I don't think we need a full ban. The problem is plastic is so damn effective and sooo damn cheap. And that countries in certain parts of the world basically dump straight into the ocean. If all the plastics just go to landfill, they're really not a problem. We have sufficient unused terra firma to store millennia worth of plastic. Space is not an issue, collection is. And that's pretty hard to solve in the long tail of developing nations.

We, as in the United States? Or we, as in every country in the world but mostly the third world?

The first one would be comparatively easy but would do almost no good. The second one would actually help, if it weren’t impossible, but it is.