5 times more CO2 is emitted during manufacture of conventional plastic than is in the plastic, whereas for compostable plastic its more like 2.

While it's better than burning oil for energy, that's still a loss for carbon emissions, though. And you still need fresh oil to produce more plastic.

I'm not saying we shouldn't do it, but this is not the end game. The end game is either:

~ 100 % reduction in plastic use.

~ 100 % recycled plastic

Those two goals are not mutually exclusive either. Yes, it might cost a lot of energy to recycle plastic. As long as that energy comes from a clean source, it shouldn't matter much.

Obviously, only the first goal reduces the amount of plastic in the ocean, soil, rivers, etc. I am hopeful that bacteria will develop that can ingest plastic, which would both get us rid of the waste, and limit plastic usefulness, but it can't really be counted on in the short term. And plastic waste has a mostly local, short-term effect. Carbon dioxide has a long-term, global effect. So I'd prefer it to be buried until it can be recycled.

Until we completely stop burning oil, it's always more worth it (environmentally) to burn plastic, vs recycle it.

Once there is no oil burned, and it's all used for plastic, then it makes sense to implement your plan. But not until then.

Have you ever burned ordinary plastic? The smell is horrific, there are some truly nasty poisons being released.

Furthermore, compostable plastics will solve the biggest problem of plastic pollution -- the a-hole that just tosses plastic garbage in the ground because he/she doesn't give a damn. Compostable plastics compost much faster in proper municipal/industrial composting facilities, so it is still important to throw the stuff away in compost bins and to have regular pickup service, but they will compost in the environment too. Thus, there is some defense against the morons that just litter.

In other words, compostable plastics fail better than all the other choices.

> Have you ever burned ordinary plastic? The smell is horrific, there are some truly nasty poisons being released.

Only if you don't use enough oxygen. Except for PVC plastic does not have any bad atoms in it, if fully burned the exhaust is completely safe (it's just water and CO2).

A proper, hot, incinerator will burn plastic very safely.

Why bother with compostable plastics if we can just bury the plastics in a landfill and forget about them? The volume of plastics is insignificant, the only problem is plastics that don't end up in landfills but in oceans instead.