To thine own self be true

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?


3 Responses to “Plastic bags – good or bad?”

  1. Edward the Bonobo said

    Er…the alternative to plastic bags isn’t paper. In sensible countries, people use re-usable (hemp) cloth bags. I’m a major than of them myself. In German, die jute Tüte.

    Reduce, Re-use, Recycle!

    Another alternative is to have your groceries delivered and unloaded straight from the green crates. Tescos now offer this as the prefered option for internet shopping. This also cuts down on private car use.

  2. Polonius said

    Well, yes, okay. I was a bit incensed by some eejit babbling on about how he used paper rather than plastic, and I lost sight of the bigger picture. Hemp is better than plastic in the same way that plastic is better than paper – it’s more reusable.

    But my other point is one that I’d like to explore further, if I could only find some figures. The most immediate threat to the environment is atmospheric carbon, and carbon sequestration is one way of addressing it. If plastics can lock up carbon for 400 years, they could be part of the solution, depending on how the energy budgets work out. TBH, I think it’s unlikely, but I think it’s worth asking the question, if only I knew whom to ask.

  3. Check out my new blog: http://fighttheplasticbagban.com/

    On my blog I have a downloads menu item. If you click on that there are a number of papers that I have written that can be downloaded.

    One paper titled “Negative Health and Environmental Impacts of Reusable Shopping Bags” deals with the health issues more extensively than you did in the article above. For example, in addition to bacteria, viruses and virus transmission with reusable shopping bags could make other sick. Also, people who have AIDS or a suppressed immune system may be more sensitive to bacteria in reusable bags then people who have normal immune systems. About 20% of the population fit in this category.

    Also, when bag bans are implemented people always complain about all those plastic bags that end up in the landfill. But they have never stopped to calculate all the stuff going into a landfill after a plastic carryout bag ban compared to before. It would surprise you to know that 3 to 4 times the amount of material goes into the landfill post ban than pre ban. Those plastic carryout bags are sure looking good. see my article titled “Fact Sheet – Landfill Impacts” for the details and the calculations.

    There is much more.

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