How do we measure sustainability?
Determining the sustainability of something is multi-faceted, because focusing too much on one particular outcome can have unintended consequences. Pretty much everything we produce or do has some impact on the planet, so to my mind what we are trying to do is reduce that impact.
Take buying a cup of coffee for example. You use a reusable coffee cup – that must be sustainable right? Well, it’s not quite that simple. You actually need reuse that cup between 100 and 250 times to offset the additional resources required to produce it and keep it clean. And if it’s made of plastic then there’s a risk that it will shed microplastics when it is washed (so go for a stainless steel one if you can). Then what if you forget your reusable cup? Since the café is using plant-based packaging using a disposable cup doesn’t matter so much does it? The answer depends on how the cup is disposed of – plant-based packaging can be composted in industrial composters, but if you put the cup in a bin on the side of the road then it won’t be separated and will end up in landfill, where it’s no better than any other disposable cup. And all this is even before you consider what kind of coffee to buy!
When you go to buy a cup of coffee you’ve got three options, drink it at the café, use a reusable takeaway cup, or get it to go in a single use cup. Leaving aside what kind of coffee you order – that opens up a whole other raft of sustainability considerations depending on whether you take your coffee black or with milk (and then if it’s dairy or plant-based) – which is the most sustainable option?
We could look at the energy required to make and keep a coffee mug clean. We could look at the carbon footprint of coffee mugs vs single use cups. But looking at those in isolation doesn’t work, because as a one off a paper cup requires the least energy to produce and has the lowest carbon footprint. Obviously the idea of the ceramic coffee mugs and reusable takeaway cups is to use them over and over again. So at a certain point you have reused them enough to make up for the initial extra energy or carbon emissions. According to CIRAIG that point is reached between at between 100 and 250 uses, reasonably easy for a ceramic cup used in a café but that could take a while to reach for your own reusable cup so is worth bearing in mind when considering how big your keep cup collection is.
Those aren’t the only factors to consider though. The raw materials used to produce the product matter too, clay in the case of ceramic mugs, a combination of steel, glass, and plastic for reusable coffee mugs, and wood pulp and plastic in single use cups, or food-based ingredients in the case of so-called compostable coffee cups. How the products are disposed of is important too – can they be recycled, or do they end up in landfill (as is the case with almost all single use cups, including the compostable ones if they aren’t collected separately). Whether the energy used to produce and keep a product clean could well make a difference too.
So, can a formula be worked out that will provide a quantitative answer to sustainability? The answer is maybe, but it’s complicated. There are a few common factors to consider when assessing a product’s sustainability though, for example whether the raw materials used are renewable or non-renewable, how durable the product is vs how frequently it is used, whether and how easily the product can be recycled, as well as the energy required to produce it and the product’s overall carbon footprint. Often how ethical a product is falls within a similar remit to sustainability so things like organic, fairtrade, vegan and animal cruelty-free are additional considerations. Assessing each factor individually and then considering overall sustainability looks to be the best approach to determining how sustainable a product is.
There will be more posts on this topic because it’s something I’m keen to develop a working theory. Ultimately you need some kind of consistent approach to be able to recommend which products and services are the most sustainable. And in case you were wondering, the most sustainable way to have your coffee is in the café using their ceramic cups due to the frequency with which they are used as well as the efficiency of their industrial dishwashers. So next time you need a caffeine hit take a bit of time out and drink in, you’ll be doing yourself and the planet a favour.