Cross-cutting
Jevons paradox
The observation that gains in resource-use efficiency can increase, rather than decrease, total consumption of that resource because lower effective costs stimulate demand.
Definition
The Jevons paradox holds that improving the efficiency with which a resource is used can lead to higher aggregate consumption of that resource, because efficiency lowers the effective cost of the service it provides and thereby expands demand. It is named after William Stanley Jevons, who argued in The Coal Question (1865) that more efficient steam engines would increase, not conserve, Britain's coal consumption.
References
Definition, Jevons 1865 origin, rebound-versus-backfire distinction
Overview
What it means
Efficiency reduces the resource needed per unit of output; if demand responds strongly enough to the resulting fall in effective price, total consumption rises above its original level ("backfire"). Where demand rises but by less than the efficiency saving, the effect is called rebound — savings are smaller than engineering estimates predict, but still positive.
How it is used
The concept informs energy and climate policy analysis (why efficiency standards alone may not deliver projected savings), assessments of fuel-economy and appliance programmes, water-use and digital-infrastructure studies, and critiques of decoupling claims in green-growth debates.
Why it matters
It warns that technology-led efficiency gains are not automatically equivalent to absolute resource reduction, strengthening the case for pairing efficiency policy with pricing, caps or sufficiency measures.
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