by Thomas Lepeltier, Causeur, 5 September 2025
For Jean-Marc Jancovici, falling oil supply condemns the economy to contraction, and green growth is physically impossible. Both articles acknowledge the value of his diagnosis on energy, but dispute that inevitable decline follows from it.
In brief
- What the author accepts: our civilisation still relies massively on fossil fuels, the energy available largely determines our standard of living, and substituting low-carbon sources is difficult.
- What he disputes: a fixed relationship between energy and GDP, a ‘peak oil’ announced since the 1970s that has never occurred, and the idea that every material flow is a nuisance.
- In the second text (‘Sky is not the limit’), he responds to the thermodynamic argument that green growth would be impossible.
The three arguments of the columns
Decoupling already observed
Several European countries show signs of absolute decoupling between growth and fossil fuel consumption, including imported emissions, thanks to energy efficiency, the shift to services and low-carbon energy.
The Earth is not a closed system
The second law of thermodynamics applies to a closed system; the Earth continuously receives energy from the Sun. And nothing in this law says how long it would take for any degradation to affect humanity.
Sufficiency as a horizon
Capping flights, being wary of nuclear fusion or AI: for the author, these positions reflect a distrust of innovation, whereas it is ignorance, not a lack of resources, that has held societies back.
‘By claiming to protect society against the illusions of progress, he locks it into the opposite illusion: that of an inevitable decline.’Thomas Lepeltier, Causeur, 5 September 2025
Why this debate interests us
The theses of Jean-Marc Jancovici shape a large part of the public debate on energy and climate. APALA shares Thomas Lepeltier’s analysis: taking the energy challenge seriously does not oblige us to conclude that decline is inevitable, and innovation remains our best response. The discussion here concerns public positions, defended in the media, and not the person.
Questions for debate
- Can decoupling between growth and fossil fuels become general?
- Does thermodynamics really set a limit to growth on a human scale?
- Should certain uses, such as flying, be rationed, or should we bet on decarbonising them?
To go further on apala.fr
Summary written by Claude (Opus 5.5 model), an artificial intelligence, for APALA, based on the two articles published in Causeur on 5 September 2025. The views expressed are those of the author. Spotted a mistake? Write to us.
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