I don't think it follows that there is no way of setting an appropriate price. No policy will be perfect, but a carbon tax is a really effective way to reduce

I don't think it follows that there is no way of setting an appropriate price. No policy will be perfect, but a carbon tax is a really effective way to reduce emissions efficiently. You don't even need to figure out the right price all at once-you can start low and keep increasing the tax until you get your desired rate of emissions reductions. In fact, to really get to net zero emissions requires an ever-increasing tax, in my opinion. In any case, we shouldn't let the perfect be the enemy of the good. I don't know of any policy that I would consider to be as effective and efficient as a carbon tax.