Remember the article about the great ocean garbage patch? I have some good news for you if you were concerned. There is a new form of plastic that is biodegradable. The plastics that are normally used are petrolium based but this new plastic is manufactured from biomaterial.
But it is not that easy. For instance you cannot just bury it in any landfill. You must put it in compost areas or they will not decompose properly.
Secondly, they release a small amount of Co2 when they biodegrade, I guess that this is a small price to pay for all the good that it will bring .
The Sun Chip bags and the new PaperMate pens have this ability along with some plastic dinnerware.