Food Miles and Carbon Emissions: Rethinking the Distance-to-Table Debate
Examining the real carbon footprint of food miles and why 'eating local' is not always the climate solution it seems.
Understanding Food Miles and Their Climate Impact
The journey food takes from fields and farms to our plates—popularly known as food miles—has become a central conversation in sustainable eating. The notion that the further food travels, the greater its environmental toll, has inspired many to eat local in hopes of reducing their carbon footprint. But what does the science really say about the climate impact of food miles, and how significant are transportation-related emissions in the broader context of the global food system?
What Are Food Miles?
Food miles refer to the distance food travels from the point of production to the final consumer. This includes journeys by road, rail, sea, or air, and is commonly measured in tonne-kilometres (tkm), which accounts for the mass transported and the distance covered. Each mode of transport has its own emissions profile, and the complexity of global supply chains means some foods crisscross continents before reaching your shopping cart.
- Domestic food miles: Cover distances traveled within the same country, typically using trucks, which are less carbon-efficient.
- International food miles: Often involve shipping which, while relatively carbon-efficient, covers vast distances.
- Air-freighted food miles: The most carbon-intensive, though only a tiny percentage of our food is moved this way.
The Global Carbon Footprint of Food Miles
Recent research has provided comprehensive estimates of the emissions generated by food transport on a worldwide scale. A 2022 study published in Nature Food found that the annual emissions from global food miles are much higher than previously thought, equating to around 3.0 gigatonnes of carbon dioxide equivalent (GtCO₂e) per year. This figure accounts for about 19-20% of the total carbon footprint of the food system, an eye-opening proportion that puts food transportation solidly in the climate spotlight.
- The total greenhouse gas emissions of the global food system were estimated at 15.8 GtCO₂e, accounting for roughly 30% of global emissions.
- Fruit and vegetable transport was found to contribute disproportionately, making up 36% of food mile emissions—about twice as much as is released in their cultivation.
- Food miles make up just 18% of global freight miles but constitute 27% of total freight emissions, mainly due to high-emitting modes of transport and the volume of perishable goods shipped worldwide.
Despite these numbers, it is crucial to recognize that research methods and definitions vary. Some analyses using narrower definitions of food miles and food-system boundaries—such as those from prior authoritative studies—suggest these emissions stand at 5-9% of food system emissions. Much depends on whether upstream and ancillary transport (fertilizers, packaging, inputs) are included.
How Are Food Mile Emissions Calculated?
Calculating food mile emissions on a global scale is a daunting task. Researchers use multi-region input-output models that factor in:
- Country of Origin: Where the food is produced.
- Destination: Where it is consumed.
- Transport distance: Total distance covered along the supply chain, not merely the last leg to the consumer.
- Food commodity mass: The total weight of food moved at each stage.
- Type of Transport: The emissions profile of trucks, ships, trains, and planes.
What others are reading
Transport by ocean shipping is the most common for international food trade, and despite the immense distances, it is the most carbon-efficient per kilogram per kilometer. In contrast, trucks dominate domestic food movements and are responsible for more than 80% of food transport CO₂ emissions due to their higher emissions per kilometer. Air-freight is rarely used for food but is highly polluting when it is.
Where Do Most Emissions Come From?
| Emission Source | Typical Share of Food System Emissions |
|---|---|
| Food Production & Land Use Change | 80–90% |
| Food Miles (Transport) | 5–20% |
| Packaging | ~5% |
It is essential to emphasize: most emissions from food are generated during production, not transport. The type of food you eat typically has a far greater impact on your carbon footprint than how far it has traveled. For example, producing 100 grams of protein from beef can cause 10 to 100 times the emissions of producing it from beans or peas.
Is Eating Local Always Better for the Planet?
The common wisdom that buying local food always leads to a lower carbon footprint is, surprisingly, not supported by the science. Here’s why:
- Transport is a small part of most food’s carbon footprint: Usually, it is less than 10% of the total. While local food travels fewer miles, the way it is produced (farming practices, energy use, land conversion) usually matters much more.
- Domestic transport dominates emissions: Most of the CO₂ from food transport is due to trucking food within countries, not shipping it across oceans.
- Few foods are air-freighted: Air transport, though extremely carbon-intensive, is reserved for highly perishable, out-of-season items, representing less than 1% of all food miles.
- Shipping is efficient: Bulk international shipping emits significantly less CO₂ per mile than road or air transport.
This means local food isn’t always the greenest choice, especially if it is grown in inefficient conditions (out of season, using heated greenhouses, etc.). Instead, the environmental impact comes down to how the food is produced and what type of food it is.
Which Foods Contribute the Most to Food Mile Emissions?
Studies indicate that fruits and vegetables are the biggest contributors to food mile emissions, accounting for about 36% of the total despite being much less carbon-intensive to produce than animal-based foods. Their need for rapid, cold transport and high perishability explains their outsized role. In contrast, staple grains, oils, and animal products have a lower share of food mile emissions by volume but a much higher emissions profile from production itself.
How to Reduce the Carbon Footprint of Your Food
- Prioritize low-emission foods: Shifting toward plant-based diets, especially pulses, grains, and vegetables, has a greater impact than focusing solely on local sourcing.
- Be aware of air-freighted produce: Avoid buying highly perishable foods flown in from distant countries (usually labeled as air-freighted or arriving far out of season).
- Support sustainable production: Choose foods grown with renewable energy, regenerative practices, or in-season to reduce both production and transport emissions.
- Minimize food waste: Food that is grown and transported only to be wasted represents unnecessary emissions at every stage.
- Buy local when it makes sense: Support local producers who use sustainable agricultural practices, but don’t assume local is always lower carbon.
Benefits of Buying Local (Beyond Carbon Emissions)
While local foods are not always the most climate-friendly, they do offer advantages that go beyond carbon emissions:
- Freshness: Food doesn’t have to spend days or weeks in transit, which often means more nutrients and better taste.
- Support for local farmers and economies: Money spent locally stays within the community and helps sustain small-scale agriculture.
- Sustainability incentives: Local markets often give farmers more flexibility to adopt sustainable and regenerative practices without the pressure of large-scale commodity agriculture.
- Biodiversity: Local food systems can help preserve regional crop varieties that aren’t viable for industrial-scale, global transport.
Systemic Solutions: Rethinking the Global Food Supply Chain
Tackling climate change through food requires more than just choosing local options. Systemic change involves:
- Decarbonizing transport networks by adopting electric or biofuel-powered delivery vehicles for farms and food distribution.
- Streamlining global supply chains to prevent inefficient back-and-forth food movements.
- Implementing policy incentives for sustainable production at both local and international scales.
- Encouraging consumers to shift diets toward climate-friendly food choices and away from high-impact foods.
Frequently Asked Questions (FAQs)
Q: What are the biggest contributors to carbon emissions in the food system?
A: The largest share of emissions comes from food production and land use change (around 80-90%), while food transport (food miles) typically accounts for 5–20%, depending on definitions and calculation methods.
Q: Does eating local food always lower my carbon footprint?
A: Not always. For most foods, how they’re produced is more important than how far they travel. Some foods (like out-of-season or air-freighted produce) have higher transport emissions, but overall, emissions from food miles are lower than those from production.
Q: What foods have the highest food mile emissions?
A: Perishable produce—especially fruits and vegetables—often have higher food mile emissions due to the need for fast, sometimes refrigerated transport. However, their production emissions are typically low compared to animal products.
Q: Should I avoid imported foods?
A: Not necessarily. What matters more is whether the food was produced sustainably. Shipping is efficient, so foods grown in their ideal climate and shipped by sea may have a lower footprint than local foods grown in artificial or energy-intensive environments.
Key Takeaways
- Food miles are significant, but production emissions matter more.
- What you eat—especially a shift away from high-emission animal products—has a greater effect than eating locally.
- Focus on climate-friendly diets, reduce food waste, and support sustainable agriculture for systemic impact.
- Buying local brings many benefits, but not always a lower carbon footprint.
- Policy, innovation, and informed consumer choices are all crucial for reducing the environmental impact of our food system.
Shifting perspectives from “food miles” alone to a more comprehensive view of the food system can guide individual and collective efforts toward a genuinely sustainable future.
References
- https://environment.ec.europa.eu/news/field-fork-global-food-miles-generate-nearly-20-all-co2-emissions-food-2023-01-25_en
- https://www.sustainabilitybynumbers.com/p/food-miles
- https://skoot.eco/articles/what-are-food-miles-and-how-do-you-reduce-a-restaurants-carbon-footprint
- https://ourworldindata.org/data-insights/most-carbon-emissions-from-food-miles-are-produced-by-trucks-on-the-road
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