Implications of environmental constraints and opportunities on livestock production and emissions: New Zealand as a case study

New Zealand (NZ) is an important global exporter of various livestock products, however its potential for production is being constrained by environmental restrictions. The aim of this study was to explore future pathways for NZ livestock (dairy, beef, and sheep) production from grazed pastures, which includes changes in land use, GHG mitigations, increased dairy-beef and net carbon neutrality. Life cycle assessment methodology was used to determine national level environmental impacts of livestock production in NZ. Carbon, reactive nitrogen (Nr) and Eutrophication Potential (EP) footprints on a total production basis at national level from livestock systems could be decreased by 39%, 36% and 30%, respectively. Achieving net carbon neutrality of all livestock production with a multiple mitigation scenario gave corresponding emission reductions of 41% for Nr and 36% for EP, requiring afforestation of 0.9 Mha of sheep and beef land. However, transitioning to carbon neutrality for all production reduced total livestock protein production by 7% for current systems and by 21% for the mitigation scenario compared to no carbon neutrality changes. In contrast, increased integration of dairy-derived beef increased national livestock protein production by 3%. Optimized livestock production through greater dairy beef integration and use of multiple mitigations offers the most promising pathway for low environmental-impact livestock production in NZ. However, this should aim at minimizing effects on livestock production due to the large impact on global food exports, while higher value or premiums for low environmental-impact products will be important to encourage changes to meet the environmental constraints.