Carbon pricing (carbon tax or cap-and-trade) is the most economically efficient instrument for reducing emissions. It prices the externality and lets the market find the cheapest way to reduce.
The politics are difficult: the costs are immediate and concentrated (fuel prices rise); the benefits are diffuse and delayed (future climate stabilization). This is the opposite of what political systems do well.
The evidence from existing carbon prices (EU ETS, British Columbia carbon tax, RGGI in the US Northeast) suggests they reduce emissions meaningfully without major economic disruption. The problem is that existing prices are too low and too narrow.