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 (GtCO(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 GtCO(2) eq. yr(-1); emissions from land use change, due to deforestation and peatland degradation, were 3.5 GtCO(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 GtCO(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 postproduction processes emitted the most CO2 (3.9 GtCO(2) yr(-1)), preceding land use change (3.3 GtCO(2) yr(-1)) and farm gate (1.2 GtCO(2) yr(-1)) emissions. Conversely, farm gate activities were by far the major emitter of methane (140 MtCH(4) yr(-1)) and of nitrous oxide (7.8 MtN(2)Oyr(-1)). Pre- and post-production processes were also significant emitters of methane (49 MtCH4 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 GtCO(2) eq. yr(-1)). They also more than doubled in nonAnnex I parties (to 3.5 GtCO(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 MtCO(2) eq. yr(-1)), the USA (700 MtCO(2) eq. yr(-1)) and the EU-27 (600 MtCO(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 nonCO(2) gases within the farm gate and on CO2 mitigation from land use change. The information used in this work is available as open data with DOI https://doi.org/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.