Eat local food to fight climate change

Researchers have suggested that adopting a ‘locavore’ diet — that is, eating only food produced within a 100 miles, or 161 kilometres, radius — could substantially reduce carbon emissions from food production.

University of Sydney scientists looked at the amount of carbon emissions that were produced by the transport of food, finding that almost a fifth of emissions from the global food system come from transport alone.

“Our study estimates global food systems, due to transport, production and land use change, contribute about 30% of total human-produced greenhouse gas emissions. So, food transport — at around 6% — is a sizeable proportion of overall emissions,” said Dr Mengyu Li, who is the lead author of the study. “Food transport emissions add up to nearly half of direct emissions from road vehicles.”

Nutritional ecologist and co-author Professor David Raubenheimer said: “Prior to our study, most of the attention in sustainable food research has been on the high emissions associated with 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.”

The researchers used a framework called FoodLab to calculate emissions from food transport. It turns out that roughly three gigatonnes of emissions is produced by the transport of food, which means it accounts for 19% of food-related emissions. This value is also somewhere between 3.5 and 7.5 times higher than had previously been estimated.

China, the United States, India and Russia produce the most emissions from transporting food and high-income countries in general produce a disproportionate amount of these kinds of emissions. In fact, countries such as the United States, Germany, France and Japan constitute 12.5% of the world’s population but generate 46% of food transport emissions, and Australia is the second-largest exporter of food transport emissions, due to the breadth of volume of its food production.

The kind of food being transported defines its levels of emissions. The transport of fruit and vegetables generates almost double the amount of emissions of their production and accounts for 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 think that eating locally may be the solution to this problem. They calculated that if everybody only ate locally grown food, emissions would reduce by 90%, down to 0.38 gigatonnes. However, this isn’t a realistic proposition globally, since many regions are unable to be entirely self-sufficient in food supply. It could be implemented selectively though.

“For example, there is considerable potential for peri-urban agriculture to nourish urban residents,” co-author Professor Manfred Lenzen said. Importantly, richer countries can reduce their food transmissions through investing in cleaner energy for vehicles and incentivising food businesses to use production and distribution methods that emit less.

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

“Changing consumers’ attitudes and behaviour towards sustainable diets can reap environmental benefits on the grandest scale,” said nutritional ecologist and co-author Professor David Raubenheimer. “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 research was published in Nature Food.

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