More than just the material: Why the life cycle matters
The first part of the new series ‘Packaging Fact Check: Materials, Impact, Recycling’ examines the question of how packaging can be meaningfully compared. This is because it is not the image of the material that determines its actual environmental impact, but rather its entire life cycle – from function and material use to transport, reuse and recycling.
Many factors come into play
Glass is regarded as natural, paper as a renewable resource, aluminium as particularly valuable, and plastic is often seen as problematic. Yet such generalisations do not tell the whole story. How sustainable a piece of packaging actually is depends on its entire life cycle: from raw material extraction through to production and transport, right through to reuse and recycling – and, not least, on its intended use.
The environmental impact of packaging cannot therefore be judged by the material alone. The decisive factors are the function it fulfils, how much material is required to do so, and what happens to it after use. Weight, product protection, transport distances, the proportion of recycled material, reusability and the existing recycling infrastructure all have a significant influence on the outcome.
Compare function, not kilograms
A simple comparison per kilogram of material can therefore be misleading. Depending on the packaging system, very different quantities of material are required for the same volume of contents. Meaningful life cycle assessments therefore compare packaging that fulfils the same function across its entire life cycle.
The examples of 0.5-litre drinks and 1-litre milk also illustrate the extent to which material, weight, recycled content and packaging system can affect the carbon footprint. These examples compare different PET, HDPE, glass, aluminium and cardboard solutions, taking into account not only the packaging itself but also factors such as filling, distribution, transport, and recycling or disposal.
This makes it clear that: Even within a single material group, the results can vary – for example, due to the proportion of recycled material or whether a packaging solution is used as a single-use or reusable option.
The specific application is the deciding factor
The question “Glass, aluminium, paper or plastic?” is therefore too broad. For a well-founded assessment, it must first be clarified what function the packaging is intended to fulfil and under what conditions it will be used.
How much material is required? How well does the packaging protect the product? What is the weight to be transported? What is the proportion of recycled material? Does reusable packaging make sense under the given transport conditions? And can the material actually be collected and recycled after use?
Combining these factors provides a reliable picture
Lightweight materials in particular, such as PET and HDPE, can offer significant advantages here: they combine high stability with low weight. This means less packaging material is needed and transportation efforts are reduced, resulting in these packaging solutions having the smallest carbon footprint in most cases. What matters, then, is not a material’s image, but how efficiently a specific packaging solution fulfills its purpose throughout its entire life cycle.
The next part of the series will show where these differences arise. It will focus on the raw materials and manufacturing processes of glass, aluminium, paper and plastic – and on where the key environmental levers lie for each material.
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