Global livestock supply chains have significantly altered nitrogen (N) flows over past years, thereby threatening environmental and 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 Asia and 68% is associated with feed production. Most emissions originate from locally produced animal-sourced food, although N emissions embedded in international trade are significant for some importing countries. Given the magnitude of its impacts and its central role in both domestic and international N challenges, the livestock sector urgently requires a global initiative to tackle N pollution while supporting food security.

在过去的几年中，全球牲畜供应链极大地改变了氮的流量，从而威胁到环境和人类健康。在这里，我们提供了对畜牧业对全球氮流量和排放（包括国际贸易）影响的分类评估。结果表明，该部门目前排放65 Tg N yr ^-1，相当于目前人为排放的氮的三分之一，并且足以满足N的行星边界。其中，有66％分配给了亚洲，而68％与饲料生产有关。尽管国际贸易中的氮排放量对某些进口国而言是重要的，但大多数排放量均来自当地生产的动物源性食品。鉴于其影响的巨大程度及其在国内和国际氮素挑战中的核心作用，畜牧业迫切需要一项全球倡议，在支持粮食安全的同时应对氮素污染。