| 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." |