It’s difficult to say whether packaging really is sustainable

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Consumer ratings not always realistic

Sustainability is trendy. Also, or perhaps we should say particularly, in packaging. That’s why retailers and manufacturers are increasingly turning to sustainable packaging materials – or rather to materials that are considered to be sustainable. After all, in surveys conducted in Germany, a clear majority of consumers regularly express the desire for sustainable packaging. Supposedly, a clear majority of consumers in the country are even willing to pay more money for food packaging if they themselves perceive it as sustainable. This was the result of a recent study carried out by the Martin Luther University Halle-Wittenberg (MLU). So which packaging is not only perceived as being environmentally friendly, but really is sustainable as well?

As the authors of the MLU study explain, respondents in earlier studies on the acceptance of different packaging materials could only choose between a few packaging alternatives, for example between conventional plastics and bioplastics. That’s why in the new study they chose a broader range of options, including unpackaged products, so that the respondents could choose between different product alternatives with different types of packaging, just as they would when shopping in a supermarket. These products also differed in price. The participants were then asked to rank the packaging materials according to their sustainability and to indicate their own knowledge about individual packaging materials as well as what they would like to see when it comes to the way their everyday purchases are packaged.

Consumers willing to pay more for sustainability

Unpackaged food proved to be particularly popular. But packaging made of recycled plastics and paper was also preferred to that made of conventional plastics. The consumers surveyed were also willing to spend more money on alternatives to conventional plastic packaging if these alternatives were perceived as more sustainable, reported the author of the study, Dr Katharina Sträter. The economist noted that this was true even if, as in the case of unpackaged food, they would effectively be paying more for less, so to speak. She described another important result of the study: the problem that so far there is no consensus on which packaging materials are actually sustainable. Here, the researchers believe it is the responsibility of science and politics to clarify this issue.

Bioplastics received particularly poor ratings in the MLU study. The respondents justified their negative assessment by saying that they knew too little about the material and its properties. “Our results indicate that with the term ‘bioplastics’ people tend to assume that it’s a product that’s just as bad for the environment as conventional plastics,” explained economist and study co-author Christoph Herrmann.

Other studies, such as the Statista report Sustainable Consumption 2021, also make it clear that a growing number of consumers are guided by environmental criteria when making their purchasing decisions. And for many consumers, sustainable consumption includes sustainable packaging. According to the Statista report, most respondents consider packaging to be sustainable if it is biodegradable and made of recycled or recyclable materials. This then also includes plastics. However, paper and cardboard (with 70 per cent approval) and glass (62 per cent) are considered to be the most sustainable packaging materials in this context. Measured against these values, beverage cartons, plastic packaging and cans perform considerably worse.

‘Sustainability’ not precisely defined

But when does packaging earn the right to be called ‘sustainable’ and can the assessment of this by consumers really be considered to be objective, or must it be put into perspective as being subjective? After all, the relevant studies repeatedly show that consumers consider the sustainability of packaging to be highly complex and difficult to understand. This is not surprising, since the term ‘sustainable’ and what it means are not clearly defined, especially in the packaging sector. This is not least because sustainability goals sometimes diverge significantly. 

Take the reusable glass bottle as an example. It conserves resources. However, the glass bottle’s greater weight means it leads to more CO2 emissions during transport than is the case with a PET bottle. This effect is particularly marked when the bottle has to be transported over long distances from the filling plant to the point of sale. The greater the distance, the worse the eco-balance of the glass bottle! And on top of this, a considerable amount of energy is required to melt down used glass. 

Overall, the German Federal Environmental Agency concludes that depending on where they are used, glass and PET bottles differ only slightly in terms of their eco-balances, and both can thus be regarded as sustainable. The PET bottle comes out slightly better than the returnable glass bottle when it comes to transporting 1000 litres of mineral water.

Consumer’s ‘gut feeling’ often deceptive

This example illustrates how consumers can have a ‘gut feeling’ about the sustainability of packaging that differs from the scientifically proven reality. After comparing the results of numerous relevant studies, the Federal Environmental Agency has come to the clear conclusion that from an ecological point of view, reusable bottles made of either glass or polyethylene terephthalate (PET) are definitely a better choice than single-use plastic bottles or beverage cans.

The picture is similar when it comes to the packaging materials paper and cardboard: They are made from renewable raw materials and are easy to recycle. However, as soon as cardboard packaging is coated, for example to achieve a barrier effect, the composite can only be recycled with difficulty, or even not at all.

All things considered, experts agree overwhelmingly that packaging can be classified as sustainable if as few resources as possible are used to produce it. This can be achieved, for example, by using thinner plastic films or lighter weight cardboard. And packaging should be recyclable and be circulated in a loop!

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