CO2/mile

James over at Reality Based Community suggests ignoring and scrapping the miles per gallon rating on automobiles. He says MPG "is now an obsolete and misleading measure."

The problem here is that his view point is based solely from the basis of slowing and reversing man made climate change. He wants to replace MPG with a grams per mile rating where grams is the amount of CO₂ is emitted.

What James is missing, in my mind, is that much of the public is worried about how much gasoline they will have to burn to get to grandma's house on Thanksgiving. In reality, it's not how much gasoline will be burned but how much it is going to cost them. Although James' CO₂/mile rating is a decent proxy for MPG it does not easily translate into $35 of gasoline to drive to Grandma's.

I do like the CO₂/mile concept but it isn't going to replace the MPG rating though because it is measuring something else entirely. Still, the more information that is available to consumers the better. I think it would be a valuable additional piece of information for consumers to have.

One other note, James asks why American's have so many negative feelings towards Diesel powered cars. Despite the vast improvements he hints at, I think most Americans still remember the Diesels of the 70s and 80s. They were noisy, messy, and had dramatic performance issues in inclement weather. The image is poisoned and no company will spend money to introduce a Diesel to an unreceptive public without incentive. With no good options in the market to the contrary the opinions people won't change.