David R. Henderson  

Slaying the Myths about Plastic Bags

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Though it was meant as irony, there was an essential (if accidental) truth behind the speech [in the movie American Beauty]. The technology behind plastic grocery bags is so useful it won a Nobel Prize. Employing an unimaginably small amount of base material, manufacturers can create tools of surprising strength and durability. Far from being the environmental threat activists make them out to be, plastic bags are not particularly to blame for clogged sewers, choked rivers, asphyxiated sea animals, or global warming. Instead, they are likely our best bet for carrying all of our junk in a responsible manner.
This is the closing paragraph in Katherine Mangu-Ward's article "Plastic Bags Are Good for You." It's in the October issue of Reason. It's subtitled "What prohibitionists get wrong about one of modernity's greatest inventions." And she backs every claim in the above paragraph.

One excerpt:

[Julian] Morris and [Brian] Seasholes reconstructed an elaborate game of statistical telephone to source this figure back to a study funded by the Canadian government that tracked loss of marine animals in Newfoundland as a result of incidental catch and entanglement in fishing gear from 1981 to 1984. Importantly, this three-decade-old study had nothing to do with plastic bags at all.

Porpoises and sea turtles are undeniably charismatic megafauna--the pandas of the deep--and it's understandable that environmental groups would want to parade them around in a bid to drum up sympathy, almost certainly driven by the sincere belief that plastics put the beloved animals at grave risk. But in the end, there's little evidence that that's true. As David Santillo, a senior biologist with Greenpeace, told The Times of London, "It's very unlikely that many animals are killed by plastic bags. The evidence shows just the opposite. We are not going to solve the problem of waste by focusing on plastic bags. With larger mammals it's fishing gear that's the big problem. On a global basis plastic bags aren't an issue."

Mangu-Ward is one of Reason's best writers. This piece is no exception. Along with the various myths she slays, she also tells an exciting entrepreneurial story. I'm a sucker for such stories: the mix of accidental discovery and purposeful leveraging of a discovery.

One amazing fact:

Here is a list of things that are thicker than a typical plastic grocery bag: A strand of hair. A coat of paint. A human cornea.




COMMENTS (12 to date)
Steve writes:

I generally go along with this, but as a DC resident, I perceive one big positive effect from our 5-cent bag tax (er, fee). I hate seeing bags in trees. Once they're there, they'll stay a year or more. It doesn't take much wind to pick one up and, plop, they're there. Since the bag fee was enacted, I see many fewer bags in trees. That's worth a nickel to me.

Capt. J Parker writes:

Ms Mangu-Ward crafted a compelling story but the cornea thickness comparison is off. Corneas are pretty thick; .020 inches or about .5 mm - much thicker than a plastic grocery bag. Ms Mangu-Ward might have had in mind the thickness of corneal epithelium, which is the outer layer of the cornea that is peeled back so the underlying part of the cornea can be modified during a vision correcting lasik procedure. Corneal epithelium is around .002 inches or .05 mm which puts it in the ballpark with plastic bag thicknesses. But, corneal epithelial thickness is a pretty obscure unit of account, unless you're at an eye surgeon's convention.

Henri Hein writes:

Agreed on Mangu-Ward. She's also one of my favorites and I always perk up when I see her byline.

Larry writes:

Then there's this:

http://zmescience.us8.list-manage.com/track/click?u=7431083f9ab1b95fec8f03864&id=a241ea38d6&e=4b6f193547

The tech is amazing. If they could make it degrade not disintegrate) in seawater, I'd be fine with them.

guthrie writes:

@Steve,

Perhaps for you. Others might value paying a person to take the bags out of trees more than being forced to pay an extra charge for bags.

David R. Henderson writes:

@Steve,
I would much prefer a 5 cent charge to an absolute ban. In Pacific Grove, where I live, and Monterey, it’s a ban.

Anonymous writes:

I always found it a little funny how a characteristic that has always been seen as a good thing - durability - becomes a bad thing when it comes to plastic bags, and gets a new name, 'non-biodegradable'.

Things have been made from metal and stone for a very long time, and neither of these materials is biodegradable. I can certainly understand why plastic bags hanging around for decades might be an issue, but it's not exactly like the concept of a material that doesn't quickly rot away is new to humanity.

Nathan W writes:

I once lived for a few months in a town in China (Dali, in Yunnan) which had banned plastic bags. An alternative material was used, which was compostable. Perhaps each resident spends 10-20c a year more annually to offset the additional cost. Is it worth it? I dunno, but people there seem quite content with zero plastic bags. (The rule applies to standard retail sales, but plastic bags are still often used for takeaway food, which in China often comes in plastic bags instead of styrofoam containers.)

I also lived in another city (Toronto) which mandated that plastic bags could not be given out for free. Now stores charge 5 cents for a bag. Probably this results in millions fewer bags used per year.

That having been said, I think that anti-plastic bag lobbyists could direct their attention to far more important environmental issues ... like, just about anything.

Justin Rietz writes:

Even with the ban in Cupertino where I live, my family uses the same amount of plastic bags. The reason is that we reused plastic grocery bags as trash can liners. Now we buy plastic trash bags. Net environmental benefit? Zero.

Tom West writes:

I suspect that if people had to pay for the actual cost of the disposal of the bag, it would amount to a lot more than 5 cents (usually very close to zero, occasionally, a quite large amount).

The other aspect is that the cost to the merchant (at least for smaller businesses) is a lot more than 5 cents (I was quite surprised).

It is government intervention, but at least in the form of cost per bag, it's bringing the cost of the bags *closer* into line with their actual cost.

The "free" bags encouraged over-consumption.

Mirjam Badwy-Kraan writes:

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aez writes:

We just re-use them. The food pantry at my church can use as many as the congregation can supply!

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