A carbon tax is necessary

According to Elon Musk here. Sure we need a transition from fossil fuels to renewables, but he's certain we won't get there until we tax fossil fuel production to account for all the externalities it generates. Which of course will price it out of the market, as well it should, for that form of energy is costing us our very lives via climate change. Add that into the mix and the price of gas will no longer be feasible.