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

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.