Beyond just its chemical properties, the other problem with corn-based compostable packaging, which to my understanding is most of what's available in this country, is that although it doesn't depend as heavily on petroleum as plastics do the genetically modified (what else is there?) corn used to make it is heavily fertilized with chemicals derived from petroleum. So the deception is just one layer removed.
Not to make plastic per se any less evil, BUT... as Tom Outerbridge reminded me, most plastics are a byproduct of petroleum refining, so it's not as though more or less oil will be drilled depending on demand for packaging. Furthermore, there are conflicting reports about the impact of producing plastic versus biodegradable packaging. "To produce a film plastic material from trees is incredibly energy intensive, and Eucalyptus trees have their own mixed reputation as water-sucking poor-habitat-producing species, " said Outerbridge, who established New York City's composting program during his tenure at the Department of Sanitation and now works for a recycling company.
Outerbridge also mentioned that a biodegradable bag in landfill may even produce more methane than a plastic one. Plastic also produces methane as it biodegrades, but more slowly, over 450 years. (Again, damned if you do, damned if you don't.) Still, Outerbridge concludes: "If you knew the pulp was coming from a sustainable forest and you could direct the package at the end of its life to a composting system, I expect that would be preferable."
So ... in the end, we bought plastic. In my defense, I thought we'd be able to recycle the plastic, and for weeks saved our spent wrappers for the recycling bin. Then I found out that once at the recycling facility, they were promptly separated out and carted off to the landfill. Foiled again!
It's hard to recycle plastic in New York. The Whole Foods in Chelsea has a "Gimme 5" bin which is for #5 plastic (bottles, yogurt cups, etc), but thin bags like ours don't qualify. Outerbridge notes that in principle, polypropylene is a recyclable plastic, but polypro bags are not recyclable in terms of recycling programs available to New Yorkers, or most curbside recycling programs. Plastic cups may eventually be allowed in the NYC curbside recycling program if the city passes a new recycling law under consideration (up for review this summer/fall), but for our wrappers, there is no answer, for the foreseeable future anyway.
I can't think of a way to tie this post up neatly. Seriously, people of the world—scientists, lawmakers, consumers, farmers—what are we supposed to do?