The law of unintended consequences strikes China’s plastic bag ban

Jocelyn Ford of the the Science Friday blog lives in Beijing, and she has posted an account of the on-the-ground repercussions of China’s plastic bag ban. China banned extremely thin single-use plastic bags, but not the thicker bags more common in the US. Ford admits that the new bag surcharge has made her more careful about bringing her own bags to the food market, but worries that banning thin bags has only led to more widespread use of thick bags:

Take my local hole-in-the wall shop that sells stuffed pancake (yum!) Until last week, the shop did takeaway orders in ultra thin bags less than 0.025 millimeters, or 0.00098 inches thick. It’s now upgraded– the shop not only uses thicker bags, it’s ordered bags with the shop name on them. The shopkeeper proudly told me they were “environmentally friendly.” Looks to me like the new regulation has encouraged him to add to the garbage and pollution problem. The tiny bags are not easy to reuse.

In a classic case of the law of unintended consequences, Ford says that many shops have also started to give away free paper bags, which create more air and water pollution than plastic bags. (It’s true! See this handy chart from the Washington Post.) Ford believes that China should have legislated biodegradable bags – except, as she point out, they are made from corn.

So are biodegradable bags a solution? The corn starch bags Ford mentions are still under development, and they are based off ethanol biofuel byproducts. Since corn ethanol biofuel has proved to be food-price debacle, this is probably not the solution. Most commercially available biodegradable bags are based off a mixture of corn starch and petroleum-based polyesters. While they do biodegrade (which does solve the problem of cute large animals choking and drains clogging), it means that biodegradable bags are both competing with food supplies and polluting the environment with tiny molecular- and cell-sized bits of polyester. Little bits of plastic can be a huge problem at the base of the food chain, due to accidental ingestion by non-charismatic but ecologically critical animals like insects and earthworms

I still think that plastic bag bans are a move in the right direction, but Ford’s anecdotes about the Chinese ban show that a nuanced approach may be necessary. Should all disposable bags, including paper, be taxed? How can the Chinese government encourage people to reuse bags instead of simply switching types of disposable bag? And what approach might the US (when we finally catch up with Ireland, Bangladesh, and South Africa) take to control the plastic problem?


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