Polonius

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Archive for the ‘Environment’ Category

Plastic bags – good or bad?

Posted by Polonius on 1 November, 2007

Today’s PM programme on Radio 4 did a piece to mark 6 months of the ban on plastic bags in the Devon town of Modbury. A search on the BBC News Web site reveals several articles on the subject, but all seemingly aimed at one vital sector of the BBC’s demographic. Let’s not forget that the BBC has a duty to its viewers, and some of them are not the most discerning. They invented That’s Life and now The One Show for people who would like to keep abreast (Fnarr! Fnarr!) of current affairs through The Sun, but lack the necessary level of literacy.

How do plastic bags compare with the competition, which I’ll assume is paper? I’m finding it very difficult to find any figures, but let’s at least consider what the issues are. Plastic is well-suited to reuse; paper rapidly disintegrates, especially when wet. The manufacture of both doubtless produces unpleasant chemical by-products. In the absence of any information to the contrary, let’s assume that paper produces one quarter of the chemical by-products of plastic. If you use a plastic bag four times, that’s parity; eight times and it’s half the chemical impact.

The most immediate threat to the environment today is atmospheric carbon dioxide. If, as seems likely, the energy used in manufacturing bags is generated from fossil fuels, some atmospheric carbon will result. Assume that paper requires a quarter of the energy of plastic. The same argument applies as for chemicals.

But then there’s the carbon incorporated into the bag itself. Paper rapidly breaks down, liberating carbon into the atmosphere to wreak its terrible impact on the environment. Plastics can lock it up for 400 years, helping to buy us time to find a long-term solution. Discarded plastic bags may be unsightly, but they could be part of the solution, rather than of the problem.

Of course, I’m making assumptions here in the absence of data. Does anybody have any data?

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