Biodiversity accounting in life cycle assessment – a novel method

Abstract

Biodiversity accounting in life cycle assessment – a novel method

Life cycle assessment (LCA) of products may be an indispensable tool in the transition towards a sustainable lifestyle and planetary wellbeing – but parameter evaluation has often been limited to greenhouse gas emissions and inclusion of biodiversity effects has shown to be notoriously difficult. I developed a new and universally applicable method for biodiversity accounting in LCAs. The biodiversity effect measure BE quantifies the change in extinction risk of all species in an assemblage as a result of a land use change or some other kind of external influence impinging on the species, summed across the assemblage. It consists of four components, impact overlap IOi, population impact PIi, national and international Red List risk categories (PEnat, i; PEint, i), and a concentration measure Ci. Impact overlap IOi quantifies the spatial relationship between impact area and species range. Population impact PIi specifies the degree and direction of the land use change consequences for a population of the species i within the impact area. The use of national and international Red List categories is based on the consideration that extinction risk change owing to land use change intervention depends on extinction risk in the first place – the first derivative of an exponential function is also an exponential function. Finally, the effect on a particular species depends on the concentration of populations Ci in the impact area; the more a species is restricted to the impact habitat and impact area, the higher the quantitative weight of the species within the assemblage. The measure BE, accounting for biodiversity effects in a standardized area, is then obtained by summing up the values obtained for single species. To obtain universally comparable values, the quantification method is currently restricted to mammals, birds, amphibians and reptiles, organism groups for which Red List categorizations are largely complete and ecological information is in most cases easily accessible. The method can be applied both to subtle local changes in land use intensity and to large-scale or global product comparisons, as three application examples show. The first example quantifies the biodiversity effects of setting aside field margins as flower strips in Central Europe. The second example compares the biodiversity effects of conventionally grown potatoes and potatoes from organic agriculture. The third example quantifies the biodiversity effects of soybeans cultivated in Austria with those cultivated in Brazil based on several land use change scenarios. Reduction of the equations developed for the general case – biodiversity accounting in LCAs – makes the method applicable to special cases, for example biodiversity accounting in monitoring or Environmental Impact Assessment.