Challenges in developing regionalized characterization factors in land use impact assessment: impacts on ecosystem services in case studies of animal protein production in Sweden

The UNEP-SETAC Life Cycle Initiative has recently developed a guideline framework for land use impact assessment. This article evaluates the feasibility and highlights the challenges of applying a set of methods that adhere to this framework, and identifies the strengths and weaknesses of the indicators used in these methods, for the purpose of supporting further methodological development. The methods were tested in two case studies of animal protein production in Sweden: dairy milk and pork. The reference situations were defined as the potential natural vegetation. County-level characterization factors (CFs) were calculated and occupation impacts were assessed for five ecosystem services, using six ecosystem service indicators: carbon flow change, groundwater recharge, mechanical filtration capacity, physicochemical filtration capacity, soil loss, and soil organic carbon, at two geographic scales: county and biome. Strengths and weaknesses of the ecosystem service indicators were identified using an evaluation framework for selected quality characteristics: representativeness, reliability, feasibility, and transparency. Occupation impacts at the two geographic scales, and for the two production cases, differ both in absolute numbers, and-for mechanical and physicochemical filtration capacity-in the ranking of cases. Results at both geographic scales indicate positive effects-or lower negative impacts-in protein production from dairy milk compared to pork, due to grass production on dairy farms, and lower use of land per unit protein. However, some of the observed benefits may be exaggerated due to challenges in adequately representing the reference situations. Most indicators were assigned medium or high degrees of representativeness, feasibility, and transparency, but several were assigned low degrees of reliability, due to the weak scientific basis upon which they were selected, low degrees of accuracy, and insufficient information on how they should be assessed. Occupation impact results should be interpreted with caution due to challenges in applying the methods and use of indicators with identified weaknesses. The most challenging part of developing regionalized CFs was finding suitable land areas from which to derive representative data to parameterize the reference situations. More research is needed to provide adequate support to life cycle assessment practitioners who wish to calculate regionalized CFs and to address the identified weaknesses.