The humble sandwich is having an impact on the climate. About 11.5 billion sandwiches are consumed each year in Britain, and these have much the same impact on carbon emissions as driving more than eight million cars. Researchers at the University of Manchester studied the carbon emissions over the life cycle of sandwiches, from farms to consumers, and found the chief culprits were ready-made sandwiches.
The greatest offender was the all-day-breakfast sandwich made with egg, bacon and sausage, estimated to release the equivalent of 1,441g of carbon dioxide, much the same as driving a car for 12 miles. The best of the commercial sandwiches tested was egg mayonnaise and cress, equivalent to 739g of CO2, although the most climate-friendly sandwiches tended to be made at home, which can reduce emissions by half.
Up to two thirds of a sandwich’s carbon footprint comes from farming and food processing, especially from meat and dairy because of the methane released from cattle, and the need to grow food for livestock. There are also the environmental costs of keeping sandwiches chilled in supermarkets, shops and refrigerated trucks, as well as the carbon emissions in transporting and packaging.
Then there is the waste from unsold sandwiches, which could easily be reduced by relaxing use-by dates. “Commercial sandwiches undergo rigorous shelf-life testing and are normally safe for consumption beyond the use-by date stated on the label,” pointed out Professor Adisa Azapagic at the University of Manchester. Extending the shelf life of sandwiches could help to save at least 2,000 tonnes of wasted sandwiches annually. Further cuts in the carbon footprint could be made by changing the fillings, such as cutting down or leaving out ingredients with a high carbon footprint, such as lettuce, tomato, cheese and meat. Reducing packaging would benefit the climate and reduce waste going to landfill.