In the long term, if we eventually make it to the scenario where we stop putting CO2 into the atmosphere on net, then each kg of CO2 input into the atmosphere must be compensated by a kg of CO2 removed by some mechanism or another. The reasonable thing to do in that equilibrium would be to set the price to output CO2 - collected by governments as a carbon fee - equal to the price to capture CO2, paid out by governments as a negative carbon reward. Of course we could just do that now, the trick is how to get to that equilibrium scenario without collapsing the economy in the process.