How Car Mileage Demonstrates Problems With a Carbon Tax

The Wall Street journal has a powerful

infographic on the front page of the Personal Journal section today, showing

the 1986 Honda Civic CRX and the 2007 Honda Civic DX Sedan. The former got 52

miles per gallon in the city; the latter gets just 30 mpg.

The accompanying article shows how small cars are much bigger than they used

to be, with more powerful engines – and therefore much lower fuel economy.

"Even the smaller Honda Fit, considered almost impossibly small today,

is larger than the mid-1980s Civic CRX," notes Jonathan Welsh. And Toyota’s

Scion xB, which had vaguely acceptable fuel economy of 30mpg in the city (and

it’s very much a city car) has now been retooled all the way down to a dreadful

22mpg. Even the Smart car, hugely popular in Europe and now being introduced

in the US, gets nowhere near the mileage of that old Honda Civic.

I wonder what all this means for proponents of a carbon tax like Greg

Mankiw, who cites

with approval an article

by Robert Samuelson on gas prices. Samuelson notes that demand

for gasoline is very high, its record price notwithstanding, but adds that "steep

prices, imposed by the market or by taxes, will encourage energy conservation".

Which is as may be, but I think the WSJ article does point up just how difficult

that energy conservation will be to implement, at least in terms of gas mileage.

It’s been a long time since new cars have had any difficulty making it up steep

hills, and the general reaction of Americans who visit Europe seems to be utter

astonishment that families could possibly manage with such small cars. In other

words, a gasoline tax might be much better at raising revenues than at reducing


Which is one of the reasons why I prefer a cap-and-trade system to a carbon

tax: the former guarantees lower carbon emissions, while the latter merely hopes

for them, with relatively little data about the elasticity of demand for energy.

This entry was posted in cities, climate change. Bookmark the permalink.