If we were trading off "all excess CO2" for "all litter" I might agree with you, but we're measuring the impact of the CO2 involved in nonplastic bag production

If we were trading off "all excess CO2" for "all litter" I might agree with you, but we're measuring the impact of the CO2 involved in nonplastic bag production vs the litter from all plastic bags. What percentage of total worldwide CO2 emissions does nonplastic bag production represent? I'm not a subject matter expert, but I would shocked if the portion was more than minuscule. Whereas plastic grocery bags represent a pretty signifiant percentage of litter. Since this boils down to "how much CO2" vs "how much litter", I really don't find this question easy to answer.