Reference situations for biodiversity in life cycle assessments: conceptual bridging between LCA and conservation biology

In life cycle assessment (LCA) literature addressing land use impacts on biodiversity, several potential reference situations are proposed. However, the lack of guidance on how to apply the proposed reference situations fosters confusion within the topic and raises questions about implications of different reference conceptions. The purpose of this article is to contribute to an improved methodology for assessing biodiversity impacts in LCA through developing the use of reference situations in life cycle impact assessment (LCIA) models of land use. We analyze how reference situations are currently used when assessing the impacts from land use on biodiversity, as well as how such are defined and used outside LCA, specifically in biodiversity conservation. Based on this review, we provide recommendations to the LCIA research community on how to modify its use of reference situations to enable more relevant assessments of impacts on biodiversity. It is shown how, in the LCA framework, the use of so-called baseline references dominates, and what shortcomings this implies, including unclear definitions of what “naturalness” and “pristine nature” represent, as well as the lack of reliable data. By contrast, biodiversity conservation, typically aiming at ensuring a favorable conservation status for biodiversity, normally uses limit and target references. These reference situations have the advantage of reflecting, often at an aggregated level, society’s preferences, and values related to biodiversity. Because of this, they also include biodiversity that is dependent on a certain level of management, as in, e.g., semi-natural pastures. This is an important aspect as much of the biodiversity highly valued today belong to this category. We recommend that reference situations for biodiversity in LCIA models should be developed based on biodiversity targets aligned with society’s conservation frameworks. Only measurements of deviation away from or closer to a desired reference situation make it possible for decision makers to distinguish the varying biodiversity-related costs and benefits that are associated with different production systems.