Pre- and post-production processes increasingly dominate greenhouse gas emissions from agri-food systems.

We present results from the FAOSTAT emissions shares database, covering emissions from agri-food systems and their shares to total anthropogenic emissions for 196 countries and 40 territories for the period 1990–2019. We find that in 2019, global agri-food system emissions were 16.5 (95 %; CI range: 11–22) billion metric tonnes (Gt CO 2 eq. yr -1), corresponding to 31 % (range: 19 %–43 %) of total anthropogenic emissions. Of the agri-food system total, global emissions within the farm gate – from crop and livestock production processes including on-farm energy use – were 7.2 Gt CO 2 eq. yr -1 ; emissions from land use change, due to deforestation and peatland degradation, were 3.5 Gt CO 2 eq. yr -1 ; and emissions from pre- and post-production processes – manufacturing of fertilizers, food processing, packaging, transport, retail, household consumption and food waste disposal – were 5.8 Gt CO 2 eq. yr -1. Over the study period 1990–2019, agri-food system emissions increased in total by 17 %, largely driven by a doubling of emissions from pre- and post-production processes. Conversely, the FAOSTAT data show that since 1990 land use emissions decreased by 25 %, while emissions within the farm gate increased 9 %. In 2019, in terms of individual greenhouse gases (GHGs), pre- and post-production processes emitted the most CO 2 (3.9 Gt CO 2 yr -1), preceding land use change (3.3 Gt CO 2 yr -1) and farm gate (1.2 Gt CO 2 yr -1) emissions. Conversely, farm gate activities were by far the major emitter of methane (140 Mt CH 4 yr -1) and of nitrous oxide (7.8 Mt N 2 O yr -1). Pre- and post-production processes were also significant emitters of methane (49 Mt CH 4 yr -1), mostly generated from the decay of solid food waste in landfills and open dumps. One key trend over the 30-year period since 1990 highlighted by our analysis is the increasingly important role of food-related emissions generated outside of agricultural land, in pre- and post-production processes along the agri-food system, at global, regional and national scales. In fact, our data show that by 2019, pre- and post-production processes had overtaken farm gate processes to become the largest GHG component of agri-food system emissions in Annex I parties (2.2 Gt CO 2 eq. yr -1). They also more than doubled in non-Annex I parties (to 3.5 Gt CO 2 eq. yr -1), becoming larger than emissions from land use change. By 2019 food supply chains had become the largest agri-food system component in China (1100 Mt CO 2 eq. yr -1), the USA (700 Mt CO 2 eq. yr -1) and the EU-27 (600 Mt CO 2 eq. yr -1). This has important repercussions for food-relevant national mitigation strategies, considering that until recently these have focused mainly on reductions of non-CO 2 gases within the farm gate and on CO 2 mitigation from land use change. The information used in this work is available as open data with DOI 10.5281/zenodo.5615082 (Tubiello et al., 2021d). It is also available to users via the FAOSTAT database (https://www.fao.org/faostat/en/#data/EM ; FAO, 2021a), with annual updates. [ABSTRACT FROM AUTHOR]