Environment

Is the humble sandwich a climate change culprit?

Sandwiches have a surprisingly large carbon footprint
Sandwiches have a surprisingly large carbon footprint
View 1 Image
Sandwiches have a surprisingly large carbon footprint
1/1
Sandwiches have a surprisingly large carbon footprint

Scientists at the University of Manchester have found a surprising global warming culprit – sandwiches. In the first study of its kind, the researchers carried out an in-depth audit of various sandwiches throughout their life cycles and found the triangular meals could be responsible for the equivalent annual carbon emissions of 8.6 million cars in Britain alone.

In 1762, or so the story goes, the fourth Earl of Sandwich rocked the culinary world when he couldn't be bothered to leave the gambling table to eat and ordered the servants to just stick some meat between two slices of bread for him. Since then, the modern sandwich has become one of the most popular of food formats.

According to the British Sandwich Association (BSA), the United Kingdom spends £8 billion (US$11.3 billion) annually on 11.5 billion sandwiches, with half made at home and the other half bought at shops, supermarkets, kiosks, and service stations. To better understand the environmental impact of all these sarnies, the Manchester team looked at over 40 different sandwich types, recipes, and combinations as well as how they are made, packaged, transported, and stored. In addition, they considered the waste produced in making them, as well as the stale, rotten, or simply outdated sandwiches that are thrown away.

What the researchers found was that not all sandwiches are created equal and that some varieties have larger carbon footprints than others. The highest footprint was found in premade, prepackaged, all-day-breakfast sandwiches. These contain eggs, bacon, and sausage and are kept packaged and refrigerated until sold and eaten – all of which is estimated to add up to 1,441 g (3.18 lb) of carbon dioxide equivalent, or roughly the same as driving a car for 12 miles (19 km).

By contrast, the smallest footprint is that of a homemade ham and cheese sandwich. Overall, making your sandwiches at home potentially halves the carbon emissions compared to their prepackaged equivalents.

According to the team, a number of factors affect the sandwich's carbon footprint. Ingredients is one of them, with items like meat in general and pork in particular, cheese, prawns, lettuce, and tomatoes being particularly large footprint culprits. Producing these ingredients, as well as the bread and condiments, can account for 37 to 67 percent of the carbon dioxide produced. Other factors are the packaging, which makes up 8.5 percent of emissions, transportation (especially in refrigerated trucks) for 4 percent, and refrigeration at point of sale making up another 25 percent.

The Manchester researchers aren't anti-sandwich, but they do say that changing recipes and packaging while reducing waste could result in a 50 percent drop in sandwich-related carbon emissions. Along with the BSA, they claim that something as simple as reforming the sell-by-date system could save over 2,000 tonnes of sandwiches in Britain being wasted each year.

"We need to change the labeling of food to increase the use-by date as these are usually quite conservative," says team member Professor Adisa Azapagic. "Commercial sandwiches undergo rigorous shelf-life testing and are normally safe for consumption beyond the use-by date stated on the label."

The research was published in the Journal of Sustainable Production and Consumption.

Source: University of Manchester

51 comments
vernon
"Scientists at the University of Manchester have found a surprising global warming culprit – sandwiches." Every time one of these brain farts is discredited & shot down, another takes its place to keep the hysteria and hype going about "climate change." There have been many of these: Dairy cows' flatulence causes global warming; radical progressives have come up with a new theory on the cause of global terrorism…climate change; Steven Koonin (Obama's Energy Department Undersecretary) pointed to a National Climate Assessment in 2014 showing hurricane activity has increased from 1980 as an illustration of how federal agencies fudged climate data. Koonin said the NCA’s assessment was technically incorrect. It is an unbelievable act of hubris to suppose that a group of natural scientists and economists, armed with computers, can today make quantitative predictions of how much massive new taxes and draconian regulations will make people better off in the year 2150.
pete68
Perhaps any kind of food is the reason for global warming and the solution is for everyone to stop eating, die, and save the world! But you first!
geo39
This research is a complete waste of time and money.
TheWorldsGoneMad
They must not realize the more “evidence” they publish, the more batsh*t crazy they prove themselves to be.
Tim Craig
I avoid sandwiches as much as I can, because life is to short for bread. But I do eat food (I eat little else). So do I create more CO2 than the redoubtable Earl? Perhaps this could be the subject of a new project for Professor Azopagic to raise some more of my tax contribution to keep his students out of mischief.
OedipusTax
Climate change is more religion than science, more superstition than facts, more politics than logic. Articles like this one make climate change advocates look insane.
roger05
I am more frighten that these idiots if given money would do something to make the weather worse and then blame it on us.
Mickey61
Soon they will have a poop tax because poop causes global warming.
Gompers
"There have been many of these: Dairy cows' flatulence causes global warming; " The actual assertion is that eructation (belching) by cattle (dairy and meat) releases a lot of methane. That's true. Flatulence has not been named by scientists in this regard. It's also a fact that methane is a far more potent greenhouse gas than carbon dioxide (CO2), having the ability to block 17 times as much heat.
mh06
Progressives, in particular, have a tendency to defeat their own point/cause by abusive and ridiculous claims like this.