With growing demand for diverse food products1, transportation has emerged as a key link in worldwide food supply chains. This study estimates the carbon footprint of food miles, using a global multi-region accounting framework.
‘Food miles’ are based on the distance travelled by food items from production to consumption, to indicate environmental impact (i.e. energy use or emissions). Food miles are measured as tonne-kilometres (tkm), the transport of 1 tonne of food over 1km – the distance travelled multiplied by the mass of the transported food item.
Carbon footprint assessments of food miles are limited, with only a few selected food items having underdone this type of analysis – due to the large amount of data required to model all food types. The carbon footprint of the global trade of food, accounting for the entire food supply chain is lacking, yet, without this data it is not possible to assess the relative importance of food miles. This study provides a comprehensive estimate of the carbon footprint of food miles, using a global framework – inputting countries of origin, destination countries, transport distances and food commodity masses.
The researchers calculated ‘food miles’ emissions using a global multi-region model incorporating transport distance, food mass, type of transport with relevant emission factor (rate at which that particular vehicle releases CO2 into the air). They also calculated total food-system emissions which include food-miles emissions, food production and land-use-change emissions.
When the entire food supply chain was considered in this analysis the researchers found that global food miles equate to about 3.0 gigatonnes of carbon dioxide equivalent (GtCO2e) – higher than previously thought. This indicates that transport accounts for 19% of total food system emissions. The transport of fruit and vegetables contributes 36% of food miles emissions – around twice the amount of greenhouse gases (GHG) released during their production. Food miles only contributed 18% of the total freight miles, but the researchers found that the emissions from these made up 27% of total freight emissions, mostly from international trade (18%).
The researchers also estimated the global food-system emissions to be 15.8 GtCO2e, equating to 30% of the world’s GHG emissions. With global food expenditure around US$5 trillion (€4.85 trillion) in 2017 and the global population rising annually, it is useful to consider the impacts of food miles on climate change. The researchers say that this should be coupled with more locally produced food items and add that improved food security through better food-systems management also requires integration of environmental protection targets.
- These included cereals and oils for human and animal consumption.
Li, M., Jia, N., Lenzen, M., Malik, A., Wei, L., Jin, Y. and Raubenheimer, D. (2022) Global food-miles account for nearly 20% of total food-systems emissions. Nature Food, 3(6): 445–453.
To cite this article/service:
“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.
Notes on content:
The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.
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- 25 Eanáir 2023
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