Grocery Bags

NPR has an article about how San Francisco may become the first city in the country to ban the use of plastic grocery bags due to concerns about their environmental impact. I find this interesting because, as I was growing up, I distinctly remember the use of paper bags being phased out and the use of plastic bags phased in for the exact same reason. The article cites the fact that paper bags are recyclable - aren't plastic bags? I wonder if it is the case that plastic is less efficient than paper to recycle - that might explain it.

I'm very tempted to think that the shift in thinking has no real rational or scientific basis but is rather fueled by the shift from the fad of caring about trees to that of caring about global warming and, by extension, petroleum products.

Since groceries presumably have to be carried out in something, other than plastic and paper bags (both of which are disposable) another option would seem to me to be durable bags made out of fabric or some other material. My instincts would normally say that this would be a great alternative since it would cut down on waste and energy consumption. I am uncertain, though, because I recently heard a fascinating statistic that I have been heretofore unable to verify: when I was in college, the cafeteria was stocked with styrofoam cups and we would go through many cases per meal. Many people advocated bringing a personal mug to meals so as to cut down on the amount of styrofoam we went through. This seemed, like the durable bags idea, to be a great solution. The aforementioned statistic, however, has thrown that instinctual judgment into doubt for me. Supposedly, it takes just as much energy to produce a mug as it would to produce 18,000 styrofoam cups. Faced with that reality, one wonders if the best thing to do wouldn't be to continue using 3 styrofoam cups per person per day since it is quite likely that a single mug wouldn't last as long (6,000 days) due to breaking, getting lost, etc.

If anyone is able to confirm or refute that statistic, I would love to hear about it. Also, if there are other data concerning similar resource consumption ratios between durable and disposable alternatives for the same product, I would love to hear about them.