Michael Bloomberg went ahead last week and announced a six-cent surcharge on all plastic bags in New York City, so as to try to cut down on waste. But will it actually work? Maybe: Just look at the Ikea in Brooklyn, which began charging customers five cents per bag in 2007 and cut bag use in half. Or Ireland, which imposed a hefty 33-cent tax on plastic bags in 2002 and saw plastic-bag consumption drop 94 percent—by the time the year was up, most everybody was toting around a reusable cloth sack. Still, my favorite commentary on this whole trend is a piece by Susan Dominus in the Times today, which suggests that, in France, social norms are far more effective than the tax itself at getting people to abandon plastic bags:

You’d start loading your groceries onto the conveyor belt, and then would have to explain to the clerk that you’d forgotten your bags. She would grimace. For some reason, ringing up the bags was slightly more laborious for her, and checkout time at E.Leclerc was a precise, even tense, exercise in speed.

Our neighbors timed their grocery shops to the minute: By 11:45, the store was empty, with everyone at home cooking up whatever they’d just bought for lunch. So not only was the store clerk irritated, but the people in back of us were too. Tell the clerk you need to buy bags, and you would get the same reaction that people in New York do when they announce, in some grocery store express line, that they have to pay by check. Groaning, shifting of feet, loud, deliberate sighing.

But it was not just the extra time it took that made those sighs so loaded, those groans so embarrassing. It was the knowledge that most likely, in that entire store, we were the only ones foolish enough to be shelling out $3 for bags that we had sitting around at home, empty, in some pile in the pantry.

So maybe if Bloomberg really wanted to discourage plastic-bag use he'd just drop this tax idea and instead require that all plastic bags in supermarkets be kept in some back storeroom, so that if any shopper wants one, they (and everyone behind them in line) will just have to wait a few agonizing minutes while someone goes to fetch the bags. That'll turn things around pretty quickly....

P.S. Also, I'm still confused by all these conflicting studies about whether plastic bags or paper bags are worse for the environment. One argument holds that paper bags actually do more damage to the atmosphere because you use energy producing them and more fuel transporting them to the stores. Cecilia Goodnow takes the high road and explains that they're both destructive in their own way (she tallies up the pros and cons of each) and that everyone should just bring their own. Unless maybe you need paper bags to stuff your recycling in. Or...

Anyway, my usual argument here is to say we should focus instead on pricing the negative externalities—carbon-dixoide emissions, say—and let that sort things out, as disposable bags naturally become more expensive, and so on. But, of course, you have to know what the externalities actually are before you can price them properly... For instance, I see that in India and Bangladesh, plastic-bag litter often clogs street drains, causing floods that end up killing people. How do you price that?

--Bradford Plumer