Abstract
We have developed a new global food emissions database (EDGAR-FOOD) estimating greenhouse gas (GHG; CO2, CH4, N2O, fluorinated gases) emissions for the years 1990–2015, building on the Emissions Database of Global Atmospheric Research (EDGAR), complemented with land use/land-use change emissions from the FAOSTAT emissions database. EDGAR-FOOD provides a complete and consistent database in time and space of GHG emissions from the global food system, from production to consumption, including processing, transport and packaging. It responds to the lack of detailed data for many countries by providing sectoral contributions to food-system emissions that are essential for the design of effective mitigation actions. In 2015, food-system emissions amounted to 18 Gt CO2 equivalent per year globally, representing 34% of total GHG emissions. The largest contribution came from agriculture and land use/land-use change activities (71%), with the remaining were from supply chain activities: retail, transport, consumption, fuel production, waste management, industrial processes and packaging. Temporal trends and regional contributions of GHG emissions from the food system are also discussed.
Generated Summary
This article presents a comprehensive analysis of global food systems’ contribution to greenhouse gas (GHG) emissions. The study, titled “Food systems are responsible for a third of global anthropogenic GHG emissions,” utilizes the EDGAR-FOOD database, a novel global food emissions database developed by the authors. The research builds upon the Emissions Database of Global Atmospheric Research (EDGAR) and incorporates data from FAOSTAT to account for land use and land-use change emissions. The primary aim is to provide a detailed, consistent, and spatially resolved assessment of GHG emissions across the entire food system, from production to consumption, addressing the lack of comprehensive data at the country level. The study investigates sectoral contributions, temporal trends, and regional variations of GHG emissions, offering insights into potential mitigation strategies and the evolution of food systems. The methodology involves a bottom-up approach, aligning with IPCC guidelines, with high sectoral disaggregation to provide a granular view of emissions sources. The analysis covers the period from 1990 to 2015, providing a detailed assessment of GHG emissions from food systems and their evolution over time.
Key Findings & Statistics
- In 2015, food-system emissions totaled 18 Gt CO2 equivalent per year globally, accounting for 34% of total GHG emissions (ranging from 25% to 42%).
- The largest contribution to food-system emissions came from agriculture and land use/land-use change activities (71%).
- In 2015, global GHG emissions from the food system were 18 Gt CO₂e yr⁻¹ (95% confidence interval (CI) 14–22 Gt CO₂e yr⁻¹).
- 27% (or 4.9 (95% CI 3.7 to 6.4) Gt CO₂e yr⁻¹) of food-system emissions were emitted by industrialized countries.
- 73% (or 13 (95% CI 10 to 16) Gt CO₂e yr⁻¹) were emitted by developing countries, including China.
- In 2015, 71% of global GHG emissions from the food system was associated with the land-based sector.
- In industrialized countries, the contribution of the downstream energy-related sectors (53%) was larger than the land-based sector.
- In developing countries, agriculture and LULUC were the dominant fraction (73%).
- In 2015, six top emitting economies had individual contributions larger than 6% to the global total GHG.
- China accounted for 13.5% of global food-system emissions, with 2.4 Gt CO₂e.
- Indonesia contributed 8.8% (1.6 Gt CO₂e), the United States 8.2% (1.5 Gt CO₂e), Brazil 7.4% (1.3 Gt CO₂e), the European Union 6.7% (1.2 Gt CO₂e), and India 6.3% (1.1 Gt CO₂e).
- Food-system GHG emissions increased by 12.5% from 1990 to 2015.
- The share of total GHG emissions from food systems decreased over time, from 44% in 1990 to 34% in 2015.
- Global food production, using cereals as a proxy, increased by over 40% during the same period.
- In developing countries, the share of food-system emissions decreased from 68% in 1990 to 39% in 2015.
- LULUC accounted for 32% of total food-system emissions in 2015, with 5.7 Gt CO₂e yr⁻¹.
- Emissions from LULUC in developing countries were 5.0 Gt CO₂e yr⁻¹.
- Energy-related activities contributed almost a third of food-system emissions.
- Production stages contributed 39% to total food-system GHG emissions in 2015 (7.1 Gt CO₂e yr⁻¹).
- Distribution, processing, consumption, and end-of-life disposal contributed 29% in 2015 (5.2 Gt CO₂e yr⁻¹).
- CH4 emissions accounted for 35% of food-system GHG emissions.
- In 2015, the share of CO2 emissions from the energy sector increased to 21%.
- The use of F-gases in industry increased by more than 100% since 1990.
- Packaging contributed about 5.4% (or 0.97 Gt CO₂e yr⁻¹) of total food systems emissions.
- Transportation contributes 4.8% (or 0.86 (95% CI 0.30 to 1.5) Gt CO₂e yr⁻¹) to food-system GHG emissions.
- The use of fertilizers increased by 24%.
- In the agricultural sector, the use of energy increased by 15% compared to 1990.
Other Important Findings
- The study highlights the regional variations in food-system emissions, showing significant differences between industrialized and developing countries.
- In 2015, almost one-third of food-system emissions came from LULUC, mainly due to deforestation and the degradation of organic soils.
- The global food system is becoming more energy-intensive, with a substantial portion of emissions linked to energy-related activities.
- The share of food-system emissions as a percentage of total anthropogenic GHG emissions varies significantly across countries and regions, indicating the influence of factors like the strength of the agri-food sector and the nature of the economy.
- Emissions from food distribution are increasing, with packaging and transport being significant contributors.
- Refrigeration in the retail sector is a significant contributor to GHG emissions, particularly in developed countries.
- The share of emissions from the food production sector decreased in Brazil, which was primarily due to decreases in deforestation rates.
- In sub-Saharan African countries, land-based food-system GHG emissions are high.
- The study found that the main factors driving emission increases were related to population growth, economic development, and changing dietary habits.
Limitations Noted in the Document
- The study acknowledges the limitations associated with the use of global average values for shipping, aviation, and railways, which may not fully reflect the conditions in individual countries.
- The data on refrigeration is not country-specific, which poses a limitation.
- The authors note the high uncertainty associated with LULUC emissions data.
- There is an overestimation in the component for industrialized countries.
- The uncertainty evaluation of the packaging and the chemical industry is high due to data limitations.
- The study acknowledges that a detailed picture of transport across all countries is limited.
- The authors note that detailed data was available only for Europe and the United States for road transport, with an average value used for other countries.
Conclusion
The EDGAR-FOOD database offers a detailed view of the evolving global food system and its impact on GHG emissions, demonstrating a decoupling of population growth and food-related emissions at the global level. However, regional analyses reveal a more complex scenario, with varying emission trends linked to factors such as economic development, dietary changes, and land-use practices. The study emphasizes that the food production sector is not solely dominated by CO2 emissions from fossil fuels. Land-based emissions are highly relevant, indicating a need for dedicated mitigation policies in this area. Also, there is an increasing importance of energy use, industrial activities, and waste management in food-system emissions. Therefore, mitigation strategies should focus on enhancing energy efficiency and decarbonization within the food sector. The research concludes that the EDGAR-FOOD database provides a foundation for understanding how the global food system has evolved. It facilitates estimations of emission changes due to consumer behavior and technological advancements. The authors suggest that this dataset can be used to monitor GHG emissions from food systems effectively. Additionally, it emphasizes the need for comprehensive policies that address both food production and consumption to promote sustainable food systems. The study’s findings underscore the critical role of the food system in global GHG emissions and emphasize the need for targeted strategies to mitigate its environmental impacts and support more sustainable practices in the future. The findings also provide a more comprehensive perspective on the impact of human activities on the environment, while addressing the need to focus on specific sectors or groups of sectors, freely aggregating and splitting data to design their investigations.
IFFS Team Summary
- In 2015, global food-system emissions amounted to 18 Gt CO2 equivalent per year, representing 34% of total GHG emissions.
- This 34% figure is higher than the typical figure used for all agriculture-related emissions of 26%
- The most accepted range was from the IPCC who estimated agricultural emissions equalled 21-37%
- The variance that the authors concluded here in this 2021 Nature Food study was 25-42%
- This study used a new global food emissions database (EDGAR) along with previous data from FAO Stat
- They state 57% of these food emissions are from animal production. So the total is 57% of 34% which is 19% of global GHG emissions, in line with Xu et al.’s 20% estimate. Note, this does not include the carbon opportunity cost of land.
- 73% of these total global GHG emissions of agriculture were technically classified under ‘developing’ countries (including China). However the article states how this is an over simplified representation, since many agricultural products are (ie. beef and soy feed crops) are grown in developing countries but consumed in rich countries.
- Land use and ‘land-use-change’, which denotes deforestation, but also alteration of soil, wetlands, and grasslands, was a primary source of emissions from developing countries (many in tropical regions). The authors pointed out the FAO stat of 32% of global GHGs associated to food systems to be from land use/land-use change (5.7Gt CO2e Yr−1 in 2015)
- This further emphasizes the need to consider carbon opportunity cost of land better purposed
- ie. grazing or feed crop land would be better purposed as a forest or rewilded land for carbon sequestration
- Of the world’s top emitting economies, agriculture emissions were highest in:
- China, Indonesia, the United States, Brazil, the European Union, and India.
- While the proportion of global GHG attributed to agriculture has slightly decreased since 1990, that’s largely due to an increase in fossil fuel use during that time, and to be noted is the below quote from a 2020 paper in The Lancet:
- “If the livestock sector were to continue with business as usual, this sector alone would account for 49% of the emissions budget for 1.5°C by 2030” (Scientists call for renewed Paris pledges to transform agriculture; Harwatt et al., 2020).
- Including animal to plant protein shifts in climate change mitigation policy: a proposed three-step strategy (2019)
- CH4 emissions accounted for 35% of food-system GHG emissions (expressed in CO2e) consistently across developed and developing countries (32–37%) mainly due to livestock production, farming and waste treatment.
- This is important as many developing countries source more beef from grass-fed systems, which shows these are not any better in terms of mitigating methane.
- Methane was measured over a 100 year GWP, which lowers it’s calculated impact by 2.5 x compared to a shorter 20 year timeline. A 20 year timeline for methane is more appropriate, since it more closely mimics the true duration that methane stays in the atmosphere.
- Rice cultivation is also an important source of methane emissions, though much lower than ruminant livestock. Note that per calorie / protein intensity of rice is not compared here, nor the larger amount of people fed by rice, or the methane differences by varying types and techniques of rice cultivation.
- Methane’s share of total agricultural emissions has increased by 3% since 1990
- In terms of food distribution, this study mirrored others that showed ‘food miles’ are less important than packaging.
- Transportation of food equalled only 4.8% of total food system GHGs.
- Limitations:
- Only a partial breakdown of emissions by food category (animal sourced foods vs. plant-proteins)
- No breakdown of emissions by land used per country
- No mention of the carbon opportunity cost of land occupied by agriculture.
