Debunking the Jevons Paradox: Nobody goes there anymore, its too crowded

The “Jevons paradox,” asserts that increasing “the efficiency with which a resource is used tends to increase (rather than decrease) the rate of consumption of that resource.”  It is mostly if not entirely bunk, as the scientific literature and leading experts have demonstrated many times (see “Efficiency lives “” the rebound effect, not so much“).

But it lingers on in part because it is one of those quirky, ill-defined contrarian notions that the media can’t get enough of and in part because those who oppose clean energy, often for bizarre ideological reasons, keep pushing it.

So I’m reposting two debunkings written by Real Climate Economics expert Dr. Jim Barrett.  As noted in the second post (whose Yogi Berra quote I repeated for my headline), “Though he discovered it nearly 100 years after Stanley Jevons, I believe [Berra’s] exploration of the Jevons effect is more complete and accurate than Jevons’ own, as well as being vastly shorter. The notion that we could get so efficient at using energy that we’d end up using more is about as valid as the idea that a restaurant could get so crowded that it was empty.

Barrett “has 13 years of experience working in the nexus of climate change, energy efficiency and economics and has written extensively on the role of efficiency in achieving environmental and economic goals.”  He was a senior economist on the Congressional Joint Economic Committee and is now Chief Economist at the Clean Economy Development Center.

This post by Dr. Barrett originally appeared on the Great Energy Challenge blog, in partnership with National Geographic and Planet Forward.  It is reposted from Real Climate Economics.

Rebounds Gone Wild

Energy efficiency has become very popular in recent years. So much so that it’s becoming cool for the truly hip to hold it in disdain.

Case in point: David Owen’s piece in this week’s New Yorker: The Efficiency Dilemma” (subscription required).

It reads like he’s being contrary just for the sake of being contrary. I don’t want to make a habit of highlighting this type of work, and to do a thorough job of dismantling the piece would take more time and space than I have. But it generated some genuinely interesting conversations in my email this week and I have a hard time letting such poor and frankly lazy reasoning pass without comment.

As a compromise, I’ll try to focus more on the serious issues in the article and less on the serious issues I have with the article itself. Wish me luck.

The focus of the article is something called the Jevons paradox (named after economist William Jevons), or the more common and more broadly defined “rebound effect.” In essence the rebound effect is the fact that as energy efficiency goes up, using energy consuming products becomes less expensive, which in turn leads us to consume more energy.

Jevons’ claim was that this rebound effect would be so large that increasing energy efficiency would not decrease energy use. The rebound effect would eat up all (or more than all) of the energy savings.

To be clear, the rebound effect is real. The theory behind it is sound: Lower the cost of anything and people will use more of it, including the cost of running energy consuming equipment. But as with many economic ideas that are sound theory (like the idea that you can raise government revenues by cutting tax rates), the trick is in knowing how far to take them in reality. (Cutting tax rates from 100% to 50% would certainly raise revenues. Cutting them from 50% to 0% would just as surely lower them.)

The problem with knowing how far to take things like this is that unlike real scientists who can run experiments in a controlled laboratory environment, economists usually have to rely on what we can observe in the real world. Unfortunately, the real world is complicated and trying to disentangle everything that’s going on is very difficult.

Owen cleverly avoids this problem by not trying to disentangle anything.

One supposed example of the Jevons paradox that he points to in the article is air conditioning. Citing a conversation with Stan Cox, author of Losing Our Cool, Owen notes that between 1993 and 2005, air conditioners in the U.S. increased in efficiency by 28%, but by 2005, homes with air conditioning increased their consumption of energy for their air conditioners by 37%.

Owens presents this as clear and obvious proof of a Jevons effect. Case closed.

Here is where Owen gets lazy: A few key facts disprove the point. Facts that are not hard to track down. I write for this blog in my spare time (for free), and I managed to find it without breaking a sweat. I’m not sure why a paid writer for a magazine like The New Yorker couldn’t do the same.

Consider the following:

Real (inflation adjusted) per capita income increased by just over 30% over that time period. All else being equal, when people have more money, they buy more stuff, including cool air.

The average size of new homes increased from 2,095 to 2,438 square feet, over 16%. More square feet means more area to cool and more energy needed to cool it.

In 1993, of homes that had A.C., 38% only had room units while 62% had central air. By 2005, 75% of air conditioned homes had central units. Bigger units covering more rooms means more cool air and, you guessed it, more energy.

(Real electricity prices were mostly flat over this time period, falling by just over 1%, contributing little, if anything, to the increase.)

Finally, even though air conditioners were 28% more efficient in 2005 than in 1993, air conditioners last between 15 and 25 years. Using the mid-range lifespan of 20 years, and assuming that efficiency increased gradually from 1993 to 2005, and accounting for the introduction of new AC units associated with new home construction (about 1.5% of the housing stock in any given year), I calculated the efficiency of the average central air unit in service in 2005 to be about 11.5% more efficient than the average unit in 2009.

Accounting only for the increased income over the timeframe and fixing Owen’s mistake of assuming that every air conditioner in service is new, a few rough calculations point to an increase in energy use for air conditioning of about 30% from 1993 to 2005, despite the gains in efficiency. Taking into account the larger size of new homes and the shift from room to central air units could easily account for the rest.

All of the increase in energy consumption for air conditioning is easily explained by factors completely unrelated to increases in energy efficiency. All of these things would have happened anyway. Without the increases in efficiency, energy consumption would have been much higher.

Worse, and even more transparently wrong, Owen points to the increasing use of air conditioning in the developing world, especially India and China, as evidence of a globally expanding Jevons effect. Never mind the fact that income in China is growing something like three times as fast as in the U.S. and that the cost of air conditioning as a share of average incomes are falling at an even greater rate.

It’s one of the well-established frustrations of the energy efficiency world that people pay too much attention to the up-front cost of goods and not enough to the cost of energy needed use them. More expensive highly-efficient products have a hard time competing. Suddenly, however, Owen wants us to believe that falling up-front prices and rising incomes couldn’t possibly explain the accelerated market penetration of air conditioners in China and that rising efficiency is the reason.

It’s easy to be sucked in by stories like the ones Owen tells. The rebound effect is real and it makes sense. Owen’s anecdotes reinforce that common sense. But it’s not enough to observe that energy use has gone up despite efficiency gains and conclude that the rebound effect makes efficiency efforts a waste of time, as Owen implies. As our per capita income increases, we’ll end up buying more of lots of things, maybe even energy. The question is how much higher would it have been otherwise.

The even more interesting question is whether efficiency growth can ever overpower the effect of income growth and start reducing energy consumption in absolute terms.

— James Barrett

Rebounds and Jevons: Nobody Goes There Anymore. It’s Too Crowded

This is the second post in a series on the rebound effect and energy efficiency by Real Climate Economics blogger James Barrett. It is reposted from Real Climate Economics.

My last post on David Owen’s piece in the New Yorker and on the Jevons effect stirred up some interesting questions and discussion that I want to follow up on here. My last one purposely avoided some of the more technical parts of the issue to keep it readable and under my word limit. I think I’m about to undo that.

But first we should pay thanks to the great 20th Century philosopher, Yogi Berra, from whom I shamelessly stole the title of this post. Though he discovered it nearly 100 years after Stanley Jevons, I believe his exploration of the Jevons effect is more complete and accurate than Jevons’ own, as well as being vastly shorter. The notion that we could get so efficient at using energy that we’d end up using more is about as valid as the idea that a restaurant could get so crowded that it was empty.

Dictating Terms

Though I hate having arguments about how we should argue, there are a few things we need to get straight:

First, as originally observed and defined by Jevons, the Jevons effect is a decidedly micro issue. He observed that increased energy efficiency in coal fired steam engines resulted in increased use of coal to fire steam engines as they were used in more applications and more intensively in existing ones.

Further, the central point of Jevons’ theory was that advances in energy efficiency forced increases in energy consumption. Not merely that consumption increased despite efficiency, but that efficiency caused the increase.

So, if you believe that energy consumption would have been higher without advances in energy efficiency then, by definition, you do not also believe in the Jevons effect.

Much of the debate around this, including the comments to my last post, seem to center around a weaker form of the Jevons effect, i.e. that energy efficiency can’t keep up with demand growth. This is a very different argument than the strict form of the Jevons effect.

The distinction is important, because more than once I have found myself arguing that the Jevons effect doesn’t widely exist, and demonstrating that with examples, only to have people say that Jevons doesn’t mean we shouldn’t invest in efficiency and that I’m missing the macro question, neither of which are consistent with the definition of the Jevons effect, at least in the strict form.

I believe it is this second argument, over the weaker form of Jevons that most people are really arguing about, which is really about the size of the rebound effect.

With this in mind, let’s take a look at the different potential sources of rebound.

Home Economics 101

Looking first at household energy use (which is very different from using energy as a factor of production), I believe there is very little evidence for any Jevons effect.

Increased energy efficiency can often be treated as a decrease in energy prices, which can be broken down into two separate effects. The substitution effect and the income effect. When the price of any good falls, it frees up some amount of money we would have spent on it, essentially increasing disposable income (thus the name “income effect”). If consumption patterns don’t change, we would expect people to buy more of everything more or less proportionately.

Of course, falling energy prices do impact peoples’ consumption patterns. When energy prices fall, we tend to buy more of it because it is more affordable. This is the substitution effect. Because energy has become cheaper relative to other goods, we buy more energy and less of some other things, substituting one for the other.

For households, both these effects tend to be small. The substitution effect is small because energy is already so cheap that it tends not to influence our decisions to watch TV, use our computers, or put lights on. Most people have no idea how much it costs to run a TV (about 5 cents an hour), so owning a more energy efficient TV will have little impact on how much TV they watch.

The income effect also tends to be fairly small because (as you can see in this nifty graphic) the average household spends less than 12% of its income on gasoline and utilities (which here includes water, garbage etc as well as electricity). For the average household, if everything suddenly became 10% more efficient, energy would fall to 10.8% of their income, and their disposable income would go up by 1.2%. Energy consumption would rebound to about 10.93% (10.8% x 101.2%), producing an 11% rebound, far below the 100% needed for Jevons.

The places where you should expect the combined substitution and income effects to be large are where energy consumption is more of a luxury than a necessity. Using an air conditioner or heating our homes above a certain minimum level are good examples because when energy is expensive or the budget is tight, this is where people will economize. But, as I showed about air conditioning in my previous post, and Matt Kahn showed about driving in his, even for non-necessities, the Jevons effect is hard to find.

And admit it, while high gasoline prices might make you cancel the family road trip to the Grand Canyon this summer, nothing, not even free gasoline, could make you do it twice.

Industrious Efficiency

For industry, the income effect is the fact that with the price of energy (more appropriately “energy services”) falling, they become more profitable on a per unit basis. This increase in profitability should lead to an increase in production levels, though how large is hard to know. If we make the conservatively high assumption that businesses plow all of the increased profits back into making product, we can do the same type of calculation as we did for households. In 2006 (the most recent data available), energy consumption made up just over 3% of total input costs in the manufacturing sector (labor was about 21%). So, by the same calculation as above, the income effect would create a very small rebound effect: a 10% increase in operating efficiency in the manufacturing sector would result in a 9.7% reduction in energy use, a 3% rebound.

The substitution effect is even smaller in industry. Though we can often think of increases in efficiency as reductions in energy prices, that’s really just a form of intellectual shorthand. Increases in industrial end-use efficiency typically result from things like investments in more efficient equipment or higher expenditures on labor for operations and maintenance. These represent substitutions of physical capital and labor for energy in the industry’s production process. Because increasing expenditures on labor and machinery are what cause the cost savings in energy, firms can’t take advantage of this efficiency by shifting expenses back to energy. That would undo the savings they created in the first place.

And all of this is supported, if not proved, by actual data. Again, I can’t let Owen (remeber him? He started all this) off the hook for laziness. All of this is easily accessible from the DOE’s Manufacturing Energy Consumption Survey and BEA’s Input Output tables. I took a look at some of the heavier and more intensive industries, ones that would be most sensitive to energy prices and most likely to show large rebounds or even a Jevons effect. Between 1998 and 2006 (the periodicity of some of the data is a little odd), here is what I found:

This shouldn’t be surprising to anyone: Energy efficiency leads to reduced energy use, with some rebound. The pattern is consistent across the manufacturing sector. Despite a 26% increase in GDP and a 7% increase in manufacturing output over that time period, both energy intensity and energy use fell for the sector as a whole and for almost all of the sub-sectors that I looked at. Try it for yourself.

So you’ll have to pardon my incredulity when I hear people like Owen claim that Jevons effects are everywhere, because everywhere I look, I can’t find them.

Some of the Whole and All of Its Parts

A final word about the macro question. There is nothing particularly magical about the macroeconomy, it is merely the sum of all the micro parts. If we can’t find a Jevons effect in all the individual places we look, it will continue to be absent if we sum them all up.

The one exception to this is the question of productivity. If energy efficiency increases overall productivity (it does), which in turn accelerates economic growth (it should), then there is a third source of rebound effect that won’t show up in the income or substitution effects I describe. A self-fulfilling income effect, perhaps.

This is tough to address in a few words (or even in many), because it links back to very technical questions of multifactor productivity and the like. But looking at past increases in gasoline prices, history shows that for every 1% increase in gasoline prices, GDP tends to decline about 0.05%, so that a doubling of gas prices might knock a half a point off of GDP. If we’re willing to assume that this is at least the right neighborhood for all energy types and that the response to a reduction in prices would be about as large as it is for an increase in prices (and there are good reasons to doubt this), then this productivity effect would still be pretty small. A 1% across the board increase in energy efficiency might produce an increase in GDP of 0.2% (not insignificant given historic annual growth rates in the 3% neighborhood). This, in turn, would lead to an increase in energy consumption of slightly less than the same relative magnitude, a rebound effect of less than 20%.

Putting all of these things together, the most you can reasonably expect is a total rebound effect of 30% under some pretty generous assumptions. Combine this with income growth caused by other things, population growth, and other factors, and the gains from efficiency can get buried in the weeds. All that’s really clear is that for significant periods, energy efficiency has not increased fast enough to cause energy use to go down.

But, and this is the key point, this is not the same as saying, and it does nothing to justify saying that efficiency can’t grow fast enough to reduce overall energy use. That is exactly as valid as saying that nuclear power can never reduce our use of fossil fuels, because even when we made large investments in nukes, fossil use still increased. I’ll have plenty more to say about nukes later, but nuclear advocates would rightly respond that this is proof only of the fact that our investments in nuclear were not large enough to offset increases in electricity demand. The same is true for efficiency. If efficiency investments have never forced energy use to decline, that’s proof only that we, as a nation, have never really given it a try.

So while there may be many good reasons to go to a crowded restaurant, being alone isn’t one of them.

— James Barrett

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21 Responses to Debunking the Jevons Paradox: Nobody goes there anymore, its too crowded

  1. There is a good explanation of Jevons paradox at the micro level in wikipedia at It points out that:

    Jevons paradox very obviously does not apply to policies that promote conservation by increasing the price of energy, such as a carbon tax or cap and trade. Jevons paradox says that increased efficiency lowers the price and so promotes more consumption; if we raise the price to promote efficiency, this clearly is not true.

    Jevons paradox only applies if demand is elastic. Eg, elasticity of demand for gasoline in the US is about .2, and so more fuel efficient cars would reduce gasoline consumption. The coefficient of .2 means that, if we cut the price of gas per mile in half by making cars twice as fuel efficient, mileage driven will increase by 20%; therefore overall demand for gasoline will decline by 40%. (Elasticity of demand for gasoline is undoubtedly higher in developing nations, and it is plausible that an extremely fuel-efficient car like the Nano will make it possible for so many more people to drive that overall gasoline consumption will increase. This is an empirical question.)

    Less work has been done on Jevons paradox at the macro level, but it seems to me that it is not logically possible for it to apply. Eg, imagine that energy efficiency is doubled across the entire economy. What will people do with the money they save on energy? If they use 100% of that savings to consume more energy, then overall energy consumption will remain the same. But they obviously will spend some of that savings on something other than energy, so overall energy consumption will fall.

  2. paulm says:

    this holds true in a world of restrictive rising energy costs.

  3. Bob Lang says:

    Charles S. #1

    Good point.

    Upon closer analysis, “black-and-white” turns into “shades of gray”.

  4. Nigel Moore says:

    There is rarely a backfire (a rebound effect that actually increases overall consumption of the resource, but often some rebound effect exists when dealing with activities for which energy, or operational costs are high (such as driving a car). This is because of prices. I agree with you Joe that efficiency improvements are a very important part of climate policy, but the rebound effect does exist to a certain degree. I’m curious as to ehy you attack it so vigorously? Your absolute claims in this area seems kinda anti-science to me in all honesty.

    have you read the UKERC report ( I think its a good one.

    Keep on bloggin’, I’m a fan of the site.


  5. mikkel says:

    I wish to step back from Jevons paradox and its classical/neoclassical origins and focus on the nature of energy use. The second post and also Charles’ “But they obviously will spend some of that savings on something other than energy, so overall energy consumption will fall” are treating energy use too narrowly on the macro level.

    It is not just the direct energy consumption that needs to be looked at (e.g. running the AC more, driving more) but the associated energy use across all forms of consumption. From a biophysical economics perspective, energy is not just a ledger item, it is the driver of all economic feedback effects.

    In fact with this view it is clear that on the micro level you shouldn’t see much of a rebound effect in a directly measurable way since a) it is hard to look at overall energy consumption in terms of embodied energy and the like on the small scale and b) if only a few individual consumers become more efficient it is unlikely to increase aggregate demand. It is primarily on the macro level that this effect can be observed.

    Indeed the wikipedia article states:
    “At the microeconomic level (looking at an individual market), even with the rebound effect, improvements in energy efficiency usually result in reduced energy consumption.[6] That is, the rebound effect is usually less than 100 percent. However, at the macroeconomic level, more efficient (and hence comparatively cheaper) energy leads to faster economic growth, which in turn increases energy use throughout the economy. Saunders concludes that, taking into account both the microeconomic and the macroeconomic effects, technological progress that improves energy efficiency will tend to increase overall energy use.”

    [JR: There is no evidence on behalf of this statement. Saunders never offers any. I will show tomorrow, indeed, that the reverse may well be true.]

    I posit that far from the first post pointing out that the Jevons paradox is invalid [in observation if not in explanation], it demonstrates that rising energy efficiency is potentially a factor in the increased largess of our society. Indeed per capita energy consumption has remained flat over that time period even as homes increased in size and AC use spread; not to mention all the extra “stuff” we have.

    [JR: I posit that your statement has provided not a whit of evidence.]

    From a biophysical perspective, the increased efficiency has allowed us to consume more total resources per capita, enabling both our population and “lifestyles” to rise at the same time. At its core it challenges this notion: “All of the increase in energy consumption for air conditioning is easily explained by factors completely unrelated to increases in energy efficiency. All of these things would have happened anyway. Without the increases in efficiency, energy consumption would have been much higher.”

    [JR: Again, you seem to be mashing up the natural rate of change of energy intensity with actual efforts aimed at energy efficiency.]

    Of course the idea that this means we shouldn’t pursue energy efficiency is absurd. It means that we should tax energy to reduce overall consumption, increase the taxes as efficiency rises (but not at the same rate) and lower them in order to provide a buffer against intermittent energy price spikes. This would provide a stable price foundation to make long term ROI calculations for investment and also make efficiency gains lower the ecological burden instead of increase consumption.

  6. José M. Sousa says:

    I agree with Charles that the Jevons Paradox is valid at the macro level if prices decreases with efficiency.

    [JR: And 1 + 2 = 4 if 2 is 3.]

  7. José M. Sousa says:

    Well, about the last part, not exactly true the conclusion, because people that didn´t have acess to energy consumption will probably enter the market when prices fall due to the doubling efficiency and so increase consumption.

  8. Jeven’s “Paradox” is promoted by the same people who believe that lowering tax rates increases revenues received.

  9. Carter says:

    One of the New Yorker article’s shortcomings was that the obvious solution was hinted at and referred to but not called for. If you assume, as the article did, that the Jevons paradox is real, the way to save energy is to make it more expensive.

    The author did not make that point emphatically or specifically, but he did say that mandating efficiency is politically easy compared to taxing energy. That was the point I drew from the article. Whether or not efficiency mandates save energy, they are achievable.

    So I give the article credit for raising an argument in favor of a carbon tax. Readers who have not pondered energy issues as the readers of this blog have, will end up questioning the doctrine that says we can avoid making energy any more expensive by mandating more efficiency.

  10. Villabolo says:

    Somewhat off topic but let me introduce the “Villa” effect:

    “The more expensive you make energy for the rich and upper middle classes, the more of it you have, at less expense, for the rest.”

    This is how it works. You create a multi-tiered pricing system based on zip codes where you price, let’s say, Natural Gas at much higher rates for different income levels.

    Then you wait for Peak Oil.

    1. The elite (the rich). They get to pay 10 times as much than the lowest rate for a fixed amount. Then 20X for any amount over that.

    2. The wannabe elite (upper middle class). They will pay 5 times as much for a fixed amount that would e sufficient for hot showers and cooking.

    After that, if they want to heat their McMansions, they’ll pay 10X as much up to a fixed level (sufficient to heat their palaces for the occasional party). Then it will be 15X for any amount above that.

    3. What’s left of the middle class. They’ll pay 1X just for hot showers and cooking (with a generous safety margin). Then it will rise to 2.5X (for occasional home heating), followed by 5X the rate.

    4. The rest of us. We’ll pay 1X for basic non heating consumption; 1.5X for occasional home heating; then 2.5X after that.

    Employment will rise for electric blanket and warm pajamas production.

    You see? I didn’t even mention G****l W*****g.

    Glenn Beck will finally have a schizophrenic breakdown and Rush Limbaugh will suffer a stroke.

    Coming to an alternative universe near you. ;-)

  11. Joan Savage says:

    Today, the WSJ ran “Exxon Struggles To Find New Oil.” Exxon revealed that they have been replacing their reserves at a rate that is 95% of consumption.

    This highlights what seems to be a very limiting assumption in Jevon’s Paradox, the assumption that total availability of energy stays nearly constant, allowing efficiency to free up more of it.

    The reality of declining petroleum energy supply means that even with efficient use of energy, there is less of that form of energy to use altogether.

  12. The climate change Jevons effect.
    The science is definite-only zero carbon emissions will stop the global temperature and ocean acid rising (or bring them down)because 20% of all CO2 emissions last in the atmosphere 1000 years. By their sectoral nature global GHG emissions are constant. Therefore improving carbon efficiency (while virtuous) makes global climate catastrophe a sure thing. Only a policy for the total conversion of the world economy and world energy supply can lower atmospheric carbon.
    Peter Carter

  13. Mimikatz says:

    Barrett seems to assume that incomes will rise forever. First, “incomes” haven’t been rising. Incomes at the top 5% have, but everyone else is pretty stagnant. The top 5% are pretty extravagant, but they don’t spend everything by any means. Second, it is not likely that this sort of income skewing is going to continue indefinitely. If “incomes” do rise, it will have to be because of some kind of redistributive policies.

    What seems more likely is that energy costs will rise because peak oil and increased regulation of coal will ripple through the system and transportation costs will at some point become pretty prohibitive for bulky cargoes like oil. People will become more efficient and/or ratchet down their consumption, perhaps working less and spending more time getting or growing food. Look at the end of the Soviet Union for parallels and divergences.

  14. David Stern says:

    I’m not so sure that the stronger version of Jevons paradox is bunk especially in developing countries. In some sense the whole industrial revolution can be considered an example of Jevons paradox. Making steam engines and other energy using devices practical by improving their efficiency greatly increased their use. And energy use is essential for economic growth. So the innovations of the industrial revolution that used energy more efficiently were a big part of the story of how modern economic growth got going.

    The bottom line is that Jevons paradox/the rebound effect should not be an excuse to do nothing about climate change. Rather it shows why efficiency only and “direct action” are likely to be ineffective approaches and why caps on total carbon emissions and/or carbon taxes are needed.

  15. Jeff Huggins says:

    Different Questions

    Many of the following questions are different questions, related in some ways but not in others, of course:

    * Do efficiency improvements (somehow?) “force” increases in energy consumption? (I use the term “force” here only because it was used in categorizing one view.)

    * Do efficiency improvements (always, never, sometimes?) cause increases in consumption, and if so, by how much?

    * Do efficiency improvements, if reflected in prices, (always, never, sometimes?) “tend to” “contribute to” increases in consumption, and if so, by how much, and under what circumstances?

    * Does consumption sometimes increase despite efficiency improvements?

    * Are efficiency improvements sometimes sufficient to accomplish the task of reducing total absolute consumption of a resource? Are they sometimes insufficient to accomplish the task of reducing total absolute consumption of a resource? Even when they are insufficient, do they (always, never, usually, sometimes?) contribute to accomplishing the task of reducing total absolute consumption of a resource?

    * Via their influence on prices (if the efficiencies are reflected in prices), do efficiency improvements sometimes contribute to some degree to increases in consumption, the degree to which will depend on all sorts of factors?

    * If human pregnancies lasted only three days, and if you could feed a child on one piece of toast and a glass of water per week, and if all women and all men could find mating partners more efficiently, and then leave them more efficiently, might that tend to contribute to an increase in human population, even beyond the current problems we’re having with population, given that we humans aren’t all that great at self-discipline or at voluntarily constraining our own appetites and creativities?

    * What precisely did Jevons say and not say, and to what degree, and in what context, and what did he actually mean and not mean? And to what degree does that really matter (what Jevons thought, that long ago) relative to the actual facts of the matter as they relate to specific questions and specific conditions?

    * Should we conclude that energy efficiency is not important? (No, of course not. It’s very important.) On the other hand, should we conclude that energy efficiency alone will address the climate problem, even if (because of all sorts of factors) human consumption continues to increase and increase? (No, of course not. It would be a disaster to do so.)

    Although I appreciate this post (in its several parts), and have learned from it and from the comments, the post helps to add clarity in some ways but also seems to be dancing around a bit among questions and tasks. At least it feels that way. I’m not sure what the point is of jumping on Jevons himself? Although there is much that I don’t read, most of the time someone refers to the Jevons paradox, as far as I can tell, the concern that they’re really trying to express is that GIVEN OTHER FACTORS AND GIVEN HUMAN TENDENCIES, and GIVEN HOW HUMANS OFTEN BEHAVE AS EFFICIENCIES IMPROVE, improvements in efficiencies (by themselves) cannot be counted on to achieve reductions in the absolute total consumption of a resource as time progresses. Human appetites often result in consumption growth despite improvements in efficiencies. This happens for a wide range of reasons, of course, and whether it happens depends on the specific matter/question at hand. These people may not be referring to “Jevons paradox” in a technically correct way — I don’t know, I haven’t read Jevon himself directly, i.e., the source material, in context — but the concern that they’re trying to express is a good one. (I’m not talking about the article in The New Yorker, of course.) Nobody that I know claims that efficiency improvements “force” an increase in consumption, as if we’re talking about some supposed physical law rather than matters of human consumption, economics, and multifaceted influences. How could efficiency improvements “force” consumption increases?? In my experience, most people who mention Jevon seem to do so in the broader/weaker sense in their attempts to raise the concern that we ALSO have to address population growth and consumption of the finished goods, so to speak, not just improve efficiencies. And they raise this point for good reason, of course: Although improving efficiency is vitally important, and beneficial, in our culture we are often told that “things will all be fine” BECAUSE OF the efficiency improvements — i.e., that those alone will suffice and we won’t have to make any other changes. Computers are coming: so life will be fine. More efficient cars are coming: so life will be fine. The internet is coming: so life will be fine. Efficiencies are on the way: so life will be fine.

    This creates a very important communications challenge if we are to keep things straight and to maintain credibility. While it’s important to argue correctly against people who say that “efficiency is not important” or that “efficiency will necessarily result in more usage of the resource, not less”, it’s equally important to argue correctly that we can’t COUNT ON efficiency ALONE to solve the problem, and we will have to address issues such as population and consumption patterns too. Given the different ways that people use the name ‘Jevon’, and whether they are talking about the precise or broader/weak interpretation, or even other interpretations, I don’t think that it helps, much, to take a stand “WITH JEVON” or “AGAINST JEVON”. In my view, it’s best to keep matters clear — efficiency is vitally important, but (often) not nearly sufficient — i.e., other changes will be needed too — and also to focus on clear questions in context. The answers to these questions often depend on the specifics.

    In any case, Cheers for Now!


  16. Alec Johnson says:

    I’m surprised to find no mention of the Khazoom-Brooks postulate which is similar to Jevon’s Paradox, but with an important difference. They find something like Jevon’s occurs, but in “unregulated markets.” This is yet another reason to regulate things like carbon.

  17. Edward says:

    JJevons paradox worked in the year 1750, the year the first “practical” steam engine was invented. James Watt’s steam engine resulted in the burning of more coal in steam engines. Prior steam engines were so inefficient that they used more coal than they helped extract from the mine. Before 1750, horses were used to power the pumps that pumped water out of the mines. With Watt’s engine, it made sense to use steam rather than horses to pump water out of the mine.

    Further improvements in efficiency did not change the decision to use steam rather than horses for that application. Just because Jevons paradox worked in the year 1750, doesn’t mean it worked in any other year. Steam engines continued to increase in number and power, and efficiency continued to improve, but that is not proof that Jevons paradox continued to work. There are lots of other reasons to buy a steam engine.

    Asserting Jevons paradox today is an example of a mistake called “over generalization.”

  18. Edward says:

    Thermodynamics puts upper limits on efficiency. Getting the last little bit of efficiency is harder than getting the first big chunk. Remember that the subject we are interested in is GW and GW is caused by CO2. Efficiency can help, but switching to a source of energy that doesn’t generate CO2 helps more.

    Remember also that it isn’t the total amount of energy that we use that counts. It is how much CO2 we generate in the process. Many people make the mistake of thinking that reducing the amount of energy that we use will reduce GW. Human energy usage is so minute compared to natural energy flow that human energy use is irrelevant. Heat is easily dissipated to the cold of deep space if CO2 is low.

  19. Lewis C says:

    James Barret wrote :

    “The rebound effect is real and it makes sense. Owen’s anecdotes reinforce that common sense. But it’s not enough to observe that energy use has gone up despite efficiency gains and conclude that the rebound effect makes efficiency efforts a waste of time, as Owen implies. As our per capita income increases, we’ll end up buying more of lots of things, maybe even energy. The question is how much higher would it have been otherwise.

    The even more interesting question is whether efficiency growth can ever overpower the effect of income growth and start reducing energy consumption in absolute terms.”

    Given that we have a 250 year track of economic growth reflecting growth in energy consumption, underpinned by the growth in the efficiency of energy conversion, it seems clear that improving energy efficiency has raised profitability which has raised investment in additional energy consumption.

    So long as there is no material or legal constraint on increased energy usage, this effect continues unabated.

    Moreover, in an exact parallel to the deployment of non-fossil energy techs, the fuel I avoid burning by improved energy efficiency is being bought and burnt elsewhere by someone else. Thus if energy efficiency were raised to 99%, intensive fossil fuel usage would become affordable to billions more people – predictably resulting in significantly raised global extraction and consumption of those fuels.

    It seems worth asking the question in the context of controlling fossil carbon combustion:
    if cutting the cost of useful energy by raising conversion & use efficiency does not result in significantly increased fossil fuel sales,
    then why should raising the cost of useful energy by setting a price on carbon emissions have the effect of significantly reducing fossil fuel sales ?

    Then there is also the consideration that every rise in the efficiency of fossil fuels’ conversion to useful energy is directly helping them to retain market share against the emerging non-fossil energies.

    In the absence of a declining global cap on fossil fuel usage, the sole benign function of energy efficiency gains appears to be in raising policy-makers’ confidence in negotiating that declining global cap. The higher the energy efficiency in prospect, the more rapid the decline of fossil fuel usage that can be agreed without fear of collapsing the economy and the treaty’s operation.



  20. daniel smith says:

    Goodness. Such vehemence, so many hot buttons. Of course Owens’ article was sloppy, and of course Jevons should not be assumed as a blanket, and of course there are benefits to efficiency–even where Jevons is robust–especially as it helps grease the skids for the ultimate transformation that hopefully, one of these days, will be driven by a global agreement on greenhouse gases. But really, to state baldly that Jevons is “bunk” is, as someone said earlier, deeply anti-empirical and a hugely flawed (or limited) reading of the literature. No, I don’t have the cites and stats at my fingertips, but there is a large literature on this in environmental sociology (and elsewhere, I’m sure) and to say that it is “bunk” is to mirror the know-nothingism that has got us into this mess.

    I will say that I’m glad to see this discussion at least making it on the page here. I actually posted something short on Jevons a few months ago. It was in the comments section for a few hours and–poof!–it disappeared. We’ll see if this meets the same fate; that way I’ll know if the prior case was accidental or not.

  21. Larry Shultz says:
    This is an article about how energy efficiency can lead to greater carbon dumping to sinks