Are impact assessment approaches effective for addressing researches on GHG emissions from pastoral systems?

The environmental impacts of livestock systems have been often under discussion in relation to their negative impacts to climate change. For several years, conventional assessments of such impacts have been preferably adapted and implemented on industrialized livestock systems. On the contrary, when applied to extensive systems such as pastoral ones, they have created distortions in the attribution of the related climate impacts. In the context of the in-depth studies on the topic conducted by the ERC research project PASTRES, several case studies of contextualized research on GHG emissions of three different pastoral systems in Africa, Asia and Europe were analyzed. Different assessment methodologies were compared, without or with the use of the Life Cycle Assessment (LCA) approach. Some limitations emerged from the analysis that concerned: 1) the analysis of emissions in a broader context/ecosystem-based approach 2) the definition of Functional Units 3) the provision of ecosystem services, with particular attention to biodiversity and the inclusion of C sequestration within the LCA calculation. These limitations penalize a complete and adequate estimate of environmental impacts and, consequently, a correct evaluation of implementation scenarios that aim to create conditions of greater sustainability of pastoral systems. The analysis suggests that the assessment of the impacts of pastoral systems, strongly characterized by land occupation, use of environmental resources, seasonal climate and social relations, requires a systemic approach that adapts and extends the LCA methodology, through the harmonization of alternative metrics based on both conventional LCA and the assessment of the social and nutritional implications of pastoral farming.