The study presented in this article provides a comprehensive assessment of greenhouse gas (GHG) emissions from diets comprising 140 products in 139 countries or areas in 2019. The analysis is based on a global consumption-based emission inventory that includes data on GHG emissions generated during supply chain processes. The inventory allocates all emissions to final consumers of food products, providing a detailed account of emissions from agricultural land use, agricultural activities, and beyond-farm processes.
The study also quantifies dietary emissions from different expenditure groups by matching diets with a household-expenditure dataset. This allows for an examination of the differences and potential inequality of dietary emissions across various consumer groups. Additionally, the research framework includes a model that measures the emission impact of transitioning from diets in 2019 to the widespread adoption of the planetary health diet.
The data used in the study are derived from various sources, including the FAOSTAT database, the Global Consumption Database, and previous research studies. The consumption-based food emissions inventory provides national emission accounts of supply chain processes, while the household-expenditure dataset offers insights into the differences in dietary emissions across expenditure groups.
The study classifies 140 food products into 13 aggregated food categories based on the planetary health diet. This classification allows for a comparison of nutritional contents with the reference level from the planetary health diet. The analysis also includes the calculation of dietary energy intake and emissions, accounting for food consumption and supply chain emissions.
Furthermore, the study explores the concept of GF-Gini coefficients to measure the inequality of GHG footprints across expenditure groups within countries, regions, and globally. Regression analysis is used to examine the relationship between national GF-Gini coefficients and per capita GDP.
The scenario of the planetary health diet is set by assuming that individuals from different expenditure groups will reach the reference intake level of 13 food categories. The emission changes resulting from adopting the planetary health diet are calculated, taking into account the gaps between present dietary intake and the reference level.
In conclusion, while the study provides valuable insights into dietary emissions and the potential impact of transitioning to a planetary health diet, there are limitations to consider. These include data availability constraints, assumptions made in scenario setting, and the focus on present emission inequality without considering potential changes in income and expenditure levels. Future studies may address these limitations to provide a more comprehensive analysis of the implications of dietary shifts on greenhouse gas emissions.
