The conclusion: Various packaging materials have various advantages – and the intensive debate about the plastic carrier bag affects only a fraction of the annual consumer carbon footprints.
In various countries, a ban on plastic carrier bags is being hotly discussed. Some politicians and environmental organisations have requested a ban and/or already implemented it. “It makes one wonder that a topic with such little environmental relevance is receiving such attention”, says denkstatt environmental expert DI Mag. Harald Pilz from Austria. “I only wish that just as intensive debates were being conducted about each litre of fuel consumption, heating oil consumption and gas consumption as about that 0.66 litre of diesel which corresponds to the annual plastic bag consumption of one Austrian consumer.”
In February 2011, the Austrian research and consulting firm in the area of environmental and sustainability issues compared carrier bags made of conventional plastic (polyethylene), bio-degradable starch-based plastics and paper in its study. The mass of the carrier bags from the foodstuff industry that were examined was 30 grams per unit for plastic, 38 grams per unit for bio-degradable plastic and 57 grams per unit for paper.
Furthermore, the climate footprint for the small transparent carrier bags for batches of fruit and vegetable made of conventional plastic and paper was examined. In this case, four different types were examined which were standardised to a comparable functional unit. In this regard, a calculation model was used which was developed during the course of the last ten years within the parameters of studies commissioned by Plastics Europe. The data quality and methodology were confirmed by two independent institutes – the EMPA in Switzerland and the University of Manchester in the UK. The results from this study were supposed to provide an answer to the question: What relevance does the theme “plastic bag” indeed have for the protection of the climate and resources?
The examinations were restricted to Austria’s national market. In this case, the average annual consumption is approx. 33 carrier bags and 60 small fruit carrier bags per person. According to the company, this annual consumption by one consumer creates approx. two kilograms of CO2. That corresponds to 0.14 per mille of the entire consumer carbon footprint for one consumer. “The carbon footprint for the annual plastic bag consumption thus corresponds to the carbon footprint for 0.66 litres of diesel. With consumption of five litres per 100 kilometres, this corresponds to a route length of 13 kilometres”, the study concluded.
An additional result is the knowledge gained that the weight of packaging is frequently underestimated. Thus, paper is almost twice as heavy as conventional plastic while carrier bags made of bio-plastics are approx. 27 percent heavier. According to denkstatt, the climate footprint from carrier bags made of paper is approx. just as large as for conventional plastic. But, in this case, differentiation must also be made between the individual types of paper: Brown carrier bags made of unbleached paper have clearly better effects while white carrier bags frequently have worse effects on the climatic balance than conventional plastic carrier bags. In this area, however, the carrier bags made of bio-degradable plastic have the best effects of all: Their climate footprint is 25 to 40 percent lower.
The results were different still for the fruit carrier bags. In this case, paper is approx. five times heavier than plastic so that the climate footprint for the fruit carrier bags made of paper is supposed to be approx. 50 percent above the climate footprint for the plastic carrier bags.
The company emphasises that all results apply exclusively to the specimen packaging products specified in the study and the depicted framework production conditions (European average) and the Austrian waste disposal industry. Company-specific production conditions or other segments of exploitation and disposal options may affect the results. Moreover, it must be kept in mind that the carbon footprint is indeed an environmental aspect that is important for the products being examined, but additional economic and social effects must nonetheless be taken into consideration for a comprehensive assessment of sustainability issues.