Transport is one factor, but shouldn’t be thought of as the most important one
On average, transport constitutes around 12% of the UK food’s climate impact, without 1 accounting for food’s land use impacts.
This makes it overall a much smaller deal than what the food actually is – a meat-eaters’ diet can have double, or more, of the impact of a vegetarian or vegan one.
It is still worth reducing transport emissions, but nearly all of the studies done since the 1990s, when the term ‘food miles’ was first coined, have shown that measuring food miles on their own is not good enough as a way of judging overall climate impact. This is because other factors can easily outweigh the transport component. Fruit and vegetables grown out of season in the UK in a heated greenhouse can easily have a higher climate impact than if they are grown abroad and transported here. Basically, rather annoyingly, it is complicated.
It is also worth noting that 12% is an average. The emissions of animal products from ruminants (animals that chew the cud and thus produce a lot of methane – cows, sheep and goats), are much higher than plant-based ones, so transport is a much lower proportion of it. For more information on the emissions of animal products, see the Poore and Nemecek paper below, or a summary of it in the Guardian here:
There are huge differences in the emissions of different modes of transport, which depend on speed and size. Going fast uses dramatically more energy, and bigger vehicles are more energy efficient per tonne km. (As the vehicle itself always weighs a fair bit, you can spread that over more freight). Basically, for minimum impact, get your food carried by an enormous sloth.
Ocean freight carriers, which are giant slow hulking things, emit about 25-250 less greenhouse gasses per tonne-kilometre than trucks, while air freight emits about five times more.
For this reason transport can be a much bigger portion of a food’s climate impact when it is air freighted. Air freight is expensive and so it isn’t used that often. At an international level it accounts for only 0.16% of food miles, and about 1% in the UK. However it is used 5 when a food is extremely perishable and has to come a long way, meaning that transport by boat is too slow, and has a reasonably high value for its weight, which can cover the cost of the flight. Key fruit and vegetables that are commonly air freighted are asparagus, green beans, peas, and berries.
Percentage of various UK vegetables from outside Europe that come by air or sea. This is the proportion of its journey within the UK, the vast majority of food travels by road.
Getting the food home
Driving to the shops can end up being a significant proportion of foods’ emissions. Amazingly, personal shopping trips can use more energy than the entire upstream supply chain. It is therefore important to get this down- consumers can do so by walking, bicycling, taking public transport or using an efficient or electric vehicle. In urban areas this can be supported via local food hubs, markets or shops being easily accessible from residential areas, via bicycle routes or key public transport links.
Deliveries and veg boxes can also save greenhouse gases when compared with everyone driving individually to the shops as loads that are going in the same direction can be combined. However, it does depend on the details – there are much more likely to be a lot of loads to combine in urban areas, highlighting the importance of food hubs and coordinated distribution networks.
Case study: Regather Cooperative, Sheffield
Regather believes that ‘everyone should be able to afford decent food that supports local 9 producers and doesn’t mess up the environment.’
To support this vision, it has set up a number of initiatives, including a fruit and veg box scheme, that delivers local, seasonal and organic produce direct to homes across Sheffield and surrounding areas. It also offers an electric trike delivery option for Sheffield orders.
Where possible produce is sourced from local organic growers and in the summer months, their boxes are 100% full of Sheffield grown produce. When forced to look elsewhere – across the UK and further afield, produce is always shipped and never air freighted.
“We want to be part of a sustainable food system and help transform local food by making more local produce available to the people of Sheffield”.
To increase the supply of local produce, it has gone on to set up a new farm – a 15-acre site on the edge of Sheffield – where they are establishing a market garden, orchard, polytunnels, beehives and an agroforestry project. With time, the harvest from this will be distributed to local residents via its veg box scheme.