Fundamental error in Puma “green” shoe comparison
10/10/2012
Mr Zeitz used the occasion to call on governments to end tariffs on synthetic substitute materials to make them a more affordable alternative to leather for his company (see separate story on leatherbiz on October 9). As on previous occasions, such as his outburst at the United Nations Rio+20 earth summit at the end of June, large numbers of news outlets around the world carried his comments.
However, the comparison Puma has presented appears to us to contain the most basic flaw imaginable.
There are many tendentious remarks in Puma’s announcement. For example, it refers constantly to the InCycle Basket, made from materials including linen and organic cotton, as biodegradable, implying that the suede shoe is not. It says: “At the end of its life, the Puma InCycle Basket is 100% compostable while the traditional Puma Suede will likely be disposed of in landfills or incinerated, furthering its environmental footprint. Composting has the lowest greenhouse gas emissions in the end-of-life treatment of products.” A suede shoe could be made to be compostable too, but the Puma statement makes no mention of that and just presents a supposition about how consumers are likely to dispose of it at the end of its life. It presents no justification for this at all.
This is not the most obvious problem with the comparison, though.
The analysis compares the two shoes in four areas: greenhouse gas emissions, water, air pollution and land use. It converts each shoe’s performance into an environmental cost for each aspect and then shows a total environmental cost per pair as well as the recommended retail price for each. It seems from the original explanation of its methodology, a series of seven documents distributed as part of the press kit for the announcement, that Puma has attributed 15% of the impact of cattle upstream of the abattoir to the suede, acknowledging that its approach is “conservative”, meaning that it puts a higher burden onto tanners than other lifecycle analysis methodologies.
Puma has since given sportstextiles extra information to clarify this point. It told us: “The 15% weighting is the highest value for a specific country within the Puma supply chain, whereas in fact, the average weighting is between 5% and 8%.”
As a result of its analysis, it calculates the environmental cost of each pair of Suede shoes at EUR 4.29. The environmental cost of each pair of InCycle Basket is presented as EUR 2.95.
Our contention is that, because the traditional Puma shoe is made of suede, from splits, the same hide will have yielded a similar quantity of grain leather for the same environmental impact. In other words, for each EUR 4.29 of environmental cost, Puma could make not one but two pairs of shoes.
The true environmental cost of the pair of suede shoes remains open to question because Puma has not explained clearly enough how it reached its totals, but regardless of how it did it, its figure for the Suede shoe should only be half, EUR 2.15, per pair making the environmental cost of the Suede shoe substantially better than that of the InCycle Basket, even uses Puma’s own figures.
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