Recent years have seen plastic become the villain of the food packaging world, with many companies suddenly switching to paper, glass or new ‘biodegradable’ materials instead. But how can we be sure that – from an environmental perspective – this is the right decision? How should we compare one material against another?
To answer this question, researchers use a technique called Life Cycle Analysis (LCA). “In a nutshell, a LCA assesses all the environmental impacts for the materials, resources and emissions associated with a product’s complete lifecycle, including extracting the materials, manufacturing, transport, the use phase and the end of its life,” says Dr Rukayya Ibrahim Muazu, a chemical-environmental engineer at the University of Sheffield. LCAs are highly rigorous, governed by an international standard,1 and generally done by practiced experts.
Comparing Different Packaging Types
A good LCA will consider a wide range of environmental impacts, including carbon emissions, energy consumption, land and water use, toxic chemicals, and of course, what happens to the material at the end of its life. But even when done properly, an LCA can only give us an approximation or a range for a material’s impact because it will depend on exactly how individual pieces of packaging are produced, used and disposed of.
For example, an LCA of a packaging material might consider the energy used to produce it (was it sourced from renewables, or fossil fuels?), where the raw materials come from (does it contain any recycled content? For paper, was the wood harvested from sustainably-managed forests?), how heavy it is and how it’s transported around the world (by land, sea or air?), how easily can it be recycled or reused (does it contain special food-safe coatings that prevent recycling?), and whether that recycling process uses energy or produces wastewater or toxic chemicals. LCAs taking a broader view might also consider social issues, such as whether production involved unfair pay for workers, or forced or child labour.
Context is key
One issue with LCAs is that they can be very reductionist. As the table above shows, every type of packaging has both good and bad features. For instance, despite the recent backlash against single-use plastic, it has proved immeasurably useful during the COVID-19 pandemic for producing PPE, protective screens and vaccine syringes. The most environmentally-friendly packaging for one context won’t be the same as for another.
Consider glass as an example. Certain brands of yogurts and chilled desserts have switched from plastic to glass because glass is often seen as being ‘better for the environment.’ But whilst glass can be recycled indefinitely, transporting and remelting it have high associated carbon emissions. It’s why Santiago Navarro, CEO & Co-Founder of Garçon Wines2 decided to launch a new type of wine bottle for his business; flat bottles made from recycled PET plastic. “Our flat bottles pack like books, meaning we can fit up to 91% more wine on the same transport pallet compared with using round, glass bottles. Combined with the lightweight nature of PET, this reduces the carbon emissions of our bottles by approximately 50%, according to two LCAs conducted by third parties on our bottles,” he says.
However, in a closed-loop or deposit-return system, such as a milk delivery round, glass containers may be the best option, since they can be washed and reused directly for the same purpose many times. In such a system, it's thought that glass milk bottles have a lower carbon footprint than single-use plastic bottles after being reused just 20 times.3 Similarly, more durable containers can also be the lowest-impact option for new home-delivery subscription services, such as TerraCycle’s Loop, where they can be simply washed and reused many times over.
Sometimes single-use is the best
But whilst it’s easy to reuse containers in some situations, in others reusing or recycling food packaging is much more difficult. In these cases, single-use, disposable packaging may actually be - counterintuitively - the most environmentally-friendly option.
For instance, an LCA study4 which compared different single-use takeaway boxes concluded that, across all 18 environmental impact categories assessed, non-recyclable Styrofoam containers had a much lower total impact than recyclable plastic or aluminium containers. “Because expanded polystyrene (EPS) containers have low density (Styrofoam can be more than 95% air), they don’t require much material” lead author Dr Alejandro Gallego-Schmid from the University of Manchester explains. “We found that, depending on the impact category, you would have to reuse a Tupperware container between 16 and 208 times, until it became a better environmental option than EPS - and when it comes to terrestrial ecotoxicity, reusing Tupperware is often actually a worse choice because of the chemicals involved in washing the container and the electricity required to heat the water.”
Nevertheless, there are other issues with single-use, disposable takeaway containers - including a high propensity to be littered and the pollution of ocean ecosystems with microplastics - which are not always included in or well considered by LCAs. Perhaps the ideal solution would be for the takeaway food industry to be designed with reuse in mind, so that containers could be used hundreds of times over and washed in bulk (using non-toxic detergents) to minimise their environmental impact. Pilot schemes (such as Fresh Bowl in NYC, which encourages customers to return their reusable glass jars in return for free credit) show it may be possible, but doing this on a large scale will require considerable investment, as well as national policies that all stakeholders - including packaging producers, consumers and retailers- can commit to.
Designing better systems
Clearly, to reduce packaging waste without causing even more damage to our environment, we have to consider more than just the materials we are using. If we want reusing packaging to be the most environmentally-friendly option every time, we need to optimise entire systems, taking into account waste management infrastructures and human behaviour.
Though plastic pollution remains a major issue, plastic itself is not intrinsically evil - indeed, plastic packaging can play an important role in reducing food loss, particularly for perishable products such as salads and some vegetables. In an ideal system, it's likely that every packaging type will have a role to play. To achieve this, we’ll have to shift away from over-generalising and be prepared to embrace different packaging types - perhaps even single-use plastic - when the evidence shows it makes the most environmental sense.