[ColdNoMore]

Originally Posted by skyking

To legitimize the extra effort and energy consumption that producing tote bags requires, consumers need to use their reusable bags—a lot. One study out of the United Kingdom found that you’d have to reuse a cotton tote 327 times to achieve the same carbon-usage ratio as using a paper bag seven times, or plastic bag used twice. As strange as it sounds, plastic bags have the lightest per-use impact of the various bags the study examined. Cotton totes, on the other hand, in terms of production and distribution, actually have according to the Atlantic, “the highest and most severe global-warming potential by far.”

Do you have a link by any chance, backing up your 'memory'...of the UK study you reference?

I did find the UK study (I assume it's the same one you're talking about), but I can't find where it supports your statement(s) and since it's a 120 page PDF...I'm not going to even try to link it.

This link is a lot easier to read/understand, includes a summary of the UK study...and even has additional studies.

Reuse Bags (bag it here)

Here's how many times you actually need to reuse your shopping bags.


Once all of this information has been distilled, scientists can usually offer a fairly straightforward guide: the number of times a given bag should be reused when compared to the standard supermarket plastic bag.

A 2018 Danish study, looking at the number of times a bag should be reused before being used as a bin liner and then discarded, found that:

-polypropylene bags (most of the green reusable bags found at supermarkets) should be used 37 times
-paper bags should be used 43 times
-cotton bags should be used 7,100 times.

Another UK study, which only considered the climate change impact, found that to have lower global warming potential than single-use plastic bags:

-paper bags should be used three times--
-low-density polyethylene bags (the thicker plastic bags commonly used in supermarkets) should be used four times
-non-woven polypropylene bags should be used 11 times
-cotton bags should be used 131 times.

Note, however, that if a plastic bag is reused (even as a bin liner) the number of times an alternative needs to be used increases.

It's worth noting that, according to the 2018 Danish study, using organic cotton has a greater environmental impact than non-organic due to higher production costs. Our assumptions about what is environmentally friendly don't always stand up to scrutiny.

A 2014 study in the United States found that reusable LDPE and polypropylene bags do have a lower environmental impact than the usual plastic bags found in supermarkets – but only if they are reused enough times. This study found that about 40% of shoppers forgot to bring their reusable bags and therefore end up using the plastic bags. This then adds to the environmental burden of shopping.

One final consideration is how many bags you need. The Danish researchers equalised the volume of the bags so that evaluations were made on the same volume of space (this meant that for some assessments it was necessary to consider the impact of two bags).

As with all matters environmental, it's essential that we have the right knowledge to make informed decisions. After looking at all this data, here are the things I'd like you to remember:

-whatever bag type you use, use it as many times as possible

-choose bags made from recyclable materials

-avoid bags that have printing or decorations – these alone can add significantly to the environmental burden of the bag

-never allow a bag to become litter – recycle, reuse and repurpose your bags.