Planet Money explains in “Are Plastic Bag Bans Garbage?“
“…sales of garbage bags actually skyrocketed after plastic grocery bags were banned…So about 30% of the plastic that was eliminated by the ban comes back in the form of thicker garbage bags…. On top of that, cities that banned plastic bags saw a surge in the use of paper bags, which she estimates resulted in about 80 million pounds of extra paper trash per year. paper bags are actually worse for the environment. … They require cutting down and processing trees, which involves lots of water, toxic chemicals, fuel, and heavy machinery. … the huge increase of paper, together with the uptick in plastic trash bags, means banning plastic shopping bags increases greenhouse gas emissions. That said, these bans do reduce non-biodegradable litter.”
Organic cotton tote bags need to be used 20,000 times before its use is better than a plastic grocery bag. “…the best reusable ones are made from polyester or plastics like polypropylene. . Those still have to be used dozens and dozens of times to be greener than plastic grocery bags, which have the smallest carbon footprint for a single use.”
“As for bag policies, Taylor says a fee is smarter than a ban. She has a second paper showing a small fee for bags is just as effective as a ban when it comes to encouraging use of reusable bags. But a fee offers flexibility for people who reuse plastic bags for garbage disposal or dog walking. … The best policy, Taylor says, imposes a fee on both paper and plastic bags and encourages reuse.”
15Apr2019 update: Another economics podcast on plastic packaging (Cellophane). It presents the data and decisions that have made the modern plastic world and illustrates nicely the counter-intuitive conclusions that come up all the time in plastic packaging.