How much do food miles matter and should you buy local produce?

The person is Michael Le Page.

You can reduce your carbon footprint by eating local. It has long been known that food that travels thousands of kilometres can have a lower carbon footprint than local produce.

That is what many studies have come up with. According to research published today in the journal Nature Food, global food miles account for 20 per cent of food related emissions. We thought food miles mattered more than they did. They don't

Reducing food-related emissions is important to limiting further global warming because the production of the food we eat is responsible for more than a third of global greenhouse gas emissions. What should consumers do to help?

The emissions from food miles are small compared to those from growing it, according to previous studies.

Air or sea can be used to calculate emissions. A study of the US diet found that transporting food from farms to shops produced just 4% of the food-related emissions.

If you want to reduce the carbon footprint of your diet, you should focus on buying food with lower carbon footprints than those that don't have to travel far. Eating less meat and dairy is what this entails.

Producing 1 kilogram of beef can emit as much as 99 kilograms of carbon dioxide or equivalents, and making a kilogram of cheese can emit as much as 24 kilograms.

Read more: Should we eat local to cut food miles, or does it make no difference?

What you eat is more important than where it came from. Local isn't always better with the same food types Tomatoes grown in a country with a cooler climate will have a higher carbon footprint than those grown in a country with a warmer climate.

The study doesn't change anything. The main reason why food miles account for such a high proportion of food-related emissions is that they include all the transport involved, not just the transport of food.

The study looked at the entire supply chain for food consumption and naturally non-food commodities are part of it.

Hannah Ritchie is the head of research at Our World in Data and she says that the team should use a term other than "food miles" to avoid confusion.

If the standard definition were used, food miles would make up only 9 percent of the emissions. She thinks that it is still an overestimate.

The study shows that even if it were possible to produce all food in the countries where it is eaten, the emissions would still go up. Even though food wouldn't travel as far, more of it would be transported by road than by ships.

What you eat has a bigger impact on emissions than the distance that food has to travel to reach you.