After switching to a more fuel-efficient car, you find yourself driving a little farther every weekend. Because fuel costs less, there are more days when you take the car out without a second thought. Less fuel is needed to travel the same distance, yet if driving increases enough, total monthly fuel use can rise. When the increase in use caused by greater efficiency exceeds the expected savings and raises total consumption, this is called the Jevons paradox.
Put simply, the Jevons paradox means that “the efficiency with which a resource is used improves, yet as a result total consumption of that resource does not fall but actually rises.” When efficiency goes up, the cost of doing the same thing goes down, and people do more of it because it has become cheaper. That is why it is hard to believe that efficiency gains alone will solve resource problems on their own.
In this piece we will look in turn at the background against which the Jevons paradox was first raised, the mechanism by which efficiency increases consumption, easy everyday examples, and finally the limits and remedies that policy should not overlook.
The Structure of a Paradox: How Efficiency Invites Consumption
What Is the Jevons Paradox?
The concept was first discussed by the British economist William Stanley Jevons in his 1865 book The Coal Question. At the time, there was great concern in Britain that coal reserves were being depleted quickly, along with the hope that better technology would reduce coal use.
Jevons focused on the exact opposite picture. When James Watt greatly improved Thomas Newcomen’s steam engine and raised its coal efficiency, coal became a far more economical source of power. Steam engines then spread across many industries, and although each machine used less coal, the nation’s total coal consumption rose sharply. Jevons pointed out that it is a confusion of ideas to treat the economical use of fuel as the same thing as reduced consumption, and that the truth is the very opposite.
- Jevons paradox: the phenomenon in which total consumption of a resource rises as the efficiency of its use increases.
- The Coal Question: Jevons’s 1865 book arguing that efficiency gains would not prevent the exhaustion of coal.
How Efficiency Increases Consumption
The Jevons paradox arises from a chain in which efficiency, price, and demand follow one another.
(1) The cost of use falls
When efficiency rises, less of the resource is needed to get the same result, so the real cost per result becomes cheaper. If fuel economy doubles, you can drive twice as far for the same fuel bill.
(2) People use more because it is cheaper
The law of demand, which says that quantity demanded rises when price falls, comes into play. The way part of the savings from efficiency returns as increased use is called the rebound effect.
(3) The rebound exceeds the savings
The more sensitive demand is to price, the larger the rebound. If increased use gives back more than 100% of what efficiency saved, total consumption ends up higher than before the efficiency gain. That is precisely the moment the paradox appears.
- Rebound effect: the effect in which consumption rises again because efficiency has lowered the cost of use.
- Price elasticity of demand: the degree to which quantity demanded responds to changes in price.
- Backfire: the state in which the rebound effect exceeds 100% and total consumption actually increases.
Understanding the Jevons Paradox Through Easy Examples
The relationship between efficiency and consumption can be seen throughout daily life. Still, the paradox does not always occur, so it helps to look at counterexamples as well.
(1) Fuel-efficient cars
When fuel economy improves, people drive more often and farther. Real-world studies have also observed a rebound in which distance driven increases after fuel economy improves. In mature markets, however, this rebound is usually not large, so overall fuel use often still goes down.
(2) A related phenomenon: reservoirs and water use
Expanding reservoir capacity can encourage development and higher water demand, leading to renewed shortages. This is a related example of supply expansion and demand growth reinforcing each other. However, expanding a reservoir does not itself reduce the water needed to perform the same task, so it should be distinguished from the Jevons paradox.
(3) Distinguishing falling agricultural labor use from resource consumption
In U.S. agriculture, productivity has risen while labor input has fallen and output has grown. However, a decline in worker numbers or employment share alone does not show that total consumption of resources such as energy or water has fallen. Assessing whether the Jevons paradox occurs requires specifying which resource’s efficiency and total use are being compared.
Limits and Remedies Efficiency Policy Should Not Overlook
In the 1980s, the economists Daniel Khazzoom and Leonard Brookes revisited this question, and in 1992 Harry Saunders formulated it as the Khazzoom–Brookes postulate. It holds that efficiency gains make energy relatively cheaper and boost income and growth, which can drive up energy use across the economy as a whole.
The counterarguments are considerable too. Many studies find that in individual markets the rebound effect usually falls short of 100%, so efficiency gains still reduce consumption. And even when consumption does not fall, the value of efficiency, being able to make more with the same resources, remains.
Efficiency improvements can be considered alongside policies such as environmental taxes or emissions caps. Environmental taxes put a cost on pollution, while cap-and-trade limits total emissions from covered sources. Allowance prices vary with markets and program design; the system does not keep the cost of use fixed. Actual effects depend on coverage, the cap, enforcement, and other design choices.
- Khazzoom–Brookes postulate: the hypothesis that improvements in energy efficiency increase energy consumption across the economy as a whole.
- Cap and trade: a system that sets a total emissions limit and allows emission rights to be bought and sold within it.
The Jevons paradox is the insight that when efficiency improves and a resource becomes cheaper to use, the increased demand can exceed the savings and raise total consumption. This question, which began with steam engines and coal, continues today in discussions of cars, water, and modern technology.
Welcoming more efficient technology while also watching where the savings it brings end up flowing: that is the first step toward the wisdom of truly conserving resources.
