I didn’t believe it was about energy use. Cotton bags don’t kill fish and break into micro plastics. I’m yet to see a cotton bag floating down the Thames.

Like most of my friends, I’ve taken to carrying a rucksack around, with an additional bag-for-life inside. I don’t recall the last time I had to buy an additional bag. I guess I’ve saved around 300 bags in the past year.

It's not even that though - with the 5p charge and them not being the default, I've stopped using them in instances where I wouldn't have needed them, but would have taken them anyway.

I'd always get a plastic bag with my £3 meal-deal from Tesco, but since it came in, I've just carried the stuff.

Haven't delved into the numbers yet, but am assuming they don't take into account recycled cotton, or if they're upcycled from other products. As for non-cotton alternatives - heavy duty plastic bags (i.e. Ikea ones or "bag for life"), rucksacks or handbags, re-used boxes, personal trolleys, etc... there are dozens of alternatives to single use plastics.

We still do get single use plastics for meat sales, and I reuse them as my bathroom bin-liners, so still have double duty without the dozens of other pointless plastic bags per trip

My counter anec-data: I got a canvas tote bag from the coffee festival years ago, its usage is easily in the 4 figures now, and still seems strong as an ox.

I read [2] because that seems to be the one that discusses the numbers you present.

The number of reuses for cotton bags that you need to make up for climate change reasons is 52 for conventional cotton and 149 for conventional cotton.

The 7,100 number for conventional cotton and 20K for organic cotton is for impact to ozone depletion alone. If you remove that, then the next biggest impact is for water usage which is 1,400 for conventional and 3,800 for cotton.

I do not believe that the ozone depletion due to the production of cotton is an issue that is causing a problem. A google search of "ozon depletion cotton" turned up only this paper for me.

Water usage of cotton processing is a concern and it is well documented. However, I have cotton T-shirts. In fact, I have more cotton T-shirts than I really need. If we need to reduce cotton usage (and I think that's a pretty good idea), then we should aim at that directly. The increase in cotton production from carrier bags will have a minimal impact on total cotton production. If we are going to reduce cotton useage let's do it for things that are less important than reusable carrier bags.

Finally, I have a carrier bag that my wife made me 5 years ago. It is still in perfect condition. I use it every single day. I expect to use it for at least another 5 years , if not 10.

From the paper:

"The number of times for “all indicators” refers to the highest number of reuse times among those calcu- lated for each impact category. For light carrier bags (LDPE, PP, PET...) the high numbers of reuse times are given by a group of impact categories with similar high values. Conversely, for composite and cotton the very high number of reuse times is given by the ozone depletion impact alone. Without considering ozone depletion, the number of reuse times ranges from 50 to1400 for conventional cotton, from 150 to 3800 for organic cotton, and from 0 to 740 for the composite material bag. The highest number is due to the use of water resource, but also to freshwater and terrestrial eutrophication. Results for the number of reuse times for each impact category, minimum-maximum ranges and average number of reuse times are provided in Appendix C."

People are missing the point on why you should be using cotton bags instead. Yeah they are more expensive to produce, and it is doubtful if you will ever be able to use the cotton bag enough to balance out the production costs, but that was never the point. It is trash reduction that is the goal, and the impact if the bag is left in nature. The cotton bags are a lot less harmful if they get end up outside in nature compared to plastic bags.

Here in the UK the trend now is to use stronger plastic bags that are more easily reusable as opposed to cloth. We have several in a drawer at home, and I keep one in my rucksack at all times so it gets a lot of use. But I'd be interested to know how much more efficient it is than the cheap thin plastic. While I do my best to reuse it, I'd be surprised if it lasts 100 shops.

But what I think the article fails to mention is that it's not about stopping the use of plastic bags, but more about encouraging their reuse instead of just throwing them away. The idea being that if fewer are produced, fewer are likely to end up in the environment.

After reading through the results of parent's [1] I'm wondering: Are they simply comparing environmental impact of the bags?

If so the numbers might be misleading because if someone buys a plastic bag the number of reuses is very limited. Let's say you buy 10 plastic bags a year for 5 years as compared to reusing 1 cotton bag in the same time period.

This would mean that in order to compare the environmental impact of both scenarios over that timeframe you'd need to divide the numbers of the cotton bag by 50 (10 plastic bags for 5 years) to get comparable results.

If this logic is correct this would mean that you'd need to reuse a conventional cotton bag 142 times and an organic bag 400 times over 5 years to get the same impact.

These numbers sound quite reasonable/realistic to me, assuming other people use their cotton bags as often as we do.

In Italy all supermarkets and grocery shops now use biodegradable bioplastic bags. They are not very strong so you need to use more of them, so you don't fill each one too much. You can then use them to collect compostable waste.

I have no clue how much energy producing them requires, but if they work as advertised they seem to solve the after-use-pollution problem.

Perhaps an alternative is the "old way".

bring your own bottle to be filled with milk / wine / oil.

Buy meat from the butcher wrapped in paper.

Buy bread from a baker wrapped in paper.

I remember that all happening as a child

But that was expensive time consuming and frequently unhygienic

For me, the alternative is to use something that already exists in my house (my backpack, a bag that was already given to me, etc) rather than consuming multiple plastic bags on every trip. Not everyone is going out and buying cotton bags to replace plastic so this seems inaccurate. It’s more about changing habits.

We bought some reusable cotton when the ban first came in, and they're all still going. We have a few of the heavier weight plastic too> As yet only one has failed and that was one of the throwaway style but simply thicker. The better ones have stitched reinforcement and handles and seem like they'll go indefinitely.

We used to get so many disposable bags that we had never in a decade or two bought bin bags, and still managed to keep accumulating. Now we have to buy those, although we try to keep use to the absolute minimum by being creative with the unavoidable plastic we do get. It's a bit frustrating.

I'd prefer paper and card once again, as those tended to disappear quite benignly if thrown away carelessly, single use bags were an ugly blight everywhere.

> what’s the alternative here?

Not using disposable bags, plastic or not. I live in London and I see a lot of people at my local Sainsbury's with e.g gym bags to carry their stuff.

Sure, if you had to get a plastic bag do use it for rubbish, but even then there are biodegradable ones.

> what’s the alternative here?

Reusable plastic? Or even reusing the same 'single-use' plastic? Or just carry stuff with your hand when you're capable of doing so, even if it's mildly inconvenient. I already do that and I'm glad I don't get a plastic bag for no reason when it's just a handful of things I can carry.

> what’s the alternative here?

The alternative is to reuse the cotton bag that you already have for other purposes.

Anecdotally, I use a backpack that I acquired in grade school 20 years ago. I use the same backpack as a day bag for many other types of trips. The zippers fell off track at one point and I had it repaired. It can also carry 20lbs or 40L of food (and on the shoulders instead of the hand) pretty easily.

But also, bags made from hemp instead of cotton. Especially if the leaves are used for other purposes and you're using the stalks.

The negative externalities of plastic bags to the environment after use are currently not priced by bag manufacturers into the product.

I’d imagine cotton or hemp bags have a very low environmental impact once they’ve become landfill or worst case ended up in a waterway vs plastic.

It’s obviously very complex pricing negative externalities which is why it’s almost never done but something to consider even if cotton bags have a much higher up front cost to produce vs plastic.

Since New Zealand started cracking down on single use plastic bags - your habits change massively. Go to the beer store and pick up a couple of cans of craft brew? 1 year ago I would get them in a bag. Now? Just hold onto them you lazy bugger between the counter, the car, and when you get home. Various forms of other bags constantly reused.

You seem to leave out the results of the second study, and slightly misrepresent the numbers you state.

The second study focusses on global warming potential (kg CO2 eq.). It states that Cotton bags break even with the most efficient solution "HDPE with 100% reused as bin litters" at 327 times, and "HDPE reused 3 times" at 393.

The explanation of the 7.100+20.000 numbers of the first study is incomplete. They refer to ALL impact categories. Not just energy and water requirements. If we focus on the climate change impact (kg CO2), cotton breaks even at 52/149 reuses.

Obvioulsly you'd have to consider the total impact at some point. Here, their methology is important. They say that: "Cotton bags are assumed to be manufactured in Europe, but the cotton used for the manufacturing is assumed to be retrieved from the market. The dataset used for cotton pro-duction (Ecoinvent, version 3.4, consequential) is based on a global average based on inputs from China, India, Latin America, and Turkey." (page 39).

The cotton production should be the greatest reason for the bad environmental impact considering all impact categories. Shouldn't it? The countries listed aren't really known for their environmental friendly policies. The menufactoring process itself is just some rather simple sewing.

Both studies also seem to NOT consider the environmental impact of plastic bags being thrown away. Which should be important as their aren't biodegradable.

I think the overall impact of non-plastic bags leaves room for discussion/further research. Based on the global warming potentiall, cotton bags seem like a good alternative. Reuse rates of 50-400 are realistic.

There are also different materials like jute or hemp where the production should be more environmentally friendly compared to cotton with similar perks (high reuse rate, biodegradable). Hanf can even be grown in Europe/NA such that there is less CO2 impact due to transport.

- Paper bags

- Reusable plastic bags

Cotton bags might require more energy but they're essentially biodegradable and don't pose such a threat to wildlife

I've gotten second-hand information about the first study, and the guy who wrote it says he's being misinterpreted. His study only looks at a very narrow invironmental impact, namely the production costs and impacts. It is not a full cradle-to-grave study, it does not cover environmental impact from improper disposal, nor a host of other factors.

The most important missing factor is the fact that cotton bags can be repaired and repurposed. I have a handful of heavyweight cotton bags (the oldest my grandpa bought sometime before I was born), only one of which I've purchased myself. They're all holding up very well, some of them with decades of use, and if they ever start to fray in the stitching or wear out, I can patch them very easily. Alternative, worn-out bags can be used as patches for other items or cut into cleaning cloths and similar things.

We need to move away from our single-use-then-throw-away lifestyles and relearn how to repair and reuse our stuff.

As a bonus, cotton bags biodegrade nicely, if they do happen to be discarded by mistake.

As for other cotton, I don't just throw out t-shirts because they get a few holes in them. They get repaired or delegated to DIY work or concert duty (shirt with holes are very punk/metal), or if they're too far gone they get turned into DIY band patches or used as cleaning cloths. It's all about getting the most use out of what you buy.

> Studies have shown multiple times [1], [2] that cotton bags require far more energy and water to produce than almost everything else and need to be reused circa 7.100 times for non organic and twenty-thousand times for organic cotton until they surpass plastic bags.

This "7000 times" number is based on a misrepresentation of a danish study. See here:

https://twitter.com/arthurhcyip/status/1115749675762581504

tl;dr 7000 times worse is for one category (ozone depletion) of the overall impact.

> ...but what’s the alternative here?

It’s really just a lack of imagination. Simply use any of a wide variety of containers which most people already have. Just quickly thinking of containers I have within my house: a bunch of different sized duffle bags, a couple swag bags both stuffed full of other swag bags from conferences, multiple backpacks, various suitcases with handles and wheels, cardboard boxes (which millions of businesses crunch up and throw away), random plastic storage boxes of a dozen different sizes. I’m sure we’re i to walk through my house and garage I’d find a ton more random containers.

Now that I’m thinking about it, I’m wondering why suitcases aren’t used far more often? While I know some of us probably travel more than the average person, but I wonder what percentage of owned suitcases get taken out of their house more than once year.

Anyway, if there is one thing we’re not typically short in, it’s containers to hold stuff. We just need to normalize the idea that they can be used for more than one purpose.

The alternative is bags that dont end up as litter, either because they cost more and there are less of them, or because they break down

> "and need to be reused circa 7.100 times for non organic"

No. The conclusion in that study is flawed. They compared across a range of different dimensions, and then took the worst dimension they could find and used that scale only. That's bullshit. Miljøstyrelsen took some flak over it.

Not all energy is created equal. Plants (cotton, trees for paper) don't really compete with other energy sources. You just grow them, they "consume" sunlight and CO2, and give us products. Water use could be an issue, but there's plenty of areas of the world that have enough water (yeah if you grow cotton in Saudi Arabia that might be... not the most efficient). (In the future, this might change, but I'm not sure cutting down the forests and paving the planet with solar planets is desirable, even if they're more energy efficient.)

Unless of course they're saying that production of bags (from raw material) takes more energy than the whole oil extraction infrastructure... which I find hard to believe.

The best alternative is to not even use a bag. 13 days out of 14, I don’t even need a bag or any other container, but that’s in part due to some lifestyle choices that put me in walking distance of a good grocery.

The next best alternative is to already have bags you can use, a backpack that you carry other stuff in for example with some extra room.

Beyond that, dedicated cloth bags work, or you can buy paper bags as you need them, and reuse them until they’re too worn; or use them as trash bags. Yes, they’ll require more resources to manufacture, but they won’t adversely impact the surrounding environment nearly as much as they degrade, and that has to be balanced against resource usage. If it helps, you can purchase a bag that already exists from a thrift shop or some other secondhand store so long as it seems sturdy enough and easy to clean. It’s been broken in already, seen actual use, and isn’t going to encourage the manufacture of a new bag to take its place once bought, or give more money to the original manufacturer.

A cloth bag can also be repaired, seams can be sewn up, and any holes that appear can be patched up. A badly beaten up bag can be saved as a resource to repair the other bags with, as can any other tattered clothes you might have.

Also consider baskets, as in old fashioned woven baskets. It only recently occurred to me so I haven’t thought this one through, but this entire conversation is built around the dichotomy of reusable versus single use bags. Baskets as a means of transporting groceries doesn’t seem to be on anyone’s radar or in any of these discussions. Supermarkets sometimes have leftover shipping boxes that you can pack your groceries in as well, but depends on the market. If you order a lot online, you might even have a number of boxes of your own you can save for your next grocery run.

The point of these bag fees, at the end of the day, isn’t to force people to pay a fee, or to specifically buy reusable bags. The point is force people to be conscientious about their bag usage and to consider a change of habits, and some other alternatives to just accepting the otherwise complementary bags that you don’t have to even think about taking.

We stopped using waste bags a while ago for all residues except food waste (for which the council required potato starch bags). We have containers at home where we place the plastic waste, which we rinse if it's too dirty, and clean the container with a hose if it's smelly after dumping it in the council bin we have in the driveway.

It usually requires a bit of thought to stop using 90% of single-use plastic, but my family has found it possible.

The question is whether the reduced plastic pollution will make it worth it to slightly increase CO2 output on grocery bags. Given that the absolute cost in CO2 equivalent for a cotton bag is only 3.9kg according to the study you linked, I'd argue that it is negligible compared to the costs of plastic pollution. Ultimately, this seems like a tiny contribution to climate change, but a huge improvement in terms of pollution.

If you live in a city and are doing your shopping close to your house, you can[] just carry stuff with your hands? Or throw it into the backpack you're already using to carry other stuff if you shop coming home from school/work.

[] there are definitely people where this is less feasible. I think the bulk of the waste is from people where it _is_ feasible.

In the UK, single-use bags have pretty much been replaced with strong re-usable bags at the checkout. They tend to cost 10p each.

This is both the challenge for and simplification possible by proper carbon taxes. If you apply the carbon tax either at the well, or the point of fuel consumption, and do so internationally to avoid it being arbitraged away, then we can stop doing all these complicated calculations and look at the end price of the thing.

When I shop, I carry a backpack and/or a medium sized bag. Some of these bags are 5-10 years old and still going strong. I have them sitting in cupboard whether or not I'm using them, the environmental cost of producing has already transpired.

In this world, we can definitely be a lot more efficient in how we use our resources.

Many things are delivered to the supermarkets in cardboard boxes.

Many supermarkets leave those boxes in a box or cage near the tills.

I'm sure energy and agricultural water are easier to manage environmentally than plastic pollution.

Exactly! In many situations, plastic actually is the most environmentally friendly option. If by banning plastic bags the use of paper bags rises, that‘d be counterproductive. But sure, the best thing would be to simply carry groceries in a backpack you already own.

I’ve noticed in SF that places are giving me slightly thicker, “reusable” plastic bags in lieu of traditional plastic bags. I don’t know anything about plastics - would those still be LDPE? Because that sounds like the perfect medium

Using a cloth back seven times is trivial! I've been using mine for seven years. I expect it will last the rest of my life and if my children aren't ungrateful shits this bag will be their inheritance.

> I‘m as much against (single use) plastics as the next guy but what’s the alternative here?

Strong, reusable plastic bags? I'm using those for years and they're as good as the cotton ones.

I've been using my bag for >12 years. The brand is "Freitag" (which should date it for those in the know), and it's made from up-cycled truck tarpaulins.

so what actually happens in britain is you buy a plastic bag and reuse it to avoid the 5p/10p cost. It's quite smart imo. Same thing is happening with reusable coffee cups which i think is brilliant

So yeah paper/cotton bags being used in mass are a not a huge thing here. Plus people reuse them easily hundreds of times.

"For a cotton tote to have less environmental impact than a plastic bag, it has to be reused 7,100 times. So why do tote bags have such good PR?"

https://www.newstatesman.com/politics/environment/2019/07/ho...

I wonder how hemp bags would compare.

> disintegrate or some seams come apart

Don’t throw them away when this happens. Sew them back together.

Multiple-use plastics. You can use a plastic bag way more than a few times.

The fact that they don't last forever is an advantage.

no point in using bags that last many generations for shopping, cotton is better

Paper bags?