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

oleh: F. N. Tubiello, K. Karl, K. Karl, A. Flammini, A. Flammini, J. Gütschow, G. Obli-Laryea​​​​​​​, G. Conchedda, X. Pan, S. Y. Qi, H. Halldórudóttir Heiðarsdóttir, N. Wanner, R. Quadrelli, L. Rocha Souza, P. Benoit, M. Hayek, D. Sandalow, E. Mencos Contreras​​​​​​​, E. Mencos Contreras​​​​​​​, C. Rosenzweig, C. Rosenzweig, J. Rosero Moncayo, P. Conforti, M. Torero

Format: Article
Diterbitkan: Copernicus Publications 2022-04-01

Deskripsi

<p>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<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>), 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<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>; emissions from land use change, due to deforestation and peatland degradation, were 3.5 Gt CO<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>; 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<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>. 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<span class="inline-formula"><sub>2</sub></span> (3.9 Gt CO<span class="inline-formula"><sub>2</sub></span> yr<span class="inline-formula"><sup>−1</sup></span>), preceding land use change (3.3 Gt CO<span class="inline-formula"><sub>2</sub></span> yr<span class="inline-formula"><sup>−1</sup></span>) and farm gate (1.2 Gt CO<span class="inline-formula"><sub>2</sub></span> yr<span class="inline-formula"><sup>−1</sup></span>) emissions. Conversely, farm gate activities were by far the major emitter of methane (140 Mt CH<span class="inline-formula"><sub>4</sub></span> yr<span class="inline-formula"><sup>−1</sup></span>) and of nitrous oxide (7.8 Mt N<span class="inline-formula"><sub>2</sub></span>O yr<span class="inline-formula"><sup>−1</sup></span>). Pre- and post-production processes were also significant emitters of methane (49 Mt CH<span class="inline-formula"><sub>4</sub></span> yr<span class="inline-formula"><sup>−1</sup></span>), 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<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>). They also more than doubled in non-Annex I parties (to 3.5 Gt CO<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>), 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<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>), the USA (700 Mt CO<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>) and the EU-27 (600 Mt CO<span class="inline-formula"><sub>2</sub></span> eq. yr<span class="inline-formula"><sup>−1</sup></span>). This has important repercussions for food-relevant national mitigation strategies, considering that until recently these have focused mainly on reductions of non-CO<span class="inline-formula"><sub>2</sub></span> gases within the farm gate and on CO<span class="inline-formula"><sub>2</sub></span> mitigation from land use change. The information used in this work is available as open data with DOI <a href="https://doi.org/10.5281/zenodo.5615082">https://doi.org/10.5281/zenodo.5615082</a> (Tubiello et al., 2021d). It is also available to users via the FAOSTAT database (<span class="uri">https://www.fao.org/faostat/en/#data/EM</span>; FAO, 2021a), with annual updates.</p>