[perl4ever]

"the one that would have worked was "Tax externalities and reduce CO2 emission"."

Why?

Internalizing externalities with a tax only works if the actual correct amount of those externalities equals or exceeds the amount that would reduce demand for fuel enough to stop climate change.

This is a huge assumption that I never see anyone even acknowledge needs to be demonstrated.

I think in fact they are far less, but my point is that debating that would be a red herring, since people seem to talk of externalities while never even believing in the concept, and that tension needs to be resolved.

The externalities are a number that in principle has a correct value, and the increase in price to change behavior sufficiently to stop warming is another number that independently has a certain value. But you have to have a logical reason for thinking they match if you think internalizing the costs is a solution.