In considering the sustainability credentials of different packaging types it is important to be clear about the relationship between the natural resources used to produce the materials that are then formed into individual packaging items.
Resources are of different types: biomass, fossil fuels, elements and minerals and are processed into materials that have fundamentally different intrinsic properties and characteristics. A variety of management strategies are therefore required for responsible stewardship of different resources and materials.
- Natural resources: (e.g. bauxite, iron ore, oil/petrochemicals, silica, trees, plants);
- Materials: (e.g. aluminium, steel, plastics, glass, wood, paper/board and combinations of materials);
- Packaging items: (e.g. cans, bottles, pouches, trays, films, tubes, boxes, cartons).
In considering natural resources, a division is often made between renewable resources and non-renewable resources:
- Renewable resources are those that belong to the natural environment, and are replaced by natural processes as part of the eco-system (eg trees, plants, animals, soil, water) in a timescale of years or decades that supports the rate of consumption.
- Non-renewable resources are those natural resources that exist in a fixed amount, or are consumed at a faster rate than nature can create them, as they are replenished over geologic time spans (eg fossil fuels). The assumption therefore is that these resources will eventually be used up. For this reason the consumption of non-renewable resources is sometimes considered to be less preferred. We see this in recent attempts to substitute fossil fuel based plastics by plant based plastics.
So how should metals, including aluminium, be considered?
Bauxite is mined from the earth’s crust and processed into alumina/aluminium. Because the ore is mined, it is often said that natural resources are being depleted. However, an important point is missing from the story here; metals such as aluminium are elements and so cannot be destroyed.
Aluminium is a material that can be transformed into packaging and many other product applications, automotive, aerospace, construction etc. Once these product applications reach the end of their useful life, the aluminium can be recycled and used again to make another product application. This gives rise to a virtuous circle.
Note: it is the product application (can, car, plane etc) that reaches the end of its useful life, not the material, in the case of metals. The aluminium remains as a permanently available material resource to be used again by recycling. With every new cycle a new product application can be formed and this cycle can occur an infinite number of times while retaining the properties of the metal.
Can we say therefore that metals are “renewable”?
Commonly accepted convention states that the term “renewable” is applied only to those natural resources described above (trees, plants etc). Hence the focus is on responsible resource management of, for instance, forests.
Conversely the focus of metals is on responsible materials management, the materials themselves being a permanently available resource to be used again and again. It is obvious therefore that alongside the distinction between renewable and non renewable resources there is an equally valid distinction to be made between permanent and non permanent materials.
- It is misleading to equate mining of metal ore with depletion of the earth’s resources.
- Metals are elements and cannot be destroyed.
- Aluminium can be recycled without loss of properties and can be used again and again to form new packaging and other product applications.
- Aluminium is a permanently available resource; and what is more sustainable than permanence?
- Aluminium recycling benefits present and future generations by conserving energy and other natural resources. It requires up to 95% less energy to recycle aluminium than to produce primary metal and thereby avoids corresponding emissions, including greenhouse gases.
- Approximately 75% of all the aluminium ever produced is still in productive use, having been through countless loops of its lifecycle.