You've all heard the claims -- plastic bags kill marine animals.  Hundreds of thousands of them.  And not just the slimy, icky ones, but the cute ones too, like baby seals. 

Have you ever seen a animal more adorable than a baby seal?  How could anyone in good conscience possibly carry home groceries in a plastic bag?

So dutiful consumers lined up shoulders to bandwagon, and millions called on their politicians to solve this critical problem.  Nations like Ireland placed a whopping 20 cent tax on each bag.  San Francisco banned them outright, and cities from Boston to Portland considered following suit.  Even in areas without a ban, stores made spent tens of millions of dollars to make paper bags available to outraged costumers.

The only problem?  It was all bunkum. 

Apparently, the problem started with a typo in an 2002 Australian Government report.  It attempted to quote from an Canadian study 15 years earlier, which found that up to 100,000 marine animals had been killed over four years by "discarded nets" from the fishing industry.  Somehow, the 2002 report replaced that phrase with "plastic bags."  The statement was quickly seized upon by environmentalists looking for a cause.  Somewhere along the way, the "four years" was dropped as well, and the myth of our shopping bags strangling hundreds of thousands of poor animals every year sprang up.  Voilà!  ... a star was born.  Protesters carried placards, and thousands of complaisant reporters parroted the claims.

The Australian report was eventually corrected four years later, but no one noticed.  The myth was now self-supporting, with hundreds of sources all pointing to each other for verification.   A few scientists tried vainly to correct the record, but no reporter was interested in interviewing them.

But finally science seems to be winning out.  According to David W. Laist of the Marine Mammal Commission, and author of a primary research paper on the subject, "plastic bags don't figure in entanglement.  The main culprits are fishing gear, ropes, lines and strapping bands."  Professor of Marine Biology Geoff Boxshall concurred, “I’ve never seen a bird killed by a plastic bag".  

Quick, someone tell San Francisco. 

Plastic bags are much cheaper than paper, which is why stores favor them.  They take less resources and energy to produce, they're far cheaper to ship and store, they're recyclable and some are even biodegradable.  Those savings aren't just for the stores, they translate into lower food costs and less damage to the environment.