Apparently, plastics are indestructible.
I've always been somewhat conscientious when it comes to picking up trash. If I see some crap laying around, I'll pick it up. But I became doubly conscious of plastic trash after reading this book. I go out of my way to pick it up now. Much to my alarm, the reading of this book was the first time I'd ever heard of the Pacific Garbage Patch - that Texas-sized-and-growing gyre of floating plastic crap. Since then six more (to my knowledge) have been discovered, including a North Atlantic version.
The problem is, since there are currently no microbes that do a good job of breaking down the tough polymer bonds of plastics, they stick around forever. Oh, that's not entirely true. Plastic pieces do break down into smaller and smaller pieces. Possibly to the point where they become indestructible little microscopic pieces - small enough to clog up filter feeders like baleen whales, and sponges, and clams and mussels. Possibly small enough to clog up plankton.
That would be a hell of a thing. Plankton die offs, the bottom of the food chain, choked to death on plastics? And then the famine slowly makes its way up the food chain until it gets to us.
Likely? I really don't want to find out any more than I want to know what drowning in my own puke is like.
Death by plastic.
For an intelligent species, it's an embarrassing way to go extinct.