A carbon tax contributes nothing to the massive investments required in low/no carbon emissions facilities and equipment required to actually reduce carbon emissions. However, it would add massive costs on top of the investment requirements.
Also, please note that, in the ~35 years since the end of the global cooling panic, there is no unique, broadly accepted goal for global annual carbon emissions reductions.
"You've got to be careful, if you don't know where you're going, because you might end up someplace else." Yogi Berra, American philosopher