What's the True Price for a Gallon of Gasoline?

Ed Kerr writes:

How do we assess “cost” to fossil fuels vs “solar” energy?  If the scenario that Malcolm Light posits in a post that he wrote for the Arctic Methane Emergency Group at the Arctic-News.blogspot comes to pass (namely the near term extinction of mankind along with most of the other life on the planet) how much more expensive, then, are fossil fuels compared to clean solar energy? How much shall we say that we paid for a gallon of gasoline? or a KWH of electricity?

Please, I’d like to know the answer…

Ed:  I can’t comment on Mr. Light’s analysis, and I certainly won’t attempt an answer to your rhetorical question.  But you bring up a point that I make regularly here: our refusal to “price in” the external costs of fossil fuels is arguably the single most reckless thing that we’re doing in our modern-day society.