Nitrogen emissions along global livestock supply chains

Global livestock supply chains have significantly altered nitrogen (N) flows over past years, thereby threatening environmentaland human health. Here, we provide a disaggregated assessment of the livestock sector’s impacts on global N flows and emissions, including international trade. The results show that the sector currently emits 65 Tg N yr−1, equivalent to one-third of current human-induced N emissions and sufficient to meet the planetary boundary for N. Of that amount, 66% is allocated to Asiaand 68% is associated with feed production. Most emissions originate from locally produced animal-sourced food, althoughN emissions embedded in international trade are significant for some importing countries. Given the magnitude of its impactsand its central role in both domestic and international N challenges, the livestock sector urgently requires a global initiative totackle N pollution while supporting food security