Abstract
New estimates of greenhouse gas (GHG) emissions from the food system were developed at the country level, for the period 1990–2018, integrating data from crop and livestock production, on-farm energy use, land use and land use change, domestic food transport and food waste disposal. With these new country-level components in place, and by adding global and regional estimates of energy use in food supply chains, we estimate that total GHG emissions from the food system were about 16 CO2eq yr−1 in 2018, or one-third of the global anthropogenic total. Three quarters of these emissions, 13 Gt CO2eq yr−1, were generated either within the farm gate or in pre- and post-production activities, such as manufacturing, transport, processing, and waste disposal. The remainder was generated through land use change at the conversion boundaries of natural ecosystems to agricultural land. Results further indicate that pre- and post-production emissions were proportionally more important in developed than in developing countries, and that during 1990–2018, land use change emissions decreased while pre- and post-production emissions increased. We also report results on a per capita basis, showing world total food systems per capita emissions decreasing during 1990–2018 from 2.9 to 2.2 t CO2eq cap−1, with per capita emissions in developed countries about twice those in developing countries in 2018. Our findings also highlight that conventional IPCC categories, used by countries to report emissions in the National GHG inventory, systematically underestimate the contribution of the food system to total anthropogenic emissions. We provide a comparative mapping of food system categories and activities in order to better quantify food-related emissions in national reporting and identify mitigation opportunities across the entire food system.
Generated Summary
This research article presents new estimates of greenhouse gas (GHG) emissions from the food system, developed at the country level for the period 1990–2018. The study integrates data from various sources, including crop and livestock production, on-farm energy use, land use and land use change, domestic food transport, and food waste disposal. The research aims to provide a more comprehensive understanding of the food system’s contribution to global anthropogenic emissions, highlighting the importance of food-related GHG mitigation strategies. The methodology involves developing a comparative mapping table of food system categories and activities to quantify food-related emissions in national reporting and identify mitigation opportunities. The study also reports results on a per capita basis, showing world total food systems per capita emissions decreasing during 1990–2018 from 2.9 to 2.2 t CO2eq cap–1, with per capita emissions in developed countries about twice those in developing countries in 2018. The research utilizes data from FAOSTAT, IPCC guidelines, and other relevant sources to achieve its objectives, focusing on a detailed analysis of emissions across different components of the food system.
Key Findings & Statistics
- In 2018, the total GHG emissions from the food system were approximately 16 CO2eq yr–1, which is one-third of the global anthropogenic total.
- Three-quarters of these emissions (13 Gt CO2eq yr–1) were generated either within the farm gate or in pre- and post-production activities.
- Pre- and post-production emissions were proportionally more important in developed than in developing countries.
- Land use change emissions decreased while pre- and post-production emissions increased during 1990-2018.
- Total food systems per capita emissions decreased during 1990–2018 from 2.9 to 2.2 t CO2eq cap–1.
- Per capita emissions in developed countries were about twice those in developing countries in 2018.
- In 2018, total GHG emissions on agricultural land were 10383 Mt CO2eq yr–1, with 80% generated in NAI countries.
- Emissions from the farm gate in 2018 were 7145 Mt CO2eq yr–1, 20% higher than in 1990.
- Non-CO2 emissions from the farm gate in 2018 were dominated by livestock processes, followed by synthetic fertilizers and rice cultivation.
- In 2018, total emissions from domestic food transport were 511 Mt CO2eq yr–1, with nearly 60% generated in NAI countries.
- Global emissions from food waste disposal reached 996 Mt CO2eq yr–1 in 2018, with NAI countries representing 80% of the total.
- In 2018, world total food system emissions were roughly 16 Gt CO2eq yr–1, having increased 8% since 1990.
- CO2 was the largest contributor to food system emissions, totaling 9.5 Gt CO2eq yr–1 in 2018.
- In 2018 CH4 contributed 3.9 Gt CO2eq yr–1 and N2O 2.6 Gt CO2eq yr–1.
Other Important Findings
- The research highlights that conventional IPCC categories underestimate the contribution of the food system to total anthropogenic emissions.
- The study provides a comparative mapping of food system categories and activities to better quantify food-related emissions in national reporting and identify mitigation opportunities.
- Results indicate that pre- and post-production emissions were proportionally more important in developed than in developing countries.
- Land use change emissions decreased while pre- and post-production emissions increased during 1990-2018.
- The study found that the share of food system emissions to total anthropogenic emissions decreased over the period 1990–2018.
- Emissions from the conversion of natural ecosystems to agricultural land decreased, while emissions from energy use beyond the farm gate are increasing.
- The study indicates that the food system has a larger GHG mitigation opportunity than previously estimated.
- The study highlights the need to focus on both farm gate and pre- and post-production processes for emissions abatement.
Limitations Noted in the Document
- The study uses emissions from net forest conversion as a proxy for deforestation, potentially overestimating the food-related land use change component.
- The study does not include carbon sinks on agricultural land, which may affect the overall emission estimates.
- The data for on-farm energy use included energy use in forestry and fisheries, potentially overestimating emissions.
- The study’s accounting does not include a quantification of all GHGs emitted by food system processes beyond CH4, N2O, and CO2.
- The study uses simplified methods to estimate emissions from energy use in supply chains, which may lead to overestimates or underestimates depending on the time period.
- Uncertainties in emission estimates, especially in relation to food waste and transport, are larger than estimates for AFOLU.
Conclusion
The study underscores the substantial contribution of the food system to global greenhouse gas emissions, emphasizing the need for comprehensive mitigation strategies. The findings confirm recent quantifications of the food system’s role in total anthropogenic emissions, indicating that the food system’s share decreased over the period from 1990 to 2018. The research highlights significant differences between developed and developing countries, with per capita emissions in developed countries remaining higher. The study emphasizes the importance of reducing emissions from land use change, particularly deforestation, while also focusing on pre- and post-production processes and farm-gate activities. The analysis also underlines the need for improved nitrogen use efficiencies and mitigation in solid food waste disposal. The study suggests that future mitigation efforts should concentrate on both farm gate activities and pre- and post-production processes to achieve substantial emission reductions. The research emphasizes the need for improved management of agricultural land, reduced deforestation, and the protection of natural ecosystems to advance a carbon-neutral food system. The study contributes to a better understanding of the food system’s impact on climate change and provides a basis for more effective and targeted mitigation strategies.