>If you believe that human society cannot afford to continue relying on fossil fuels, because they are an existential threat to civilisation, then it follows that the tax on those fuels also needs to become unaffordable.

I think if you cut out all fossil fuels society would just not work. At least not at the scale it currently does. Even so called "renewables" are really only possible because of the complex society that fossil fuels allow. The more I dig into reneweables the more I feel like once fossil fuels go away, we largely go back to the stone age.