breaking down plastic

I'm talking about plastic bags today. No, not Cher, the kind that you get at the store to bring home your purchased product in a safe and convenient way.
Plastic bags were only introduced in grocery stores in 1977 and are now accountable for four out of every five bags handed out in stores.
The invention and prolific distribution of plastic bags seemed a marvel invention, at first. The amount of energy and storage that was saved when compared to producing paper bags made the 't-shirt bag' movement seem worth it.
30 years later, we are are able to see a clearer picture of how things are working out.
Plastic bags are made out of chains of polymers, compact molecules that make it hard for other molecules to get between to help break them down. No one knows exactly how long it will take for plastic bags to break down because they haven't been around long enough - estimates range from 500 - 1000 years.
Plastic bags and plastic from packaging is evident everywhere in society. They have been found in autopsies of cows and turtles can mistake them for jellyfish.
So people started inventing biodegradable plastic bags which seems like a really good idea. Biodegradable plastic is good for lots of great things like planting pots that you can put right in the ground. They are also good for composting because they add carbon to the mix, and poopie diapers can be tossed directly into the garden.
They are especially good if they are made out of starch which is a natural polymer. Plastic can even be made inside of harvested bacteria.
As with any technological fix, there are arguments against the idea which should be considered. Older prototypes of biodegradable plastics, which are still on the market, are made with heavy metals like cadmium and lead. And biodegradable bags are only useful when composted. If they are thrown in with regular trash, the bags and the waste gets compacted to the point where there is too little oxygen for quick decomposition.
Cloth bags are the best alternative but this is a start.