When thinking about our carbon footprint, our attention naturally goes to transport, holidays, heating – all things that clearly use oil. However, for most households, their weekly food shop makes up a greater proportion of their carbon footprint than transport. Unlike driving your car, though, it is not immediately obvious where you are clocking up the carbon, or how you can reduce it.
It’s not all about food miles. More important is how the food travels those miles. Bananas and oranges, for example, travel huge distances, but do so by boat because they store well and are naturally well-packaged, and so their carbon footprint is modest. On the other hand, those out-of-season luxuries grown in Africa or South America and air-freighted to the UK, like asparagus, blueberries and mange tout, have a colossal footprint. To put some figures on it, a kilo of bananas has a carbon-equivalent footprint of 480 g; that of a kilo of air-freighted asparagus is 14 kg, that’s nearly 30 times as much!
Another major factor is how food is grown. Again, bananas are grown in the tropics with no input of heat and light – it definitely wouldn’t be ‘green’ to grow them locally! Major offenders in this respect are the salad and mediterranean vegetables grown in artificially heated and lit Dutch greenhouses and trucked to the UK. It actually uses less carbon to grow them naturally in Africa and air-freight them, but neither option makes any sense. Tomatoes grown in artificial conditions in winter can have a carbon footprint of up to 50 kg per kilo, compared with 0.4 kg when grown in unheated greenhouses locally in summer.
The third main factor in your food carbon footprint is whether it is animal or plant based. When you feed soya or grain to animals instead of directly to humans, they use most of the calories to walk around, keep warm and generally do their thing, and little to actually make meat or milk. Beef has a carbon footprint of around 16 kg per kilo, compared with less than 1 kg for wheat. Chicken and pork have a far smaller footprint than red meat, because they are ready to eat at a much younger age and they don’t produce methane in digesting their food.
All of these figures are obviously approximate, but they make it easy to see the difference between different kinds of food. Cutting down on winter tomatoes or having a meat-free day once a week will have a major impact on your food carbon footprint, as will sticking to the UK season for asparagus, but its not worth depriving yourself by cutting out bananas and oranges.