Supermarkets. Maybe it’s their special offers, their dazzling choice or their all-under-one-roof convenience. Whatever the reasons, few Britons buy much of their food anywhere else. Of every pound spent on food in the UK, more than 85 pence goes into a supermarket till. Despite this enormous success, supermarkets are regularly criticized in relation to a wide range of environmental – as well as broader ethical – concerns. So how green are supermarkets compared with the alternatives? Should we believe their numerous environmental claims, or do they represent little more than green wash?
The short answer is that although there are environmental problems with supermarket shopping, the important ones from a climate change perspective aren’t those that get the most publicity. For example, despite huge media coverage, the giving out of plastic bags at supermarket tills is not a major concern in terms of global warming. The same is true for food packaging. There’s no doubt that much food is grossly over-packaged in supermarkets (and indeed elsewhere), and it’s true that all packaging causes some emissions in its manufacture, transport and disposal. Compared to the food it contains, however, most packaging isn’t particularly significant in terms of climate change – especially when it’s made of light materials, as in the case of foam trays and plastic wrap. The carbon footprint of a glass wine bottle – which is heavy and bulky to transport and energy-intensive to produce and recycle – is likely to be hundreds of times higher than that of the polythene wrap around a cucumber or bunch of grapes.
Moreover, it’s worth bearing in mind that some packaging of fresh produce can help reduce the amount of food that’s spoiled in transit and storage. Packaging can also increase the lifespan of the food, thereby reducing the chance that it will be thrown away in the home. In some cases, then, plastic packaging, however aesthetically unpleasant it might be, may actually be beneficial in terms of climate change, since the emissions generated in its production will be lower than that of the wasted food it avoids. Unfortunately, it’s not always easy or possible to know which packaging is wasteful and which is serving a useful purpose. But the fact remains that, while there may be other reasons to object to it, light plastic packaging isn’t likely to be a key issue in terms of the carbon footprint of your diet.
Another popular criticism of supermarkets is that they sell products high in “food miles”. It’s probably true that supermarkets are worse than other outlets in this regard. In particular, it seems likely that the supermarket retail model, with its fast turnover and focus on premium products, has done the most to drive the increasing number of air-freighted products being consumed in the UK. To be fair, however, food transported by air can be found in smaller shops and indeed markets, too, so the big retailers can’t be held entirely responsible. Furthermore, as we’ve seen, air-freight accounts for only a tiny proportion of the food and groceries we buy. When it comes to the ships and lorries that deliver the rest, no one knows with any certainty how supermarkets compare with other outlets. About all that it’s possible to say for sure is that food transport emissions will usually be lower if you get your fresh produce via a farmers’ market (presuming you don’t need to drive too far to get there) or an organic box scheme that consciously keeps food miles to a minimum.
One less discussed but probably fairly significant issue is refrigeration. Supermarkets sell a large and growing proportion of their food in the form of pre-prepared ready meals. Although there isn’t a great deal of data available to prove the point, it seems highly likely that buying ingredients and cooking them at home will typically cause fewer emissions than buying a ready meal that has been created in a factory, transported in a chilled lorry and then displayed in an open-fronted fridge or freezer.
Doorless fridges and freezers aren’t the only example of energy-profligacy in supermarket stores. As George Monbiot documented in his book Heat, the stores are also lit to unusually high levels of brightness and are often wasteful with heat, as in the case of warm air machines in entrance-ways. According to a study by ENDS (Environmental Data Services) and the University of Edinburgh, the operation of supermarket stores and transport fleets is directly responsible for around 1% of UK greenhouse gas emissions, even before you consider the food they sell.
A final environmental argument against supermarkets is their tendency to refuse to accept fruit and vegetables on pernickety cosmetic grounds. Size is specified to within a few millimeters, and perfectly natural bumpy or uneven shapes, and varying colors, are disallowed. Critics claim that this obsession with how produce looks leads to a great deal of waste, and encourages farmers to increase their use of agrochemical inputs.
All these arguments aside, it’s worth bearing in mind that where we shop will typically be less important than what we buy. The carbon footprint of a basket of seasonal vegetables picked up at the local supermarket will typically be significantly lower than that of a basket of organic, artisan meats and cheese from the local farmers’ market.