I had the same thought that the litter created by single-use plastic bags is worth weighing in the equation.

However, a look at a similar study in the US (Life Cycle Assessment of Grocery Bags in Common Use in the United States [1]) points out that "A compilation of all of the statistically-based studies of litter in the U.S. and Canada over an 18 year period shows consistently that “plastic bags” (which includes trash bags, grocery bags, retail bags and dry cleaning bags) make up a very small portion of litter, usually less than 1%. "

So our vision of plastic bags getting into every nook and cranny may not be an accurate perception of reality.

1. https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=...