[imtringued]

Making things illegal is prone to micromanagement. If there are ten thousand industries dependent on CO2 emissions how are you going to pick the non essential ones and only ban the ones that are truly bad for the environment? What's the likely hood that officials will simply misjudge a specific industry? (maybe even on purpose?)

The reasoning behind the carbon tax is simply that every participant can make a decision for themselves. "Do I need CO2 emissions to run my business?" "Does a different business have a greater need to emit CO2 emissions?" This is the type of thinking one is trying to encourage with the introduction of a CO2 tax.