Slaying the Myths about Plastic Bags

From David Henderson of EconLog.

"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."