Kaid Benfield Archive


The Jevons paradox and why more efficient cars won’t solve our emissions problems

Kaid Benfield

Posted February 9, 2009 at 1:38PM

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By and large, the environmental community - including my own organization - has put far more resources into making our vehicle fleet more efficient than into reducing our dependence on driving through better land use.  While we need to do both, the relative lack of commitment to land use strategies is a mistake.

elecric car in Portland (by: Todd Mecklem, creative commons license)In part, this is because land use strategies pay off with multiple benefits - not only reducing greenhouse gases and other tailpipe emissions, but also conserving land, promoting fitness through physical activity, reducing stormwater runoff, rejuvenating disinvested neighborhoods, and saving money on infrastructure, among other rewards.  Land use continues to deliver its benefits for the long haul, too; buildings last longer than cars.

But there may be another reason:  in a provocative new article in The Progressive ("The Myth of the Efficient Car"), Alec Dubro argues that making cars more efficient will actually encourage their use, wiping out some or all of the benefits of efficiency:

"In 1865, English economist William Stanley Jevons discovered an efficiency paradox: the more efficient you make machines, the more energy they use. Why? Because the more efficient they are, the better they are, the cheaper they are and more people buy them, and the more they'll use them. Now, that's good for manufacturers and maybe good for consumers, but if the problem is energy consumption or pollution, it's not good.

"The so-called Jevons Paradox was resurrected in the 1980s by a variety of environmentalists and is occasionally referred to as the Khazoom-Brookes postulate or the more explicative rebound effect. It's been neatly summarized as, 'those energy efficiency improvements that, on the broadest considerations, are economically justified at the microlevel lead to higher levels of energy consumption at the macro level.' Or, in short, you make money on each transaction and lose it in volume."

Make it easier to drive, and people will drive more.  Hmmmm.  I've wondered about this, especially when gasoline prices climbed so high for a while last year as, given global demand, they are bound to do again.  walkable Georgetown, in DC (by: Dmitry Lyakhov, creative commons license)The market responded with more purchases of smaller cars and reduced driving, and we have stayed there since, probably in no small part because the economy has gone down the toilet.  But do we really want to make it less expensive to drive?

Dubro goes on to challenge the trendy premise that a 100-mpg "hypercar" is the key to a sustainable transportation future, and suggests that our continued love affair with driving needs to end, for a variety of reasons.  He argues for more controls on sprawl and more compact, walkable neighborhoods, though he isn't overly sanguine that it will happen soon.  He does allow that smart growth policies are a good step in the right direction - better, in his view, than a single-minded focus on efficient cars.

NRDC believes we need to do both, and I agree.  But we and other environmental groups need to do more for land use.  Dubro's article is well worth a read.