In the last decade or so, the term life cycle assessment has been become more mainstream. Despite understanding the individual words well enough, taken as a whole, things become a little blurred. And no, it’s not some sort of gloomy self-assessment questionnaire of what you’ve achieved (or not) in your lifetime. It’s actually a tool to help us understand how much impact a product has on the environment, from resource extraction (cradle) to its disposal (grave).

Indeed, a life cycle assessment (LCA) is a technique used to determine the environmental impacts associated with all the stages of a product’s life: from the raw material extraction through processing, manufacture, distribution, use, and disposal or recycling. The aim is to provide an overall view of the raw materials, the energy used and the environmental releases of a particular product and thus evaluate its potential impacts. Opportunities as to where improvements in a product’s life cycle can be made are then revealed and this can assist decision makers and provide marketing opportunities for products, such as using LCA data for eco-labelling.

In terms of packaging LCAs, by looking at a product’s impact when contained within different materials, we can hope to determine what sort of packaging is the best environmental option for the job and show whether lightweighting, for example, or even changing a product’s closure system, can provide a better alternative to changing materials.

It all sounds relatively straightforward, but as with most things that sound simple, it rarely is. Packaging has a complex life cycle, from the emissions involved with extracting the raw materials to those at its disposal, and LCAs are extremely complicated bits of analysis. To make things more consistent, LCAs follow the ISO 14000 series and, as such, have to include four phases: Goal and Scope Definition; Life Cycle Inventory (LCI); Life Cycle Impact Assessment (LCIA); and Interpretation.

The first step sets out, amongst other things, the context of the study and its audience. It also defines the functional unit (a comparable measurement, which enables evaluation of two different systems, i.e. 1,000 pints of milk), the boundaries (an LCA usually begins at the extraction point of raw materials and finishes at disposal), and assumptions a“nd limitations.

The LCI then outlines the inputs and outputs of a product system. It shows which activities are going to be assessed, the data required per functional unit and the technical system boundaries. Data
is typically collected through survey questionnaires, often from a sample of producers, or obtained from specialist software databases. Crucial to an LCA is accurate and current data, especially when comparing different LCAs, which makes the data collection the most resource-consuming part of the LCA. Reuse of data from other studies can simplify the work, but this must be made with great care so that the data is representative.

Next up, the LCIA evaluates the significance of the environmental impacts of the previous step and puts them into categories, e.g. CO2 is assigned to global warming. And finally, the interpretation phases identifies, quantifies, checks and evaluates information from the results to determine the level of confidence in the results and communicate them in a fair and accurate way.

Once completed, LCAs can be effective tools for understanding what is really involved in the production of a product. However, LCAs should be viewed with a certain amount of caution. For one thing, accuracy and availability of data can be difficult to ensure, as data may be based on averages, unrepresentative sampling, or outdated results. And also, not everything can be reduced to a number – human toxicity, product usability and social implications, for example, are difficult to quantify. In terms of beverage packaging, for instance, people may prefer the ‘feel’ of drinking wine from a glass bottle over a plastic one or may enjoy the ease of returning a milk bottle to the milk man, rather than carting the plastic bottle to the bring bank!

I remember at the end of last year, while debating the merits of artificial versus real Christmas trees with colleagues, coming across an LCA into just this issue. The ‘Comparative Lifecycle Assessment of Artificial vs Natural Christmas Trees’ concluded: ‘The natural tree is a better option than the artificial tree, in particular with respect to impacts on climate change and resource depletion. The natural tree, however, is not a perfect solution as it results in important impacts on ecosystem quality. Clients who prefer using the artificial tree can reduce their impacts on all categories by increasing the life span of their tree, ideally over 20 years.

‘Although the dilemma between the natural and artificial Christmas trees will continue to surface every year before Christmas, it is now clear from this LCA study that, regardless of the chosen type of tree, the impacts on the environment are negligible compared to other activities, such as car use.’

Apart from making the office argument seem rather pointless, it highlighted the fact that you could swing the argument either way, if you chose to do so.

Likewise, a piece of LCA research commissioned by the Environment Agency that hit the headlines in 2005 looked at the environmental impact of nappies, and the difference between reusable and disposable ones. The results suggested that there was little difference. Environmental groups immediately questioned the data and suggested it made very broad and sometimes incorrect assumptions about how people washed and dried th“e nappies. Another study was commissioned. The 2008 study showed that, used responsibly, ‘real nappies can be 40 per cent better for the environment than disposable nappies nappies at full heat and using a tumble dryer can increase the global warming impact by 75 per cent.) A victory for real nappy advocates, perhaps, but it highlighted the range of variables and assumptions that have to be made in such LCA studies.

And call me cynical, but even WRAP, when told about our ‘material face off’ (glass versus plastic, over the page) was keen to point me in the direction of footnotes that explained the limitations of LCAs.

Yes, we do need to assess the environmental impacts of different types of packaging and LCAs can be useful tools to aid system developments, but comparing systems is, at best, open to interpretation. Saying that, over the page we do exactly that... Just remember to pick up that pinch of salt before writing in!