Several people have now sent me this Nature commentary on the “rebound effect,” saying something to the effect of, “See? The rebound effect isn’t a problem!”

That’s a peculiar thing to say. Indeed, the commentary itself is quite peculiar.

For those who have missed my previous posts on this, the “rebound effect” refers to the fact that a) energy efficiency makes things cheaper, and b) when things are cheaper, we consume more, which c) erodes some of the energy-saving benefits of efficiency.

If you want to dig in on this — it’s a fascinating subject — I wrote a three-part series on it last year:

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Here’s the short version: Yes, the rebound effect is real. It varies wildly depending on technology and economic circumstances. (It’s a lot higher in developing countries, where consumption is constrained, than it is in rich countries, where most basic consumption preferences are already satisfied.) In most cases it’s fairly small; only in very rare circumstances is it big enough to wipe out more than half the energy savings; it’s hardly ever big enough to wipe out all of them. It is not, in any way, shape, or form, an argument against energy efficiency — in fact, it’s just another way of phrasing the fact that energy efficiency stimulates economic growth.

So, yeah: It exists, but has very few policy implications. It might temper how much energy reduction we expect from efficiency policies, but that’s about it.

So why on earth are climate and clean-energy folks so defensive about it?

Occasionally you see something goofy like David Owen in The New Yorker vastly exaggerating the significance of rebound. There’s always a market for this kind of self-consciously counterintuitive, hippies-are-wrong-after-all kind of stuff. You can find similar stuff about any climate or energy policy. (Electric car batteries have toxic heavy metals! Wind turbines kill birds! Carbon taxes just displace emissions to other countries!) Such is media.

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But in my experience, climate hawks are uniquely touchy about rebound. I don’t really get why.

Anyway, the Nature commentary reviews the evidence on rebound and confirms basically what I said above, but with a weird gloss. Take this:

Macroeconomic models estimate total combined rebound effects to be in the range of 20–60%.

In sum, rebound effects are small and are therefore no excuse for inaction.

Uh, 60 percent is not “small”!

But so what? The rebound effect is usually small, especially in developed countries. And even when it’s big, it’s not an argument against efficiency. So why this weird insistence on shouting it down?

I don’t get it.