Researchers reveal which popular sandwich is the biggest polluter

25 Jan 2018

Image: Lenakov/Shutterstock

The humble sandwich might seem pretty inoffensive, but new research shows that it’s leaving a massive carbon footprint in its wake.

Sandwiches are a popular food staple for many people, whether it’s their packed lunch every day for work, or ones bought daily from shops and supermarkets.

While it is hard to estimate a global figure, in the UK alone, The British Sandwich Association estimates that 11.5bn sandwiches are consumed every year, while those in the US eat 300m sandwiches every day.

But, little did we know, the carbon footprint from every one of those popular lunch items is enormous, right from its beginning to end.

Research conducted by the University of Manchester and published in the journal Sustainable Production and Consumption looked at 40 different sandwich types, recipes and combinations.

The supposed first ever study of their effects on the environment took into account both homemade and pre-packaged sandwiches, as well as how they are sourced, packaged, shipped and disposed of.

And so, the researchers came to the conclusion that the most carbon-intensive variety is a sandwich popular with many in the UK and Ireland: the breakfast roll.

With contents of egg, bacon and sausage, the breakfast roll generates 1,441g of CO2 equivalent (CO2e) emissions, equal to almost 20km in a car.

On the other end of the scale, a lunch classic – the ham and cheese sandwich – was deemed the least carbon-intensive. Homemade sandwiches are, unsurprisingly, better for the environment.

Bready-made solution

“Given that sandwiches are a staple of the British diet as well as their significant market share in the food sector, it is important to understand the contribution from this sector to the emissions of greenhouse gases,” said Prof Adisa Azapagic, a member of the research team.

“For example, consuming 11.5bn sandwiches annually in the UK generates, on average, 9.5m tonnes of CO2e, equivalent to the annual use of 8.6m cars.”

Looking at which parts of the supply chain create the most CO2e, the agricultural production involved can account for between 37 and 67pc, depending on the type of sandwich you get.

Supermarkets are also major contributors, with the chilled section for pre-packed sandwiches producing a quarter of their greenhouse gas emission equivalent.

There is a solution, however, with the team suggesting that the carbon footprint could be reduced by as much as 50pc if a combination of changes were made to the recipes, packaging and waste disposal. The researchers also suggest extending sell-by and use-by dates to reduce waste.

Colm Gorey was a senior journalist with Silicon Republic