My eco confession

Through a combination of laziness and contrarianism I have delayed transitioning to the eco-friendly alternatives of the plastic supermarket bags. Despite the very bad press they have been getting I somehow could not bring myself to ditch them. I knew all along that both the disposable paper bags and reusable cotton bags are better but chose to do nothing.

My complacency was partly due to the fact that plastic bags feel a lot lighter than the alternatives – it is amazing how thin a wade of 100 or 200 of them is at the supermarket checkout. Paper bags on the other hand are a lot more substantial and appear heavier. The problem with the multi-use cotton bags is that I tend to either lose them or forget to take them with me. Also, if something like meat juices spill in them, cotton bags are very unhygienic but to stop the leaks meat must be double bagged which means more plastic. To ease the burden on my conscience I always tried to re-use the plastic bags – as rubbish bin liners, to collect kitchen or garden waste etc. I know – excuses, excuses but at least I have come out clean which must count as a mitigating circumstance?

With a guilt-laden conscience I read the article on Stuff which compared the environmental footprint of the plastic, paper and cotton bags and immediately felt better. Surprisingly, the study conducted in 2011 by UK Environment Agency concluded that low-density polyethylene (LDPE) plastic shopping bags may in fact be the most eco-friendly solution, especially if re-used. Some enlightening quotes for your consideration:

Paper bags are often seen as more environmentally friendly because paper is recyclable. But paper bags could be the worst of the lot because of the difficulty in reusing them (…) the process of making paper bags takes almost four times as much water, and releases more than three times as many greenhouse gas emissions than conventional plastic bags. In 2007, San Francisco banned non-compostable plastic bags but the policy led to an increase in the use of single-use recyclable paper bags. Only 38 per cent of paper bags were recycled, the rest went to landfill where they take up five times more space than plastic bags. Paper bags usually do not biodegrade in landfill because there is no oxygen. The UK study found paper bags need to be reused three times if they are to have less of an environmental impact than a conventional plastic bag used once, but the study found “no significant reuse of paper bags,” not even as bin liners.

Ok so, unless you re-use them (does anyone do that?), paper bags are much worse for the environment than even single-use LDPE plastic. What about cotton though?

The study found cotton bags need to be used at least 173 times if they are to do less environmental damage than a plastic bag that is used once. If a plastic bag is reused three times, for example being used twice in the supermarket and then as a bin liner, the cotton bag has to be used almost 400 times to have lower global warming potential than plastic. This is because of the amount of energy and use of non-renewable resources it takes to extract cotton, make the bags and then ship them.

Again, unless used every second day for a year (does anyone do that??), the cotton bags are less eco-friendly than single-use LDPE. And if you put them through a wash once in a while the equation looks even worse.

It is interesting that the intuitive preference we tend to have for “natural” (paper, cotton) materials is not always the best thing for the environment.



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