000;Lindeijer etal.2002).In an LCA contextland use was defined (Lindeijer etal.2002)as intensive human activities,aiming at exclusive use of land for certain purposes and adapting the properties of land areas in view of these purposes.Land use and land use change are considered by the international community as a significantaspectof global change, which may induce climate change (Kalnay & Cai 2003; Lavy et al 2004), desertification (Lavy etal.2004;Asner & Heidebrecht2005)and loss of biodiversity and life support functions (Lindeijer 2000;Lindeijer etal.2002;M iles etal.2004;M ilài Canals etal.2007).Several methods have been developed for the assessmentof environmental impacts generated by land use and land use change (e.g.monitoring procedures,standards withprinciples,criteria and indicators (PC&I),environmental impactassessment(EIA)and life cycle assessment(LCA)(Baelemans & M uys 1998)).These methods and tools still face specific and shared problems regarding the land use impactassessment.Among these problems the selection and definition of relevantand measurable indicators seems one of the mostpersistent(Baelemans & M uys 1998).Discussions on land use impactin LCA community seem to reveal a lack of consensus on whatexactly has to be assessed (M ilài Canals etal.2006;Udo de Haes 2006;Baitz2007;M ilài Canals etal.2007;M ilài Canals 2007;M ilài Canals etal.2007a).According to the authors the reason for these problems lies in theProc.of the 6thInt.Conf.on LCA in the Agri-Food Sector,Zurich,November 12–14,2008 page 22 of 414Proposing a life cycle land use impact calculation methodology lack of a solid theoretical concept which can serve as paradigm in which land use and land use change impacts can be evaluated and assessed.In this paper we propose a method to assess land use impact on the natural environment and life support functions (areas of protection). We propose to do this assessment from an ecosystem perspective, using a theoretical concept describing how ecosystems are structured and how they function The rationale behind this starting point is, that we can only know how we damage an ecosystem by human induced land use if we understand how it works, lives and sustains. Ecosystems are open systems subject to continuous energy influxes They tend to increase their internal exergy level, in order to evolve as far as possible from thermodynamic equilibrium. The principal of maximum dissipation means that for any site an ecosystem would tend towards maximum dissipation of the exergy influxes in form of radiation, water, nutrients, air and genetics (Schneider & Kay 1995; Bendoricchio & Jorgensen 1997; Fath et al 2001).The content of this ecosystem exergy concept is promising for further advances in land use impact. For a review on the ecosystem exergy concept see Dewulf et al (2008)

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