Thank you for providing the source. The study does not support your original claim at all. On page 79 the study specifically notes that unbleached paper bags had the best CO2 performance across all of the numerous options surveyed!

The ridiculous "43 times" number was only obtained when considering "all environmental factors", not just energy use/climate change. The methodology chosen required offsetting the worst individual factor compared to conventional LDPE bags (pp. 80). For paper bags, this was "Freshwater eutrophication" (pp. 119). So this ridiculous number is only a) due to questionable methodology used in this study (clearly chosen to give plastic bags an unrealistic environmental performance), and b) because plastic production has negligible impact on nutrient content of lakes compared to forestry.

The study seems to have altogether omitted to consider the impact of persistent plastic pollution on the marine environment. This is where recyclable/biodegradable materials, like paper, really do shine compared to nonbiodegradable and hard-to-recycle (TFA) plastic.

I think OP needs to edit their post lest many be led astray

Would if I could. HN doesn’t let me edit after so many hours.

I must say I can't blame you too harshly for misreading this. The way they arrived at the "43 times" figure is truly baffling and prone to misunderstanding and mischaracterization. Not the shiniest of work from Denmark's EPA, I am afraid.