How? Random search turned up
>According to the previously cited U.K. study, it takes three reuses of a paper bag to neutralize its environmental impact, relative to plastic. A bag’s impact is more than just its associated carbon emissions: Manufacturing a paper bag requires about four times as much water as a plastic bag. Additionally, the fertilizers and other chemicals used in tree farming and paper manufacturing contribute to acid rain and eutrophication of waterways at higher rates.
https://stanfordmag.org/contents/paper-plastic-or-reusable
I guess you can argue that paper bags are compostable, but I'm not sure whether that matters much. Plastic bags that are sitting in the landfill doesn't harm the environment, and their bulk is negligible due to how thin/light they are.