What do plastic bag bans do?

What do plastic bag bans actually achieve?  There are a couple California ballot initiatives about a potential statewide ban (I’ll be sharing more research on CA ballot initiatives soon), so I have a pressing reason for curiosity.

I don’t want to contribute to the giant plastic island in the ocean or to the amount of plastic in animals’ stomachs.  And I’d love to decrease local litter while reducing energy & pollution usage (which supporters of bans claim come from making plastic bags).  Do plastic bag bans have these effects (as claimed by supporters) without causing worse side effects?

Short answer: plastic bag bans are very good at one of the things they set out to do (dramatically reducing plastic bag litter), and they mostly get replaced not by paper but by either reusable bags or no bag.  There are predicted substantial energy savings from this shift, but from what I can tell there’s not enough data to be sure of that.  And some of the side effects/potential downsides are not as well quantified.

Okay, this post is now going to get a bit more rough draft-y. :)  These are my notes for myself from doing ballot initiative research.  If I have time later, I’ll come back and try to clean this up — but I figured I should share my work here for anyone else interested.

ARE THESE BANS EFFECTIVE? (looking here specifically at proposed California model of banning plastic & charging at least $0.10 for paper or reusable)

• at reducing plastic litter in stormdrains, creeks, large bodies of water, and the ocean? yes — strong empirical reduction found by several non-partisan studies in various cities (60-95% decrease?!)
• at reducing all litter? unknown
• at getting people to waste less by using fewer bags, period? looks like it — for one thing, asking people if they want to pay for a bag seems to cause a LOT of people to just carry things by hand (according to several observational studies looking at what people replace plastic bags with)
• at raising money for the environment? no — not directly, in the California case, anyway.  the store gets to keep those funds, so it’s not really a tax that could benefit state projects.  local government may have to expend slightly less on litter cleanup, but that won’t necessarily go toward something else environmental.
• at reducing greenhouse emissions and natural resource expenditure in “the manufacture and distribution of single-use carryout bags”?  maaaaybe — depends on what replaces plastic & number of reuses.  I found some precise numbers for energy + resource expenditure for various bag types, and some overall energy predictions based on this that predict large energy savings.  But it looks like you need to use a non-plastic bag a bunch of times to make it more energy efficient (at least 4, 11, or 131, for the three different bag types I saw evaluated), and I can’t find any numbers on how many people are doing this.  Overall, it’s probably still a good bet that energy use improves, given that many purchases (39%) just don’t use a bag at all post-ban.
• at reducing the 90% of marine birds with plastic in their stomachs, or 267 marine species with disgestion/respiratory issues due to plastic?  (in some environments; see SciAm article below for citation & specifics)  unknown, but probably somewhat helpful due to litter reduction

ARE THERE RISKS/DOWNSIDES?

• more bag breakage from paper bags?
• reduced personal freedom in those times when plastic really is the most appropriate bag?
• a new (small) regressive tax?
• some amount more cost to local government in administrative fees?

Inevitably yes to all… but I can’t find quantification of the corresponding inconvenience/harm/hardship. Don’t know if it’s completely negligible, a minor irritant that mostly just reminds people to bring their own bags, or actually a problem for a sizable set of people/circumstances.  (E.g., rainy days; very poor people who can’t invest in a bunch of reusables)

CONCLUSION

The California ban is not my ideal formulation of a plastic penalty (I’d rather offer plastic bags also — possibly at a higher fee — for rainy days, messy purchases, etc… I suspect there would still be a strong deterrent effect.  And it would be great if it was a more progressive fee structure). And before making a decision here, I wish I could see more data on the actual energy expenditure on ALL bags for their whole lifecycle, factoring in actual reusage stats — as well as more info about how much of a pain this is.  But based on my limited knowledge, my own personal value matrix says that the reduction of litter in cities and harm to the marine ecosystem is probably worth the inconviences and what I expect would probably be a small economic penalty/energy penalty based on the sources below — especially given that, if we don’t say yes to a ban, I don’t expect a better formulation to then immediately show up on the ballot next time.

Edit: related post: Tote bags vs. plastic bags, and the overall impact of consumer plastic use

SOURCES AND NOTES

Scientific American on effectiveness of bans (in 2015): “It’s hard to measure the impact of pre-existing plastic bag bans, but some initial findings look promising. A plastic bag tax levied in Ireland in 2002 has reportedly led to a 95 percent reduction in plastic bag litter there. And a study by San Jose, California found that a 2011 ban instituted there has led to plastic litter reduction of “approximately 89 percent in the storm drain system, 60 percent in the creeks and rivers, and 59 percent in City streets and neighborhoods.” [Politifact CA says 89% was later revised to 62%]  https://www.scientificamerican.com/article/do-plastic-bag-bans-work/

Politifact CA says that bans empirically decrease bag usage and plastic bag litter (though they agree with anti-ban folks’ claim that revenue from the $0.10 “tax” will go to stores and not directly to helping environment): http://www.politifact.com/california/statements/2016/oct/03/no-67/whats-bag-fee-environment-opponents-not-one-penny/

WSJ pro/con arguments (con side includes statements that alternatives often use more energy over full lifecycle, and other arguments against efficacy of ban): http://www.wsj.com/articles/SB10000872396390444165804578006832478712400

Bloomberg on how bag bans can go wrong: https://www.bloomberg.com/view/articles/2015-08-18/how-a-ban-on-plastic-bags-can-go-wrong

Media Matters myths and facts about bag bans (anti-conservative fact check site; has clearly stated slant but also cites sources): http://mediamatters.org/research/2014/10/08/californias-plastic-bag-ban-myths-and-facts/201064 — they show that if some alternatives to plastic bags are reused 4+ times, it’s a win over plastic in terms of energy consumption.  For other bags, it takes 11 uses, or in some cases 131 uses. it’s unclear to me what percentage of people actually reuse non-plastic bags enough to make them efficient.

Equinox Center study: https://energycenter.org/sites/default/files/Plastic-Bag-Ban-Web-Version-10-22-13-CK.pdf   AWESOME ALL THE DATA!!! :D

From this they then show a bunch of projected energy savings (for San Diego, where the study was focused — probably a bit skewed from what the overall state savings would be).  BUT they didn’t quantify how many of the resuable bags were getting used how often.. so they predicted based on the ratio of bags observed in the store before and after the ban that there was a big improvement in energy usage.  But we don’t actually know about reusage numbers, unless that was somehow factored in and I missed it.

Californians Against Waste (supporter of ban) has more detailed facts about the impact of various CA cities’ bans: http://www.cawrecycles.org/list-of-local-bag-bans/ — like most of the above, they don’t directly compare the carbon or waste footprint of alternatives to plastic