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University of Sydney researchers urge to eat local

University of Sydney

New research from the University of Sydney has found that transport makes up 19 per cent of global food system emissions – the equivalent to 6 per cent of emissions from all sources. 

Particularly in affluent countries, which are the biggest food transport emitters per capita, eating locally grown and produced food should be prioritised to minimise these emissions, the researchers said. 

“Our study estimates global food systems, due to transport, production, and land use change, contribute about 30 per cent of total human-produced greenhouse gas emissions,” University of Sydney School of Physics Dr Mengyu Li said, who led the study. 

“So, food transport – at around six percent – is a sizeable proportion of overall emissions. Food transport emissions add up to nearly half of direct emissions from road vehicles.” 

Co-author of the study Professor David Raubenheimer, nutritional ecologist from the Charles Perkins Centre, said that prior to this research the main focus of sustainable food research was on the high emissions created by animal-derived foods, compared with plants. 

“Our study shows that in addition to shifting towards a plant-based diet, eating locally is ideal, especially in affluent countries,” he said. 

University of Sydney
Image credit: University of Sydney.

Using their own framework, FoodLab, the researchers calculated that food transport corresponds to about 3 gigatonnes of emissions annually – equivalent to 19 per cent of food-related emissions. 

Their analysis incorporates 74 countries (origin and destination), 37 economic sectors (such as vegetables and fruit, livestock, coal, and manufacturing), international and domestic transport distances, and food masses. 

While China, the United States, India, and Russia are the top food transport emitters, overall, high-income countries are disproportionate contributors. Countries such as the United States, Germany, France, and Japan constitute 12.5 per cent of the world’s population yet generate nearly half (46 per cent) of international food transport emissions. 

Australia is the second largest exporter of food transport emissions, given the breadth and volume of its primary production. 

Transport emissions are also food type dependent. With fruit and vegetables, for example, transport generates nearly double the number of emissions than production. Fruit and vegetables together constitute over a third of food transport emissions. 

“Since vegetables and fruit require temperature-controlled transportation, their food miles emissions are higher,” Li said. 

The researchers calculated the reduction in emissions if the global population ate only locally: 0.38 gigatonnes, equivalent to emissions from driving one tonne to the Sun and back, 6,000 times. 

Though they acknowledge this scenario is not realistic, for example, because many regions cannot be self-sufficient in food supply, it could be implemented to varying degrees.  

“For example, there is considerable potential for peri-urban agriculture to nourish urban residents,” co-author Professor Manfred Lenzen said. 

This aside, richer countries can reduce their food transport emissions through various mechanisms. These include investing in cleaner energy sources for vehicles, and incentivising food businesses to use less emissions-intensive production and distribution methods, such as natural refrigerants. 

“Both investors and governments can help by creating environments that foster sustainable food supply,” Lenzen said.                                 

Yet supply is driven by demand – meaning the consumer has the ultimate power to change this situation.  

“Changing consumers’ attitudes and behaviour towards sustainable diets can reap environmental benefits on the grandest scale,” Raubenheimer said. 

“One example is the habit of consumers in affluent countries demanding unseasonal foods year-round, which need to be transported from elsewhere. Eating local seasonal alternatives, as we have throughout most of the history of our species, will help provide a healthy planet for future generations.” 

The study was published in Nature Food. 

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