Is eating local produce actually better for the planet?

Think that eating local will help save the planet? Think again. Most emissions come from food production, not transportation

In June 2005, four women spoke at a San Francisco celebration of the first World Environment Day in North America. The Bay Area locals – Jen Maiser, Jessica Prentice, Sage Van Wing and Dede Sampson – invited the audience to join them in a local food challenge: spending the next month eating only food produced within 100 miles (160km) of their homes.

Although the concept of eating locally was not new – the farm-to-table movement had kicked off in the 1960s and 70s as hippies protested against processed foods and Alice Waters opened the first farm-to-table restaurant, Chez Panisse, in Berkeley, California – these women gave it new life with a new name, calling themselves "locavores". In his 2006 book, The Omnivore's Dilemma, Bay Area local Michael Pollan also advocated for the local food movement, and by 2007 the Oxford American Dictionary had dubbed "locavore" its word of the year.

Nearly two-thirds of Americans believe that eating local food is better for the environment. But in recent years, a series of studies have shown that eating locally might not be as environmentally impactful – in and of itself – as advocates once hoped. In fact, research shows that the carbon footprint of transporting food is relatively small, and that it's more important to focus on how your food is produced. Eating local can be a part of that, but it doesn't have to be.

In 1994, the UK-based Sustainable Agriculture Food and Environment Alliance (now called Sustain) published The Food Miles Report – the Dangers of Long-Distance Food Transport, which offered scientific backing for the burgeoning local food movement. It argued that the long-distance transportation of food was only possible because of cheap, non-renewable fossil fuels that allowed transnational corporations to "exploit land, labour and resources in developing countries for the production of raw commodities to which they add considerable mark-ups before sale in the North".

"As you can perceive in the title, food miles were initially considered (almost by definition) as a big threat and contributor to climate change," Laura Enthoven, a PhD researcher in agricultural economics at the Université catholique de Louvain in Belgium and author of a recent review of local food systems research, said in an email. The farther food had to travel, the more fossil fuel was used and greenhouse gases emitted.

Those emissions are especially high for food transported by airplane: food that is flown is responsible for up to 50 times as much carbon dioxide as food transported by boat. Fortunately, very little food travels by air (think perishables that need to be eaten soon after harvest, like asparagus and berries). Many fruits and vegetables with a longer shelf life, like apples and broccoli, can be shipped by boat, truck or rail, whose food miles produce far fewer emissions.

In the 2000s, scientists began conducting full life cycle assessments of food supply chains – looking at how much greenhouse gases are emitted not just when food is transported, but also when crops are planted and fertilized, animals are taken out to pasture or kept in confinement, and food scraps end up in the garbage. What they found was that transporting food made up a relatively small percentage of food's total carbon footprint.

In a 2018 paper, a team of researchers from the UK and Switzerland found that only 1% to 9% of food's emissions come from packaging, transport and retail. The vast majority of greenhouse gas emissions – 61% – come during production, while food is still on the farm. That's supported by research published in the early 2000s in the US and Europe.

"What we eat and how it is produced makes more impact on our food carbon footprint than purely where it comes from in terms of distance," said Enthoven.

The greatest source of emissions can vary among foods. In many crops, it's the fertilizer and pesticides required to grow large quantities of food on industrial farms. In beef, for example, less than 1% of emissions come from transportation while the vast majority come just from feeding cattle (and their methane-heavy burps).

Scientists are still grappling with how to define food miles: some only take into account the emissions of transporting food while others consider the full life cycle of producing food in one region before it is moved to another. As recently as last year, a study in Nature Food found that food miles accounted for a significantly larger share of the food system's emissions than had been previously thought by taking into account the emissions from transporting fertilizers, machinery and animal feed to grow that food.

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Does the research mean there are no benefits to eating locally? "It depends," both Enthoven and Mike Hamm, a professor emeritus and founding director of the Michigan State University Center for Regional Food Systems, said separately. Eating locally can be a means of supporting farms that use more environmentally friendly production practices, such as minimizing their use of fossil fuel-rich pesticides and fertilizers.

"I’ve often said the whole idea of local foods wasn't about just reducing food miles," said John Ikerd, professor emeritus of agricultural economics at the University of Missouri. It's also a solution for people "looking for an alternative to the industrial food system".

Ikerd recalls the farm-to-table movement and hippy-led rebellion against industrial food beginning shortly after Rachel Carson's indictment of pesticides, Silent Spring, was published in 1962. That led to the birth of the organic food movement, which sought to produce food without greenhouse gas-emitting fertilizers, pesticides and other chemicals. But as more corporations began producing organic-labeled food, Ikerd saw consumers turn to local farms where they might have a better sense of how their food was grown – and more peace of mind that farmers were using regenerative agricultural practices.

"Well-designed, inclusive, local food initiatives can have a positive impact," said Enthoven. But she cautions that consumers can fall into a "local trap", a term coined in a 2007 article by researchers at the University of Washington, if they "believe that the whole system should switch to local only, which is not per se more sustainable or inclusive".

Although many local farms tout themselves as ethical alternatives to industrial agriculture, there's no rule saying they have to be organic or worker-friendly. In fact, many small farms are exempt from paying the federal minimum wage and US Occupational Safety and Health Administration safety oversight and investigations.

Local farms can be important alternatives, especially when there are disruptions in supply chains, as occurred at the beginning of the Covid-19 pandemic. But "we need a diversity of scale in our production system across product types," said Hamm, especially as we look at ways to feed 8 billion people in the era of climate crisis.