Jevons paradox
Etymology
Named for the English economist William Stanley Jevons, who observed in his 1865 book The Coal Question that more efficient steam engines led Britain to burn more coal, not less. The insight was largely forgotten for over a century before energy and environmental economists revived it in the late twentieth century, sometimes under the related term "rebound effect." Modern usage occasionally overstates it, treating any efficiency gain as self-defeating, when the size of the rebound in fact varies widely.
noun phrase · /JEV-unz PAIR-uh-doks/
The paradox that making a resource more efficient to use can increase, rather than decrease, the total amount consumed.
What it names
Why better fuel economy can mean more driving, not less gas — because efficiency lowers the effective price of using something, and cheaper things get used more — a warning that haunts every "we’ll just make it greener" plan.
Example
The new data centers are far more energy-efficient per computation, but Jevons paradox suggests that just makes AI cheap enough to run everywhere, so total power use climbs.
Related idea
The rebound effect is the general tendency for efficiency savings to be partly clawed back by increased use; Jevons paradox is its extreme case, where the rebound more than wipes out the original saving.