Transporting food from where it is produced to our dishes creates at least three times the amount of greenhouse gas emissions as previously estimated, a new study suggests.
The so-called “food miles” are likely to be responsible for about 6% of global greenhouse gas emissions, the study’s authors found after estimating that they produced 3 billion tons of greenhouse gas emissions. CO2 in the transport of food for human consumption every year.
The scientists who conducted the research, which looked at 74 countries and regions and 37 different types of food, found that the richest countries accounted for 46% of food miles emissions, but only 12 percent. 5% of the world’s population.
Fruits and vegetables had the highest emissions of food miles because they often had to be refrigerated and consumers demanded out-of-season food.
Professor David Raubenheimer of the University of Sydney, co-author of the study published in the journal Nature Food, said research to make food production more sustainable had tended to focus on comparing diets. plant-based with meat.
“We have to interpret the information around us in simplistic terms, such as‘ meat is bad and vegetables are good ’, but we wanted a much more complete picture,” he said.
“Our study shows that in addition to switching to a plant-based diet, eating locally is ideal, especially in rich countries.”
The study’s leader, Dr Mengyu Li, also from the University of Sydney, said that when miles of food were added to emissions from land use, production and livestock methane, about 30% of the world’s greenhouse gas emissions were related to food production.
“Food transport emissions account for almost half of direct emissions from road vehicles,” he said.
Sign up for the latest Guardian Australia news every morning
While meat production emits 2.8 billion tons of CO2-e, seven times more than fruits and vegetables, emissions of meat food miles for meat were only 110 million tons worldwide.
This compares with 1.06 billion tons of fruits and vegetables, and the second group of foods with the highest emissions are cereals and flour.
According to the authors, the overall total of 3 billion tons of CO2-e related to food miles was between 3.5 and 7.5 times higher than previous estimates.
In addition to calculating emissions from transferring food to the consumer, the study also included emissions from inputs used to produce food. For example, calculations would include emissions of grain that is grown and then transported for animal feed.
About 1.7 billion tonnes of CO2-e emissions came from food transport within countries, with 1.3 billion tonnes from international transport.
Raubenheimer said food supply was driven by demand and that if consumers’ attitudes changed, it could “achieve large-scale environmental benefits.”
“One example is the habit of consumers in rich countries who demand non-seasonal food all year round, which have to be transported from other places,” he said.
Total emissions of fruits and vegetables were high due to the longer distances traveled and the fact that humans eat a lot of them.
He said the next step was to use the results of the study to build a more detailed picture of the impacts of different diets, both socially and individually, on food mile emissions.
But he said a good rule of thumb was that if all the food you buy were produced locally, less meat and more fruits and vegetables would be associated with fewer emissions.
But if a plant-based diet included many imported and off-season products, this would increase emissions.
“Eating local seasonal alternatives, as we have done throughout most of our species’ history, will help provide a healthy planet for future generations, ”he said.
Options for richer countries to reduce emissions included cleaner energy sources for vehicles and offer incentives to use production and distribution methods that reduce emissions.