Comment by bobbylarrybobby

Plastic is a hydrocarbon. If bacteria can metabolize it, we have a whole new source of GHG on our hands. It looks like 5–10% of petroleum ends up as plastic, which seems like a decently sized new supply of GHG to worry about. Even if we switched entirely to renewables tomorrow, we'd still have 5–10% of all of our emissions ever just sitting there waiting to eventually be released by bacteria. (Over what time span, I have no idea.)