Integrating ecosystem services in the LCA evaluation of meat of different species
Résumé
The environmental impact of meat production assessed from life cycle assessment (further LCA impact), is highly dependent on livestock species. To produce one kg of meat, energy consumption and greenhouse gas emissions increase from chicken to pork, and from pork to beef, partly because of differences in feed efficiency. Beef production has thus the highest impact according to LCA but it can be also beneficial to biodiversity and ecosystem services (ES), if it is grass based. To integrate these aspects, a method has been proposed to allocate the LCA impacts between the strictly productive activities, and the other types of services. The method proposes allocation factors based on the capacity of production systems to supply provisioning ES (PES) and regulating ES (RES). The factors represent the proportions of LCA impacts that can be allocated to these ES (sum of RES and PES factors =1). The method has been applied to compare organic and conventional crop productions and here we apply it to the production of 1 kg of chicken, pork and grass-based beef. We modified the method to account for the fact that feeding systems can involve several land
uses. Without allocation, the differences in LCA impact between chicken and beef along the species gradient are two and a half higher for energy (~20 MJ/kg to ~50 MJ/kg), and six times higher for CO2-eq (~5 to ~30 kg CO2-eq/kg). When these differences are reallocated according to the PES factors, the energy gradient is modified with beef having the lowest impact (14 MJ/kg), and pork the highest (20 MJ/kg). The CO2-eq gradient is not modified, but the difference of impact is reduced to two times (4 to 8 kg CO2-eq/kg). These calculations indicate that depending on the species reared, feed efficiency and feeding system, the impact of one kilo of meat benefits more or less to services other than productive ones. It does not mean that the impact of producing 1 kg of beef should be considered lower than currently assessed, but that this impact can also contribute to the delivery of ES of interest.