[parsimo2010]

The problem with these studies is that you can't just correct the impact of a cotton bag, you also need to correct the impact of the plastic bags. [For me at least] The estimated impact of plastic bags is also wrong, so two wrong estimates aren't going to lead to a correct conclusion unless you get lucky. While plastic bags might get re-used only once, and cotton bags might be more durable, but that isn't the only thing to consider.

I re-use nearly all of my plastic bags, but only once. They have limited durability but wide applicability. Cat litter, trash bins in bedrooms and bathrooms, and bundling up oily paper towels in the garage. My waste management service requires that I bag all my trash, and I use my plastic bags from stores for this. If I switched to cotton bags for shopping I would still need plastic bags for my garbage, so if I switched I would actually be hurting the environment. There's no way I'm using cotton bags to bag up my trash and cat poop. I wouldn't be opposed to biodegradable bags from the supermarket though, as long as it isn't something that I have to pay extra for.

I know that not everyone re-uses all of their plastic bags, but how many people like me does it take before the world is worse off? Now we're shopping with cotton bags and buying a box of plastic bags to throw our garbage in? What is the loss rate of cotton bags? If I lose one per year am I losing them before getting to the break even point?