That's not really taxing externalities. Biodegradable solutions likely have externalities of their own at scale. In less words this solution is "tax corporation

That's not really taxing externalities. Biodegradable solutions likely have externalities of their own at scale. In less words this solution is "tax corporations that make plastic a lot and distribute the funds to the citizens leaving the mess behind for future generations". It isn't as noble when put that way. It you on the other hand took those funds and used them for environmental clean up, recycling programs, etc I'd be on board. Consumers should pay for the disposal of what they consumed.