portrait photo of William Jevons

Jevon’s paradox makes sustainability even harder

Efficiency gains should lower resource consumption but rarely does this happen, especially with energy. What can we learn from a Victorian gentleman who figured this out?

In 2022 inflation has returned to make everyday expenses a challenge. 

In Australia, gasoline prices rose by nearly 50% in weeks. Reliant on oil imports to power our vehicles, Australians have copped it from the global cabal. We also have made a mess of our energy supply systems, but that debacle is for another day.

What do I do about the high petrol price?

Drive less is the temptation. Only get in the car when it is essential, even if that is near all the time. Life revolves around the car. Nobody walks to the shops anymore.

I know. I will get a more efficient car. Trade in the gas guzzler for a small runabout that has twice the fuel efficiency. Then it’s not a problem to drive everywhere because I am saving fuel.

This is the logic of the Jevons paradox.

Energy is useful, and for a given level of resource availability, efficiency gains make it cheaper and more desirable, ultimately leading to greater rates of energy consumption and an increase in the consequences of consumption, such as greenhouse gas emissions.

William Stanley Jevons described the principle in a discussion of energy economics way back in 1865. He was convinced that the introduction of energy-efficient steam engines had accelerated coal consumption in Britain. He figured that as the cost of steam-powered coal extraction became cheaper, it should have slowed energy use. Efficiency gets more work done for less effort. Because the fuel was attractive, more coal was extracted even though it was more efficient.

What we know now is that more coal was consumed. Jevons got that bit right.

Graph of coal production and imprts in the UK from 1700 to 2019

UK production was roughly 100 million tonnes when Jevons came up with his paradox and when he died in 1882 it was 170 mt before a production peak at 292 mt in 1913. This peak coincided with the arrival of more attractive fossil fuels, oil and later gas.

Various instances of the paradox where efficiency gains expected to reduce consumption are overwhelmed by material growth and rebound. 

Suppose that the efficient vehicle I purchased meant that I saved money that I could now spend running the air conditioner. Cooler nights gave me better sleep and a more effective worker the next day at the office. With higher profits, the companies then reward the workers with raises, who in turn spend the money on goods produced overseas with coal-generated electricity. So, in this fashion, the ramifications of any given efficiency action can multiply indefinitely, spreading at a variety of rates throughout the global economy

This undermines strategies for energy efficiency as a means to achieve sustainability.

The reality of the human condition—cognitive dissonance and collective denial—means that the Jevons paradox occurs more often than not.


Irrigation efficiency 

Water is a crucial resource for global food production.

The amount of agricultural land under irrigation has increased dramatically, especially in Asia, but around the world, irrigated area has doubled since the 1940s when the agricultural intensification revolution began. 

Graph showing the increase in land under irrigation

European Commission Joint Research Centre—World Atlas of desertification. Since 1900, there has been a dramatic increase in land put under irrigation globally. The increase is particularly pronounced in south and east Asia. (AEI=area equipped for irrigation; HID=historical irrigation data set). Source: Siebert et al., 2015.

Irrigation efficiency is the proportion of consumed water used by crop plants, specifically the fraction of the consumptive use of water (defined as applied water minus any return flow) that is effective water (defined as water that is beneficially used by a crop).

More efficient irrigation technologies increase this proportion so that yield can be maintained with less water. They also allow crop production on lower-quality soils. Dropped nozzles attach to centre-pivot irrigators and hover right above the canopy of crops, thereby reducing water lost to evaporation and drift.

Drip irrigation, where water is conveyed to plants through pipes for the slow and controlled application of water, can save 25–75% of pumped water compared to flood irrigation.

This sounds good, but research shows that technology that increases irrigation efficiency does not necessarily lead to less groundwater consumption. If demand for groundwater by farmers is elastic enough if the higher efficiency technology operates at a lower marginal cost, and if the higher efficiency technology increases revenue, then irrigation efficiency will increase applied water.

Jevon’s paradox again.

Researchers in China found that although the water productivity of China’s agricultural sector has increased over the last 20 years via improvements in irrigation technology, the total agricultural water use did not decline as expected. Instead, agricultural output increased. Much of the expected water savings from more efficient irrigation technology are offset by increased water use for the resulting increase in agricultural production made possible by the more efficient irrigation technology.

Efficiency does not reduce water use but can increase it.

sunrise image of an irrigation boom arm on a ploughed field
Photo by Loren King on Unsplash

What sustainably FED suggests

Perhaps William Jevons was prescient. Maybe he could foresee the consequences of the industrial revolution before everyone else. 

Don’t forget that the arrival of cheap, powerful energy was nothing short of a miracle in his time. Before coal, the energy to drive society came from manpower, animals, and wood with a bit of whale blubber on the side. Everywhere energy was a limited resource, and so anything that increased energy efficiency was a bonus that could be spent by conserving what was precious and in short supply. 

Energy constrained economic activity until it didn’t.

Jevon’s paradox wasn’t one because coal turned out to be inexhaustible. It could be mined as fast as needed to fuel the steel mills, factories and the engines that the factories made. 

And so it has continued.

In 2020, Australia was the fifth biggest coal producer at 426 million tonnes—China produced 3,580 mt—mindblowing volumes for a Victorian gentleman. 

Jevon’s paradox is a neat reminder of what we should already know.

Humans are genius-level makers of stuff and additional humans; not least because we tap into exogenous energy sources. We can’t help ourselves.

It’s not the paradox that makes sustainability harder, it is us.


Science sources

Garrett, T. J. (2012). No way out? The double-bind in seeking global prosperity alongside mitigated climate change. Earth System Dynamics, 3(1), 1-17.

Rees, W. (2010). What’s blocking sustainability? Human nature, cognition, and denial. Sustainability: Science, Practice and Policy, 6(2), 13-25.

Sears, L., Caparelli, J., Lee, C., Pan, D., Strandberg, G., Vuu, L., & Lin Lawell, C. Y. C. (2018). Jevons’ paradox and efficient irrigation technology. Sustainability 10, 1590.


Mark

Mark is an ecology nerd who was cursed with an entrepreneurial gene and a big picture view making him a rare beast, uncomfortable in the ivory towers and the disconnected silos of the public service. Despite this he has made it through a 40+ year career as a scientist and for some unknown reason still likes to read scientific papers.

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