L'énergie définit physiquement la capacité à transformer le monde matériel, fournissant à chaque individu moderne l'équivalent mécanique d'environ 200 à 600 serviteurs virtuels à travers un parc mondial de machines. (7:50)
Le produit intérieur brut (PIB) mondial et la consommation d'énergie primaire évoluent en lien direct et presque linéaire : la monnaie ne fait que quantifier financièrement les flux matériels physiquement actionnés par les machines. (136:41)
Historiquement, l'humanité n'a jamais substitué une énergie à une autre mais a empilé les sources : la consommation mondiale de charbon par habitant n'a jamais baissé depuis 1860 et croît beaucoup plus vite que les énergies renouvelables modernes. (51:19)
Le plafonnement puis le déclin de l'énergie par habitant depuis les chocs pétroliers des années 1970 a brisé le modèle de croissance de l'État-providence occidental, provoquant une explosion de l'endettement souverain et préfigurant la crise financière de 2008. (138:18)
Detailed notes
## Background
Cette vidéo a été publiée sur YouTube le 30 juillet 2019 par la chaîne de Jean-Marc Jancovici. Elle correspond à la première partie de son cours dispensé aux élèves de l'École des Mines de Paris en mai 2019, consacrée aux fondements physiques de l'énergie et à son rôle central dans le fonctionnement des sociétés humaines.
## TL;DR
Dans ce cours inaugural, Jean-Marc Jancovici démontre que l'énergie n'est pas une simple commodité financière représentant quelques pourcents du PIB, mais la mesure physique universelle de la transformation du monde matériel par notre gigantesque parc de machines. En comparant le travail musculaire humain au potentiel colossal des combustibles fossiles, il montre que chaque citoyen moderne commande l'équivalent de plusieurs centaines d'« esclaves énergétiques », conditionnant notre niveau de vie, l'urbanisation et la quasi-totalité des emplois de service. Face à la stagnation physique des approvisionnements énergétiques amorcée avec les chocs pétroliers et accentuée depuis le pic européen de 2006, il dénonce l'aveuglement des modèles économiques classiques et avertit les futurs ingénieurs qu'ils devront piloter un monde de contraction contraint par les limites planétaires et le changement climatique.
## Atmosphere & style
Le ton oscille entre la rigueur implacable de la thermodynamique et une ironie caustique, ponctuée de formules percutantes et de mises en situation concrètes destinées à bousculer les certitudes des étudiants. Le style est direct, décapant et magistral : l'orateur interpelle constamment son auditoire, pulvérise les récits médiatiques sur la transition avec des règles de trois élémentaires et installe une tension lucide face aux contraintes du monde réel. L'expérience d'écoute est à la fois désarçonnante et intellectuellement stimulante, transformant une simple leçon de physique en une démonstration vertigineuse de notre dépendance systémique aux énergies fossiles.
## Bulletin
- [07:50](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=470s) L'énergie définit physiquement la capacité à transformer le monde matériel, fournissant à chaque individu moderne l'équivalent mécanique d'environ 200 à 600 serviteurs virtuels à travers un parc mondial de machines.
- [02:16:41](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8201s) Le produit intérieur brut (PIB) mondial et la consommation d'énergie primaire évoluent en lien direct et presque linéaire : la monnaie ne fait que quantifier financièrement les flux matériels physiquement actionnés par les machines.
- [51:19](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3079s) Historiquement, l'humanité n'a jamais substitué une énergie à une autre mais a empilé les sources : la consommation mondiale de charbon par habitant n'a jamais baissé depuis 1860 et croît beaucoup plus vite que les énergies renouvelables modernes.
- [02:18:18](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8298s) Le plafonnement puis le déclin de l'énergie par habitant depuis les chocs pétroliers des années 1970 a brisé le modèle de croissance de l'État-providence occidental, provoquant une explosion de l'endettement souverain et préfigurant la crise financière de 2008.
## Key takeaways
- [06:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=367s) Le 'raisonnement en camembert' induit en erreur : bien que l'énergie primaire ne représente que 2 à 5 % du PIB marchand, elle conditionne 100 % de l'activité productive des 95 à 98 % restants.
- [07:50](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=470s) En physique, l'énergie quantifie le changement d'état d'un système (vitesse, température, forme, composition chimique) ; consommer de l'énergie revient invariablement à altérer son environnement matériel.
- [15:09](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=909s) Une civilisation 100 % renouvelable correspond au passé historique de l'humanité, caractérisé par une population limitée à un milliard d'individus, une espérance de vie réduite et deux tiers de la population mobilisés dans les champs.
- [18:41](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1121s) La consommation d'énergie correspond au fonctionnement d'un gigantesque exosquelette de machines qui multiplie les capacités physiques de l'organisme humain.
- [28:40](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1720s) Un litre d'essence fournit un travail mécanique équivalent à 10 à 100 jours de labeur musculaire humain pour un coût monétaire marginal dérisoire par rapport au coût salarial du travail.
- [35:43](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2143s) L'hydrogène n'est pas une énergie primaire présente à l'état libre mais un vecteur énergétique dont la production par électrolyse consomme plus d'énergie qu'il n'en restitue.
- [37:57](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2277s) Les ressources primaires fournies par la Terre sont rigoureusement gratuites ; les prix payés sur les marchés ne rémunèrent que le travail humain d'extraction et les rentes des propriétaires du sous-sol.
- [44:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2647s) L'humanité a délaissé les énergies renouvelables au profit des combustibles fossiles en raison de leur densité énergétique supérieure et de leur caractère pilotable 24 h/24 sans dépendance météorologique.
- [01:00:06](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3606s) Chaque habitant de la planète commande en moyenne l'équivalent de 200 esclaves mécaniques (environ 600 en France) ; reproduire la production matérielle actuelle sans machines exigerait 1 400 milliards d'êtres humains.
- [01:05:48](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3948s) Les machines modernes puisent leur combustible dans le sous-sol, évitant ainsi le conflit historique d'usage des sols agricoles nécessaire jadis à nourrir les animaux de trait et les bûcherons.
- [01:07:09](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4029s) Les petits gestes individuels (éteindre une ampoule, installer des ruches sur un toit) ont un impact négligeable face aux flux macroscopiques que sont l'industrie lourde, les transports, l'alimentation carnée et le chauffage.
- [01:22:28](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4948s) La mécanisation et les engrais fossiles ont multiplié les rendements agricoles par 6 à 8 en Beauce, permettant l'exode rural et le transfert massif de la main-d'œuvre paysanne vers l'industrie et les services.
- [01:28:30](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=5310s) L'économie des services n'est pas immatérielle : le secteur tertiaire nécessite une abondance d'artefacts physiques et de flux de marchandises sous-jacents pour exister.
- [01:45:19](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6319s) L'énergie abondante et la voiture individuelle ont dicté l'étalement urbain horizontal, tandis que l'évolution démographique et les divorces augmentent le nombre de logements et d'équipements par personne.
- [02:09:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7747s) L'économie classique a commis une erreur fondamentale en posant comme axiome la gratuité et l'infinité de la nature (Jean-Baptiste Say), ignorant les stocks biophysiques et les auxiliaries mécaniques mis en lumière par Charles Dupin.
- [02:22:56](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8576s) L'approvisionnement en énergie par habitant dans l'Union européenne a culminé en 2006, deux ans avant la faillite de Lehman Brothers, faisant de la contrainte physique la racine de la crise économique de 2008.
- [02:31:35](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=9095s) Le changement climatique constitue le pot d'échappement en aval du flux de transformation matérielle industrielle, dont le goulot d'étranglement en amont reste la déplétion physique des ressources géologiques.
## Detailed walkthrough
### [00:13](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=13s) Introduction, Methodology, and the Power of Rules of Three
Jean-Marc Jancovici opens the course by introducing the two central subjects that will accompany the students throughout their personal and professional lives: energy and climate change. He clarifies his background immediately, stating that he is not a traditional academic researcher but a practitioner wearing several hats—a partner in a consulting firm (Carbone 4), the president of a think tank association (The Shift Project), and a public speaker involved in popularization and outreach. The lecture itself is built upon empirical observations, real-world data, and accessible, hands-on physical reasoning rather than abstract theoretical formalisms. He playfully remarks that the material is not fundamentally different from what he presents to general audiences who have not been rigorously filtered through the French *grandes écoles* competitive entrance exams, so the students at Mines ParisTech should have no trouble following along.
Before diving into the core material, Jancovici gives two practical recommendations. First, he strongly encourages taking handwritten notes, noting that even if the notes are thrown away afterward, the physical act of writing serves as an effective mnemonic tool. Second, he urges the students to adopt a mindset grounded in orders of magnitude and simple rules of three. He points out a structural bias in their academic training: elite engineering students are selected almost entirely on their ability to solve well-posed, univocal problems where all necessary data is given and exactly one clean solution exists. However, real life consists almost exclusively of ill-posed problems with missing, incomplete, or ambiguous information. In such an environment, sophisticated models frequently drift into absurdity if they lose touch with basic physics and rough estimates.
> “And everywhere in your life, if a sophisticated model is not in line with a well-established rule of 3, it is because the model is wrong!” — Jean-Marc Jancovici
- Speaker roles: consulting partner (Carbone 4), association president (The Shift Project), engineering lecturer.
- Target audience: engineering students at École des Mines de Paris, selected through competitive entrance exams (*concours*).
- Core cognitive warning: the vulnerability of high-level training that specializes in univocal, well-posed problems when confronted with open, ill-posed real-world crises.
---
[02:38](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=158s) Energy as an Economic Invoice: The Consumer Illusion and the Yellow Vests
Jancovici brings up Jean-Pierre Foucault—humorously describing him as “one of the most famous pensioners in France” who keeps returning to television—to invoke the format of the game show *Who Wants to Be a Millionaire?*. While the quiz show offers multiple-choice questions with predetermined answers, Jancovici asks the open question: “What is energy?” If one were to ask the average citizen or even the French Minister of Energy, the immediate answer would reflect the prevailing economic worldview: energy is viewed as an invoice, a utility bill, or an off-the-shelf commodity. Viewed through this narrow prism, the sole public debate revolves around whether energy is cheap or expensive, and how consumers might obtain the exact same convenience for less money.
He illustrates this mindset with the contemporary *Gilets Jaunes* (Yellow Vests) movement, which ignited over proposed increases in fuel taxes. The protesters did not take to the streets demanding a reduction in oil consumption to mitigate greenhouse gas emissions, nor did they express a desire to reduce French geopolitical dependence on oil exporters like Russia or Norway. Their grievance was purely transactional: fuel was simply too expensive. Jancovici emphasizes that evaluating energy primarily through this financial lens causes people to completely miss the fundamental nature of the problem.
Looking strictly at monetary figures, the purchase of primary fossil fuels—oil, gas, and coal—represents only a tiny fraction of global economic output. For an average French household or the broader economy, spending on energy amounts to just a few percent of total income or GDP, which is roughly comparable to what consumers spend on their monthly mobile and broadband bills across providers like Orange, SFR, or Free just to make trivial phone calls. Because energy appears as a mere line item representing two to five percent of total expenditure, society mistakenly assumes it warrants only a tiny fraction of political and intellectual attention.
> “So, the Yellow Vests never said: ‘We don't want to consume fuel because it's too much CO2’ or ‘We don't want to consume fuel because it makes us dependent on Russia, Norway and we don't want to.’ No, no. They were just saying: ‘It's too expensive.’” — Jean-Marc Jancovici
```mermaid
flowchart TD
accTitle: The Invoice Perception vs Reality
accDescr: Diagram contrasting the economic view of energy as a small cost with the political behavior it produces.
subgraph EconomicView["Economic & Public Perception"]
A["Energy treated as a commercial invoice / commodity"] --> B["Monetary cost is only ~2-5% of GDP or household budget"]
B --> C["Comparable in expenditure to monthly telecom bills"]
end
subgraph PoliticalOutcome["Political Reflex"]
C --> D["Marginalized during political debates (< 5% attention)"]
D --> E["Delegated to sector specialists / isolated minister"]
E --> F["Disconnected from pensions, diplomacy, and macroeconomics"]
end
```
---
[06:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=367s) The "Pie Chart" Fallacy: Essential Drivers vs. Monetary Value
Because energy constitutes only a small percentage of GDP, political leaders routinely treat it as a niche, peripheral topic. During election campaigns, politicians dedicate a few percent of their time to energy issues before delegating the portfolio to an isolated ministry, operating under the assumption that energy has no structural link to core topics like pensions, diplomacy, macroeconomics, or everyday industrial production. Jancovici exposes the fatal flaw in this “pie chart” thinking: breaking an economy into percentage slices tells you nothing about whether one slice is an absolute prerequisite for the survival of the others.
To highlight the absurdity of this logic, he offers two striking analogies. First, the human brain accounts for roughly 2% of total body weight; following pure pie chart logic, one could remove it and assume the person would merely suffer a minor 2% drop in overall efficiency. Second, agriculture represents only about 2% of modern GDP, leading some to assume the agricultural sector could be discarded without major consequence; however, if food production stops, the remaining 98% of the economy quickly ceases to function. In exactly the same way, the 95% to 98% of modern GDP that does not represent direct energy purchases is completely and structurally dependent on the continuous supply of that initial 2% to 5%.
> “What I'm going to tell you from now on is that this reasoning is as relevant as if I told you: ‘Your brain is 2% of your weight, so I can remove it from you, it's not very serious, you'll lose 2% in efficiency.’” — Jean-Marc Jancovici
- The Pie Chart Fallacy (*raisonnement en camembert*): conflating financial size with systemic dependency.
- Human brain analogy: 2% of total body mass, but completely controls and sustains bodily function.
- Agriculture analogy: ~2% of GDP, yet its elimination leads to total collapse of the other 98%.
- Macroeconomic reality: non-energy economic output (95-98% of GDP) is 100% physically reliant on the underlying energy flow.
---
[07:50](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=470s) Modern Civilization as Accumulated Energy, and Energy as a Physical Vector of Change
Jancovici addresses two other prevailing cultural narratives: the popular slogan that "the best energy is the energy we save," and the belief that the energy system will effortlessly become "100% renewable." He challenges the first idea by pointing out that the students sitting comfortably in a prestigious engineering lecture hall—free to listen or doze off rather than spending their days manually harvesting potatoes in a field—owe their entire standard of living and leisure to the massive, unprecedented surge in global energy consumption over the last two centuries. Modern industrial civilization was not forged by saving energy; it was built on a regime of accelerating energy abundance.
He then turns to the intuitive, everyday understanding of energy. When a person wakes up feeling "full of energy," it signifies a high capacity to act, overcome obstacles, and dictate their own destiny. In physics, energy represents the exact same thing on an environmental scale: it measures the capacity to transform one's physical surroundings. While formal physics provides various technical formulations, Jancovici offers a unified, operationally rigorous definition: energy is the physical quantity that quantifies the change of state of a given system. The more energy flows through an apparatus or society, the more the surrounding material world is modified, reshaped, and transformed.
> “In other words, the more the world around you changes, the more energy has come into play. And, the more energy that comes into play, the more the world around you changes. It's as simple as that.” — Jean-Marc Jancovici
- The potato-picking reality: modern education, intellectual work, and leisure exist because machine energy substituted for manual agricultural labor.
- Historical trajectory: two centuries of accelerating physical energy abundance, not systematic energy thrift.
- Human vitality metaphor: possessing personal energy equals having the agency to control one's destiny.
- Physical definition: energy is the precise physical quantity that quantifies the change of state of a system (modifying temperature, position, shape, chemical composition, or physical state of matter).
[10:19](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=619s) Energy as Transformation: Changing State, Speed, Shape, and Matter
Jean-Marc Jancovici explains energy through tangible, physical processes in everyday life. Fundamentally, any physical object that changes temperature—whether heating up or cooling down—uses or releases energy. Similarly, moving objects exist to change velocity: an automobile's sole functional purpose is to change the speed of its contents, carrying passengers and their holiday luggage from one place to another, which is a textbook alteration of a physical system's state. Shaping materials is another direct physical transformation. Digging soil moves it from a trench to an adjacent mound, and stamping a sheet of metal transforms a flat sheet into a finished car door; both actions are impossible without machines consuming energy.
Transformations extend down to the microscopic, chemical, and subatomic realms. Whenever a chemical composition changes, energy comes into play. The most immediate example is human digestion, which continuously breaks down ingested food precisely to provide the human body with usable chemical energy. At the electromagnetic level, interactions between magnetic fields and electric currents consume energy in electric motors or supply it in alternators. In nuclear physics, rearranging nucleons inside atomic nuclei releases vast power. Jancovici points out that the Sun operates as a massive, permanent thermonuclear fusion reactor, continuously fusing hydrogen nuclei into helium nuclei. Finally, energy governs matter-radiation interactions, ranging from the radiofrequency and light waves operating a smartphone to ultraviolet radiation on a beach.
“So, in a general way, using energy is nothing more than transforming the world around us and conversely, transforming the world around us necessarily implies that there is energy involved.”
- **Temperature change**: Heating and cooling systems exchange energy to alter thermal states.
- **Velocity change**: Transportation systems (such as cars) exist entirely to alter the speed and position of passengers and cargo.
- **Form/shape change**: Industrial stamping of sheet metal and civil excavation physically reshape matter using mechanical work.
- **Chemical rearrangement**: Digestion transforms dietary intake into metabolic fuel.
- **Nuclear rearrangement**: The Sun functions as a continuous thermonuclear fusion reaction converting hydrogen into helium.
[12:20](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=740s) The Eternal Energy Transition and the Inviolable Laws of Physics
Turning to policy and rhetoric, Jancovici addresses the modern concept of the “Ministry of Energy Transition.” He quips that such a department is actually the oldest institution in human history, given that humanity has existed in a perpetual energy transition for roughly 500,000 years. The journey began when our ancestors transitioned from relying solely on internal metabolic energy to domesticating fire, securing our first extracorporeal energy source. Antiquity witnessed the harness of renewable energies (wind, water, and draft animals) alongside minor uses of fossil fuels, such as oil usage by the Sumerians and coal extraction by ancient Chinese societies. The Industrial Revolution marked the explosive scaling of fossil fuel exploitation. Human history has always been characterized by adopting any newly discovered energy source; what makes the contemporary era precarious is not the fact of transition, but the extreme, unprecedented leap in order of magnitude within a historically minute window of time.
Because energy is a physical quantity, it obeys strict natural laws that human desire and legislation cannot alter. Jancovici dryly contrasts parliamentary politics with physics: while politicians might wish to amend Maxwell's equations to bolster consumer purchasing power, physical laws do not bend to parliamentary votes. The foundational rule governing energy is the first principle of thermodynamics—the law of conservation of energy. Applied to society, this rule dictates that humans can never create energy from scratch; we can only extract preexisting energy from the surrounding environment and channel it toward our needs.
“The energy conservation law applied to humans has a consequence that is simplistic, which is that humans can do nothing more than extract from the environment an energy that already exists and use it for their benefit.”
[15:09](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=909s) Primary vs. Final Energy and the Historical Converters
To examine energy flows, technical vocabularies distinguish between “primary energy” and “final energy.” Primary energy refers to energy as it exists in its natural state within the environment (such as crude oil in the ground, blowing wind, or raw sunlight). Final energy represents the refined product that crosses the consumer's meter—such as the natural gas or electricity supplied to a residence, heating oil pumped from a delivery truck into a domestic tank, or natural gas fed into an industrial glassmaking furnace. Converting primary sources into work requires a converter. For early humans, the sole available converter was the human body itself, which converted ingested food and ambient solar heat into an abundance of body heat and a modest quantity of mechanical work.
```mermaid
flowchart LR
accTitle: Historical Progression of Energy Converters
accDescr: Diagram tracing humanity's shift from biological converters to renewables and fossil-fueled machines.
subgraph S2["Mechanical Renewables"]
C["Water & Wind Mills<br/>(Natural Kinetic Flows)"]
end
subgraph S3["Industrial Era"]
D["Metal Machines<br/>(Fossil Fuels)"]
end
A --> B
B --> C
C --> D
```
Over time, human societies domesticated external converters. Initially, these consisted of renewable living systems, including draft animals eating renewable grass, as well as enslaved populations. Later, societies developed wooden waterwheels and windmills across ancient and medieval Europe. Jancovici emphasizes that a 100% renewable society is not an untried futuristic fantasy, but our documented historical baseline: three centuries ago, humanity ran entirely on renewable energy. However, that society supported roughly one billion people, suffered a life expectancy at birth of only 30 to 40 years, and required two-thirds of the population to work long hours in agricultural fields. The open question is whether a high-tech modern civilization, equipped with engineering schools and complex industrial infrastructure, can sustain itself exclusively on renewable sources.
“So, it must be clear that renewable energies are not the future, they are the past.”
- **Primary energy**: Energy harvested directly from the natural environment before any human processing or transformation.
- **Final energy**: Energy measured at the end-user's meter (residential electric and gas meters, fuel delivery truck flow meters, industrial burners).
- **Historical 100% renewable baseline**: Supported approximately 1 billion people worldwide with a 30–40 year life expectancy and two-thirds of the labor force tied to manual agriculture.
- **Industrial breakthrough**: Occurred roughly two centuries ago when physicists and engineers coupled metal machinery to fossil energy reserves.
[18:41](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1121s) The Illusion of "Energy Consumption": Machines as an Exoskeleton
Jancovici challenges the standard terminology of “energy consumption.” Unless one counts food intake, human beings do not physically consume energy. People do not drink crude oil, chew on industrial coal (save for medicinal charcoal tablets used to treat digestive flatulence), or breathe methane gas. Consequently, speaking of energy consumption creates an optical illusion that hides the underlying physical reality. In practice, consuming energy simply means operating machines. Whenever economic literature notes that humanity is consuming more energy, the phrase should be translated directly to: we are deploying more machines.
This vast network of motorized tools forms an enormous mechanical exoskeleton attached to modern humanity. Jancovici illustrates this omnipresence using the simple act of getting dressed in the morning. Putting on a pair of pants and a shirt takes merely a few seconds—or perhaps a few tens of seconds if one is waking up clumsy, in the dark, or recovering from a night out. Yet, in those fleeting seconds, an individual mobilizes the output of thousands of industrial machines operating around the world, from automated agricultural harvesters and petrochemical processing plants to spinning mills, automated looms, and international transport fleets.
“And in fact, the increasing amount of energy we use is nothing more than how to increase proportionally the huge mechanical exoskeleton we have created for our profit.”
[20:39](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1239s) L'armée invisible des machines dans notre quotidien : vêtements et brossage de dents
Pour illustrer l'omniprésence du parc de machines qui travaillent pour nous sans que l'on s'en rende compte, Jean-Marc Jancovici décortique les gestes les plus anodins d'une matinée ordinaire. Il commence par le simple fait de s'habiller. Si l'on porte un vêtement en textile naturel (coton, lin), on mobilise en amont tous les engins agricoles qui ont semé, récolté et égrené la fibre. Si l'on enfile un t-shirt ou un sous-vêtement en fibres synthétiques (« poly-quelque chose », nylon), tout provient du pétrole. En portant ce vêtement, on a en réalité revêtu « un morceau de plateforme pétrolière plus un morceau de vapocraqueur plus un morceau de raffinerie », ces installations industrielles colossales valant plusieurs milliards de dollars. S'y ajoutent les machines à tisser, la chimie des teintures pour tout ce qui n'est pas écru, les usines d'assemblage, les centrales électriques pour alimenter ces processus, et toute la logistique de transport (camions, trains, avions). Jean-Marc Jancovici résume l'ampleur du phénomène: « Dans quelque chose de totalement trivial qu'on fait comme on respire – qui s'appelle enfiler un vêtement –, eh bien vous ne vous en rendez pas compte, mais il y a une armée de machines qui ont travaillé pour vous, juste avec ce geste simplissime. »
Le rituel se poursuit avec l'hygiène bucco-dentaire après le petit-déjeuner. Un geste d'une à trois minutes mobilise lui aussi une infrastructure industrielle gigantesque. Jancovici montre l'image d'une usine chimique du nord de la France, appartenant au groupe familial Roquette. Cette amidonnerie reçoit chaque jour un train complet de maïs pour produire des centaines de dérivés chimiques, parmi lesquels le sorbitol. Ce substitut de sucre, indispensable pour donner un goût agréable au dentifrice sans provoquer de caries, est fabriqué sur un site employant plusieurs milliers de personnes fonctionnant en 3×8, l'une des plus grandes usines chimiques du pays. Le tube lui-même exige du pétrole, une raffinerie, un vapocraqueur et une extrudeuse industrielle. Enfin, se regarder dans la glace nécessite une ligne de verre flotté (*float*), tandis que se rincer la bouche suppose des stations de traitement et de purification d'eau potable.
```mermaid
flowchart TD
accTitle: Flux d'énergie et machines derrière les gestes du quotidien
accDescr: Chaîne de transformation industrielle mobilisée pour des vêtements et un dentifrice.
subgraph Amont["Ressources & Extraction"]
Petrole["Pétrole brut / Agriculture"]
Mines["Mines / Silos de maïs"]
end
[24:11](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1451s) Le smartphone et l'illusion du coût économique de l'énergie
Jean-Marc Jancovici aborde ensuite l'objet central de la vie contemporaine: le smartphone. Passer un coup de fil ne repose pas seulement sur un petit boîtier, mais sur des milliers de machines actives en coulisses. Un smartphone renferme à lui seul une quarantaine de métaux différents, souvent à des concentrations très faibles, impliquant des dizaines de mines et d'excavatrices réparties sur le globe, en plus des plastiques, de la silice et de l'eau ultra-pure pour l'électronique. À cela s'ajoute l'infrastructure de réseau: sans les antennes relais (qui demandent de l'acier), sans les câbles souterrains ou sous-marins déroulés par des engins spécialisés, l'appareil ne servirait à rien.
Revenant sur l'argument économique classique selon lequel l'énergie ne représenterait qu'une part négligeable (environ 3 %) du produit intérieur brut (PIB), Jancovici démonte la logique du raisonnement monétaire. Si l'on privait instantanément la Terre de son énergie, on ne perdrait pas 3 % de notre production, mais absolument tout: les transports, les banques, les réseaux d'eau potable, les hôpitaux s'arrêteraient immédiatement. Il prévient sans détour: « Vous allez crever de faim, vous allez crever de froid et vous allez vous entre-tuer. » L'énergie conditionne l'intégralité de l'activité humaine mécanisée, et juger de son importance vitale par son seul coût financier relève d'une profonde incompréhension systémique: « Tout le monde moderne dépend d'elle et qu'elle coûte 1 % ou 100 % de ce que vous gagnez n'est pas tellement le sujet. »
- Un smartphone concentre environ 40 métaux distincts extraits par des engins miniers à travers le monde.
- La dépendance aux réseaux (télécoms, eau, banques, hôpitaux) rend tout fonctionnement moderne impossible sans flux énergétique continu.
Pour quantifier ces grandeurs dans la suite du cours, Jancovici passe en revue les unités de mesure physiques. Même si le Joule est l'unique unité officielle enseignée aux concours d'entrée comme celui de Mines ParisTech, son utilisation quotidienne conduirait à manipuler des nombres avec un nombre excessif de zéros. Pour rendre les chiffres digestes, on recourt à des unités plus compactes.
Le passage au kilowatt-heure (kWh) permet de supprimer d'emblée six zéros par rapport au Joule ($1\text{ kWh} = 3{,}6\times 10^6\text{ J}$) et correspond aux factures courantes. À l'échelle individuelle, en tenant compte des biens importés (l'énergie grise consommée hors des frontières pour fabriquer les objets « faits ailleurs », comme le smartphone), un Français consomme aujourd'hui environ 60 000 kWh par an, tous usages confondus. Les compagnies énergétiques utilisent quant à elles la tonne équivalent pétrole (tep), qui efface encore quatre zéros supplémentaires. Définie comme l'énergie libérée par la combustion d'une tonne de pétrole d'une qualité moyenne donnée, elle équivaut à environ 11 600 kWh. Jancovici mentionne au passage les unités anglo-saxonnes souvent incompatibles avec le système métrique, ainsi que l'électron-volt pour la physique nucléaire, avant d'introduire une métaphore centrale: « l'équivalent-esclave ».
- **Joule (J)**: unité du Système International, peu pratique à l'échelle macroéconomique en raison de la profusion de zéros.
- **Kilowatt-heure (kWh)**: $3{,}6\times 10^6\text{ J}$; consommation moyenne d'un Français: environ 60 000 kWh/an (usages directs et importations inclus).
- **Tonne d'équivalent pétrole (tep)**: pouvoir calorifique de référence d'une tonne de pétrole moyen, valant environ 11 600 kWh.
- **Équivalent-esclave**: défini comme environ 100 kWh d'énergie mécanique par an.
[28:40](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1720s) La puissance mécanique humaine comparée à un litre de pétrole : la notion d'équivalent-esclave
Afin d'ancrer physiquement la valeur d'un kilowatt-heure mécanique, Jancovici interroge la salle sur l'effort nécessaire pour monter au sommet de la tour Eiffel. Si une personne grimpe l'équivalent de 6,3 fois la tour Eiffel dans sa journée (soit gravir un dénivelé positif d'environ 2 000 mètres), le travail mécanique produit par ses jambes ($E = m \cdot g \cdot h$) n'atteint que 0,5 kWh. C'est l'effort maximal que peut fournir un ouvrier robuste pédalant toute la journée, à l'image du film *Soleil vert* (*Soylent Green*) avec Charlton Heston. Réalisé un jour sur deux (l'équivalent de trois ascensions de la tour Eiffel chaque matin), ce travail musculaire produit à peine 100 kWh d'énergie mécanique sur l'ensemble d'une année de labeur: « Sur un an de travail, la carcasse d'un homme raisonnablement entraîné est capable de fournir environ une centaine de kilowatt-heures d'énergie mécanique si il utilise ses jambes. »
Le constat est encore plus sévère lorsqu'on sollicite le haut du corps. Déplacer 6 mètres cubes de terre à la pelle en une journée (environ 15 tonnes) ne libère que 0,05 kWh de travail mécanique utile: les bras sont dix fois moins puissants que les jambes, totalisant péniblement une dizaine de kWh au bout d'un an de travail quotidien. En face, un simple litre d'essence (vendu autour de 1,60 € à la pompe) contient 10 kWh d'énergie thermique. Brûlé dans un moteur thermique de voiture avec un rendement standard de 20 % à 40 %, ce litre délivre 2 à 4 kWh de travail mécanique pur. Ce rendement modeste ne dépend d'ailleurs pas des ingénieurs motoristes, mais du point de fonctionnement du véhicule sous la conduite de l'automobiliste. Ainsi, un minuscule volume de carburant fossile accomplit instantanément le travail de plusieurs semaines ou mois de labeur humain manuel.
| Type d'effort / Carburant | Énergie mécanique par jour | Énergie mécanique par an |
|:--- |:--- |:--- |
| **Paire de bras au travail** (terrassement, ~15 t/jour) | ~0,05 kWh | ~10 kWh |
| **Paire de jambes au travail** (dénivelé ~2 000 m/jour) | ~0,5 kWh | ~100 kWh (1 « esclave mécanique ») |
| **1 litre d'essence** (10 kWh thermiques, moteur 20-40 %) | 2 à 4 kWh mécaniques | — |
[32:27](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=1947s) The Economic Imbalance Between Human Labor and Machine Power
Jean-Marc Jancovici highlights the staggering disparity between the physical work a human body can deliver and the work extracted from fuel-powered machines. One liter of gasoline represents the equivalent physical work capacity—the power to alter the physical environment—of 10 to 100 days of strenuous human labor. Translating this physical reality into economic terms reveals why industrial civilization organized itself around fuel. To obtain one kilowatt-hour of mechanical work from human muscle, an employer must pay several hundred to several thousand euros in wages. By contrast, a machine powered by liquid fuel provides the exact same physical service for an operating cost of a few tens of cents, completely ignoring the sunk cost of the hardware.
This dramatic cost divergence explains why automation and mechanization have been systematically pursued across every sector of the modern economy. Whenever a factory worker or assembly-line operator can be substituted with an industrial robot, or an agricultural laborer with a tractor, the economic incentive to do so is overwhelming. By transitioning from human muscle to motorized machinery, the unit cost of modifying the physical world was divided by a factor of hundreds or even thousands.
- 1 liter of gasoline equals the mechanical work of 10 to 100 days of human labor using arms or legs.
- Human mechanical work costs roughly several hundred to a few thousand euros per kWh.
- Machine mechanical work costs on the order of a few tens of cents per kWh (marginal fuel cost).
- Cost reduction factor for physical transformation: roughly divided by 100 to 1,000+.
[34:09](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2049s) The Machine as the Economic Driver Behind the Abolition of Slavery
Expanding on this mechanical substitution, Jancovici argues that the exact same economic calculus drove the historical abolition of slavery. While modern sensibilities rightly view the slave trade as deeply immoral, societies historically engaged in it purely for economic gain. However, holding human beings in bondage carries massive overhead: capturing them against their will, guarding against escapes, suppressing rebellions, providing food, and managing inevitable resistance. Even with minimal subsistence, forced human labor remained 10 to 100 times more expensive than deploying mechanical power.
Unlike human laborers, machines harbor no resentment toward their condition, do not attempt to escape, never unionize or strike, and operate continuously 24 hours a day. Jancovici remarks that societies did not abandon slavery because the human genetic code underwent a moral mutation over the last two or three centuries, but because fossil-fueled machines offered a vastly superior, cheaper, and less troublesome alternative. As he bluntly summarizes: “So, what freed the slaves was oil.”
[35:43](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2143s) Primary Energy vs. Energy Vectors: The Hydrogen Fallacy
Moving to preliminary conceptual conclusions, Jancovici stresses that utilizing energy requires that energy to already exist in a usable, primary state within the environment. Public policy debates frequently suggest transitioning toward hydrogen as an energy source, but Jancovici dismisses this as a fundamental misunderstanding of physics. The universe contains vast quantities of elemental hydrogen, but the most accessible store is the sun, which is impractical to harvest directly. On Earth, hydrogen does not exist freely as a primary fuel; it is chemically bound into water molecules ($H_2O$) or living organic matter.
Harvesting this hydrogen requires breaking chemical bonds through processes like electrolysis, which invariably consumes more external energy than the resulting hydrogen combustion can ever deliver. Consequently, hydrogen is an energy vector, not a primary energy source. Similarly, fuel cells are merely electrochemical engines, not fuel sources. When assessing potential alternatives to existing primary fuels, analysts must strictly evaluate other genuine primary energies—sources naturally occurring and directly extractable from the physical world.
```mermaid
flowchart LR
accTitle: Primary Energy vs Energy Vectors
accDescr: Flowchart illustrating that primary energy comes directly from nature, whereas energy vectors require net external energy input to manufacture.
subgraph Primary["Primary Energy Sources"]
Nat["Direct Environmental Stock<br/>(Oil, Coal, Gas, Solar, Wind)"]
end
subgraph Vectors["Energy Vectors (Not Sources)"]
Elec["Electrolysis of Water"]
H2["Hydrogen Molecule (H₂)"]
Engine["Fuel Cell / Engine"]
end
- Primary energy must exist naturally in an unbound or directly usable form in the environment.
- Earth’s hydrogen is entirely locked in chemical bonds (e.g., water, hydrocarbons).
- Electrolysis requires strictly more energy to produce hydrogen than its subsequent combustion yields.
- A fuel cell is an energy converter/engine, not a primary energy source.
[36:52](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2212s) The Myth of "Clean" or "Green" Energy
Because energy serves as the physical metric of material transformation, Jancovici contends that terms such as "green energy," "pink energy," or "black energy" are physical non-sequiturs. Selecting an energy system means choosing a specific category of environmental alteration, complete with its unavoidable trade-offs and physical side effects. Every form of energy becomes destructive and polluting once deployed at sufficient scale.
Jancovici points out that if the surface of the planet were covered entirely with photovoltaic panels, solar power would instantly cease to be benign. In public discourse, an energy source is labeled "clean" solely when its current scale of deployment remains so negligible that its associated environmental damage has not yet become disruptive. Once any extraction method scales up to satisfy industrial demands, massive physical drawbacks emerge: “And choosing an energy means choosing between the disadvantages you want and those you don't want.”
[37:57](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2277s) Nature's Free Gift: Paying Only for Human Labor and Rent
A foundational physical principle that Jancovici emphasizes is that energy in nature is entirely free. While renewable advocates frequently declare that the wind and the sun are free, the exact same reality applies to fossil fuels. No human being or corporation paid nature a single cent to manufacture crude oil inside the Earth's crust millions of years ago.
The monetary cost paid at the pump or on an electricity bill reflects only two components: human labor and economic rents. Buyers pay for the labor of geologists, engineers, and workers—such as graduates who go to work for Total drilling boreholes—and they pay the rent demanded by resource-owning sovereigns who happen to sit atop the deposits. Nature itself never issues an invoice: “You've never seen nature send an invoice to anyone.”
- Energy in nature (sunlight, wind, crude oil, coal) is 100% free of charge.
- Financial transactions for energy remunerate exclusively human labor and territorial rents.
- Raw resource prices reflect human extraction effort and geopolitical bargaining, not natural manufacturing costs.
[39:23](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2363s) Energy Density, Intermittency, and the Cost Gap Between Wind and Oil
Energy prices are governed by physical constraints rather than raw universal abundance. Cosmic background radiation at 3 Kelvin is omnipresent across the void of space, yet its extreme diffusion renders it impossible to exploit. What dictates the real-world extraction cost of an energy source is its native physical concentration and the height of the physical barriers standing between human extractors and the reservoir. Historically, Edwin Drake struck oil in Titusville by drilling shallow holes, unleashing a hyper-dense, pressurized liquid.
To demonstrate the penalty imposed by low energy density, Jancovici compares wind power to crude oil. A volume of 1,000 cubic meters of air (roughly equivalent to a 10-meter cube, resembling the lecture hall) moving at 80 km/h—a severe southern French mistral or a 45-knot maritime gale—passing through a wind turbine generates an amount of electricity strictly equivalent to burning a mere 3 milliliters of crude oil. Drilling a hole in the Saudi desert to extract 3 milliliters of liquid is vastly simpler and demands far less human labor than manufacturing, erecting, and maintaining massive steel wind turbines to sweep diffuse, low-density air (1.2 kg per cubic meter).
Furthermore, crude oil represents an already concentrated, physical store of energy available on demand at any hour. By contrast, a wind turbine only produces when the weather cooperates; without wind, projectors turn off, subways stop running, parties are canceled, refrigerators cannot chill beer, and electric alarm clocks fail. Overcoming this intermittency requires grid-scale energy storage, which inflates wind electricity costs from 6–8 cents per kilowatt-hour up to several tens of cents per stored kilowatt-hour (a multiplier of 3 to 6). In stark contrast, a stored kilowatt-hour of Saudi crude oil straight from the wellhead costs approximately 0.3 cents—a factor of roughly 100 between diffuse intermittent wind with storage and concentrated natural oil stocks:
| Energy Vector / Source | Physical Density / State | Usability / Reliability | Estimated Marginal Cost per Stored kWh |
|:--- |:--- |:--- |:--- |
| **Saudi Crude Oil** | Highly concentrated liquid hydrocarbon; pre-existing geological stock. | Dispatchable 24/7; immediate use or transport anywhere, anytime. | ~0.3 euro cents |
| **Wind Power (Direct)** | Diffuse kinetic energy (air density: ~1.2 kg/m³). | Intermittent; operates only when wind blows (6–8 cents/kWh unstored). | N/A (unstored) |
| **Wind Power (with Storage)** | Diffuse kinetic converted to electricity + chemical/mechanical storage. | Dispatchable via backup systems, multiplying direct costs by 3× to 6×. | Several tens of euro cents |
Jancovici concludes by reminding the students that all current infrastructure for harvesting diffuse renewable flows—including the manufacturing and deployment of wind turbines—is itself built from scratch using abundant, cheap oil.
[44:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2647s) Pourquoi l'humanité a délaissé le renouvelable pour le fossile
L'idée selon laquelle les énergies renouvelables modernes constituent un système autonome et vertueux néglige une réalité matérielle fondamentale: le système actuel n'est pas une boucle fermée. Pour fabriquer une éolienne moderne, il est indispensable de s'appuyer sur une infrastructure industrielle lourde et hautement performante. Cette dernière extrait le cuivre, la bauxite et le minerai de fer des mines, assure la métallurgie en amont, transforme les composants, les achemine sur site et coule des socles massifs en béton. L'intégralité de ce cycle industriel repose sur les combustibles fossiles. Jean-Marc Jancovici souligne avec ironie qu'il n'est absolument pas garanti que le coût de l'électricité éolienne resterait entre 6 et 8 centimes d'euro le kilowattheure si l'ensemble de cette chaîne devait être alimenté uniquement par d'autres éoliennes. Même en bénéficiant du soutien massif des hydrocarbures, il subsiste un rapport de plusieurs dizaines à un facteur cent entre l'énergie investie et le kilowattheure obtenu entre le vent et un puits de pétrole conventionnel facile d'accès.
Historiquement, les sociétés humaines n'ont jamais opéré de transition spontanée du fossile vers le renouvelable; elles ont fait rigoureusement l'inverse. Il y a deux siècles, la marine mondiale était 100 % renouvelable, propulsée par le vent, ce qui imposait d'embarquer des citrons à bord pour prémunir les équipages du scorbut lors de traversées interminables. Pour importer rapidement des t-shirts Zara confectionnés à l'autre bout de la planète, une marine propulsée au fioul lourd s'est révélée incomparablement plus rapide et efficace. De même, les transports à traction animale ou à pied, l'agriculture biologique d'antan, le génie civil à bras d'homme et l'artisanat préindustriel étaient intégralement renouvelables. Or, cette organisation imposait un siècle pour bâtir la cathédrale Notre-Dame, des siècles pour ériger les pyramides d'Égypte, et un labeur agraire épuisant qui empêchait les enfants de paysans d'aller à l'école. Pour Jean-Marc Jancovici: “Précisément parce que les caractéristiques physiques des combustibles fossiles sont supérieures aux caractéristiques physiques des énergies renouvelables, l'Homme, qui est un animal accumulateur, a passé son temps à passer des énergies renouvelables aux combustibles fossiles, pour pouvoir accumuler plus vite.”
L'illusion contemporaine consiste à croire que l'on pourra effectuer le chemin inverse sans toucher au niveau de vie des populations, sous prétexte qu'une promesse politique l'affirme. Jean-Marc Jancovici propose une règle d'évaluation simple face aux affirmations gratuites: “Est-ce que j'accepterais de parier toutes les économies de mes parents sur ce que je suis en train de raconter?” Si le moindre doute persiste, c'est que la démonstration sous-jacente n'est pas solide. Le monde entièrement renouvelable n'est pas une utopie futuriste inconnue, mais précisément le monde de contraintes sévères dont l'humanité s'est extraite au XIXe siècle. Réduire notre empreinte est une nécessité physique, mais il est rigoureusement impossible de maintenir une consommation matérielle constante pour plus de sept milliards d'êtres humains avec ces seules sources.
```mermaid
flowchart LR
accTitle: Transition historique des énergies renouvelables vers les combustibles fossiles
accDescr: Diagramme montrant le passage d'une société renouvelable limitée à une société fossile hautement productive, soulignant l'impossibilité d'un retour à niveau de vie constant.
subgraph Passe["Monde préindustriel (100 % renouvelable)"]
direction TB
R1["Marine à voile<br/>(lente, scorbut)"]
R2["Agriculture manuelle<br/>(faible productivité)"]
R3["Artisanat et bois<br/>(temps séculaires)"]
end
subgraph Moteur["Facteur d'accumulation"]
direction TB
FOSS["Combustibles fossiles<br/>(Charbon, Pétrole, Gaz)<br/>Densité énergétique massive"]
end
subgraph Present["Monde thermo-industriel"]
direction TB
P1["Marine marchande fioul<br/>(flux mondialisés rapides)"]
P2["Tracteurs et chimie<br/>(enfants scolarisés)"]
P3["Infrastructures béton/acier<br/>(tours, routes express)"]
end
Passe -->|"Recherche d'efficacité physique"| Moteur
Moteur -->|"Accélération de la production"| Present
Present -.->|"Transition inverse sans baisse de niveau de vie: ILLUSION"| Passe
```
[48:05](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2885s) La puissance des machines modernes : des milliers d'esclaves mécaniques
En passant de la notion d'énergie à celle de puissance, l'ampleur de la démultiplication mécanique apparaît de manière éclatante. La puissance moyenne développée par un être humain au travail se situe entre 10 et 100 watts (soit 0,05 à 0,5 kWh restitué sur une journée d'effort). En comparaison, un tracteur agricole standard ou un engin de chantier développe plusieurs dizaines à une centaine de kilowatts. Une pelleteuse de 100 kW sur un chantier équivaut mécaniquement à plusieurs centaines de paires de jambes ou plusieurs milliers de paires de bras travaillant de concert. Grâce à cet « exosquelette » mécanique offert par l'énergie fossile, la productivité du travailleur agricole a été multipliée par plusieurs centaines sans qu'il ait besoin, tel le dieu Shiva, de développer des dizaines de membres. C'est également cette mécanisation généralisée — incluant cimenteries, camions et grues — qui rend possible la construction d'un logement individuel pour l'équivalent de quelques années de salaire moyen, une réalité inconcevable il y a deux ou trois siècles.
Les moyens de transport et les infrastructures industrielles modernes illustrent ce saut d'échelle vertigineux:
- Un camion développe une puissance motrice équivalant au pédalage simultané de plusieurs milliers de personnes à la place du conducteur.
- Un avion de ligne fournit une puissance équivalente aux jambes d'un million de cyclistes pour assister le pilote aux commandes.
- Un train de laminoir industriel, tel que celui du site sidérurgique d'ArcelorMittal à Fos-sur-Mer, écrase et lamine l'acier avec une force mécanique qu'il serait impossible de reproduire sans mobiliser l'ensemble de la population de l'Île-de-France munie de marteaux.
- Un vapocraqueur en pétrochimie remplace à lui seul l'effort de plusieurs millions de bras pour transformer la matière organique.
Jean-Marc Jancovici rappelle ainsi brutalement la dépendance de nos modes de vie à ces flux: “Juste pour remplacer le laminoir de Fos-sur-Mer, si on n'avait pas d'énergie, vous ne seriez pas en train d'écouter ce cours en ce moment, vous seriez en train de taper sur des tôles avec un marteau.” L'énergie n'est rien d'autre que la mesure de cette transformation physique, rendue opérationnelle par des convertisseurs qui ont cessé d'être nos propres corps biologiques pour devenir un gigantesque parc de machines.
[51:19](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3079s) L'essor continu du charbon et le mur climatique
Historiquement, l'énergie primaire exploitée par l'humanité reposait sur la biomasse. Vers 1860, un être humain consommait en moyenne environ 5 000 kWh de bois par an pour se chauffer, cuisiner, alimenter de petites forges et faire tourner les toutes premières machines à vapeur. L'utilisation massive du bois dans la métallurgie primitive a d'ailleurs représenté un facteur majeur de déforestation sur le continent européen. Depuis le milieu du XIXe siècle, la consommation de bois par habitant a décliné à l'échelle mondiale — c'est la seule énergie dans ce cas —, même si la consommation brute globale est restée significative. Pour pallier la raréfaction du charbon de bois, les sociétés se sont tournées vers la houille, appelée couramment charbon de terre, décuplant ainsi la puissance de la sidérurgie et de l'industrie naissante.
L'analyse des séries statistiques depuis 1860 révèle une réalité contraire aux idées reçues: la quantité de charbon brûlée par habitant sur Terre n'a jamais diminué. Elle s'établit aujourd'hui autour de 5 000 kWh par personne et par an. Le charbon n'a jamais représenté une énergie du passé; il constitue au contraire le socle masqué de la mondialisation moderne. Chaque bien de consommation estampillé « Made in China » est en réalité façonné à partir d'électricité et de chaleur dérivées du charbon, alimentant directement l'empreinte carbone des consommateurs occidentaux.
La structure globale des usages du charbon se décompose de manière très nette:
- Les deux tiers (environ 67 %) de la production mondiale de charbon sont brûlés dans des centrales thermiques pour produire de l'électricité.
- Environ 10 % sont constitués de charbon à coke (très riche en carbone), indispensable à la réduction du minerai de fer en sidérurgie.
- Le solde (environ 23 %) alimente des réseaux de chaleur urbains, le chauffage domestique ou des processus industriels variés.
Tandis que la France débat vivement de ses 60 gigawatts (GW) de puissance nucléaire civile, le parc mondial de centrales à charbon atteint environ 2 000 GW, soit 30 à 40 fois la capacité nucléaire française. Or, respecter l'Accord de Paris et contenir le réchauffement global sous la barre des 2 °C impose une contrainte arithmétique impitoyable: l'intégralité de ces 2 000 GW de centrales à charbon en service dans le monde devra avoir totalement disparu avant que la jeune génération d'étudiants n'atteigne la soixantaine.
[55:28](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3328s) Oil as the Queen of Mobility and the Non-Substitution of Energies
Jean-Marc Jancovici points out an undeniable reality displayed on the global consumption curve: humanity has never replaced one primary energy source with another. Oil did not substitute for coal; rather, per capita oil consumption was purely stacked on top of existing coal consumption. This non-substitution arises because different energy sources perform fundamentally different tasks. Coal powered heavy industry, metallurgy, and early stationary power, whereas oil rapidly established itself as the undisputed master of mobility. Liquid at room temperature and possessing an unmatched energy density per unit volume, oil solved the primary constraint of transport: carrying an autonomous energy supply on board.
```mermaid
flowchart LR
accTitle: Energy Addition Over Time
accDescr: Historical progression showing energy sources being stacked rather than substituting each other.
subgraph Stacking["Historical Energy Stacking"]
direction TB
C["Coal (Industry / Power)"]
O["Oil (Transport / Mobility)"]
G["Gas & Hydro"]
N["Nuclear & Renewables"]
C --- O --- G --- N
end
Stacking --> RES["Result: 20,000 kWh/person/yr<br/>(200 Energy Slaves)"]
```
To illustrate why oil came to dominate the transport sector, Jancovici dispels the misconception that the internal combustion engine is technologically or thermodynamically superior. The first automobile to cross the 100 km/h barrier was actually an electric vehicle (*La Jamais Contente*), and electric motors boast an energy efficiency three to four times higher than internal combustion engines. Despite this intrinsic thermodynamic superiority, oil won completely because electrical storage is heavy and cumbersome, making mobile autonomy far more difficult to achieve with batteries. As a consequence of oil's physical transportability, roughly 98% of all vehicles that roll, fly, or sail worldwide run on petroleum fuels today. As Jean-Marc Jancovici puts it:
> “So, it is not because the oil engine is intrinsically superior that it supplanted the electric motor in the competition that took place a century ago: it is because with electricity you have much more difficulty to take with you the energy that allows you to be autonomous.”
- **Transport reliance:** Today, 98% of everything that rolls, flies, or sails relies on oil products.
- **Motor efficiency:** Electric motors have an efficiency 3 to 4 times greater than petroleum engines.
- **Historic milestone:** The first automobile to exceed 100 km/h was an electric car.
---
[57:14](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3434s) The Reality of the Oil Shocks: The End of an Expanding World
Turning his attention to the historical break occurring during the 1970s, Jancovici examines the oil shocks. Conventional collective memory remembers these shocks merely as transient financial events: prices skyrocketed, then plummeted back down, leading people to dismiss the episode as a temporary market fluctuation. However, Jancovici stresses that price movements are only "the foam on the surface of the wave." The foundational, physical reality of the oil shocks was a permanent shift in resource availability: it marked the sudden, violent halt to the exponential growth of oil available per person on Earth.
Before the 1970s, global oil supplies were expanding rapidly in both absolute and per capita terms. The shocks shattered that upward trajectory: oil availability per human being leveled off, ceased its climb, and entered a structural plateau before stabilizing and declining. This inflection point signified the close of an era of effortless physical expansion for industrial economies. As Jean-Marc Jancovici summarizes:
> “The major feature of the oil shock is that it is the end of a rapidly expanding world.”
---
[58:15](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3495s) Gas, Nuclear, and the Optical Illusion of New Renewables
Following oil, natural gas entered the global energy system, yet again repeating the pattern of addition rather than substitution. Hydroelectricity and nuclear power were sequentially added to the mix. In modern public discourse, attention has shifted almost exclusively toward "new renewable energies" (predominantly wind and solar). However, Jancovici highlights the dramatic mismatch between the omnipresent media coverage these energies receive and their actual physical footprint in the per capita global energy supply.
Jancovici explains that in generating this chart, he intentionally chose the most generous accounting convention possible for non-thermal electricity: the primary energy equivalent convention. In traditional thermal power plants (Carnot machines burning coal, gas, or fissioning uranium), heat is converted into mechanical work with an efficiency governed by the Carnot formula $1 - T_2 / T_1$, discarding significant waste heat. Under the primary equivalent method, direct electricity from wind, solar, and hydro is scaled up to the amount of thermal energy that would have been required to produce that same electricity in a conventional thermal plant. Even with this generous boost, new renewables represent a sliver of per capita consumption. As Jean-Marc Jancovici observes:
> “Nevertheless, you can see that today, it is something that has much more space in the newspaper's pagination than it does in the actual consumption of energy in the world; and you will soon see that not only is it true in absolute terms, but unfortunately it is also true in terms of dynamics.”
---
[01:00:06](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3606s) The 200 Energy Slaves, Modern Supermen, and Economic Disconnect
Quantifying humanity's physical transformation, Jancovici calculates that the average global citizen mobilizes approximately 20,000 kWh per year of extracorporeal energy through the industrial machine park. Comparing this mechanical output to what human muscles can deliver yields a staggering ratio: each earthling commands the equivalent of roughly 200 mechanical "slaves" working around the clock. In France, where energy use is higher, the multiplier is closer to 600. Modern industrial society has effectively transformed every human being into a real-life Ironman or Superman: while Popeye relied on spinach, modern humanity devours barrels of oil and tons of coal to fuel an external machine exoskeleton consisting of tractors, washing machines, elevators, trains, and rolling mills.
Without machines, sustaining today's material output would require an impossible global population of 1,400 billion individuals. Jancovici contrasts this physical reality with modern economic accounting: while energy drives virtually 100% of physical transformations in the economy, it accounts for only about 3% of monetary expenditures. If financial ledgers accurately mirrored physical laws, energy would cost 200 times more than human wages, and starting salaries would be divided by a factor of 1,000. Under this lens, human workers in industrial production are largely present merely to steer and monitor machines. Furthermore, even a modest citizen, such as a French "Yellow Vest" (*Gilet Jaune*), lives with the physical material luxuries of a historical potentate. As Jean-Marc Jancovici remarks:
> “The material production of humanity today at 7 billion people is equivalent in volume, because of the machines, to what we would have if we had 1400 billion people and no machines.”
- **Extracorporeal energy:** Roughly 20,000 kWh per person per year on average across the globe.
- **Muscle power equivalence:** 200 virtual workers per human globally; roughly 600 per person in France.
- **Fossil composition:** Dominated by fossil fuels derived from ancient life—Carboniferous ferns for coal, ancient marine microalgae and plankton for oil and gas.
- **Economic paradox:** Energy constitutes only ~3% of GDP/costs despite providing over 99% of the mechanical transforming power in the economy.
---
[01:05:48](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=3948s) Underground Slaves vs. Ancient Renewables: The Battle for Land Surface
To conclude the comparison between modern fossil-fueled machines and historical energy systems, Jancovici identifies a profound spatial advantage of fossil energy: it frees up the surface of the Earth. Ancient renewable systems—and the draft animals that powered pre-industrial agriculture and transport—demanded massive amounts of fertile soil for feed and grazing. Consequently, societies faced a harsh zero-sum trade-off between land dedicated to producing human food and land dedicated to sustaining the energy systems (draft horses, oxen, firewood) required to farm and move goods.
Modern mechanical slaves, by contrast, feed entirely on resources extracted from the underground. Because their food source lies beneath the crust, they leave the entirety of the planet's surface free for human living space and agriculture. When society attempts to transition back toward renewable energy—such as cultivating energy crops or biofuels—it inevitably reignites these historical land-use conflicts between food production and energy capture. As Jean-Marc Jancovici explains:
> “There, the slaves of modern times, they eat from the underground.”
[01:07:09](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4029s) Orders of Magnitude: Small Gestures vs. Real Energy Consumption
Jean-Marc Jancovici presents a slide illustrating common energy usages converted into equivalent "slave-days." While noting that the underlying graphic is older and some specific figures might have shifted by a factor of two due to efficiency gains, he emphasizes that the fundamental orders of magnitude remain completely valid. The crucial takeaway for the audience is that the vast majority of energy consumed by a Western citizen—and by extension, the fleet of machines operating on their behalf—has nothing to do with domestic lighting or recyclable coffee cups. Addressing the engineering students directly, he stresses that genuine engineering requires rigorous attention to scale:
> “So, since I am going to talk to engineers who are supposed to manipulate orders of magnitude: it is not with small gestures that we avoid big problems.”
Jancovici points out that although small initiatives may serve as an entry point, they can never substitute for confronting core structural issues. He criticizes corporate culture for deliberately blurring orders of magnitude through superficial greenwashing:
> “You hide behind your little finger and say ‘Look! It's fabulous, I put a hive on the roof, I put recyclable cups in the canteen, and then one day per year people will come by bike and...’ No, it doesn't work that way.”
The components of modern lifestyle that truly register on the energy balance sheet are material consumption and transport. When evaluating climate impact, eating habits and housing conditions—specifically the physical surface area occupied, the energy needed to heat or cool it, the annual volume of manufactured goods purchased, and the number of kilometers traveled—vastly outweigh trivial everyday actions such as remembering to switch off a light bulb when leaving a room.
- Heavy-impact activities: annual purchases of manufactured goods, freight and personal transport, diet, and dwelling size/heating.
- Negligible-impact activities in comparison: office coffee cups, decorative rooftop beehives, and turning off domestic light switches.
---
[01:09:01](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4141s) Climate Stability, Demographics, and the Energy-Driven Population Boom
Alongside the explosion of per capita consumption, total global population has undergone an unprecedented transformation. Jancovici displays a reconstruction of human population over the past ten millennia. He questions the class on why the historical curve begins roughly ten thousand years ago, explaining that this threshold marks human sedentarization. Exiting the last ice age, humanity entered the warm, remarkably stable interglacial epoch of the Holocene. Under such climatic equilibrium, food resources ceased shifting across geographical zones, enabling human communities to settle permanently. At that time, Earth supported only a few million hunter-gatherers and early farmers.
By the eve of the Industrial Revolution around 1800, global population had gradually reached approximately one billion. Life expectancy at birth was under 30 years—in fact lower in urban centers than in rural areas because dense cities concentrated diseases, bad air, and infant mortality. Over the following two centuries, population growth abandoned its historic rhythm to follow a trajectory closer to a hyperbolic curve than an exponential one, coinciding with a massive surge in per capita resource throughput. Jancovici raises a fundamental question shared by a circle of systems thinkers:
> “And if the question arises as to whether 7 or 8 billion people is not a consequence of abundant energy, then obviously, at that moment, the corollary question arises: from the moment we enter a strong energy decline, do we stay at 8 billion people?”
Without fossil fuels, French cereal yields in the Île-de-France region could never have leaped from 10 to 80 quintals per hectare. Abundant energy made it possible to synthesize nitrogen fertilizers, power farm machinery, transport crops across continents, refrigerate perishable foodstuffs against rot and pests, pump drinking water, and build modern municipal sanitation to flush away deadly epidemics. Consequently, sustaining a population of seven to eight billion people is inextricably tied to massive energy subsidies.
```mermaid
flowchart TD
accTitle: Fossil Energy and Demographic Expansion
accDescr: Flowchart showing how abundant fossil fuels enabled modern agriculture, medicine, and urban systems, driving global population to 8 billion.
subgraph EnergyInput["Primary Energy Input"]
A["Abundant Fossil Energy"]
end
subgraph SocietalEnablers["Technological & Agricultural Enablers"]
B["Agricultural Yields: 10 to 80 q/ha<br/>(Mechanization & Fertilizers)"]
C["Sanitation, Drinking Water & Medicine"]
D["Cold Chain & Global Food Logistics"]
end
subgraph DemographicOutcome["Demographic Result"]
E["Historic Decline in Mortality"]
F["Global Population: 1B (1800) to 8B Today"]
end
A --> B
A --> C
A --> D
B --> E
C --> E
D --> E
E --> F
```
- Cereal yields in Île-de-France rose from ~10 quintals/hectare in pre-industrial times to ~80 quintals/hectare today thanks to fossil energy.
- Pre-industrial life expectancy was below 30 years worldwide, with urban areas suffering higher mortality than rural areas due to contagion and sanitary conditions.
---
[01:12:08](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4328s) The Global Machine Park, Non-Linear Systems, and Human Footprint
Multiplying the expanding population by individual energy use reveals the aggregate amount of energy harnessed by human society, which serves as a proxy for the size of the global machinery park. Jancovici explains that because modern engineering made machines significantly more energy-efficient, the growth in primary energy consumption actually represents a conservative lower bound on the expansion of mechanical artifacts. Between his parents' generation and that of his children, global energy consumption grew nearly tenfold, meaning that after factoring in efficiency improvements, the operating machinery park multiplied by a factor of several tens.
He cautions the students against the intellectual trap of inductive reasoning. Physical and ecological systems are intrinsically non-linear, and assuming that past growth trajectories can simply be projected forward into the future is a grave error. The generation of current students will not experience a mechanical continuation of the twentieth century's expansion. Human impact on the biosphere is essentially defined by this energetic flow of physical transformation. While human beings and their energy-fueled machines have multiplied dramatically, the planet itself has remained unchanged at 13,000 kilometers in diameter. Today's environmental crises are not qualitatively distinct from historical ones, but quantitatively unprecedented. Humanity has knocked the Earth system out of equilibrium, leaving no prospect of long-term stability:
> “And, therefore, we have, you have, I essentially have a choice between: I wait for the instability to happen as it wants to happen and I suffer it; or I trigger the instability within the limits of what I can still more or less control.”
- Energy consumption increased by nearly a factor of 10 within two generations, while the machinery park expanded several tens of times due to efficiency gains.
- The Earth’s diameter remains fixed at 13,000 kilometers while the human transformational footprint has multiplied exponentially.
- Non-linear physical systems invalidate linear extrapolation; future stability is physically impossible, leaving only the choice between managed transition or suffered collapse.
---
[01:15:41](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4541s) Media Illusion vs. Reality: The Supremacy of Coal and the True Renewable Mix
Jancovici shifts to the concrete data of world energy consumption between 2000 and 2017 to expose the profound divergence between media narratives and physical reality. Despite endless headlines celebrating the rise of wind and solar installations, the three primary energy sources that grew the most across this period—by an overwhelming margin—were fossil fuels, led by coal. Coal consumption grew by more than ten times the growth of solar energy (in primary energy equivalent) and more than five times that of wind power:
> “So, if the newspaper had a pagination reflecting the facts, for an article about solar energy, there should be 15 about coal.”
Looking at the current global energy mix, fossil fuels dominate decisively: oil sits in first place, followed by coal and natural gas. When examining renewable energy alone, the historical and present picture is equally misunderstood. Globally, as well as in France, the dominant renewable sources are not modern wind turbines or solar panels, but traditional biomass (wood) followed by hydroelectricity.
Displaying official French energy statistics published just weeks prior, Jancovici highlights that wood, utilized primarily for thermal heating, and hydroelectric dams, used for power generation, form the overwhelming bulk of France's renewable energy supply. In contrast, wind and particularly solar power occupy a marginal share at the very bottom of the distribution, contradicting public perception shaped by press coverage.
| Energy Source / Category | Global & French Reality (2000–2017 Data) | Media / Public Perception |
|:--- |:--- |:--- |
| **Coal** | Largest absolute growth of any fuel since 2000; dominates world power generation | Regarded as an obsolete 19th-century fuel |
| **Fossil Fuels (Oil, Coal, Gas)** | Supply the overwhelming majority of primary energy worldwide | Seen as actively being replaced |
| **Biomass (Wood)** | Largest single renewable energy source in France (primarily for heating) | Largely ignored in energy transition headlines |
| **Hydroelectricity** | Second-largest renewable contributor globally and in France | Rarely discussed compared to modern intermittents |
| **Solar & Wind** | Minor fraction of primary energy; coal added >10x more energy than solar since 2000 | Heavily over-represented in press and public discourse |
[01:17:51](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4671s) Renewable Energy Context and Break
Jean-Marc Jancovici wraps up the previous discussion on the French energy mix by summarizing the minor contribution of renewable energies relative to national demand. Looking at the data expressed in millions of tons of oil equivalent (Mtoe), renewable energies—comprising heat pumps, wood, waste, and other sources—fill only a modest sliver against total French consumption, which sits at roughly 250 Mtoe. Putting these figures into visual perspective illustrates just how small their share remains within the overall domestic energy balance. Before moving into the economics of energy, Jancovici pauses the lecture, telling the students: “Take the opportunity to chat a lot at that time: but five minutes, not a quarter of an hour.”
[01:18:23](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4703s) Oil Prices in Constant Currency vs. Supply Abundance
Restarting the session, Jancovici addresses a core economic tenet: the assumption that market prices directly mirror resource abundance or scarcity. Common wisdom holds that as a resource becomes scarce, its price must climb steeply, whereas abundant resources should see their prices collapse. Because oil acts as the benchmark that dictates or heavily influences the pricing of virtually all other primary energy sources, Jancovici examines a historical chart of crude oil prices in constant (inflation-adjusted) currency spanning a century and a half.
Contrary to conventional economic models, the long-term trend reveals that for roughly an entire century, the real price of crude oil remained rigorously flat, regardless of how drastically global extraction volumes expanded. Price spikes occur only during sharp inflection points or shocks—moments characterized by an abrupt variation in the derivative of production, where output growth decelerates suddenly—after which prices typically drop back toward baseline levels. Jancovici stresses that this historical evidence contradicts classical assumptions, noting: “So the idea that the price of oil is something that follows the abundance of supply is not confirmed by this graph that you see here.”
- Over a 150-year horizon, oil prices in constant currency remained virtually flat for a century despite exponential growth in extraction volume.
- Price surges occurred during sudden structural shocks (steep derivative changes in supply), followed by declines back toward historical baselines.
- The market price of crude oil does not steadily decline as supply grows, nor does it smoothly track physical abundance.
[01:19:53](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4793s) The True Price of Energy: Working Time, "Ironman", and the Yellow Vests
```mermaid
flowchart LR
accTitle: Evolution of Energy Affordability and Labor Transformation
accDescr: Flow showing how oil costs divided by wage gains and machine efficiency multiplied human physical power, leading to environmental impacts and social perceptions.
subgraph CostEfficiency["Energy Cost & Labor"]
A["150 Years of History"] --> B["Price of Oil / Wage<br/>(Divided by 15–20)"]
B --> C["Machine Efficiency Gains"]
C --> D["Cost per kWh Mechanical Work<br/>(Divided by 50–100)"]
end
subgraph HumanPower["Physical Amplification"]
D --> E["Equivalent of 200 'Slaves'<br/>per Person ('Ironman')"]
E --> F["Environmental Strain:<br/>Biodiversity Loss & Pollution"]
end
subgraph PublicPerception["Modern Perception"]
B --> G["Real Energy Cost Near All-Time Lows"]
G --> H["Yellow Vests Tension:<br/>Nominal 1.50 €/L vs. Real Purchasing Power"]
end
```
To establish the genuine economic cost of energy, Jancovici argues that monetary units are fundamentally misleading; the only truly incompressible benchmark across human history is the 24 hours in a day. The real price of any commodity is therefore the quantity of human labor required to purchase it—measured in minutes of working time, or market price divided by average income (GDP per capita). When viewed through this lens, the price of a barrel of oil relative to human earnings dropped by a factor of 15 to 20 over the past century. Concurrently, machine efficiency improved substantially, resulting in the cost of a kilowatt-hour of mechanical work being divided by a factor of 50 to 100.
This dramatic collapse in mechanical energy costs corresponds precisely to the transition from manual human labor to fossil-fueled industrialization, effectively granting each modern individual the physical working capacity of roughly 200 "slave-equivalents." Jancovici highlights the magnitude of this shift: “So, basically, no matter how you look at the problem, the transition from renewable civilization to fossil civilization has been the appearance of Superman or Ironman for each of us, with a multiplication by an order of magnitude of a hundred or several hundreds of our capacity for action on the environment.” However, this immense capacity for physical transformation inevitably scales up negative externalities by identical orders of magnitude, causing extensive land conversion, loss of biodiversity, and vast emissions of industrial pollutants. Turning to modern social movements, Jancovici points out that despite public outrage over gasoline reaching 1.50 € per liter, energy relative to average French wages has rarely been cheaper in history, even if specific groups such as the Yellow Vests (*Gilets jaunes*) experience localized hardship because individual situations vary from the national statistical average.
- In terms of working time, the real price of a barrel of oil fell by a factor of 15 to 20 over a century.
- Combined with engine and machine efficiency improvements, mechanical energy costs fell by a factor of 50 to 100.
- Each person in an industrialized nation commands an energetic equivalent of roughly 200 human workers.
- Although nominal pump prices spark public unrest, energy expenditures relative to average wages are near historic lows.
[01:22:28](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=4948s) The Two-Century Transformation of Agricultural Labor
Abundant energy fundamentally restructured human society, shifting the vast majority of the population away from manual primary production toward urban service-sector jobs. Analyzing a two-century historical series tracking French employment across agriculture (green), manufacturing/crafts (black), and services (blue), Jancovici warns that examining truncated timeframes leads to fundamental misinterpretations. Two hundred years ago, two-thirds of the French labor force worked in agriculture. A simple mathematical deduction reveals that agricultural labor productivity was roughly 1.5: every farmer produced only enough food to nourish themselves plus half an extra person.
Between 1800 and 1850, individual farmer productivity barely changed. Because the population grew, the only way to produce more food was to clear land, driving French forest cover down to a historic low of just 15% by 1850 (compared to around 25% today), leaving forests almost exclusively in steep mountainous terrains unsuitable for farming. From the mid-19th century onward, metallurgy and early industry began supplying agricultural auxiliaries—such as horse collars, iron ploughs, and eventually horse-drawn combine harvesters—gradually freeing farm laborers to enter other sectors. The true technological rupture arrived after World War II with American imports of tractors and synthetic fertilizers. Jancovici underscores this post-war revolution: “Thanks to what, as I said earlier but I will repeat it again: the cereal yield in Beauce, for example, increased by a factor of 6 and 8 between 1945 and 1975.”
- Two centuries ago, two-thirds of the French working population were farmers, with each farmer feeding only 1.5 people.
- Forest cover in France hit an all-time low of 15% around 1850 due to land clearing for agriculture before recovering to 25% today.
- Early mechanization (forges, trait collars, horse-drawn equipment) initiated the gradual displacement of agricultural labor.
- Between 1945 and 1975, the adoption of motorized tractors and chemical fertilizers boosted cereal yields in the Beauce region by a factor of 6 to 8.
[01:26:40](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=5200s) Industrial Employment: The Horse Race Between Machine Size and Energy Flow
The labor shed by agriculture migrated into manufacturing, factories, and artisan crafts. During the post-war boom (*Les Trente Glorieuses*), an expanding supply of energy allowed society to deploy an ever-increasing fleet of machinery—assembly lines, jackhammers, and construction cranes—all requiring human operators. Industrial employment grew because the growth rate of available energy per capita outpaced the growth rate of individual machine sizes. Jancovici describes this dynamic as a horse race: as long as energy supplies grew faster than unit machine capacity, the total machine stock multiplied, creating an increasing number of industrial driving and operating jobs.
Following the 1970s oil shocks, however, this balance inverted. Available energy per person plateaued, while individual machines continued to expand in scale, speed, and automation. Consequently, fewer operators were needed to run ever-larger apparatuses, causing industrial employment to decline even as overall physical output continued to expand. Addressing common misconceptions about de-industrialization, Jancovici highlights: “Industrial production in France doubled between 1974 and 2007.” Rather than producing less physical output, French industry altered its product mix—manufacturing fewer socks and more airplanes—while substituting machine scale for human labor.
- During *Les Trente Glorieuses*, the per capita energy supply expanded faster than the unit size of machines, driving net job creation in manufacturing.
- After the 1970s oil shocks, per capita energy growth stalled while machine unit size kept expanding, shrinking industrial headcount.
- French industrial output did not collapse after 1974; it doubled between 1974 and 2007 through higher mechanization and higher-value production.
[01:28:30](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=5310s) Physical Flows and the Myth of the Dematerialized Service Economy
Jean-Marc Jancovici explains how the structural evolution of employment relates directly to physical machines and energy flows. Even after per capita energy supplies ceased growing, the unitary size of industrial machines continued to expand. This allowed industry to cut payroll while operating larger units that collectively produced greater output. As direct industrial headcount shrank, employment shifted overwhelmingly into the service sector—a domain that remains strictly subordinate to the underlying physical world. Jancovici debunks the prevailing belief that a service-dominated economy is “dematerialized.” A teacher cannot function without physical buildings, transport networks to move students, and manufactured tools ranging from historical paper books to modern computers. A doctor is completely dependent on pharmaceuticals, physical hospitals, and heavy diagnostic imaging machinery. Similarly, an entire ecosystem of service jobs—bankers granting auto loans, insurance brokers, driving school instructors, and traffic police—vanishes entirely if there are no physical cars rolling off assembly lines.
```mermaid
flowchart TD
accTitle: Dependency of Service Jobs on Physical Flows
accDescr: Diagram showing how upstream industrial flows support downstream service sector jobs using the automobile as an example.
subgraph PhysicalFlows["Underlying Physical Flow"]
M["Vehicle Manufacturing"]
end
subgraph ServiceJobs["Subordinate Service Sector"]
B["Auto Loans & Banking"]
I["Vehicle Insurance"]
D["Driving School Instruction"]
P["Traffic Law Enforcement"]
end
M --> B
M --> I
M --> D
M --> P
```
Because services exist primarily to organize, sell, transport, and support physical goods, service sector jobs expanded precisely because industrial production was growing. However, when European industrial output plateaued around 2007, service employment began facing severe constraints as well. This dynamic also explains the emergence of structural unemployment following the 1970s oil shocks. Because overall energy per person stopped rising, labor productivity—which Jancovici defines as the addition of machine power to human labor—could no longer advance rapidly. Existing industrial jobs were already too productive to employ everyone in a slowing economy. Faced with this ceiling, societies had to decide how to allocate work when the only mathematical way to achieve full employment was to lower output per worker. Jancovici contrasts the French model, which refused to lower labor productivity and instead generated structural unemployment, with Anglo-Saxon and liberal economies (such as the United Kingdom, Germany, and the United States) that absorbed workers into poorly paid, low-qualification, part-time "odd jobs."
As Jean-Marc Jancovici summarizes: “A world rich in service jobs is a world in which there are a lot of flows to manage and that's why you need a lot of people to take care of it.”
- Direct industrial employment declined as individual machine sizes grew, allowing fewer operators to generate more volume.
- Service jobs depend entirely on underlying physical infrastructure and manufactured artifacts.
- Post-1973 labor productivity slowed down because energy per capita stopped climbing.
- “In other words, from the oil shocks, we are entering a time when the only way to give everyone a job is to reduce people's productivity at work,” states Jancovici regarding the structural divergence between French unemployment and Anglo-American low-wage mini-jobs.
---
[01:32:10](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=5530s) Machine Infusion, Rural Exodus, and Global Agricultural Employment
To prove that employment structures are strictly dictated by energy and machines rather than cultural choices, Jancovici presents static and dynamic datasets from the World Bank covering roughly 250 countries. Plotting the amount of energy used per person (representing the average number of machines per inhabitant) against the share of the active population working in agriculture reveals an unmistakable, universal inverse relationship. Countries with high energy consumption systematically employ only a tiny fraction of their population on farms, whereas low-energy societies remain overwhelmingly agrarian.
Looking at historical time series from 1991 to 2014, global average data confirms the exact same trend: rising per capita carbon dioxide emissions—the direct trace of fossil-fueled machines—track a relentless drop in agricultural employment. Jancovici highlights that this is not unique to early industrializers; emerging powers such as China, India, and Brazil follow the exact same path. Injecting fossil energy into a rural economy inevitably replaces human muscles with tractors and combine harvesters, systematically driving a rural exodus across every geography.
As Jean-Marc Jancovici puts it: “Tell me how much energy there is per person in the country and I'll tell you what fraction of the working population works in agriculture.”
- World Bank cross-country data proves an inverse correlation between per capita energy use (machine density) and agricultural employment share.
- Global data from 1991 to 2014 shows that rising CO2 emissions per capita consistently correspond to a declining farm workforce.
- The mechanization of agriculture mechanistically creates rural exodus regardless of national culture or geography.
---
[01:33:28](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=5608s) Meat on Energy Infusion and the Real Cost of Supermarket Food
Surging agricultural productivity dramatically altered human diets by enabling massive animal consumption. Eating animals requires vast surface areas of crops to feed livestock: roughly 80% of all agricultural land in Western countries (and 80% of what grows in France) is dedicated to livestock feed, including all permanent meadows, almost all field corn (aside from minor sweet-corn brands), half of all wheat, and nearly the entirety of global soybean production. Historically, diets were dominated by cereals and onions—which Jancovici jokingly notes gave our ancestors chronic bad breath. As machine-driven energy increased, populations progressed to animal products like eggs, then end-of-life egg-laying hens (the classic *poule au pot* championed by King Henry IV, which was essentially culled waste), followed by broiler chickens, pigs, and finally dedicated beef cattle. Raising cattle purely for meat represents an extreme thermodynamic luxury that can only exist under massive, continuous fossil fuel infusion, with the United States serving as the prime archetype.
Because machines lowered production costs, the share of household income spent on food collapsed over the past century. Using American historical data, Jancovici notes that a century ago, households spent roughly 25% of their budget on food, consisting primarily of raw farm goods prepared at home by homemakers ("Mrs. Michu"). Today, by contrast, 80% of French food purchases happen in supermarkets, where consumers are paying for services rather than actual agricultural calories. A supermarket receipt covers cashier salaries, self-checkout software engineers, warehouse rent, logistics companies like Volvo Trucks, and advertising agencies like Publicis. The raw agricultural product accounts for only a third of the shelf price in the best cases, and as little as 3% in processed goods.
To illustrate, Jancovici walks the class through the arithmetic of standard non-organic eggs: a six-pack costs roughly €1.50 at retail (25 cents per egg), while the farmer receives a mere 6 to 7 cents at the farm gate—a fourfold markup for an item that undergoes zero physical transformation. In a café, an omelet made of three eggs (75 cents worth of farm produce) sells for €5 to €6, introducing a tenfold markup. In real terms, the actual cost of agricultural food has fallen by a factor of roughly twenty over a century, while modern transport modes layered on top of this system consume ever more energy per kilometer, culminating in commercial aviation.
As Jean-Marc Jancovici emphasizes: “Being able to raise cows just to eat them is something that is the hallmark of a country under energy infusion.”
- Roughly 80% of crops and land in France and Western nations are devoted to feeding livestock rather than humans directly.
- The historical dietary shift moved from cereals/onions to eggs, culled laying hens, broilers, pork, and finally beef cattle.
- Food dropped from 25% of household budgets a century ago to a minor fraction today, with the real agricultural price dropping by roughly a factor of 20.
- Raw farmgate eggs cost 6–7 cents, retail at 25 cents in supermarkets (a factor of 4 markup without processing), and sell for €5–€6 as a café omelet (a factor of 10 markup).
- Modern transport systems exhibit progressively higher energy consumption per kilometer as they modernize, with aviation being the most energy-intensive per person.
[01:39:18](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=5958s) The Evolving Role of Transport and Energy Intensity per Kilometer
Jean-Marc Jancovici opens a parenthesis on the concept of inhomogeneities in long time series: over time, objects often drift away from their original primary function. A car today is no longer merely a mechanical instrument of mobility; it serves as a private, mobile living room that an individual can drive right up to their office doorstep, while doubling as a prominent status symbol. Looking at conceptual concepts like the autonomous connected car imagined "by IKEA," Jancovici asks rhetorically whether such an object is still a car, a living room on wheels, or simply a computer that happens to transport passengers incidentally.
Returning to the primary function of physical movement, Jancovici highlights a historical paradox of technical progress: the more modern a transportation mode is, the more energy it consumes per kilometer traveled. A passenger car burns less fuel than an airplane, but significantly more than a train; a train consumes more than a bus, which in turn consumes more than a bicycle. Plotting energy consumption per passenger-kilometer (measured in grams of oil equivalent) reveals a steady upward climb as modes modernize. Because road transport dominates passenger-kilometers traveled annually, it claims the largest overall share of transport energy. As Jancovici points out, the general direction of history has been to replace frugal modes with increasingly energy-hungry ones simply because society had ever-increasing amounts of energy at its disposal.
> “And I repeat, therefore, the way of History is to move from economical to less economical means, because there was more and more energy available per person.”
- **Modal energy intensity ranking**: Train < Bus < Car < Plane.
- **Consumption metric**: Expressed in grams of oil equivalent per passenger-kilometer.
- **Dominance**: Road transportation represents the vast majority of traveler-kilometers and aggregate energy consumption.
[01:42:03](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6123s) Flying, Historical Mobility, and the Dominance of the Automobile
Jancovici conducts an informal poll of the lecture hall, asking how many students have never flown on an airplane. Only two hands go up. He remarks that asking that same question in 1950 would have required reversing the phrasing to find out who *had* flown, which would likely have produced only two hands. For the students' demographic and socio-professional bracket, flying has become as routine as breathing, yet Jancovici cautions that this is an exceptionally recent anomaly fueled by gargantuan energy expenditures. A single round trip from Paris to New York burns roughly 400 to 500 liters of oil per passenger—an entire bathtub of crude, roughly equal to an individual's entire annual automotive fuel consumption. He quips that by 2060, Mines ParisTech's international programs might look less like flights to Kuala Lumpur or China and more like night trains to Sweden, or a month-long voyage on a semi-sailing ship to create lasting memories.
Looking back across two centuries on a logarithmic scale of kilometers traveled per person per day, Jancovici notes that roughly two hundred years ago, the average human journey was just 3 kilometers per day on foot. Peasants—who made up the bulk of the population—simply walked between their farmhouses and nearby fields, orchards, or meadows, spending their entire lives without ever traveling more than a few hundred kilometers away. Horses represented the only faster daily alternative before the rise of the railroad, which was subsequently eclipsed by the private automobile. The pivotal historical crossover where cars replaced walking as the dominant global mode of passenger transport occurred as recently as the 1950s.
> “So my parents, who were already born at that time, were born in a world in which the dominant mode of transportation for the population as a whole was walking.”
- **Transatlantic flight energy cost**: 400 to 500 liters of oil per passenger for a Paris–New York round trip (comparable to a year of private car usage).
- **Historic baseline**: 3 km per person per day on foot two centuries ago.
- **Tipping point**: Automobiles surpassed walking as the dominant mode in passenger-kilometers per day during the 1950s.
[01:45:19](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6319s) Urbanization, Industrial Efficiency, and Energy-Driven Urban Sprawl
The mechanization of agriculture drastically reduced the need for rural labor, funneling former peasants into cities where industrial manufacturing and tertiary services could be concentrated. Historically, cities developed as compact discs around centralized hubs of physical and social exchange: the marketplace for trading goods, the church for sharing moral beliefs, the town hall for civic governance, and the school for exchanging knowledge. Compactness minimized the energy required for foot and horse travel. As fossil energy became abundant, it reshaped the economic geography: factories grouped hundreds of craftsmen together under one roof as specialized industrial workers, far outstripping the efficiency of isolated artisans. With transport costs falling toward negligible levels, supply chains hyper-specialized further across distant sites, leading to contemporary logistics where truck cabins are manufactured in one facility and hauled unpainted to another purely for coating.
This structural shift in employment directly links energy consumption to urbanization rates worldwide. In 1960, slightly over 30% of the world's population lived in cities, corresponding to an average fossil carbon footprint of about 3 tons of CO2 per person; today, as average energy use has pushed emissions to 5 tons of CO2 per capita, urban dwellers constitute nearly two-thirds of humanity. Abundant transport energy also allowed cities to break out of their compact boundaries. While the dense, contiguous blocks of Haussmannian Paris represent the pinnacle of walkable, low-energy urban compactness without relying on high-rise towers, the personal automobile enabled sprawling metropolitan areas like Los Angeles. In Los Angeles, urban exchanges span diameters of 100 to 150 kilometers while preserving typical one-hour travel times. Jancovici illustrates this transition by displaying commute-distance maps of the Île-de-France region from 1975, showing how historically short, walkable trips from home to work expanded outward as mechanized transport took hold.
> “More energy, I repeat, distorts the structure of employment in the way I mentioned earlier and the jobs that appear are most effective if you increase the size of cities.”
```mermaid
flowchart TD
accTitle: Energy Abundance and Urban Evolution
accDescr: Flowchart illustrating how energy abundance transformed labor structure and urban morphology from dense walkable cities to automobile sprawl.
subgraph EnergyInput["Energy Driver"]
E["Abundant Fossil Energy"]
end
subgraph LaborShift["Labor Transformation"]
A["Mechanized Agriculture"] -->|"Frees rural labor"| B["Factory Concentration"]
B -->|"Replaces scattered craftsmen"| C["Hyper-Specialized Industry & Services"]
end
subgraph UrbanForm["Urban Morphology"]
D["Traditional Compact Disc<br>(Walkable, Haussmannian)"]
F["Automobile Sprawl<br>(Los Angeles Model, 100-150 km)"]
end
E --> LaborShift
E -->|"Mechanized Transport"| F
C -->|"Concentrates Population"| D
D -->|"Transport Energy Surplus"| F
```
- **Global urbanization vs. emissions**: Urban share grew from just over 30% in 1960 (at ~3 tons of CO2/person) to nearly two-thirds of the world population today (at ~5 tons of CO2/person).
- **Haussmannian compactness**: Achieves world-leading density without high-rise towers because buildings share party walls and eliminate dead space between structures.
- **Car-enabled sprawl**: Cities like Los Angeles maintain roughly one-hour commute times despite expanding across 100 to 150 kilometers in diameter.
[01:50:31](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6631s) Urban Sprawl, Commuting, and Why Energy Enables Divorce
Jean-Marc Jancovici traces the territorial transformation of society from a world where people walked to their agricultural fields to the situation in the early 2000s. The former agricultural population has shifted en masse into urban and peri-urban areas, taking up jobs in industry and services. Because these sectors require complex travel networks and peri-urban zones lack public transit—and, as Jancovici bluntly notes, never will have it—workers are forced to rely entirely on personal cars, producing massive commuting distances between homes and workplaces. He dryly points out the disconnect in public planning: building infrastructure like the Grand Paris Express metro system will do absolutely nothing to solve the problems of these outer peri-urban commuters, since it is laid down in dense areas where alternatives already exist.
```mermaid
flowchart TD
accTitle: Energy Abundance and the Transformation of Housing
accDescr: Diagram showing how abundant energy drives urban sprawl, increases per capita floor space, and enables household division like divorce.
subgraph Territorial["Spatial Shifts"]
A["Fossil Fuels & Cars"] --> B["Peri-urban Commuting"]
B --> C["Long-distance Car Dependency"]
end
subgraph Domestic["Housing Evolution"]
A --> D["Construction Energy"]
D --> E["Larger Surface per Dwelling"]
E --> F["Fewer Inhabitants per Home"]
F --> G["Material Feasibility of Divorce"]
end
```
Beyond daily mobility, cheap energy has profoundly altered residential life by expanding the housing stock far faster than population growth. Around the era of the 1970s oil shocks, an average French residence was 77 square meters and housed nearly three people; today, an average home is significantly larger yet houses barely over two people. This physical expansion directly underlies major social changes. Jancovici remarks with characteristic irony: “Because, to divorce, you have to have 2 dwellings where you only had one. Otherwise it's not called a divorce. It's called domestic disputes, but it's not called a divorce.” A legal and physical separation requires the material and energetic capacity to house both partners separately, making divorce one of the primary drivers inflating housing demand in contemporary France.
- **Commuting mismatch:** Suburban and rural workers are structurally dependent on cars; projects like the Grand Paris metro bypass the low-density peri-urban zones that need transport solutions the most.
- **Housing density collapse:** The average dwelling size in France grew beyond 77 m², while average occupancy dropped from nearly 3 people during the 1970s oil crises to just over 2 today.
- **Demographic demand:** Household splintering through divorce represents perhaps the single greatest upward pressure on residential construction and square footage demand.
---
[01:52:14](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6734s) The Myth of the "Clean" Service Economy and Digital Dematerialization
Addressing a widespread economic belief, Jancovici presents data examining the correlation between tertiary employment and carbon footprints. A common claim among economists and politicians is that transitioning from heavy manufacturing to a service-based economy will organically decarbonize society. However, empirical data shows the exact opposite: plotting per capita carbon dioxide emissions against the share of service-sector jobs reveals that higher service employment correlates with higher per capita emissions. Whether observed statically across nations or dynamically between 1991 and 2014, tertiary-heavy economies inevitably consume massive quantities of energy to support their physical infrastructure, transport networks, and commercial operations.
A parallel misconception exists regarding the digital economy and the belief that circulating information can substitute for the physical movement of people and freight. Jancovici stresses that historical data shows transport volumes—both freight hauled by trucks and passenger travel—grow in lockstep with information flows rather than declining. The macroscopic reality contradicts the idea of digital dematerialization: “So, today, on a macroscopic scale, to say that to circulate more information would allow us to circulate fewer people or fewer goods, that is not true.” Simply accelerating data transfer does not eliminate the physical requirements of modern logistical and human transport.
- **Tertiary emissions reality:** Worldwide data from 1991 to 2014 confirms that per capita $\text{CO}_2$ emissions increase alongside the percentage of the workforce employed in services.
- **Concomitant growth:** Telecommunications and physical mobility expand together; telecommunications optimize and expand supply chains rather than substituting for physical shipping.
---
[01:53:55](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6835s) Spatial Restructuring Across Nations and Geographical Exceptions
The influx of massive quantities of energy fundamentally restructured the geography of every industrialized country. Across the world, populations migrated from densely settled rural countrysides to concentrated, sprawling urban agglomerations, leaving the countryside largely depopulated. Jancovici highlights that this spatial trajectory—suburban sprawl, peripheral housing developments, and car-dependent retail—is uniform across every country that gained access to abundant energy, with deviations occurring only when harsh physical geography prevented it.
To illustrate this constraint, Jancovici points to Switzerland. Swiss urban centers expanded economically and demographically, but they could not sprawl horizontally across the landscape in the manner of French or American suburbs. Because many Swiss cities sit on valley floors, horizontal expansion would require building upward onto steep mountain slopes. While small chalets were built along the hillsides, mass suburbanization was mechanically throttled: “So, the countries, once again, that have not followed this evolution, it is because they have had a physical barrier that prevented them from following it.” It is virtually impossible to construct massive hypermarkets with sprawling ground-level parking lots on mountainous terraces, demonstrating how topography can override the sprawling tendencies of cheap fuel.
- **Universal territorial pattern:** Access to cheap energy invariably empties rural agricultural areas and fuels horizontal urban sprawl unless constrained by natural barriers.
- **The Swiss counter-example:** Mountain valley topography physically prevented the construction of American-style peripheral shopping centers and low-density tract housing.
---
[01:55:02](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=6902s) Free Time as a Machine-Made Luxury: The Carbon Price of Tourism
Jancovici turns to another unseen consequence of energy abundance: the creation of free time. Because fossil-fueled machines handle the physical labor required for human survival, societies have been able to delay entry into the workforce with lengthy schooling, establish funded retirements, implement weekends, pass paid vacation laws, and reduce the work week to 35 hours. Jancovici warns the students that this historical anomaly should not be taken for granted: “In a world with limited energy, it is not the increase in well-managed free time that will apply.”
```mermaid
flowchart LR
accTitle: The Energy Spectrum of Leisure and Tourism
accDescr: Flowchart contrasting low-energy vacation modes from the mid-20th century with high-energy modern aviation tourism.
To demonstrate how free time consumes energy, Jancovici details an accounting exercise he conducted measuring the greenhouse gas emissions associated with different holiday formats. His model accounts for initial travel (train, automobile, commercial flight), lodging manufacturing (tents, caravans, or new construction, joking that staying at an inherited property from an old mother-in-law carries zero construction penalty), on-site mobility, and winter sports heating (noting that skiing is difficult in hot weather, so ski chalets require substantial fuel oil heating). The contrast is stark: the original forms of leisure that emerged with the first paid holidays—taking a train or bicycle to camp in a tent—involve trivial energy, whereas modern long-distance tourism—flying thousands of miles for a weekend hotel stay—is the most energy-intensive activity per unit of time. This dynamic has sparked early cultural pushback in Scandinavia, such as the Swedish movement known as *flygskam* (flight shame), rooted in higher regional environmental awareness.
- **Machine-enabled leisure:** Extended education, old-age retirement, weekends, paid holidays, and the 35-hour workweek exist solely because mechanical energy replaced human manual labor.
- **Tourism footprint extremes:** Weekend fly-in city breaks generate orders of magnitude more fossil consumption than domestic train-and-camping holidays.
- **Skiing emissions:** Winter mountain vacations carry a hidden carbon premium because alpine accommodations are heavily reliant on fuel-oil heating systems.
- **Flygskam:** Sweden became an early adopter of flight reduction due to cultural and geographical sensitivities, causing early measurable drops in passenger flight counts.
---
[01:58:31](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7111s) The Real Cost of Flight, Petrochemicals as Matter, and Household Appliances
Jancovici reiterates an economic principle: the true cost of any good or service is best measured not in arbitrary paper currency, but in the hours of human labor required to purchase it. Over the past several decades, the price of airline tickets expressed in working hours has collapsed. This dramatic decline is simply another reflection of energy abundance; an average worker can now purchase an immense quantity of mechanical work and fossil fuel with just a few hours of labor.
Mechanical power manufactures the everyday physical world—from lecture hall desks and chairs to clothing, spectacles, scissors, cosmetics, and the digital infrastructure streaming Netflix films. Crucially, fossil fuels serve not only as an energy source to drive industrial equipment, but also as the primary physical feedstock for the petrochemical industry. Jancovici emphasizes that petroleum and natural gas are the structural backbone of synthetic materials: “So, oil today is not only something that drives a machine, it is also the basis of organic chemistry to produce all the products that surround us.”
He cites a demonstration by American researchers who attempted to remove every product derived from petroleum from an ordinary house: the dwelling was left completely bare. Doing the job properly required stripping varnish from wooden floors, taking down curtains and curtain rods, scraping synthetic paint off the walls, and eliminating virtually all furniture and finishes. Once manufactured, these objects frequently require ongoing power supplies. Jancovici concludes by showing the saturation of domestic household appliances—such as refrigerators, freezers, and washing machines—which have become ubiquitous across households, locking society into a perpetual baseline of everyday electricity and fuel consumption.
- **Aviation affordability:** Measured in human work hours, the price of air travel has plummeted over recent decades due to cheap oil and high-efficiency turbines.
- **Non-energy petroleum uses:** Fossil hydrocarbons act as primary chemical inputs for organic chemistry, plastics, solvents, synthetic textiles, paints, and protective coatings.
- **Domestic appliance saturation:** Modern homes across the developed world have reached near-total saturation of powered appliances (refrigerators, washing machines), embedding constant energy demand into daily domestic survival.
[02:01:15](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7275s) The Energy Cost of Modern Lifestyle, Equipment, and Institutions
Every modern manufactured object requires energy to produce, and many of them—from home appliances to the lawnmower—continue to consume energy throughout their operating lives. Equipment rates have climbed relentlessly, but the growth in energy consumption is also driven by evolving social structures. Divorce, for instance, serves as a striking example of structural energy inflation. When a couple separates, living arrangements duplicate: two dwellings are needed instead of one, expanding total occupied floor area and the energy required for heating and maintenance. New homes must be built, consuming materials and industrial energy, and they must be furnished twice over. While not every household item doubles, many essentials do: two beds, two sinks, two stovetops, and two sets of furniture must now be manufactured. Furthermore, if children are involved, custody arrangements mandate recurring travel back and forth between two distinct homes, adding significant transport fuel to the ledger.
```mermaid
flowchart TD
accTitle: Physical Model of Productive Transformation
accDescr: Diagram illustrating how natural resources and energy undergo transformation to produce goods, capital, depletion, and pollution.
subgraph Process ["Human Transformation Flow"]
E["Energy & Machines<br>(Exogenous work)"]
L["Human Labor & Brains"]
K["Capital<br>(Accumulated tools)"]
T["Transformation Process<br>(Physical work)"]
end
subgraph Outputs ["Outcomes"]
G["Useful Goods & Services<br>(Measured as GDP)"]
P["Pollution & By-products<br>(Climate change, waste)"]
D["Stock Depletion<br>(Extinction, ore drawdown)"]
end
NR --> T
R --> T
E --> T
L --> T
K --> T
T --> G
T --> P
T --> D
G -.->|"Reinvested share"| K
```
Societal institutions considered self-evident in advanced nations—lengthy education, extended retirement, and universal healthcare—are likewise direct functions of massive energy availability. Jancovici observes that when President François Mitterrand declared in 1981 that higher education should be open to all, it carried an unstated promise that future generations would exclusively occupy comfortable office jobs. Yet an economy where everyone works in an office is only possible if an army of machines performs the physical labor behind the scenes. In France, the healthcare sector alone represents approximately 5% of the national carbon footprint. Equipping hospitals with high-tech imaging, intensive-care suites, and pharmaceuticals is profoundly resource-intensive. While a comedian once joked that health costs could be settled simply by abolishing the last year of life, the real dilemma is physical: in a world of tightening energy constraints, society will eventually face harsh trade-offs between allocating heavy, carbon-intensive medical machinery to extend the lives of the very elderly versus supporting younger generations.
- “Because when you divorce, you have to double the housing, so you double the energy consumption of the housing.”
- “So at the time, when Mitterrand said ‘Everyone must go to university’, in fact he made the implicit promise that we would be able to live in a world of machines for eternity.”
- French hospitals account for roughly 5% of the entire country's greenhouse gas emissions.
---
[02:03:47](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7427s) Earth as a Resource: Stocks, Thermodynamics, and Free Endowment
Examining human civilization from a biophysical rather than financial perspective reveals that the economy is fundamentally an exercise in planetary transformation. Looking at the planet through an anthropocentric lens, Earth is a giant reservoir of natural resources. These divide strictly into two categories based on their renewal rates relative to human lifetimes. Renewable resources regenerate over short time horizons, such as solar radiation, grass, and biological biomass. Non-renewable resources do not regenerate on human scales: copper ore, for instance, cannot be replenished by any large-scale terrestrial transmutation, while fossil fuels require tens of millions of years of geological processing and are effectively finite.
Crucially, every single one of these primary resources is supplied entirely free of charge. From the Big Bang through primordial proton synthesis and stellar nucleosynthesis, physics and chemistry assembled the full periodic table of Mendeleev and its endless mineral and organic combinations on Earth without invoicing humanity a single cent. Human productive activity consists entirely of taking this free natural horn of abundance and modifying it into forms considered more useful than the raw state. A rough piece of flint is transformed into a knapped arrowhead to hunt game, or deer antlers are carved into functional tools. This physical conversion process is what defines transformation, and transformation invariably requires energy. For hundreds of millennia, humans relied only on muscle power and wood fires, but over a 500,000-year transition, societies learned to harness vast external energy flows to drastically accelerate the pace of extraction and processing.
- “These resources are all free and they are the result of everything that has happened since the Big Bang, all free of charge.”
- Non-renewable resources like copper or fossil fuels cannot replenish on human timescales, whereas grass and solar radiation renew rapidly.
- Human economic production began as the transformation of natural stocks using arms, legs, and fire to turn raw materials into sharper, more useful artifacts.
---
[02:06:17](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7577s) Capital Formation, Depletion of Stocks, and the Reality of Pollution
As societies intensified their physical throughput, they developed the concept of capital: setting aside a portion of transformed output instead of consuming it immediately, using it instead as machinery, infrastructure, and tools to accelerate subsequent rounds of transformation. With growing populations and exponentially expanding mechanical power, extraction has accelerated to the point where non-renewable resource stocks decline precipitously. Even in the Paleolithic era, local shortages of high-quality flint occurred, costing human lives; today, depletion extends across global reserves of hydrocarbons and mineral ores. Furthermore, industrial throughput has become so immense that human activity is now systematically liquidating renewable stocks as well—overexploiting forests, collapsing commercial fisheries, wiping out biological species, and degrading topsoils that require centuries to reform.
Every transformation of matter and energy also produces unintended consequences dictated by the laws of thermodynamics. In human language, these unwanted by-products are termed pollution. Defined rigorously, pollution encompasses all unwanted substances and disturbances introduced into the environment that degrade the quality of remaining natural assets. This rubric encompasses anthropogenic climate change, biodiversity loss, toxic chemical accumulation, and ocean overharvesting. Yet conventional economics captures none of this destruction in its core ledger. Because money only pays human labor and human ownership rather than nature, standard national accounting records only the monetary counterpart of the transformation flow itself—a metric known as Gross Domestic Product (GDP). Conventional GDP treats all transformation as pure addition, without deducting the irreplaceable loss of underlying natural capital.
- “So pollution is all the undesirable by-products of processing, i.e. those that will have an effect that we are not looking for.”
- “And then, on the day the marginal value of the last car I built is less than the marginal value of the last bits of iron ore, copper ore, lithium ore, vanadium, chromium and fossil fuels I used to make this car, I stop making cars and live ‘happily ever after’ with existing cars.”
- Renewable assets currently undergoing depletion include global fish populations, primary forest cover, biodiversity, and agricultural soils.
---
[02:09:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7747s) The Blind Spot of Classical Economics: Jean-Baptiste Say and the Labor-Capital Dogma
The modern economic accounting framework operates without any built-in physical boundaries: no rule in standard macroeconomics specifies that expansion must halt when global GDP reaches 80 trillion dollars. This structural detachment from physical reality traces back to the dawn of classical economic theory two centuries ago. Early economists founded the discipline on the premise that economics is the management of scarcity. In the early nineteenth century, what was scarce was human labor and human organization. Vast continents like North America and the Russian Empire appeared virtually boundless, empty of industrial presence, with untouched oceans and seemingly inexhaustible resources.
Under those conditions, classical economists such as Jean-Baptiste Say formulated a first-order approximation: natural resources were treated as practically infinite, meaning any drawdown divided by infinity resulted in a stock variation of zero. Consequently, non-human inputs were assigned an economic cost of zero. Jancovici warns the students—noting the arrival of the school's Director of Studies in the lecture hall—that standard economic theory taught in universities is fundamentally flawed when applied to the global Earth system. While neoclassical economics can help evaluate internal financial trade-offs between human agents, it produces pure nonsense when describing humanity's physical interaction with the biosphere. By asserting that production is generated solely by combining human labor and financial/human capital, conventional economics completely omits the physical roles of machines, energy, and natural resource stocks.
- “Economics is the management of what is rare.”
- “The whole economy you are taught at school is wrong when it comes to approaching the human system as a whole.”
- “When it comes to approaching the whole of Men in their environment, it only says nonsense.”
- Jean-Baptiste Say and classical theorists assumed natural endowments were inexhaustible, embedding the assumption that nature contributes zero value until transformed by human labor.
[02:11:03](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7863s) Charles Dupin and "Worker-Equivalents": A Missed Path for Economics
Jean-Marc Jancovici observes that the battle over how we define economic value could have taken a radically different course two centuries ago. Back then, Baron Charles Dupin—a French polytechnician and mathematician whom Jancovici wryly commends as “someone very decent”—carried out a pioneering calculation converting mechanical work into what he termed “worker-equivalents” rather than “slave-equivalents.” Dupin recognized physics at its core: he sought to catalog all the productive auxiliaries available across France and Great Britain in addition to human labor. In his census of human labor, Dupin counted children as a quarter of a worker and women as half. Jancovici jokes to the lecture hall, wondering aloud whether this archaic accounting convention is where the French idiom *ma moitié* (“my other half,” used to describe a romantic partner) originates, before playfully granting that it might also just refer to half of a couple.
Beyond human headcounts, Dupin systematically factored in the work performed by auxiliaries: water mills, windmills, draught animals, and sailing boats. By combining the human population with this mechanical and animal auxiliary workforce, Dupin could explain a phenomenon that baffled purely demographic analyses: although Great Britain and France had roughly similar human populations at the time, Britain was already producing three times more industrial output. The explanation was straightforward—production was not driven solely by human hands, but by the fleet of physical auxiliaries Britain had put to work. As Jancovici notes, choosing which thinker to follow shaped modern economic thought: “If, at the time, we had listened to Mr Dupin and not Mr Say, it is not completely certain that we would have built the economy in the same way.”
[02:12:40](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=7960s) Production as Physical Transformation and Energy as the Limiting Factor
From the standpoint of a physicist, everyday economic production is remarkably straightforward: it is nothing more than taking the 92 naturally occurring elements of Mendeleev’s periodic table and rearranging them into configurations that do not exist naturally in the environment. All manufactured goods—from cars to office chairs—are made exclusively of these 92 elements. Transforming these natural resources requires physical work. In modern civilization, that transformation capacity comes from two sources: one part is supplied by human muscles, and roughly 200 parts are supplied by our mechanical "Ironman"—the colossal global fleet of machines.
Capital goods, such as the amphitheater building in which the lecture is taking place, are manufactured through the exact same physical transformation process. The room is built from transformed iron ore (iron and oxygen bonded in specific crystalline structures), shaped stones, and processed paint. The only defining feature of capital is that it is not instantly consumed upon use: it provides lasting utility without collapsing during a lecture. Because machines do the vast majority of physical work, human labor is no longer the sole bottleneck of the system. In the contemporary world, energy is the hard physical limiting factor. Jancovici emphasizes that without energy, machines cannot run and production evaporates, regardless of goodwill in the financial sector: “In other words, if I deprive my fleet of machines of energy, I will deprive my productive system of its production capacity even if the bankers are very friendly and even if the unemployed are ready to go to work.” Similarly, if natural resources vanish—if there are no fish left in the sea—the GDP of the fishing sector collapses to zero, and a restaurant chain like Léon de Bruxelles is forced to pivot from mussels and fries to steak and fries, or cease operating altogether.
```mermaid
flowchart LR
accTitle: Physical Transformation of Natural Resources
accDescr: Flow diagram showing how natural resources and energy drive capital, goods, and GDP.
subgraph Inputs ["Physical Inputs"]
R["92 Elements of Mendeleev<br/>(Natural Resources)"]
E["Energy Supply<br/>(Machine Fleet / Ironman: 200x)"]
H["Human Muscles<br/>(Labor: 1x)"]
end
subgraph Transformation ["Transformation Process"]
T["Rearranging Atoms & Materials"]
end
subgraph Output ["Economic Realities"]
C["Durable Capital<br/>(Buildings, Infrastructure)"]
G["Consumer Goods & Services"]
M["Monetary GDP<br/>(Flow Counterpart)"]
end
R --> T
E --> T
H --> T
T --> C
T --> G
G --> M
```
[02:14:54](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8094s) GDP Since Year Zero, China's Place, and the Blindness of Current Economic Models
Examining historical reconstructions of global GDP from the year zero—the birth of Jesus Christ—up to the Industrial Revolution reveals an almost entirely flat line. In the absence of massive mechanical auxiliaries, economic growth was virtually nonexistent, and global population was comparatively stable. Because an individual's productive capacity was strictly bounded by their muscular strength, the country with the largest population was automatically the largest economy on Earth: China. Jancovici points out that this historical reality informs Beijing's contemporary geopolitical worldview: “So, China, today, is saying one thing in the concert of nations: ‘Listen, don't make us laugh. For two millennia, we have been the dominant economic power on the planet. So just because a century of oil has put the United States in our place does not mean that it will change our view of the world.’”
When fossil fuels and mechanical engines arrived en masse, economic growth exploded. Yet rather than attributing this leap to physical energy, economists constructed models that assumed perpetual growth of roughly 3% per year could continue indefinitely. Jancovici shares an anecdote from his work on the High Council for Climate (*Haut Conseil pour le Climat*). Three weeks prior, the Council was presented with France's National Low Carbon Strategy (*Stratégie Nationale Bas-Carbone*, or SNBC), drafted by graduates of elite engineering schools like the Mines. The model asserted that slashing French fossil fuel consumption by a factor of 6 or 7 would actually lead to an increase in French GDP. Jancovici laments that conventional macroeconomic models produce such absurdities because energy is treated as an incidental line item rather than an essential physical input: “Because economic models can tell you that we increase GDP by dividing energy by 10 since energy is not an input.”
[02:16:41](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8201s) The Straight-Line Model: Energy as the Physical Twin of GDP
Contrasting abstract economic theories with observable reality, Jancovici introduces what he tongue-in-cheek calls "the best macroeconomic model in the world": a straight line. Plotting global primary energy consumption on the horizontal axis—which effectively measures the aggregate number of operating machines—against global gross domestic product on the vertical axis yields an exceptionally tight, nearly linear relationship.
This tight correlation holds true both in absolute terms and in annual rates of change. A plot comparing the annual percentage variation in global energy consumption (the green curve) with the annual percentage variation in global economic output (the blue curve) shows that the two metrics move in near-perfect lockstep: when one rises, the other rises; when one drops, the other plummets. Jancovici stresses that currency and energy are simply two ways of measuring the very same physical phenomenon: “Euros only measure a flow in monetary terms, which kilowatt-hours physically measure.”
- **Historical growth rates**: Prior to the 1970s oil crises, global energy supply per capita expanded at approximately 2.5% per year, meaning the volume of operational machines per person grew by at least 2.5% annually.
- **Physical output**: Factoring in incremental gains in machine energy efficiency, overall physical production per capita grew by slightly more than 2.5% annually over this golden era.
- **Monetary counterpart**: Because physical production per capita expanded at over 2.5% per year, the monetary value of production (GDP per capita) followed suit with matching growth.
[02:18:18](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8298s) The Post-Shock Slowdown, the Welfare State Trap, and the Explosion of Debt
Following the oil shocks of the 1970s, per capita energy expansion abruptly downshifted. Across OECD Western nations, growth in energy per capita leveled off and eventually began to decline. The residual growth observed in global averages was almost entirely driven by the rise of China and subsequent emerging economies, characterized by an explosion in coal consumption. Today, China consumes roughly half of all coal burned on the planet, while Western coal usage has stagnated or fallen.
```mermaid
flowchart TD
accTitle: The Welfare State Debt Mechanism
accDescr: Sequence showing how slowing physical energy growth led to sovereign debt accumulation.
A["Energy Growth Slowdown<br/>(Post-1970s Oil Shocks)"] --> B["Physical Production Growth Slows Down"]
B --> C["Welfare State Commitments Kept Rigid<br/>(Pensions, Public Wages, Entitlements)"]
C --> D["Fiscal Deficits Covered by Borrowing"]
D --> E["Explosion of Sovereign Public Debt"]
E --> F["2005 Global Energy Plateau & 2008 Financial Crisis"]
F --> G["Unconventional Monetary Policy<br/>(Negative Interest Rates)"]
```
This physical deceleration created a structural crisis for Western welfare states. During the post-war boom, democratic nations built comprehensive welfare architectures—generous in Scandinavia, somewhat leaner in the United States, but ubiquitous across the developed world. These systems promised ever-increasing redistribution: annual wage raises tied to seniority, guaranteed pensions, and expanding public services, all calibrated to an economy growing by several percentage points every year. Critically, these states built in zero automatic stabilization mechanisms for a low-growth world. Governments never told public workers that seniority raises would freeze if growth vanished, nor did they tell retirees they would have to work longer for smaller pensions. When real physical growth slowed down, states borrowed money to honor their unadjusted social promises. Sovereign debt, which was virtually negligible across Western nations before the 1973 oil shock, exploded everywhere in its aftermath. Jancovici argues this proves the phenomenon is structural rather than purely local: “It appears and develops everywhere in all Western countries after the oil shocks precisely for this reason. Because the rate of increase in production per person is no longer sufficient to ensure the rate of increase in redistribution per person.”
Around 2005, global per capita energy supply hit another wall, stagnating globally and outright contracting within the OECD. The financial system buckled under this physical constraint: the 2008 Lehman Brothers collapse was an economic consequence of underlying energy limits rather than an isolated financial accident. In response to stalled physical growth and ballooning debt, central banks were driven to unprecedented measures, including negative interest rates, attempting to keep alive an economic architecture designed for an era of boundless energy abundance that no longer exists.
[02:21:10](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8470s) The Decoupling Illusion: Global Trends in Energy, GDP, and Debt
Jean-Marc Jancovici opens the final segment of the lecture by warning the students that the historical era of abundant energy is slowly beginning to fray, and that by the time they reach his age, this deceleration will have accelerated dramatically. Pointing to long-term data tracking the annual variation in world gross domestic product (GDP) per person and economic output per person since 1960, he highlights three distinct historical periods: the era up to the 1970s oil crisis, the intermediate era between the second oil shock in 1979 and the financial shock of 2007–2008, and the post-2008 period.
During the *Trente Glorieuses* (the Post-War Boom), energy consumption per capita expanded rapidly, and production per person grew even faster thanks to rapid gains in energy efficiency. As Jancovici explains, engineers know how to build more efficient machines, such as an engine that requires less oil to move an identical car, or a heavier car that can be sold for a higher price using the same quantity of fuel. However, following the 1970s shocks, energy per capita grew much more slowly—drifting toward 0.5% to 1% annually—and GDP per capita growth softened in tandem. After 2007–2008, the system entered a regime of severe volatility and overall stagnation. Addressing the underlying accounting, Jancovici notes that modern debt has increasingly functioned as an artifact to manufacture nominal GDP in the absence of physical production, masking the physical constraints that began diverging between the OECD and the rest of the world.
As Jancovici warns his students regarding the divergence between their generation's reality and the twentieth century:
> “So that's why your future won't be a continuation of the past.”
```mermaid
flowchart TD
accTitle: Energy Supply and Economic Growth Trajectory
accDescr: Historical progression from the post-war boom to modern energy contraction and debt accumulation.
subgraph S1["1945–1973: High Growth"]
E1["Abundant cheap energy"] --> P1["Accelerating per-capita GDP"]
end
subgraph S2["1974–2006: Slowdown & Financialization"]
E2["Energy growth slows to ~1%"] --> D2["Debt expansion masks slowdown"]
end
subgraph S3["Post-2006: Contraction"]
E3["Per-capita energy peaks & falls"] --> F3["Financial crisis & real stagnation"]
end
S1 --> S2 --> S3
```
---
[02:22:56](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8576s) The 2006 European Peak and the Crisis: It Wasn't Lehman Brothers
Examining the European Union specifically, Jancovici demonstrates that energy supply per capita rose steeply until the 1970s oil shocks, slowed down between the shocks and 2006, and reached its absolute historical peak in 2006—two full years before the collapse of Lehman Brothers. He argues that conventional financial narratives reverse cause and effect: it was not the Wall Street banking crash that induced an economic crisis and subsequently lowered energy usage, but rather the physical constraint in global energy supplies that slowed down underlying GDP growth, ultimately rendering subprime and sovereign borrowers incapable of servicing the mounting debts incurred over previous decades.
Jancovici characterizes this trap as a "two-triggers gun": society first accumulated debt to compensate for the fact that energy supply growth was slowing down, and once physical energy consumption began contracting after 2006, the economy lacked the productive throughput needed to sustain the Ponzi-like debt pyramid. Ever since 2006, genuine per capita growth in Europe has stalled. He supports this with concrete physical indicators: European industrial production, ton-kilometers moved by road freight, and the construction index all remain below their 2007 levels. As a result, Jancovici contends that much of the reported growth in European GDP over the past decade is merely an accounting fiction caused by inadequate inflation corrections.
Highlighting the true catalyst behind the Great Recession, Jancovici insists:
> “It was not Lehman Brothers that caused the economic crisis that caused a fall of the amount of energy used.”
- Energy supply per capita in the European Union peaked in 2006, two years prior to the Lehman Brothers bankruptcy.
- European road transport (measured in ton-kilometers) remains lower today than its 2007 peak.
- European industrial manufacturing and construction indices have both failed to recover their pre-2008 peaks.
---
[02:24:45](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8685s) The Mechanics of European Discontent: Brexit, Enlargement, and Communicating Vessels
Turning to European politics, Jancovici links post-2006 physical economic stagnation directly to institutional fracture and rising nationalism, including Brexit. Referencing French political history—notably Charles de Gaulle's resignation following the 1969 referendum and the French electorate's rejection of the 2005 European Constitution—he observes that voters in a referendum rarely answer the precise technical question on the ballot, but instead express their discontent toward the ruling authority that posed it.
This political backlash is exacerbated by the physics of economic integration. In a growing economic pie, wealth disparities can be bridged without conflict: when Spain and Portugal joined the European Union during an era of robust global expansion, French purchasing power could keep climbing while Spanish incomes caught up. However, when the EU expanded eastward in 2004–2005 into nations where wages were one-fifth those of the West—just before Europe hit its ceiling in per capita energy supply—the economic game shifted from positive-sum expansion to zero-sum "communicating vessels."
When total energy throughput falls, real income cannot expand everywhere simultaneously. The physical and economic equilibrium must balance out through two primary channels: lower-wage workers moving to Western capitals (popularized by the archetype of the "Polish plumber" in London), or industrial capital relocating eastwards (such as Renault establishing manufacturing facilities in Romania, triggering outrage among French factory workers). Jancovici argues that without acknowledging energy as the ultimate foundation of economic wealth, border-free economic zones with wide initial wage disparities inevitably generate internal friction and fuel nationalist exit movements.
Jancovici outlines the political consequence of stagnation:
> “So the temptation for Frexit, Italexit, Espaxit and Swedexit will increase.”
---
[02:27:22](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8842s) Managing a World of Contraction: A Challenge for Future Engineers
Looking across a 50-year trend analysis of the European Union's energy supply, Jancovici shows that the mathematical second derivative of energy supply growth has been pointing downward for decades. After decades of gradually diminishing growth rates, the European trend line has entered negative territory accompanied by rising volatility. Assuming these underlying dynamics hold, the future for advanced economies will not be one of sustained expansion, but of structural contraction, with long-term GDP growth slipping into permanently negative territory.
Addressing the engineering students at Mines ParisTech directly, Jancovici emphasizes that their technical training will be tested far more severely than that of their predecessors. Navigating an economy through contraction is an intensely complex problem of constrained optimization, vastly harder than allocating windfalls in a world of endless growth. He remarks that passing the famously rigorous French competitive entrance exams (*concours*) was simple compared to the physical challenges of maintaining social and institutional stability amidst dwindling fossil fuels. Furthermore, this dynamic is not unique to Europe; the OECD as a whole and the United States followed the exact same pattern, with US per capita energy consumption also peaking two years prior to Lehman Brothers before temporary relief from tight oil and shale gas arrived.
Jancovici underscores the intellectual challenge awaiting the room:
> “So we're going to need your creative genius because I assure you that managing a shrinking world is much more challenging as a constrained optimization exercise than managing an expanding world.”
---
[02:29:54](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8994s) Module Conclusion: Free Nature, Fossil Pockets, and the Upcoming Climate Constraint
Jancovici concludes this introductory module of the course by synthesizing how the contemporary world came to be. Civilization did not construct its present material comfort out of human labor alone, but by discovering free "pockets of sunlight" concentrated underground over geological epochs—as photographer and environmentalist Yann Arthus-Bertrand describes fossil fuels. These dense, free, highly exothermic fuels enabled humanity to extract and transform all other natural resources at unprecedented speeds, building an extraordinary urbanized society dominated by the service sector, widespread leisure time, universal meat consumption, and the luxury of simultaneously satisfying the competing demands of trade unions (the CGT) and corporate employers (the MEDEF).
However, this entire economic edifice rests on a flawed intellectual foundation developed over two centuries. Economists built models that treat physical resource flows as functionally infinite, ignoring the basic reality that the Earth has a fixed diameter of 13,000 kilometers rather than 14,000 or 15,000 kilometers. By treating nature as an unpriced free gift, modern economic theory rendered planetary boundaries invisible. Looking ahead to the next lecture, Jancovici announces that the class will investigate the primary physical constraint that manifests long before total resource exhaustion: the accumulation of waste and pollution, centered on global climate change.
Reflecting on the blindness of modern economic paradigms, Jancovici remarks:
> “And, on the basis of this axiom, which is only an approximation to the first order, I have refined my visions for two centuries but without questioning a fundamental axiom which is: Nature is free.”
[02:31:35](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=9095s) Upstream Bottlenecks: Fossil Fuel Supply and Physical Limits
Jean-Marc Jancovici concludes the introductory lecture by placing climate change into a broader physical and systemic context. Rather than treating it as an isolated crisis, he emphasizes that climate change is merely the downstream consequence of an immense global transformation flow powered by energy. The material throughput of our industrial civilization transforms natural resources into goods and waste, with global warming being the unintended atmospheric exhaust of that engine. As Jancovici summarizes: “So climate change is only the downstream consequence of this transformation flow.”
Looking ahead to the subsequent lecture, Jancovici outlines how the focus will pivot from downstream consequences to the upstream constraints that physically govern the machine. The fundamental bottleneck threatening to constrain the system upstream is the physical availability and supply of fossil fuels, which represent the primary capacity for transformation itself. While other critical physical constraints exist and could serve as limiting factors—such as the supply of metals, mineral resources, or biodiversity and biological species—the upcoming session will concentrate specifically on the depletion and extraction limits of fossil fuels that feed our industrial capacity. With that roadmap laid out, he bids the students a good evening.
```mermaid
flowchart LR
accTitle: Transformation flow from upstream supply to downstream consequence
accDescr: A diagram illustrating how upstream limiting factors feed industrial transformation capacity, which then generates downstream consequences like climate change.
subgraph Upstream["Upstream Inputs & Constraints"]
FF["Fossil fuel supply"]
Metals["Metals & mineral supply"]
Bio["Species & ecological supply"]
end
subgraph System["Industrial Engine"]
Flow["Transformation capacity & throughput"]
end
subgraph Downstream["Downstream Consequences"]
CC["Climate change & pollution"]
end
FF --> Flow
Metals -.-> Flow
Bio -.-> Flow
Flow --> CC
```
- **Downstream impact**: Climate change functions as the terminal byproduct or exhaust of industrial transformation flows.
- **Upstream limiting factors**:
- The primary bottleneck to be analyzed next: fossil fuel supply and depletion (transformation capacity).
- Alternative physical bottlenecks: metal and mineral availability, ecological and species supply.
## Notable quotes
> [00:13](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=13s) And everywhere in your life, if a sophisticated model is not in line with a well-established rule of 3, it is because the model is wrong! — Jean-Marc Jancovici
> [12:20](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=740s) The energy conservation law applied to humans has a consequence that is simplistic, which is that humans can do nothing more than extract from the environment an energy that already exists and use it for their benefit.
> [02:16:41](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8201s) Euros only measure a flow in monetary terms, which kilowatt-hours physically measure. — Jean-Marc Jancovici
> [36:52](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2212s) And choosing an energy means choosing between the disadvantages you want and those you don't want. — Jean-Marc Jancovici
> [02:27:22](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8842s) managing a shrinking world is much more challenging as a constrained optimization exercise than managing an expanding world. — Jean-Marc Jancovici
> [02:31:35](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=9095s) So climate change is only the downstream consequence of this transformation flow. — Jean-Marc Jancovici
> [44:07](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=2647s) Précisément parce que les caractéristiques physiques des combustibles fossiles sont supérieures aux caractéristiques physiques des énergies renouvelables, l'Homme, qui est un animal accumulateur, a passé son temps à passer des énergies renouvelables aux combustibles fossiles, pour pouvoir accumuler plus vite. — Jean-Marc Jancovici
> [02:14:54](https://www.youtube.com/watch?v=xgy0rW0oaFI&t=8094s) In other words, if I deprive my fleet of machines of energy, I will deprive my productive system of its production capacity even if the bankers are very friendly and even if the unemployed are ready to go to work. — Jean-Marc Jancovici
## Mentioned
Jean-Marc Jancovici, Carbone 4, The Shift Project, École des Mines de Paris, Mines ParisTech, Jean-Pierre Foucault, Qui veut gagner des millions ?, Gilets jaunes, Orange, SFR, Free, James Clerk Maxwell, Roquette, Soleil vert (Soylent Green), Charlton Heston, Total, Edwin Drake, Zara, Notre-Dame de Paris, ArcelorMittal, Accord de Paris, La Jamais Contente, World Bank, King Henry IV, Volvo Trucks, Publicis, IKEA, Beauce, Île-de-France, Haussmannian Paris, Grand Paris Express, Los Angeles, Switzerland, Netflix, François Mitterrand, Dmitri Mendeleev, Jean-Baptiste Say, Baron Charles Dupin, Léon de Bruxelles, Haut Conseil pour le Climat, Stratégie Nationale Bas-Carbone (SNBC), OECD, Lehman Brothers, Charles de Gaulle, Renault, Yann Arthus-Bertrand, CGT, MEDEF
## Video description
Partie 1 du cours de Jean-Marc Jancovici à l’École des Mines de Paris en Mai 2019
Diaporama, audio et retranscription à télécharger : https://drive.google.com/open?id=1fqoACrCFtlXKonP266DkFUcmMVj22yj_
Nouveau ! : les vidéos du cours des Mines 2019 sont disponibles dans un format audio+diaporama beaucoup plus lisible : https://slides.pimoid.fr/jancovici/mines_2019/
Audio : https://soundcloud.com/effondrement-imminent/1-lenergie-cours-des-mines-2019-jancovici?in=effondrement-imminent/sets/jancovici
Vidéo originale : https://www.youtube.com/watch?v=WQJsMmJMKOo
Le poids de cette vidéo a été réduit, pour diminuer sa consommation énergétique et donc les émissions de gaz à effet de serre induites, grâce à un tutoriel mis à disposition par le think tank The Shift Project :
https://theshiftproject.org/guide-reduire-poids-video-5-minutes/
Site de Jancovici : https://jancovici.com
Page Facebook : https://www.facebook.com/jeanmarc.jancovici/
[0:13] Jean-Marc Jancovici: And everywhere in your life, if a sophisticated model is not in line with a well-established rule of 3, it is because the model is wrong!
[12:20] The energy conservation law applied to humans has a consequence that is simplistic, which is that humans can do nothing more than extract from the environment an energy that already exists and use it for their benefit.
[136:41] Jean-Marc Jancovici: Euros only measure a flow in monetary terms, which kilowatt-hours physically measure.
[36:52] Jean-Marc Jancovici: And choosing an energy means choosing between the disadvantages you want and those you don't want.
[147:22] Jean-Marc Jancovici: managing a shrinking world is much more challenging as a constrained optimization exercise than managing an expanding world.
[151:35] Jean-Marc Jancovici: So climate change is only the downstream consequence of this transformation flow.
[44:07] Jean-Marc Jancovici: Précisément parce que les caractéristiques physiques des combustibles fossiles sont supérieures aux caractéristiques physiques des énergies renouvelables, l'Homme, qui est un animal accumulateur, a passé son temps à passer des énergies renouvelables aux combustibles fossiles, pour pouvoir accumuler plus vite.
[134:54] Jean-Marc Jancovici: In other words, if I deprive my fleet of machines of energy, I will deprive my productive system of its production capacity even if the bankers are very friendly and even if the unemployed are ready to go to work.
Original transcript
[0:13] I'm going to give you a lecture on,
let's say, two objects that will
[0:19] accompany you throughout your personal
and professional life from now on and
[0:24] besides also since the past, which
are called energy and climate change.
[0:31] So I'm not an academic.
My job is to be a consultant.
[0:36] I am a partner in a consulting firm.
I have a second job as President of an association.
[0:40] And I do extension work
that eventually led to this course.
[0:44] That's why I do this job rather than my
main job.
[0:50] The course I'm going to give you is
essentially a course based on
[0:54] observational data, relatively simple
reasoning with hands.
[0:58] I hope it will be accessible.
It is not very different (to be very frank)
[1:01] from a number of things that I
can tell in other forums for audiences
[1:04] that have not been carefully selected
through contests.
[1:06] So, normally you should be able to keep up.
I'm still going to remind you of a
[1:10] couple of little things as an appetizer.
[1:12] The first is that you will remember
much more easily what I say if you take
[1:16] notes (even if you trash them afterwards)
rather than if you don't take them.
[1:20] So it's a very good mnemonic way to take notes.
[1:23] The second thing is that I will try in
[1:25] particular to invite you to always
approach problems by reasoning by
[1:29] orders of magnitude and rules of 3.
You have entered this school having been
[1:35] carefully selected for your
above-average ability to solve
[1:41] complicated problems that are well-posed.
All right?
[1:46] You have been selected to enter this
school for solving problems that are
[1:49] univocal: they have only one solution.
Perhaps a little complicated,
[1:52] but they have only one solution,
and they are well-posed.
[1:54] That is to say, in the problem, you
have all the information you need to
[1:57] find the solution.
Life and what I'm going to tell you
[1:59] from now on, is essentially made up of
ill-posed problems where you don't have
[2:03] all the information. All right?
[2:05] And when we approach a problem that is
ill-posed and that we do not have all
[2:08] the information, there is something
that is extremely effective in
[2:11] addressing these problems -- and it
will be particularly true in what I am
[2:14] going to tell you -- it is to reason by
orders of magnitude and rules of 3.
[2:17] And everywhere in your life, if a
sophisticated model is not in line
[2:22] with a well-established rule of 3, it
is because the model is wrong!
[2:26] So here are some elements that I give
you as a preamble to the course that we
[2:33] will have the pleasure of going through
together.
[2:38] This is one of the most famous
pensioners in France.
[2:42] He is retired because he would have
said he was going to stop working, but
[2:45] that must not be entirely true because
from time to time, we see him do things
[2:48] that are less fun than that.
It doesn't matter.
[2:50] So we're going to get him back in a
little bit of service.
[2:55] When you ask a question in the
Millionaire Game, for those of you who
[2:58] have already watched this excellent
game, you know that you are given 4
[3:02] answers in advance.
That is, you are told : “Here is the
[3:05] student sitting there in the second
row, does he have a shirt a) blue,
[3:09] b) green, c) yellow, d) black” and all
those who were currently sleeping are failing,
[3:14] the others have the right answer.
[3:15] Now, we will imagine that he asks a
question in an open way, that is, he
[3:19] asks you: “What is energy?”
You know that in France there is a
[3:22] Minister of Energy so you could ask
him: “What is energy?”
[3:25] Normally, he should know since he is
the Minister of Energy.
[3:28] Well, you would realize, if you asked
the question (I'll give you an example
[3:32] in a few minutes), that in fact, the
first answer that comes to the bulk of
[3:35] the population, I mean the bulk of the
population, so I'm not talking about
[3:39] the world in which you live on a daily
basis.
[3:41] It's this.
That is, if you say “energy” in a
[3:45] number of forums and in particular in a
forum that we call “general public”;
[3:53] the first thing that will come to mind
for many people -- and in fact it is
[3:57] normal because it is something that is
also the first way to present energy in
[4:01] the world of economists -- is that it is
something that is bought: a convenience.
[4:05] It's a thing to buy and so the main
[4:09] subject is whether it's expensive or
cheap, and if we could do it
[4:11] differently to get the same thing for
less expensive.
[4:14] This is particularly true in the news
since for all of you who have followed
[4:19] this kind of movement, you know that it
started with a dispute over fuel prices.
[4:24] So, of course, that is not the main
[4:27] issue at the end of the day, but it
started with this dispute, which was a
[4:31] dispute over fuel prices.
So, the Yellow Vests never said: “We
[4:34] don't want to consume fuel because it's
too much CO2” or “We don't want to
[4:37] consume fuel because it makes us
dependent on Russia, Norway and we
[4:40] don't want to.”
No, no.
[4:40] They were just saying: “It's too
expensive.”
[4:44] All right?
So what I'm going to try to explain to
[4:46] you during part of the rest of this
course is that, if you look at the
[4:49] problem from that perspective,
unfortunately, you're missing the
[4:52] point.
There are several reasons why we are
[4:54] missing the point.
The first is that if you look in
[4:58] strictly economic terms what it costs
to buy energy in relation to what you
[5:03] earn.
And you can represent it in several
[5:06] ways.
One of the ways I represent it, is to
[5:09] look at what it costs to buy each year
from the whole economy, to buy the oil,
[5:13] gas and coal that made it work.
So, I look at the whole economic
[5:17] product of the year and I look, in
relation to this economic product, what
[5:21] it costs to buy on the market all the
oil we consume in the year, all the gas
[5:25] we consume in the year (I speak for the
world as a whole) and all the coal we
[5:29] consume in the year.
Well, the result I get is that it costs
[5:33] a few percent of what we earn.
A few percent of what we earn.
[5:36] I will show you a graph in a short
while on how much it costs the French
[5:40] to buy energy and I assure you that to
pay Free, SFR or Orange (sorry I didn't
[5:45] name anyone) to say: “Hello, I'm late”
[5:47] or “Where are you?”
[5:48] It costs roughly the same price. About
the same price.
[5:52] It costs a few percent of what we earn.
And from the moment an object placed in
[5:57] an economic debate represents a few %
of the debate, well, at that moment,
[6:02] the normal reflex will be to say: “I
will take care of it a few % of the time.”
[6:07] And typically, what you see right now
[6:09] in political debates is: I'm interested
in energy at election time a few
[6:12] percent of the time and then, the rest
of the time, I give this to someone to
[6:16] whom I delegate the problem by telling
them: “Make sure that this thing is
[6:19] managed in your own corner, it's not
really my problem.
[6:21] I do not see the link with pensions,
diplomacy, economic policy or the
[6:27] number of printers in the country.
There is no connection.
[6:31] So I will consider it a subject that
can be detached from the rest and only
[6:34] requires a few percent of my time.”
What I'm going to tell you from now on
[6:38] is that this reasoning is as relevant
as if I told you: “Your brain is 2% of
[6:43] your weight, so I can remove it from
you, it's not very serious, you'll lose
[6:47] 2% in efficiency.”
So, “pie chart” reasoning (and that's
[6:51] something that's broader than just
energy) “pie chart” reasonings never
[6:56] tell you if the “pie pieces” are
enslaved to each other or not.
[7:00] There is another funny reasoning of the
same type which is to say:
[7:03] “Agriculture is 2% of GDP so we don't
care, we can dump it, it doesn't matter much.”
[7:08] Well, yes, except that if you stop
[7:10] eating, the remaining 98% of GDP, quite
quickly, will be problematic.
[7:15] So, the “pie chart” reasonings, you
always have to be very wary of the fact
[7:18] that it doesn't represent the
dependence you can have on one “piece
[7:21] of pie” to another.
And what I'm going to show you now is
[7:25] that, in fact, the dependence of the 97
or 98 or 95% of GDP that are not energy
[7:30] purchases, in fact, is totally 100%
dependent in the modern world on the 5%
[7:35] in question.
So, energy is not an invoice, even if…
[7:39] Well, objectively, it is not just an
invoice even if that is how we reason
[7:45] in the economic world in which we live.
There is another thought that often
[7:50] comes to mind when we talk about
energy.
[7:52] It's people telling you: “Ah, energy,
good energy, that's the energy we save.”
[7:55] So, the second thing I'm going to show
you during this course is that if
[7:59] you're in this room right now with the
time, at your choice, to sleep for
[8:03] those who take a nap or to listen,
instead of being picking potatoes, it's
[8:07] precisely because the World has been
increasingly consuming energy over the
[8:11] past two centuries. [Sorry.]
[8:12] So, in fact, the result of the world we
live in today is a world of growing
[8:17] energy abundance and not at all a world
of growing energy savings.
[8:21] So, in fact, the right energy, in the
sense of the one that allowed the
[8:25] emergence of the industrial
civilization in which we live, is
[8:29] precisely the one that we have not
saved.
[8:32] The third topic that is very popular at
the moment is that: “Energy is not
[8:37] very serious to know what it is.
What is important is that it will
[8:41] become 100% renewable.”
You will see that, in fact, that is not
[8:44] exactly how it happened.
And, in fact, the right way to approach
[8:48] energy could be the poet's.
That is, energy is what you are filled with
[8:52] on a morning when you are in good
shape (or an afternoon, it depends on
[8:56] when you get up). Well, in fact, this
way of seeing things is the right way
[9:00] because, when you consider that you are
full of energy, in fact what it means
[9:04] is that you consider you have a great
ability to control your destiny.
[9:08] “I have a lot of energy, I'm very fit”,
that means, basically, “there's not much
[9:12] I am afraid of”,
and so, “I have a great ability to
[9:15] control my destiny”.
But energy, as we will see from now on,
[9:18] is that, having a lot of it, is precisely
having a great ability to control your
[9:22] environment.
It's that by definition.
[9:25] By definition, having a lot of energy
means having a great ability to control
[9:29] your environment.
And why is that?
[9:32] Because energy, before being an invoice
or before being a subject of debate, is
[9:36] a physical quantity.
So you know it well because you have
[9:39] done a little bit of physics to get
into this amphitheatre, energy is a
[9:44] physical quantity.
It's quite funny, moreover, because in
[9:46] physics there is no totally univocal
definition of energy.
[9:49] I'll suggest one for you.
For me, energy is what quantifies the
[9:52] change of state of a system.
All right?
[9:54] Energy is what quantifies, I mean
quantifies, calculates, the change of
[9:59] state of a system.
In other words, the more the world
[10:02] around you changes, the more energy has
come into play.
[10:05] And, the more energy that comes into
play, the more the world around you
[10:09] changes.
It's as simple as that.
[10:12] So if I take this back to
transformations in everyday life, here
[10:15] are some of them, or more precisely
objects that transform the environment
[10:19] in everyday life.
These are objects that transform the
[10:22] temperature.
These are objects that are intended to
[10:24] change a temperature, which I show you
here.
[10:26] Either to heat or to cool down.
And these objects use or eventually
[10:31] release energy.
Here are some objects to change a
[10:34] velocity.
That's all a car is for.
[10:36] It is used to change the speed of what
is contained in the car, eventually you
[10:41] and your luggage when you go on
holiday.
[10:44] Well, a speed change is a change in the
state of a system.
[10:47] Here are some objects to change a
shape.
[10:51] You had soil, the soil is excavated, it
is placed next to the hole.
[10:54] Change of form.
You had a sheet metal, the sheet metal
[10:57] is stamped and you have a car door.
Change of form.
[11:00] These machines use energy.
You have energy that comes into play
[11:04] when you change a chemical composition.
And, by the way, the first chemical
[11:08] composition that constantly changes to
provide energy in your immediate
[11:12] universe is called your digestion of
the food you eat.
[11:15] Actually, that's what they're for.
They are used to provide you with
[11:17] energy.
You have energy that comes into play
[11:19] when you have magnetic fields that
interact with electric currents.
[11:22] So, it can either consume it, in an
engine, or “supply it”, in an
[11:28] alternator.
You have energy that comes into play
[11:31] when you rearrange the nucleons of a
nucleus.
[11:34] And you know the sun spends its time
doing that.
[11:37] It is a large permanent thermonuclear
bomb that spends its time assembling
[11:42] hydrogen nuclei to make helium nuclei.
You have energy that comes into play
[11:47] when you have material-radiation
interactions.
[11:50] So, the interaction of matter and
radiation that interests you the most
[11:53] is your smartphone.
But in the end, there is more to it
[11:55] than that in the interaction of matter
and radiation.
[11:57] One that will be of great interest to
you, and to me too in a month and a
[12:00] half represented by this young woman on
the right.
[12:02] So, in a general way, using energy is
nothing more than transforming the
[12:09] world around us and conversely,
transforming the world around us
[12:15] necessarily implies that there is
energy involved.
[12:20] So, once I told you that, a first small
remark.
[12:25] Man is in transition.
You know that we currently have a
[12:28] Ministry of Energy Transition and not
just a Ministry of Energy.
[12:31] We have a Ministry of Energy
Transition.
[12:32] Well, the Ministry of Energy Transition
is probably the oldest Ministry in the
[12:36] human community, since Men have been in
energy transition for 500,000 years.
[12:40] 500,000 years ago, the only energy that
humans could use was their bodily
[12:44] energy.
And then, they started to domesticate
[12:47] the fire, so a first extracorporeal
energy.
[12:49] In Antiquity, we started to domesticate
all renewable energies and, by the way,
[12:54] even some fossil fuels.
For example, oil was known to the
[12:58] Sumerians, coal was known to the
Chinese a few thousand years ago, so in
[13:02] small doses all this.
And in fact, the industrial revolution
[13:06] was the domestication of fossil fuels,
we will come back to that.
[13:11] And so, the energy transition is a
permanent state of human beings.
[13:16] Every time they find a way to use a new
energy source, they do it.
[13:21] What characterizes the modern era (and
you will see that it characterizes it
[13:25] extremely strongly and that is what
poses a problem) is that we have
[13:30] radically changed the order of
magnitude in all these processes in a
[13:34] very, very short time.
So energy, as I told you, is a physical
[13:38] quantity.
From the moment I said that energy is a
[13:41] physical quantity, it means that there is
every chance that energy will be
[13:46] governed by laws that we cannot change.
That's the charm of the laws of
[13:50] physics.
It's that you can understand what
[13:52] Maxwell's equations are, but once you
understand them, you can't change them.
[13:56] You can't say: “Well, it would be nice
for the purchasing power of consumers
[14:00] if we could change Maxwell's equations
a little bit.”
[14:02] No need to try.
Well, as far as energy is concerned,
[14:04] you have a few laws that
apply to us and that cannot be changed.
[14:07] So, it is not to say that we do not try
to change them from time to time
[14:10] implicitly by votes in the National
Assembly, but, nevertheless, it is
[14:13] better to know them.
So, as I told you, energy is what
[14:16] quantifies the transformation of the
environment.
[14:19] The first cardinal law that is very
simple to keep in mind when it comes to
[14:23] energy and that you all know by heart,
of course, is the first principle of
[14:27] thermodynamics or energy conservation
law.
[14:29] So, the energy conservation law
applied to humans has a consequence
[14:33] that is simplistic, which is that
humans can do nothing more than extract
[14:37] from the environment an energy that
already exists and use it for their
[14:41] benefit.
That's all Men are capable of doing.
[14:44] If Men were able to make energy appear
within them without communicating with
[14:50] the outside, we would be violating the
first principle of thermodynamics.
[14:55] So, I'm sure that in a good Harry
Potter, you can do that, but in the
[14:59] real world it's more difficult...
So, any energy we use, we have to find
[15:05] it in the environment.
Everything.
[15:09] An energy that is in the environment is
called “primary energy” in the jargon
[15:14] of energy experts.
All right?
[15:16] So when you see the term “primary
energy” passing through the statistics
[15:20] (which I may ask you to look at)
it means that it is energy as it
[15:24] is found in the environment.
There is another term that is very
[15:28] common in energy (we will come back to
it in a few classes) which is
[15:31] the “final energy”.
The final energy is the energy that
[15:34] passes the final consumer's meter.
So, who is the final consumer?
[15:38] It is you when you are at home and you
have a gas meter or an electricity
[15:42] meter or you have an oil tank (it's
very bad, you can't tell anyone) and a
[15:46] meter on the truck that delivers the
fuel or when you are an industrial, you
[15:49] have a meter because you use gas in a
glass furnace.
[15:52] There you go.
So, as soon as you are an end consumer,
[15:54] individual or industrial and you buy
energy that will allow you to operate a
[15:58] machine, it is called final energy.
The energy found in the environment is
[16:02] called primary and in between, you
obviously have the energy system.
[16:05] So historically, the only primary
energies that humans know how to use
[16:11] are food and the warmth of the sun.
There are two of them, I should have
[16:16] put the heat of the sun on too.
So, historically, the only converter
[16:19] that people have at their disposal is
themselves.
[16:22] Because, to use energy, you need a
converter.
[16:24] We have to get this into something that
will transform it.
[16:28] So, the only converter that people have
is themselves.
[16:30] So, they eat, they heat themselves in
the sun and from these energies that
[16:36] they absorb or ingest, it comes out
heat, a lot, work, a little.
[16:41] And then, over time, we started to be
able to domesticate other converters.
[16:47] So, apart from wood, a very rustic
converter, we started to domesticate
[16:52] all possible renewable energies.
So, at the time, renewable energies
[16:57] included other living organisms,
because they were completely renewable.
[17:01] Draught animals are perfectly
renewable.
[17:03] It eats perfectly renewable grass and
therefore provides you with perfectly
[17:07] renewable energy.
Wind and water were also domesticated
[17:11] through the mills.
Ancient Europe was covered with water
[17:14] and then windmills.
And so, it must be clear that renewable
[17:18] energies are not the future, they are
the past.
[17:20] So not in the sense that there is
nothing to expect from the future.
[17:22] What I mean is that renewable energies
were part of our daily lives a few
[17:26] centuries ago.
So, a world 100% renewable energy, I
[17:28] know very well what it looks like.
I have at least one sampling point,
[17:32] it's the world three centuries ago.
This one is 100% renewable energy, it
[17:36] works very well.
So, a world with 1 billion people on
[17:40] Earth, 30-40 years of life expectancy
at birth and two thirds of the
[17:45] population in the fields, that, I know
it works in 100% renewable energy.
[17:50] There is no problem, since we did it
once.
[17:53] Obviously, the debate today is: “Can
we achieve civilization with the
[17:56] engineers at MinesParisTech and all the
machines we use today with 100%
[17:59] renewable energy?”
So, we'll come back to that later.
[18:02] And then, two centuries ago, there were
a few brilliant engineers and
[18:07] physicists who said: “We could use
other converters, converters that are
[18:12] non-renewable, in this case machines
made of metal, and we will give them an
[18:17] energy that we do not yet know how to
use on a large scale today, called
[18:22] fossil fuels.”
So here, I summarize for you in one
[18:25] sheet what has been the energetic
history of men.
[18:28] First the converter is us.
Then it's other living organisms.
[18:32] There were slaves in it too.
Then, renewable energies and,
[18:37] ultimately, metal machines with fossil
fuels.
[18:41] And so, what I'm telling you also is
something that's absolutely essential
[18:46] is that, in fact, we don't consume
energy, except what you eat.
[18:50] So, when you see “energy consumption”
somewhere, it's an inappropriate term.
[18:54] Because unless I'm mistaken, I don't
think you've ever drunk oil.
[18:58] If anyone has ever done this here, let
them tell me, but normally not.
[19:02] I don't think you've ever eaten coal
except the one used for flatulence.
[19:06] And you didn't breathe gas, at least
not methane, the one that gives
[19:09] Mickey's voice maybe.
So, we don't consume energy with our
[19:14] own bodies.
In fact, when we say that we consume
[19:16] energy, it is an inappropriate term --
but it is an inappropriate term that
[19:19] induces an optical illusion that is
extremely strong.
[19:21] Consuming energy is actually
domesticating a machine.
[19:24] So, wherever you are going to see
“energy consumption”, including in my
[19:28] slides – because from time to time I
use this shortcut even if I try not to
[19:31] You replace by “using machines”.
And wherever you see that we are
[19:36] “consuming more and more energy”, you
cross over and replace it with: “We
[19:40] are using more and more machines”.
That's what you have to understand.
[19:44] And in fact, the increasing amount of
energy we use is nothing more than how
[19:50] to increase proportionally the huge
mechanical exoskeleton we have created
[19:56] for our profit.
It's this, energy.
[19:59] And this world of machines is the world
in which you live.
[20:02] So, unless I'm mistaken too: moral and
weather conditions make you come to
[20:08] this class dressed.
If you are dressed, it means that you
[20:11] have put on a piece of clothing at one
time or another.
[20:13] So, putting on a piece of clothing
takes exactly a few seconds, even if
[20:17] you are extremely clumsy.
In the dark, badly awake, after the
[20:20] ingestion of substances that I will not
name, perhaps a few tens of seconds but
[20:24] never much more.
A few seconds, then.
[20:27] Well, in a matter of seconds you have
mobilized thousands of machines for
[20:32] your benefit without realizing it.
You have mobilized thousands of
[20:35] machines for your benefit.
You started by mobilizing all these
[20:39] agricultural machines for your benefit
if you have a so-called natural textile
[20:43] garment: cotton, linen, etc.
You started by mobilizing all the
[20:47] agricultural machinery that sowed,
harvested and eventually processed
[20:51] cotton for your benefit.
You have, if you use a synthetic
[20:55] textile fiber (so everything that is
poly-whatever, nylon-thing,
[21:00] all this comes from oil).
So, if you put on an underwear that has
[21:05] synthetic fibers or a t-shirt that has
synthetic fibers, well, you have put on
[21:10] a piece of oil platform plus a piece of
steam cracker plus a piece of refinery,
[21:15] those little 5 billion-dollar beasts
right there that you see in that
[21:19] picture.
If you have something other than an
[21:21] unbleached fabric, it has been dyed, so
it was necessary to make the dyes.
[21:25] So, you have the chemical industry that
has worked upstream, then you have
[21:29] machines that have....
Sorry, we had to weave the fibers
[21:32] first, excuse me.
So, these are mechanical machines
[21:35] again.
It had to be dyed, so this is the
[21:37] chemical industry.
It had to be transported because
[21:40] obviously it is not where you grow the
cotton that you weave it, that you dye
[21:45] it, etc.
So, you have other machines that have
[21:47] been involved at all the intermediate
stages of the chain called trucks,
[21:51] trains, planes.
It was necessary to manufacture boxes
[21:54] in which refineries were installed, in
which chemical plants were installed,
[21:59] etc.
So, you also have these machines that
[22:01] have come into action.
It was necessary for power plants to
[22:04] supply part of the process.
So, these machines also came into
[22:07] action.
In short, in something totally trivial
[22:10] that we do as we breathe – that is
called putting on a garment --, well,
[22:15] you don't realize it but there is an
army of machines that have worked for
[22:19] you, just with this very simple
gesture.
[22:22] So, after you get dressed, those who
have proper hygiene will brush their
[22:27] teeth after breakfast.
Again, it's the same: brushing your
[22:31] teeth is something that takes three
minutes if you follow the doctor's
[22:34] advice, one minute if you're in a
hurry.
[22:36] You have again used considerable
quantities of machines simply to make
[22:41] this gesture.
You have here a picture of a chemical
[22:45] factory in northern France that belongs
to the Roquet family group and that
[22:51] produces a sugar that is found in
toothpaste, called sorbitol.
[22:56] Then you know that sugar causes
cavities.
[22:58] So, if you put sugar in your toothpaste
that causes cavities, it's still a bit
[23:00] of a stretch.
So, it turns out that the sugar we want
[23:02] in the toothpaste -- so that it tastes
a little nice -- is a sugar that does
[23:05] not cause cavities.
It's a different molecule and, in fact,
[23:09] it's one of the few hundred molecules
you're going to take out of a factory
[23:13] called a starch factory, into which you
put a full train of wagons loaded with
[23:18] corn every day and you take out
hundreds of different chemicals.
[23:22] And, on site, there are a few thousand
people working on a plant that runs in
[23:26] 3/8.
It is one of the largest chemical
[23:28] plants in France.
Then you have your tube that is made of
[23:32] plastic.
Now there are no longer really any
[23:34] metal tubes.
So, in plastic!
[23:35] New oil platform / refinery / steam
cracker / etc.
[23:39] And your plastic tube, it does not
appear by the operation of the Holy
[23:43] Spirit from the plastic.
You need an extruder, that you see
[23:47] here.
You brush your teeth in front of a
[23:48] mirror because otherwise you do stains
everywhere.
[23:51] So, we had to make the mirror.
Here you have a train-float that makes
[23:55] the mirror and, again, you need boxes,
trucks, etc.
[23:58] And then you brush your teeth with
purified water and this is a water
[24:01] purifying device, for example.
So, again, an army of machines that
[24:06] have worked for a daily gesture called
brushing their teeth.
[24:11] Now, I come to the most important thing
in your life: your phone.
[24:14] Well, it's the same thing.
When you make a phone call, you have
[24:19] mobilized an army of machines for your
benefit.
[24:23] It was necessary to manufacture
plastics for the telephone, to
[24:28] manufacture purified water, etc.
Steel must be manufactured for antenna
[24:32] supports.
You have 40 different metals in a
[24:35] smartphone.
40!
[24:37] Some present at extremely low
concentrations and several tens.
[24:40] So, there are as many mining activities
here and there, so there are as many
[24:44] mining machines, etc.
Let's take the telecom network, that
[24:47] makes possible to operate the
– because if you're the only one with a
[24:50] smartphone and others don't, it's not
much use,
[24:53] you have to be able to communicate with
others.
[24:57] So, we need a network.
Here is for example a machine to run
[24:59] cables to make the network, etc.
So, making a phone call is also
[25:03] something that will involve thousands
of machines for all the intermediate
[25:09] stages of construction and operation of
the device.
[25:13] So, I say it again.
Today, we live in a world of machines
[25:17] and all these machines without
exception use energy.
[25:21] All of them!
And you understand well, to reverse the
[25:25] reasoning I showed you earlier on: It
doesn’t matter if it's 3%: if you
[25:31] instantly deprive the world of energy,
it's not 3% of GDP you're going to
[25:37] lose...
It's quite simple to understand.
[25:41] You no longer have a means of transport
that works.
[25:44] You no longer have banks, no water
networks, no hospitals, no transport of
[25:50] any kind because no energy.
All right.
[25:53] So, you will starve, you will freeze to
death and you will kill each other.
[25:57] Basically, that's what happens if
tomorrow morning, instantly, we deprive
[26:00] the world of energy.
So, the whole modern world depends on
[26:04] it and that it costs 1% or 100% of what
you earn is not so much the subject.
[26:08] Well, it's a subject, but it's not the
only one.
[26:13] From now on, we will look at a number
of quantitative elements.
[26:17] So how do we count energy?
You know that when you are given an
[26:20] exercise to enter to MinesParisTech,
generally the unit you are allowed and
[26:24] the only one is the Joule.
I'm not going to use it much because if
[26:29] I expressed in Joules the quantities
we're going to discuss from now on,
[26:35] there would be so many 0’s on the slide
that you'd take too long to look at it.
[26:41] So often we'll use units of energy a
little different from the Joules
[26:46] because it avoids Gigas and Megas and
it allows us to have smaller things.
[26:52] So, already the first way to remove 6
zeros in Joules, is to switch to
[26:57] kilowatt-hours (kWh).
And the advantage of the kilowatt-hour
[27:01] is that it is what appears on the bills
(even if energy is not just a bill).
[27:05] It also brings us closer to things that
are more familiar in everyday
[27:12] discussions.
A French individual today uses, all
[27:16] uses included, imports included (i.e.
including the energy that has been used
[27:20] outside France to operate the machines
that supply his consumption in France –
[27:25] because, to take the example of your
smartphone, from now on, it is “made
[27:30] elsewhere” in its entirety),
well, it is around 60,000 kWh a year.
[27:36] As for energy companies, they have a
unit that they also like, which still
[27:41] allows them to gain 4 zeros, which is
the ton of oil equivalent.
[27:45] The ton of oil equivalent has a very
simple definition:
[27:47] it is the equivalent of the energy
released by the combustion of one ton
[27:51] of oil.
So, a ton of oil does not always have
[27:54] the same combustion energy, it depends
on the nature of the oil.
[27:58] That's why we usually add “average
quality” and it's worth about 11600
[28:02] kWh.
From time to time, you will also have
[28:06] units in the energy that are brought in
by the Anglo-Saxons, especially the
[28:11] Americans; and you know that American
units are rarely compatible with the
[28:17] metric system.
There you go.
[28:18] So, the ton of oil equivalent is part
of that big whole.
[28:23] OK.
I'll use a little bit of the electron-volt.
[28:25] Not often.
And finally, I will also use
[28:30] the “slave equivalent”.
So, the “slave equivalent” is about
[28:34] 100 kilowatt-hours of mechanical energy
and I will explain why right now.
[28:40] Who has done this before in this
amphitheatre?
[28:43] Oh, not more?
Well, who has already walked up the
[28:49] Eiffel Tower?
Well, that's better already.
[28:51] So, let's imagine that for some reasons
that interest you, you decide to climb
[29:04] the Eiffel Tower 6.3 times during the
day.
[29:11] Who has already climbed the Eiffel
Tower 6.3 times?
[29:15] Ah, that's good.
It's to impress the Japanese or...
[29:20] No, it's for another reason?
So, if you climb the Eiffel Tower 6.3
[29:26] times during the day, with the Eiffel
Tower at just over 300 m, you will
[29:33] experience a difference in altitude of
around 2000 m during the day.
[29:39] In doing so, you will generally use
your legs since using your arms is
[29:45] harder...
Well, the mechanical energy that you
[29:49] are going to release with an effort of
this nature (which is not a totally
[29:54] marginal effort for everybody)
is E = m*g*h.
[29:58] So, it's extremely simple.
Well, actually, it gives a ridiculous
[30:02] half a kilowatt-hour over a day.
So, a man at work who uses his legs to
[30:07] power any mechanical device like
Charlton Heston who pedals in “Green
[30:13] Sun”, at the end of the day, he will
have been able to restore or provide
[30:19] about half a kilowatt-hour of
mechanical energy.
[30:23] If you imagine that this man at work
makes this effort every two days.
[30:27] Which is another way of saying that you
climb the Eiffel Tower three times
[30:31] every morning.
Well, by the end of the year, your legs
[30:35] will have provided about a hundred
kilowatt-hours of mechanical energy.
[30:40] So, over a year's work, the carcass of
a reasonably trained man is capable of
[30:45] providing about a hundred
kilowatt-hours of mechanical energy if
[30:50] he uses his legs.
If you use your arms (and let's say by
[30:53] passing a little bit of back also and a
shovel -- it's more difficult with bare
[30:57] hands), and that you pour six cubic
meters of soil, that is to say about 15
[31:01] tons of soil in a day,
well, in addition to blisters, you will
[31:06] have provided 0.05 kWh of mechanical
energy.
[31:09] That is to say, you are even “ten
times more ridiculous” than the person
[31:13] who climbed the Eiffel Tower three
times with his legs.
[31:16] So, a pair of arms at work during the
day is 0.05 kWh, a pair of arms at work
[31:24] during the year is about 10 kWh of
mechanical energy.
[31:29] If you burn a liter of petrol, that
costs the scandalously high price of
[31:35] 1.60 € (which justifies finding it too expensive)
you're going to get 10 kWh of thermal
[31:42] energy.
And if you want to have a strict
[31:45] comparison, obviously you have to put
it into a machine that will convert
[31:50] this thermal energy into mechanical
energy; even with the best engineers in
[31:56] the world to make cars, you will get 2
to 4 kWh of mechanical energy, no more.
[32:01] It doesn't depend on the engineer, the
2 to 4, it actually depends on how the
[32:06] car functions
(if it is close to its optimal
[32:09] performance or not).
Well, so if it's 2, it's the driver's
[32:13] fault, it's not yours.
So, you will get 2 to 4 kWh of
[32:16] mechanical energy.
That is to say, in a single liter of
[32:21] petrol (which we will see in a short
time that the French still consume not
[32:27] far from 1000 liters per year), you
have the same work content, the same
[32:33] capacity to change environment, as in
10 to 100 days of hard work by a human
[32:40] being.
I am telling you again
[32:42] when you use a machine that consumes a
liter of gasoline, you are able to
[32:47] change the environment, that is to
provide work, at the same level as 10
[32:52] to 100 human beings who would use
either their legs or their arms.
[32:57] I don't know if you realize the
difference you have between the energy
[33:02] we use through the machine and our own
body.
[33:06] If we convert all this into money,
another way of saying the same thing is
[33:10] that the kWh of mechanical energy, if I
pay a man at work to provide it, I will
[33:15] pay him from a few hundred to a few
thousand euros, while the machine at
[33:19] work provides me the same service for a
marginal cost (I did not put the
[33:24] machine in there) in the order of a few
tens of cents.
[33:27] So, when I go from man to work to
machine to work, outside the cost of
[33:32] the machine, I divided the cost of a
unitary transformation of the
[33:36] environment by a factor of a few
hundreds to a few thousands.
[33:40] The reason why we are mechanizing
everything we can in the economic world
[33:46] is there.
So as soon as you can replace a worker
[33:49] with a robot, you do it.
As soon as you can replace a worker
[33:53] assembler on a chain with a robot, you
do it.
[33:55] As soon as you can mechanize anything,
a farmer, replace it with a tractor,
[34:00] you will always, always, always, always
do it, because of this absolutely
[34:05] considerable difference in price
between human labour and energy.
[34:09] That is why we have always been looking
for effective machines to replace
[34:16] people with machines.
It even worked for the replacement of
[34:20] slaves.
If you take a slave, which is usually
[34:24] not a youthful vocation…
Well, this slave, to make him work,
[34:29] you're going to have to go get him
against his will.
[34:31] You have to pay money.
I would remind you that there was a
[34:34] time when there was a slave trade that
was a completely immoral business by
[34:38] current standards, but in the meantime,
it was still done for economic reasons.
[34:42] You have to stop him from killing you,
you have to stop him from getting out
[34:46] of here, you have to feed him and so
on...
[34:49] And when you look at what it costs to
get a slave's work, you realize that
[34:53] even that, it will cost you 10 to 100
times more than the machine that has
[34:57] nothing against its condition as
machines, that does not seek to get out
[35:00] of the way and that does not go on
strike and works 24h/24.
[35:03] So, the reason why slavery has
disappeared in societies that have had
[35:09] access to energy is not because the
genetic code has changed.
[35:13] So, I'm going to make a little
incursion into the course you didn't go
[35:16] to for some of you: it's not because
our genetic code has changed.
[35:19] Our genetic code is exactly the same as
that of our ancestors two or three
[35:23] centuries ago.
Simply, there are no longer any
[35:26] incentives to do things that we were
doing at the time because we found much
[35:32] better and much less annoying to do the
same thing.
[35:36] So, what freed the slaves was oil.
[35:43] At this stage, there are some initial
[35:45] conclusions that I propose to you.
So, I remind you that using energy
[35:52] implies that energy already exists in
the environment.
[35:55] So, sometimes in a debate, you see
people telling you: “We could use
[35:58] hydrogen.”
Hydrogen in the environment, there is a
[36:00] place where there is a lot of it, it's
called the sun.
[36:02] It's not very convenient to pick it up.
The rest, it is everywhere in bound
[36:05] form.
In water, there is plenty of it.
[36:07] You have a lot of it in life, etc.
But everywhere, it is in bound form, so it
[36:12] is not available as an energy source.
The molecule is available, the energy
[36:18] is not.
You have to break the bonds, so for
[36:20] example electrolyze water and for that
you need more energy than the energy
[36:24] you get from hydrogen combustion.
So, hydrogen is not a primary energy
[36:29] source.
When you are told: “We could use the
[36:31] fuel cell.”
Well, it's an engine. The fuel cell is
[36:34] not an energy source.
So, what we have to compare to the
[36:38] primary energies we use today is other
primary energies, i.e. things that can
[36:42] be found in the environment and that
are usable as they are in the
[36:46] environment.
The rest is not accessible.
[36:52] As energy quantifies transformation,
you have no “green energy” (or, by
[36:58] the way, no “pink energy” and no
“black energy”).
[37:03] In fact, choosing an energy means
choosing a type of transformation and
[37:07] choosing advantages and counterparts.
Any energy is dirty if you bring it to
[37:13] a sufficient level of use.
Any one of them.
[37:17] The day you cover the entire planet
with photovoltaic panels, it stops
[37:22] being clean.
So, clean energy, in general, when you
[37:25] look at the figures, you realize that
it is an energy that is used in
[37:29] sufficiently small quantities that its
disadvantages are also small.
[37:34] In general, this is a clean energy.
As soon as energy begins to be used in
[37:38] massive quantities, regardless of how
it is extracted from the environment,
[37:43] there are disadvantages.
And choosing an energy means choosing
[37:47] between the disadvantages you want and
those you don't want.
[37:51] That's the point.
Something that is absolutely essential,
[37:57] I will come back to it several times
during this first module of the course,
[38:01] is that energy (I am not talking about
what makes it possible to extract it
[38:05] from the environment) energy is free!
So, you all heard, the wind is free,
[38:11] the sun is free.
So, there's no reason not to use it.
[38:13] In fact, wind and sun are free, no one
in this room has paid a penny for the
[38:18] sun to exist, for the wind to exist.
But no one in this room paid a penny
[38:23] for oil to exist either!
Oil is free of charge.
[38:29] What needs to be paid is the
willingness to share of the person who
[38:33] is lucky enough to be sitting on it.
That's what you pay for.
[38:36] And what needs to be paid is the work
of the few of you who will go to Total
[38:41] (it's very bad, don't tell anyone!) to
go make holes in the ground and bring
[38:45] out the oil.
That's what you pay for.
[38:48] Oil is free of charge.
It's free of charge.
[38:55] So, when we pay for energy, all we pay
is human labor and human rents to
[39:05] access energy that is free.
We only pay men and the money is used
[39:12] to pay only men.
You've never seen nature send an
[39:17] invoice to anyone.
So, we only pay men.
[39:23] As energy is physics, and as what you
pay for is not energy itself but
[39:31] the work you have to dedicate to extract it
from the environment, the price of an
[39:37] energy does not depend on the abundance
of energy (because you could say
[39:40] “if the energy is very
abundant, it is thus even more free
[39:43] than the others”). In fact, that is not
what matters.
[39:45] If an energy is very abundant, it can
still be very difficult to extract from
[39:49] the environment.
You know, there is an energy that is
[39:51] totally superabundant in the universe,
it's the 3 Kelvin degrees radiation in
[39:55] the void.
I can tell you that you will never do
[39:57] anything with it, although there are
absolutely considerable quantities.
[40:01] So, the fact that there are absolutely
considerable amounts of energy does not
[40:05] tell us anything about how easy it is
to extract it and use it for our
[40:09] benefit.
What will count for the cost of energy,
[40:12] i.e. the ease with which it can be
extracted and used for our benefit, is
[40:17] the fact that the pre-existing energy
source in the environment is already
[40:23] very concentrated and with few barriers
separating us from access to this
[40:28] source.
And so, the archetype of this thing is oil.
[40:31] Oil is hyper-concentrated (less than
nuclear energy, but nuclear energy is
[40:35] more complicated to use).
It's very concentrated and the barriers
[40:39] that separate us from its access are
not very hard to cross.
[40:43] Historically, Mr. Drake went to Titus
City to make three holes and the oil
[40:48] spilled.
It's not very complicated historically
[40:51] to get oil out.
The more energy is separated from us by
[40:55] large barriers and the more diffuse it
is, the more expensive it will be to
[41:00] extract from the environment.
It's just physics.
[41:03] And then I'll show it to you with a
quick comparison.
[41:07] Let's imagine that I take the volume of
air in this room, which is not very far
[41:11] from representing a cube of 10 m on
each side.
[41:14] Let's imagine that I blow it at 80
km/h, which is either a good mistral
[41:19] for the southerners, or 45 knots of
wind for the sailors.
[41:23] And I'm running this through a wind
turbine.
[41:25] If I put this wind through a wind
turbine, it will put this wind mill in action and
[41:30] provide me with electricity.
This electricity is an energy, I can
[41:34] count it.
Well, the amount of electricity I
[41:37] recover with a thousand cubic meters of
air at 80 km/h that passes through the
[41:42] wind turbine is the same as the amount
of energy I recover by burning 3 ml of
[41:47] oil, 3!
Not 3 tons, not 3 liters, not 30
[41:52] liters: 3 milliliters, 3
mini-milliliters.
[41:57] With regard to the amount of human work
to invest, in your opinion, is it
[42:02] easier to go and make a hole in the
Saudi desert and bring out 3 ml of oil
[42:07] or is it easier to build a wind
turbine, wait for the wind to blow and
[42:12] recover the electricity that comes out?
Well, the answer is in the prices.
[42:18] Since money only pays men.
If you use a wind turbine, in Europe,
[42:23] you will pay 6 to 8 cents for your kilowatt-hour of
electricity (for the wind turbine part)
[42:29] and at that price, there is class
when there is wind.
[42:33] When there is no wind, the video
projector does not work.
[42:36] Well then, I can yell a little loud,
there's no microphone, it's okay.
[42:40] I can do with my hands without a
projector, but for all of you who have
[42:43] come by subway, there is no subway
either, it's a little more annoying.
[42:46] There is also no party tonight if the
wind is not blowing.
[42:49] This is starting to get really, really
annoying.
[42:52] There's no alarm clock tomorrow morning
if it runs on electricity.
[42:55] The fridge: you can't cool the beers,
well, it's a disaster.
[42:59] So, if there is no wind, the system
stops.
[43:02] If you don't want the system to stop
when there is no wind, you have to add
[43:06] the cost of storage.
And then, at that moment, you multiply
[43:08] roughly by 3, sometimes by 6.
So, the order of magnitude of the
[43:12] kilowatt-hour stored with wind is a few
tens of cents.
[43:17] In contrast, the order of magnitude of
the cost per kilowatt-hour already
[43:20] stored (since when you take your oil
out of the ground it is already a
[43:23] stock),
at that time, you can already use it
[43:26] today, tomorrow, the day after
tomorrow, next week, or at 3am, exactly
[43:31] as you wish.
Well, this kilowatt-hour of oil already
[43:35] stored out of the Saudi desert is worth
0.3 cents.
[43:39] So, between the cost of one
kilowatt-hour extracted and stored from
[43:43] the wind
(diffuse source, the air is not dense:
[43:46] 1.2 kg per cubic meter, it's really not dense)
and the cost of a kilowatt-hour
[43:51] coming out of a Saudi oil well
[43:54] you have a
factor of about a hundred
[43:58] on the cost of making available
a stored kilowatt-hour.
[44:02] And again, there, the wind turbine, you
made it with oil.
[44:07] The system is not closed-looped.
That is to say, to manufacture the wind
[44:11] turbine, you have benefited from a very
efficient industrial system that has
[44:15] extracted the copper from the mine,
extracted the bauxite from the mine,
[44:19] extracted the iron ore from the mine,
metallurgy upstream, assembled all this
[44:23] stuff, transported, erected the
concrete block, etc.
[44:26] All this was done with fossil fuels.
If you had to do all this with other
[44:29] wind turbines, it is not completely
certain that the price of the wind
[44:33] turbine would always be 6 to 8 cents
per kilowatt-hour.
[44:35] We can take the bets.
My bet is that it would be worth a
[44:38] little more.
So even if you do the wind turbine with
[44:42] fossil fuels, you realize that you have
a factor of a few tens to a hundred
[44:47] between a kWh out of the wind and a kWh
out of an easy oil well.
[44:52] And that's irremediable because it's
physics.
[44:55] So that's why historically we haven't
switched from fossil fuels to renewable
[45:00] energy, but we have done the exact
opposite.
[45:04] Two centuries ago the navy was 100%
renewable and moreover as the wind does
[45:07] not always blow, it was necessary to
take lemons on board to be sure that
[45:11] sailors did not catch scurvy.
And it came to us that, to bring you
[45:14] the Zara t-shirt quickly (because the
t-shirt is not made in France), it's
[45:18] still much better to have a 100% fossil
navy.
[45:20] It's much more efficient.
It goes a lot faster.
[45:23] We had a 100% renewable transport
system a few centuries ago and we
[45:27] thought that, nevertheless, to supply
the Ecole des Mines for lunch, it's not
[45:31] terrific, it's much better to have 100%
fossil transport, it works better.
[45:35] We had a 100% renewable agriculture and
we thought that, nevertheless, to have
[45:40] a very productive agriculture and for
farmers' children to go to school, it
[45:44] is not terrific, it is much better to
have a 100% fossil agriculture.
[45:48] We had 100% renewable civil engineering
-- that's how the Romans built the
[45:52] Roman roads -- it wasn't very fast to
build a million kilometers of roads in
[45:56] France, it's still much faster to use
We had a 100% renewable construction
[46:01] industry.
A century to build Notre-Dame.
[46:03] So now it's going to go a little faster
to rebuild the roof.
[46:07] And probably a few centuries to build
the pyramids: it wasn't very effective.
[46:11] To build Tower D2 at La Défense, it's
much better to use fossil fuels, it
[46:15] goes much faster.
We had a 100% renewable industry.
[46:19] Again, it wasn't very effective making
all the objects you have on you, at low
[46:23] cost: it doesn't work well.
It is still much better to have a 100%
[46:27] fossil industry.
We had 100% renewable dryers, that is
[46:30] to say the sun, and it is still not
very efficient: it is much better to
[46:34] have dryers that run on gas, it goes
faster.
[46:36] So, it's been two centuries.
Precisely because the physical
[46:40] characteristics of fossil fuels are
superior to the physical
[46:44] characteristics of renewable energies,
that Man, who is an accumulative animal, has
[46:49] spent his time switching from renewable
energies to fossil fuels, to be able to
[46:54] accumulate faster.
That's exactly why we went that way.
[46:59] And so, when you see that, you tell
yourself that to go the other way, like
[47:03] that, simply because the political
promise is that you will get there
[47:07] without touching people's standard of
living, just by seeing that, you tell
[47:11] yourself: “Oh, yeah?
Oh, yeah?
[47:13] Are we totally sure?
Do I sign with all my savings plus
[47:18] those of my parents plus those of my
grandparents, on the fact that it will work?”
[47:23] Incidentally, when you have a doubt
[47:25] about something, it's a very good
question to ask yourself.
[47:28] That is: “Would I agree to bet all of
my parents' savings on what I am saying?”
[47:34] There you go.
[47:35] End of the parenthesis.
If you have a very slight doubt that
[47:37] the answer is not yes, it is because,
in essence, you are not totally
[47:41] convinced by the argument or by what
one is telling you.
[47:44] So, we know renewable energies very
well.
[47:47] This is the world from which humanity
comes out.
[47:50] So, I insist, I'm not saying we
shouldn't go back.
[47:52] I'm just preparing you for the
conclusion that we're probably not
[47:56] going to go back with constant
consumption.
[47:58] Certainly not.
With 7 billion people on Earth...
[48:05] So that's it, our converters of ancient
times, they were completely immoral,
[48:12] and not at all effective.
However, it was completely renewable.
[48:18] And we have now moved on to modern-day
converters that are much more
[48:23] efficient, no doubt about it.
So, if I don't talk “energy” but talk
[48:27] “power” now.
Well, you see, a man at work whom I
[48:31] told you earlier in a day's work, he
can do between 0.05 and 0.5 kWh.
[48:35] If you relate that to 5 hours of work
(actually it's 10 but whatever), you
[48:39] see that it means that his average
power over that time is somewhere
[48:42] between 10 and 100 W.
Let's take a tractor.
[48:46] An ordinary tractor today has a power
of a few tens of kilowatts (kW).
[48:54] A tractor has the same power, by the
way, as a construction machine that
[48:58] makes a hundred kilowatts.
If, one day, you're a little curious,
[49:01] the next time you pass by a
construction site
[49:03] on all construction machinery, you have
a small plate that gives you the power
[49:07] of the motor that is hidden somewhere
under the pivoting part.
[49:10] Anyway, it's not very complicated to
locate
[49:13] go check it out by curiosity,
you will see the power of the device:
[49:17] a few tens of kilowatts up to 100 kW for
a large shovel.
[49:20] If you substitute legs, a few hundred,
if you substitute arms, a few thousand.
[49:24] So, the two machines you have here are
capable of replacing a few hundred
[49:28] pairs of legs or a few dozen draught
animals with the tractor.
[49:31] And, for civil engineering or
construction machinery, a few thousand
[49:36] pairs of arms.
It is thanks to this that we have been
[49:39] able to increase a farmer's
productivity by a few hundred: because
[49:42] he did not grew hundreds of arms and
hundreds of legs like in Shiva.
[49:46] The farmer was simply given an
exoskeleton.
[49:50] And it is thanks to this that, today,
we can build a house (that plus a whole
[49:54] lot of other machines, cement
factories, trucks, etc.) that we can
[49:58] build a house today for the cost of a
few years' salary: thing that was
[50:02] totally unthinkable for an inhabitant
of ancient times.
[50:05] Until two or three centuries ago, it
was just unthinkable that someone could
[50:09] have their house built for a few years'
salary: it didn't exist.
[50:13] A truck pedals like a few thousand
times the driver's legs.
[50:20] A plane, thanks to the young and
handsome pilot who is well paid, pedals
[50:23] like a million times on the pilot's
legs.
[50:26] The “Aeroflot” one probably didn't
pedal hard enough.
[50:29] An industrial rolling mill hammers and
crushes the steel like the whole of the
[50:39] Île de France to whom I would have
given a hammer.
[50:41] So, you see.
Just to replace the Fos-sur-Mer rolling
[50:44] mill, if we didn't have any energy, you
wouldn't be listening to this course
[50:49] right now, you'd be hitting metal sheets with
a hammer.
[50:52] Just to replace the rolling mill in
Fos-sur-Mer.
[50:55] The whole of Île-de-France with a
hammer, hammering all day long.
[51:00] This is another agricultural auxiliary
that has saved a few million pairs of arms:
[51:07] it's called a steam cracker, and
it's something that helps you prepare
[51:14] organic chemistry.
[51:19] At this point, we agree that energy
[51:23] quantifies transformation.
On the fact that, to use energy, you
[51:27] actually need a converter.
On the fact that most of the converters
[51:31] we use today are no longer our own
bodies but are machines.
[51:35] And now I will quantify the number of
machines and how they are broken down
[51:42] by individual.
So, I told you, historically, what we
[51:45] were using was mainly renewable energy.
So here you have a graph that starts in
[51:49] 1860 and quantifies only one of the
renewable energies that we have used
[51:52] since ancient times -- because for wind
and water, it is difficult to have
[51:56] statistics in long series.
I'm sure someone would be able to
[51:58] reconstruct that, but I didn't find it.
So now we're already going to start
[52:00] with the wood.
So, wood, a century and a half ago, was
[52:05] used by humanity.
Humanity uses it to feed stoves, to
[52:09] heat itself, to feed forges.
And, by the way, the beginning of
[52:13] metallurgy has been a massive factor in
deforestation or a very important
[52:17] factor in deforestation in Europe.
And to operate the first steam engines
[52:22] that are about to emerge here and
there.
[52:25] At that time, an inhabitant of the
world, an earthling, consumes an
[52:30] average of 5000 kWh of wood per year.
So, you see that, per person, since
[52:35] that time, the amount of wood used has
decreased.
[52:39] Not in total, but per person it has
decreased.
[52:42] It is roughly the only energy that
has followed this evolution.
[52:47] After that, Men started using coal.
So, some of the coal substituted
[52:53] wood.
For example, in Europe, we started
[52:56] using coal.
Before, we used charcoal and then we
[52:59] started using so-called “bituminous coal”
(both called “coal”) to run the forges.
[53:04] And then to run the steam engines.
And you see that the amount
[53:09] of coal used per person in the world
that was extremely low a century and a
[53:14] half ago is now about 5000 kWh per
person per year.
[53:18] What you see on this graph as well is
that the amount of coal used per person
[53:22] in the world has never decreased since
we started using coal.
[53:25] So, never, at any time, has coal been
an energy of the past for Men.
[53:29] Never, at any time.
And in fact, today, you unknowingly use
[53:34] a lot of coal through everything that
is imported from countries where it is
[53:40] “made in coal”, starting with China.
So as soon as you see something “made
[53:47] in China”, it is “made in coal” and
it feeds your consumption, indirectly
[53:54] of course, of coal.
Two-thirds of the coal used on Earth
[53:58] today are actually used by an
intermediate machine in the energy
[54:02] system called the power plant.
So, two thirds of the coal extracted on Earth
[54:07] are used to power a power plant.
In the rest, you have a roughly 10%
[54:13] that feeds the metallurgy.
So, they are coals very rich in carbon
[54:18] that are called “coke coals” and
otherwise, the rest is used to operate
[54:24] heating networks, stoves, district
heating and finally domestic heating, etc.
[54:30] But two thirds of it are power plants.
[54:32] You know that in France we have a great
debate on our nuclear power plants.
[54:36] Remember that, today, in the world, you
have between 30 and 40 times, between
[54:44] 30 and 40 times, the nuclear power
installed in France in coal-fired power plants.
[54:51] In France, we have 60 GW of nuclear power,
[54:53] and about 2,000 GW of coal-fired
power plants installed worldwide.
[54:56] We will come back to this at the time
of the climate course, but the Paris
[55:00] agreement (rings a bell?)
and more exactly the 2ºC objective
[55:04] contained in the Paris agreement
assumes, for example, that all these
[55:08] coal-fired power plants have
disappeared by the time you are my age.
[55:15] All right?
So, three meters separate us.
[55:17] So, by the time you're my age, not that
far away, I can assure you, all the
[55:23] coal-fired power plants in the world
must have disappeared...
[55:28] We're not really there yet...
Then, Men used oil.
[55:33] So, what you see on this graph in an
absolutely spectacular way, is that oil
[55:37] has never replaced coal.
Oil has not replaced coal.
[55:41] You can see that the use of oil per
person is added to the use of coal per
[55:48] person.
The reason is that oil is not used
[55:51] for what coal is used for, not at all.
Oil is the queen energy of mobility
[55:56] because oil is the energy that has the
best ratio of energy transported per
[56:02] unit volume.
All right?
[56:04] In a liter, so a cubic decimeter, if
you put something that you use for your
[56:10] energy supply, there is nothing better
than oil.
[56:14] It's liquid at room temperature, so
it's something that's extremely easy to
[56:19] store and transport.
And since it is the densest per unit
[56:23] volume, well, in the modes of transport
where you have to take your energy with
[56:27] you (so you are sure to be able to go
where you want) it is oil that has won
[56:32] the battle of the modes of transport,
hands down.
[56:34] Today, 98% of everything that rolls,
flies or sails uses oil.
[56:39] While I remind you that, the first car
in the world to have exceeded 100 km/h
[56:44] was an electric car.
I would also remind you that the
[56:47] efficiency of the electric motor is
four times higher, three to four times
[56:50] higher than the efficiency of the oil
engine.
[56:52] So, it is not because the oil engine is
intrinsically superior that it
[56:56] supplanted the electric motor in the
competition that took place a century
[57:01] ago: it is because with electricity you
have much more difficulty to take with
[57:05] you the energy that allows you to be
autonomous.
[57:08] That's the reason.
You also see here something that happened
[57:14] before you were born.
The sudden stop, and I really mean
[57:19] sudden, of the amount of oil available
per person on Earth.
[57:23] This episode, it has a rather special
name in the history of energy.
[57:26] It's called “oil shocks”.
I will come back to this at length.
[57:30] The oil shocks, everyone kept in mind
that it is a moment when the price
[57:34] became very high, then it became very
low again, and “next subject please,
[57:38] let's forget it”.
In fact, we don't forget at all.
[57:41] This is the moment when the oil supply
grew strongly and stopped growing
[57:46] strongly; and when the oil supply per
person grew strongly and, not only
[57:51] stopped growing, but then began to
decrease and stabilize.
[57:56] So, oil shocks are not just a price
episode.
[58:00] In fact, it's the foam on the surface
of the wave.
[58:02] The major feature of the oil shock is
that it is the end of a rapidly
[58:07] expanding world.
These are the oil shocks and we will
[58:11] soon come to what they mean in economic
terms.
[58:15] The gas comes in.
So, gas, bis repetita, has not replaced
[58:19] oil.
It came to be added on top of it.
[58:22] Hydroelectricity comes along.
Same thing, hydroelectricity was added
[58:26] on top of that.
Then comes the nuclear, which has been
[58:29] added to it, and now arrive the new renewable
energies (that you see there)
[58:34] which is THE thing that everyone is
talking about.
[58:38] We talk about nothing but
new renewable energies.
[58:41] Here you have, brought down to the
individual, what these new renewable
[58:45] energies represent in the world.
And, as I am, despite appearances, a
[58:50] nice guy, I took the nicest possible
conversion convention to account for them.
[58:55] Because, as many of these energies are
[58:57] purely electrical energies (solar and
wind) you have two ways to account for them.
[59:03] Concerning electrical energy, you have
[59:05] two ways of counting it in the energy
balances.
[59:06] As historically most of the electricity
has been produced by thermal modes
[59:10] (these are Carnot machines -- power
plants -- for the most part: you burn
[59:14] coal, you burn gas, you burn oil, you
fission uranium, etc.) it produces heat
[59:18] and with this heat, you operate a
turbine.
[59:20] It's a Carnot machine.
In a Carnot machine you have a maximum
[59:25] efficiency (1-T2/T1) and often,
electricity is counted in primary
[59:30] equivalent i.e. we count the thermal
energy that would have been necessary
[59:36] to make the same amount of electricity
for the modes that are purely electric,
[59:41] hydropower in the lead, solar and wind.
And that's the convention I used for
[59:46] this graph.
Nevertheless, you can see that today,
[59:49] it is something that has much more
space in the newspaper's pagination
[59:53] than it does in the actual consumption
of energy in the world; and you will
[59:57] soon see that not only is it true in
absolute terms, but unfortunately it is
[60:02] also true in terms of dynamics.
On the other hand, another thing that
[60:06] is crucial when you see this graph, is
that today, the amount of energy
[60:12] mobilized per person per year
(extracorporeal energy I should specify)
[60:16] is about 20,000 kWh.
So, on average, an earthling mobilizes
[60:21] 20,000 kWh per year through the
enormous exoskeleton of the machine park.
[60:28] With the little equivalence I gave you earlier...
[60:30] So that's primary energy, that's thermal energy.
So, in mechanical energy
[60:34] it would obviously be less, but
in this case, you're going to replace
[60:38] legs, but you're also going to
replace arms, so I used a rough
[60:42] one-for-one convention. So, I'm telling you:
it's as if, basically, each
[60:46] earthling had 200 people at his
disposal: 200 slaves who would work for
[60:50] him all the time.
I will tell it differently: the
[60:54] machinery we have built up and that
works for us has the same mechanical
[60:59] strength as if our muscle power were
multiplied by 200.
[61:03] So, you are, I am, we are, we have
become Superman for real.
[61:11] It's not a matter of the mind.
Except that, contrary to Popeye
[61:13] devouring boxes of spinach and becoming
super-powerful, we devour barrels of
[61:17] oil and become super-powerful.
Well, not us, but our exoskeleton, i.e.
[61:20] the machines.
I'll tell it again in a different way.
[61:23] The material production of humanity
today at 7 billion people is equivalent
[61:30] in volume, because of the machines, to
what we would have if we had
[61:36] 1400 billion people and no machines.
Is that clear?
[61:40] Obviously, we cannot afford to feed
1400 billion people on Earth.
[61:45] So, in fact, thanks to energy and
machines, we have been able to develop
[61:50] a productive capacity that is beyond
the muscular power of our body and we
[61:56] spend our day using prostheses.
The train that brings me here is a
[62:01] prosthesis.
It's an extension of my legs.
[62:04] The car you may use, and the plane even
more so, are prostheses.
[62:08] They're extensions of our legs.
Okay, we spend our time using
[62:12] prostheses.
Most of this energy is fossil fuel.
[62:18] Then why “fossil”?
Simply because they are remnants of
[62:23] ancient life.
A fossil is very simple once again.
[62:27] It has a definition: it's a remnant of
ancient life.
[62:29] We will see it at the next class,
coal is a remnant of plant life
[62:34] (ferns that grew in the Carboniferous era)
and oil and gas are remnants of
[62:40] plankton and microalgae that lived
anytime between a few million years ago
[62:44] and a few hundred million years ago.
So, it is fossil energy by far that
[62:50] dominates the global supply today.
And this energy, it has therefore made
[62:57] it possible to set in motion a growing
exoskeleton that has made each of you
[63:05] Ironman for real.
So, we all became Ironman for real.
[63:09] We don't have the little light shining
in the center and the things in front
[63:12] of our eyes there, but that's exactly it.
[63:14] So here are some little bits of your
Ironman costume and mine: washing
[63:18] machines, elevators, vacuum cleaners,
tractors, Ariane rockets, satellites,
[63:23] water purifiers, rolling mills, etc.
All these are little bits of your
[63:26] Ironman costume.
And without this Ironman costume, you
[63:30] would have the life that French farmers
had a few centuries ago with 30 years
[63:35] of life expectancy at birth, no
increase in income between birth and death...
[63:40] The idea that income increases with age
[63:42] is something that is modern: it didn't
exist in ancient times.
[63:45] So, what has literally changed the
lives of humanity is the energy and the
[63:50] machinery that makes it possible to use it.
[63:53] That's why the fact that it's only
worth 3% of what we spend is an optical
[63:59] illusion!
It's at the center of 100% of what
[64:02] happens to you.
100%!
[64:03] In fact, with the little economic
convention I showed you earlier,
[64:09] the energy today and the machinery it
operates is 200 times the muscle power
[64:15] of Men.
If the accounting were to be consistent
[64:18] with this physical reality, in
companies' accounts, energy would be
[64:22] worth 200 times more than wages.
That's what should happen.
[64:26] So, your hiring salary should be
roughly divided by a factor of 1000.
[64:35] Roughly.
That is about what we should do if we
[64:39] were to have the same accounting
balance on costs as we have the
[64:44] physical balance on the contribution to
the transformation of the world.
[64:49] I'll tell it another way because I'll
get to it in a little while: today,
[64:53] people in production are only needed to
operate machines.
[64:56] For the rest, they are useless.
So most of the jobs we do today in the
[65:01] world, I cut off your 2 arms, your 2
legs, and I allow you to order a
[65:04] computer with your brain, it still
works.
[65:07] It still works.
So, this exoskeleton, with its own
[65:13] energy, allows it to have the same
productive capacity, so on average
[65:18] worldwide it is 200 the factor, but on
average in France it is rather 600.
[65:23] So, the French Yellow Vest who doesn't
realize it (and that's the unspeakable
[65:28] political truth) still lives like a
nabob.
[65:31] He lives like a nabob.
So, what pisses him off is that Bernard
[65:35] Arnault lives even more like a nabob
than he does (and he's probably right
[65:39] to think so), but in the meantime, he
himself already lives like a nabob.
[65:44] Because of that.
These modern-day slaves have another
[65:48] absolutely considerable advantage over
the renewable energies of ancient
[65:52] times: it is that they free up the
entire surface for us.
[65:56] Because the energy slaves of ancient
times, either renewable energies or
[66:01] other living organisms that were
needed, mobilized soil.
[66:05] A draught animal mobilizes soil.
Therefore, the soil that is necessary
[66:09] to feed the draught animal is no longer
available to feed Men or a transport
[66:14] animal.
At the time, therefore, there was a
[66:18] particular need in agriculture to
mobilize a large part of the land in
[66:23] order to be able to cultivate the rest
of the land for humans, with draught
[66:28] animals.
There, the slaves of modern times, they
[66:31] eat from the underground.
So, they leave all the available space
[66:35] to us.
And that is one of the reasons why,
[66:38] when we talk about returning to
renewable energies, you see land use
[66:42] conflicts appear.
For example, to grow crops for energy
[66:46] purposes, it directly conflicts with
food crops.
[66:50] So, in fact, it means that we are
obliged, for part of the energy we use,
[66:54] to return to the ground compared to the
advantage we had of just hitting the
[66:59] underground.
So, we are returning to a
[67:00] two-dimensional system, whereas we had
succeeded in moving to a
[67:03] three-dimensional system.
In a way.
[67:09] Some orders of magnitude of common
energy usages.
[67:11] This thing is very old but the order of
magnitude is still valid.
[67:15] There's probably a dividing factor of 2
that's been running around for some of
[67:18] them, but that's okay, it's just for
fixing your ideas.
[67:21] What you see then, all that I can
translate into “slave-days”, which I
[67:26] did.
Above all, remember from this graph
[67:29] that most of the energy consumption of
a Westerner, and therefore the machines
[67:34] he uses for his benefit, is not light
and is not recyclable coffee cups.
[67:40] So, since I am going to talk to
engineers who are supposed to
[67:43] manipulate orders of magnitude: it is
not with small gestures that we avoid
[67:47] big problems.
We can have small actions to start tackling the
[67:50] big problems, but that doesn't replace
tackling the big problem.
[67:55] So, I say this because in the world in
which I live, which is the business
[68:00] world, it is still very, very often
that we confuse orders of
[68:04] magnitude, deliberately!
You hide behind your little finger and
[68:07] say “Look! It's fabulous, I put a hive
on the roof, I put recyclable cups in
[68:12] the canteen, and then one day per year
people will come by bike and...”
[68:16] No, it doesn't work that way.
Obviously. So here you have some orders
[68:21] of magnitude of energy consumptions.
You see that something that will weigh
[68:27] very, very heavy, is what you buy and
how you move around.
[68:33] When we talk about climate change, we
will also see that the way we eat is
[68:37] something significant, and the way we
lodge.
[68:40] So, basically, the size of the
accommodation you occupy, the energy
[68:44] you use to occupy it, the amount of
stuff you buy in the year and the way
[68:48] you travel and the number of kilometers
you drive in the year, is much more
[68:53] impacting than turning off the light or
not when you leave a room.
[68:57] It is not at all the same order of
magnitude.
[69:01] So, at the same time as, per person
(because until now I talked in “per
[69:04] person”) the orders of magnitude have
fundamentally changed.
[69:08] The size of the population has also
fundamentally changed.
[69:11] You have here a reconstruction
(approximative obviously because ten
[69:14] thousand years ago INSEE was a little
less efficient than today)
[69:16] you have an approximate reconstruction
of the human population.
[69:20] Then why ten thousand years ago?
Why does this graph start ten thousand
[69:27] years ago?
[69:36] It is the sedentarization of Men.
[69:38] That is, ten thousand years ago
(and we'll see about that in the climate
[69:42] change course)
we get out of the last ice age,
[69:46] we are at the beginning of the warm
interglacial era, which is the one we
[69:49] knew until we started to initiate
human-induced climate change.
[69:53] This means a period of very strong
climate stability that allows people to
[70:01] settle down.
That is to say, in a stable climate,
[70:04] the resource that allows you to feed
yourself does not move around because
[70:07] it moves with the changing climate.
It always stays in the same place so
[70:11] you can start settling down.
At that time, there are a few million
[70:15] humans on Earth.
Again, INSEE was not very successful at
[70:20] that time.
At the beginning of the industrial
[70:23] revolution – I recall the life
expectancy at birth of the inhabitants
[70:28] of Earth in 1800: it is a little less than 30 years.
By the way, it was less in the
[70:33] city than in the countryside because
at the time, cities were a place where
[70:38] miasmas of all kinds were concentrated
and therefore as soon as there was a
[70:41] disease, it was much easier to catch it
and die from it than when you were in
[70:44] the countryside.
You also had the same thing for infant
[70:47] mortality...
And there are 1 billion of us.
[70:50] And, what you see is that in the time
frame of two centuries, we have
[70:53] experienced an evolution that is closer
to hyperbolic than exponential, at the
[70:58] same time as the quantity of resources
of all kinds consumed per individual
[71:02] has also increased.
So, in fact, some of the people I know,
[71:06] including myself, are wondering whether
this demographic change would have
[71:11] taken place if we had not had abundant
energy.
[71:14] Because if we had not had abundant
energy, it is not completely certain
[71:17] that cereal yields would have increased
from 10 to 80 quintals/hectare in
[71:20] Ile-de-France.
It is not entirely certain that food
[71:23] could have been transported wherever it
is needed from where it grows.
[71:28] It is not completely certain that we
would have been able to protect it from
[71:31] the hot, cold and all the little
animals that want to eat it in our
[71:34] place.
It is not completely certain that we
[71:36] could have brought drinking water and
evacuated the miasmas from cities, etc.
[71:39] And so, there are a lot of things that
are not completely certain in a world
[71:42] where we would not have had fossil
energy, and so it is not completely
[71:44] certain that we would have grown to 7
or 8 billion people.
[71:47] And if the question arises as to
whether 7 or 8 billion people is not a
[71:51] consequence of abundant energy, then
obviously, at that moment, the
[71:55] corollary question arises: from the
moment we enter a strong energy
[71:59] decline, do we stay at 8 billion
people?
[72:01] It's not completely certain either.
If I make “population times individual
[72:08] use” this is what I obtain
regarding the total amount of energy
[72:14] used by Men.
That is, basically, the evolution of
[72:17] the machinery park, knowing that
between here and there it takes much
[72:22] less energy to run a machine, because
your predecessors and mine were astute
[72:27] on how to run the machines, and
therefore gained in efficiency.
[72:31] So, what you are seeing here is a lower
bound of the number of machines in
[72:38] operation around the world.
So, in my opinion, here we are close to
[72:42] the machinery park, and this is more
like one-tenth of the machinery park in
[72:46] operation in the world.
What you see is that, between my
[72:49] parents' generation and my children's
generation, the amount of energy used
[72:54] by Men has increased by a small factor
of 10 and, in my opinion, with the
[72:59] energy efficiency gain that there has
been in the same period of time, the
[73:05] number of machines in operation in the
world has increased by a factor of a
[73:10] few tens.
It is not completely certain that the
[73:13] same thing will happen between you and
your grandchildren's generation.
[73:17] It's even pretty certain that it's not
going to happen.
[73:21] So, it is quite certain that the world
you and I will know for the few decades
[73:26] that I still have to live (if all goes
well) will not be a world of
[73:30] prolongation of the trend we have had
in the past.
[73:34] I remind you that physical systems are
exceptionally linear systems.
[73:38] In general, they are non-linear
systems.
[73:41] And that, in non-linear systems, you
cannot reason by induction.
[73:45] It is better to avoid it.
If I look at the mark of Man on his
[73:51] environment.
I can approximate it by the amount of
[73:55] energy he uses since, I repeat, the
amount of energy we use is the flow of
[74:00] transformation that we operate (by the
very definition of what energy is).
[74:04] So, for that, I take the energy per
person times the population and it
[74:09] gives me something that looks like the
evolution of the human print on its
[74:13] environment.
Well, here is the population.
[74:17] I do “times energy used per person”
and this is in first approximation how
[74:22] Man's print on his environment evolved
on a planet that was 13,000 kilometers
[74:27] in diameter at that time, and still is
13,000 kilometers in diameter at that
[74:33] time.
And so, you understand that the
[74:35] environmental problems we have today
are not necessarily problems that are
[74:40] qualitatively different from what we
had in the past.
[74:43] However, they are quantitatively
different from what we had in the past.
[74:47] Today we have a tiny little problem of
order of magnitude.
[74:50] And when you see that, you also
understand that we have put the system
[74:54] out of balance (a tiny little bit) and that it
is not completely certain that it will
[74:59] remain in that state for extremely
long.
[75:01] So here I am preparing you for
something that I will detail in other
[75:08] courses, which is: things will happen
anyway in the future, and anyway, in
[75:15] the future, the world will not remain
stable.
[75:20] Anyway.
And, therefore, we have, you have, I
[75:24] essentially have a choice between: I
wait for the instability to happen as
[75:28] it wants to happen and I suffer it; or
I trigger the instability within the
[75:33] limits of what I can still more or less
control.
[75:36] But it will be one or the other.
Two small additions on the evolution of
[75:42] the amount of energy used in the world.
Here you have the variation in the
[75:48] amount of energy used by Men between
2000 and 2017.
[75:54] And, what you see is that --
notwithstanding the media discourse on
[75:57] the fact that it's really good because
we have more and more wind and solar
[76:00] production --
what you see here is that the 3
[76:03] energies that have increased the most
over the period (and by far) are the
[76:08] three fossil fuels, and in particular
coal.
[76:12] So, the fossil energy that has
increased the most since we started
[76:17] having major debates on climate change,
is coal.
[76:21] Coal, over this period, increased more
than ten times more than solar energy
[76:26] (in primary equivalent) and more than
five times more than wind energy.
[76:31] So, if the newspaper had a pagination
reflecting the facts, for an article
[76:36] about solar energy, there should be 15
about coal.
[76:38] All right?
That's what should happen.
[76:42] And if you look today at what you have
in terms of supply, so I'm pie charting
[76:46] the historical evolution I showed you
just before, you see that it is fossil
[76:51] fuels that dominate the global supply
with head and shoulders.
[76:55] First, oil, then coal and gas.
If I just look at renewable energies,
[77:02] you see that what comes first is wood,
followed by hydroelectricity.
[77:06] I would like to point out that the
first two terms of France's renewable
[77:09] supply are the same two: wood and
hydroelectricity.
[77:12] Just because the newspaper talks about
wind and solar power, again, doesn't
[77:15] mean that it's what counts the most in
French renewable energy supply: it is
[77:19] wood and hydropower by far, the other
terms afterwards being much, much
[77:23] weaker.
And so, here is the French renewable
[77:26] supply.
A little graph I made just yesterday
[77:28] with statistics that were published no
later than two weeks ago.
[77:32] What you see is that the first two
terms (by far) in the French renewable
[77:36] supply are wood (which is mainly used
for heating) and hydroelectricity
[77:40] (which is used to make electricity).
Here you have wind and solar power.
[77:44] You can see that solar energy is in
fact one of the weakest terms in the
[77:51] French renewable energy supply behind
many other things, heat pumps, waste,
[77:57] etc.
Here are all these renewable energies
[77:59] (so these are millions of tons of oil
equivalent, I told you that I would use
[78:04] tons of oil equivalent) in a French
consumption that is about 250 with this
[78:08] same unit.
So, you see what renewable energies
[78:12] represent in this whole.
Now I'll let you go for five minutes.
[78:17] Take the opportunity to chat a lot at
that time: but five minutes, not a
[78:21] quarter of an hour.
Thank you.
[78:23] I'm going to go back to prices a little
bit now.
[78:28] You have probably (for some of you)
heard (I will come back to this in the
[78:34] next course but I will already give a
little overview today) that the price
[78:41] of energy
(which can't be discussed in the last
[78:45] row of this amphitheatre)
must increase sharply if energy becomes
[78:51] scarcer, which means that more abundant
energy should see its price fall
[78:57] sharply.
The price of all energies is in fact
[79:00] more or less subject to the price of
oil.
[79:04] So here you have the oil price
expressed in constant currency, i.e. in
[79:09] a currency adjusted for inflation over
the past century and a half.
[79:14] So, you see something quite
interesting: it is that this oil price,
[79:18] in fact, on a long trend, there is a
century during which it was rigorously
[79:22] stable (expressed in constant currency)
regardless of the quantity produced.
[79:27] You see that at the moment of the oil
shock (characterized by a strong
[79:30] variation of the derivative, i.e.
production rises rapidly and stops
[79:33] rising rapidly) the price rises
sharply then returns more or less to
[79:37] its previous level, then again you have
a shock where the price rises sharply
[79:40] and returns to something that is not
very far from its previous level.
[79:44] So the idea that the price of oil is
something that follows the abundance of
[79:49] supply is not confirmed by this graph
that you see here.
[79:53] On the other hand, the real price of
things -- in fact it is not the price
[79:56] expressed in currency, it is the price
relative to the only magnitude that
[80:00] remains incompressible over time, which
is the 24 hours of a day.
[80:04] In other words, the real price of
anything is not the price expressed in
[80:08] money, it is the price expressed in
minutes of working time.
[80:11] If you want to express a price in
minutes of working time, it means that
[80:15] you have to relate a price to what
people earn, and therefore in this case
[80:19] you have to relate the price of oil to
what people earn, which is what you
[80:24] see here, that is, the GDP per person.
And then, at that moment, we fall back
[80:27] on our feet.
You see that over the past century and
[80:30] a half, or over the past century, the
price of a barrel of oil has been
[80:35] divided by 15 to 20, which means that
with the efficiency of machines, which
[80:40] has increased at the same time, the
price of a kilowatt-hour of mechanical
[80:45] energy has been divided by 50 to 100.
We find the same dividing factor as the
[80:49] one you have when we compare the price
of an old renewable energy with the
[80:54] price of a modern fossil energy.
We will always fall back on this
[80:58] dividing factor or multiplier factor of
a few tens to a hundred, which also
[81:03] represents the passage of a human being
producing with his arms and legs at 200
[81:08] slave-equivalents per person.
So, basically, no matter how you look
[81:12] at the problem, the transition from
renewable civilization to fossil
[81:17] civilization has been the appearance of
Superman or Ironman for each of us,
[81:22] with a multiplication by an order of
magnitude of a hundred or several
[81:26] hundreds of our capacity for action on
the environment.
[81:30] And of course, as a result, all the
undesirable by-products of this ability
[81:34] to act have also been multiplied by
several hundreds.
[81:36] So, we have removed a lot of surface
area for other living things, which is
[81:40] why there is a loss of biodiversity.
We have induced a lot of pollutions of
[81:44] all kinds in the environment.
So, there are a whole bunch of
[81:46] undesirable substances that have been
released in the environment as the
[81:49] transformation flows have increased.
This is a perfectly logical
[81:52] consequence.
If we look at a more recent period,
[81:56] however, here you have the price of
energy in relation to what the French
[82:01] earn.
Well, you see that the Yellow Vests may
[82:04] be right for their particular case.
They are wrong for the population as a
[82:09] whole because the price of energy in
relation to what people earn, as a
[82:13] first approximation, has almost never
been as low as it is today.
[82:16] So, when one says: “Aaaah! the liter of
gasoline at 1.50 €!”
[82:20] OK.
Except that we forget that people's pay
[82:24] slips have increased proportionally and
even a little faster.
[82:28] So, I've already said it implicitly.
I will say it again more explicitly.
[82:33] This abundant energy allows you to sit
in this amphitheatre today, and in
[82:38] general, has radically changed the
world around us in terms of work and
[82:44] professions.
Almost all the people you know today
[82:47] work in services, work in the city and
work in the service sector.
[82:51] I mean almost everyone you know.
This is a very recent situation that is
[82:57] the consequence of the increase in
energy supply.
[83:00] Here you have the evolution of the
number of employees in France, broken
[83:06] down into: farmers in green, workers in
black, and service employees in blue.
[83:13] These three curves cover two centuries.
So, I'll just digress for a moment.
[83:19] When you are interested in a process,
the longer the series you have, the
[83:23] better.
The best way to misinterpret a process
[83:27] is to have a series that is too short
compared to the characteristic time
[83:32] scales of variation of what you are
looking at.
[83:36] So, you have to have sufficiently long
series if you want to understand
[83:39] something.
What you see is that two centuries ago,
[83:42] two-thirds of the working population
worked in agriculture.
[83:46] So, they are farmers.
You also deduce one thing from that
[83:49] case: if two-thirds of the working
population are in the fields, it is
[83:53] because a farmer's productivity at that
time is enough to feed himself plus
[83:58] half a person who does something else.
That's what it means.
[84:03] So, a farmer is feeding 1.5 people.
And then you see that the number of
[84:11] people in agriculture is increasing
slowly, slowly as well as the volume
[84:18] until 1850.
So, what's going on at the time?
[84:21] At that time, you did not have a
significant increase in agricultural
[84:25] productivity.
Basically, an 1850 farmer is about as
[84:28] productive as an 1800 farmer, a little
more but not much more.
[84:31] On the other hand, what is happening is
that the population is increasing and
[84:35] therefore, forests are being cut down
to increase the cultivated areas.
[84:40] We are deforesting in Europe, just as
we are deforesting now in Latin America
[84:45] or Southeast Asia.
Just as we have done in the United
[84:48] States and Russia.
At all times, population growth has
[84:52] meant that sedentary populations have
had to cut down forests to set up
[84:57] cultivated areas instead.
That is what the Europeans do, and
[85:01] therefore the French, and so we cut
down forests until there is not much
[85:05] left to cut down.
That is to say, in 1850, we go through
[85:07] the minimum forest level.
15% of France is covered with forests,
[85:11] no more.
Today it's 25%.
[85:12] And the 15% covered with forests are
essentially complicated areas to
[85:17] cultivate, especially mountains.
And then, the industry begins to
[85:22] develop agricultural auxiliaries that
make the farmer more productive.
[85:27] We start to develop trait collars, we
start to develop ploughs, etc.
[85:31] It was the beginning of the forges and
industry that made it possible to
[85:34] multiply the number of auxiliaries for
the farmer.
[85:37] The first combine harvester in memory
was at the end of the 19th
[85:39] century-beginning of the 20th century.
It was pulled by horses at the time, of
[85:43] course.
And so, auxiliaries are brought to
[85:46] farmers to reduce the number of farmers
and replace them with machines or
[85:51] draught animals in the fields.
At that moment, of course, it frees up
[85:57] some people to do something else and it
feeds, but not only, the growth of the
[86:02] workforce in other sectors.
And then, after the war, this time
[86:07] Ironman will arrive for real.
You know that Ironman is an American
[86:10] creation.
It's Marvel's Comics.
[86:12] Well, it's really the Americans.
In this case, the Americans are
[86:14] bringing the tractors and fertilizers
they had started to develop back home.
[86:17] And we will replace human and animal
workforces with much more efficient
[86:24] ones.
That is, tractors and fertilizers.
[86:28] Thanks to what, as I said earlier but I will repeat it
again: the cereal yield in Beauce, for
[86:33] example, increased by a factor of 6 and
8 between 1945 and 1975.
[86:37] 6 to 8!
I don't know if you realize that.
[86:40] And at that moment, we can free up a
lot of pairs of arms and legs that are
[86:45] in agriculture to send them elsewhere.
So where do we send them somewhere
[86:49] else?
Well, we send them into the industry.
[86:50] So, industry or craft is the same
thing.
[86:54] So, in industry and crafts, we will be
able, thanks to the increasing energy
[86:57] supply, to start up an increasing
quantity of machines and each time I
[87:01] have a machine that starts up, I need
someone to drive it.
[87:04] I have a car production line, I have
workers working on the line.
[87:09] I have a jackhammer, I need a worker to
operate the jackhammer.
[87:13] I have a crane, I need someone to
operate the crane.
[87:15] So, more and more machines will be
built and it turns out that the energy
[87:18] supply at that time -- we are at the
glorious thirty – you have seen the
[87:22] speed at which oil per person is
increasing.
[87:24] The energy supply at that time
increases faster per person than the
[87:28] unit size of the machine.
It's a horse race.
[87:33] And so, despite the fact that I have
bigger and bigger machines, I can
[87:39] create more and more jobs because the
flow, the machinery, basically, is
[87:44] increasing.
The machine fleet is increasing because
[87:48] the unit size of the machine is
increasing at a slower rate than the
[87:53] energy supply per person.
So, I can increase the number of
[87:56] machines and therefore increase the
number of jobs in the industry.
[88:00] After the oil shocks, the opposite is
true.
[88:03] The unit size of the machine continues
to increase while the energy supply per
[88:08] person stops increasing.
At that moment, I need fewer and fewer
[88:11] people to drive machines that are also
getting bigger and bigger and will
[88:14] continue to increase industrial
production.
[88:17] Industrial production in France doubled
between 1974 and 2007.
[88:20] So, after the oil shocks, we did not
de-industrialize ourselves, we made
[88:25] another industry (fewer socks and more
planes), but what happened was that the
[88:30] unit size of the machine continued to
increase even though the energy supply
[88:36] per person stopped increasing.
So, we reduced the number of employees
[88:40] in the industry to operate machines
that were unitary larger and that
[88:44] together produced more.
But now, what I'm looking at is the
[88:47] number of people, not the productive
power.
[88:49] So, the number of people is decreasing
and we also have a second category of
[88:54] jobs that is increasing, which are jobs
that are subjected to the industry.
[88:59] So here too, something that is very
important to keep in mind is that
[89:04] service jobs do not exist without
physical flows.
[89:07] A service job as a teacher, for
example.
[89:11] If you do not have physical flows to
make a teaching building, if you do not
[89:16] have physical flows to bring students
and the teacher to the site, so means
[89:21] of transport, if you do not have
physical flows to make teaching
[89:25] materials, books in ancient times,
computers today, you do not have a
[89:29] teaching system.
Take a doctor.
[89:32] A doctor, if you don't have enough
money to make drugs, medical equipment,
[89:37] imaging equipment at the hospital, the
hospital itself and the transportation
[89:43] to run all this, you don't have
doctors.
[89:46] If you don't have a manufactured car,
you don't have a banker to do car
[89:50] credit, you don't have an insurer to
insure cars, you don't have a driving
[89:55] school instructor to learn to drive and
you don't have police officers to check
[90:00] that people are driving well.
All these jobs become useless in a
[90:04] world in which you do not have the
underlying physical flow of
[90:08] manufacturing cars.
So, something you have to get out of
[90:11] your head (and besides, I'm going to
show you the correlations showing that
[90:15] you really have to get it out of your
head in a little while), is the idea
[90:19] that a world rich in service jobs is a
dematerialized world.
[90:22] It's the exact opposite.
A world rich in service jobs is a world
[90:26] in which there are a lot of flows to
manage and that's why you need a lot of
[90:31] people to take care of it.
So, service jobs increase as industrial
[90:35] production increases because you have
to keep going, you have to manage, you
[90:39] have to sell, you have to provide, you
have to teach, etc.
[90:43] And you see that there is a period
where service jobs continue to increase
[90:46] because industrial production continues
to increase while industrial jobs begin
[90:51] to decline.
On the other hand, from 2007, when
[90:53] industrial production stops increasing
in Europe, we are also starting to have
[90:58] a topic on service jobs.
And you also see a new category emerge
[91:02] that did not exist before the oil
shocks, namely the unemployed.
[91:06] That is to say, the energy supply per
person overall no longer increasing,
[91:11] the labour productivity does not
increase much since labour productivity
[91:16] is the addition of machines.
Labour productivity is increasing
[91:20] little and existing jobs are too
productive for you to give everyone a
[91:25] job in an economy that has stopped
growing rapidly.
[91:29] In other words, from the oil shocks, we
are entering a time when the only way
[91:35] to give everyone a job is to reduce
people's productivity at work.
[91:41] And there, the equation is different
according to the different countries.
[91:43] Some do not accept, and at that moment,
they create unemployed people: France.
[91:47] Others accept, and at that moment, they
start creating poorly paid, poorly
[91:52] qualified, odd jobs, part-time jobs,
it is the more liberal systems:
[91:57] England, Germany, America, etc.
But, it is one of the two possibilities
[92:01] that is being set up.
So that's the dynamic evolution in
[92:06] France.
Now I will show you some static or
[92:08] dynamic developments that corroborate
what I just said.
[92:10] Here you have a graph in which, with
the World Bank data, each point
[92:13] represents a country.
On the x-axis, I have the amount of
[92:16] energy used per person, that is, the
average number of machines per person
[92:20] in the country; and on the y-axis, I
have the fraction of the active
[92:23] population working in agriculture.
Well, you see, it's very simple.
[92:26] It's: “Tell me how much energy there
is per person in the country and I'll
[92:29] tell you what fraction of the working
population works in agriculture.”
[92:32] All right?
It's very simple.
[92:35] Then, here is another graph that will
tell you the same thing.
[92:39] Here, it is the evolution from 1991 to
2014 of two data in the world (so this
[92:44] is the world average)
it's the CO2 emissions per person (here)
[92:48] and the fraction of the
working population in agriculture.
[92:51] Well, you see that, the more CO2
emissions increase (which is the case
[92:54] when you follow the chronological
order) and the more fossil energy you
[92:58] have per person, the fewer farmers you
have in the active population.
[93:01] So, it's true for the world but it's
true for India for example. But it's
[93:05] true for China. And it's true for
Brazil. I have 250 countries in the
[93:09] database, I'm not giving them all.
[93:11] But it's something you see almost
everywhere.
[93:14] So, you put energy into a country,
which means that you put machines in
[93:17] the country, and you take farmers out
of agriculture.
[93:19] And so you create a rural exodus.
Everywhere the same.
[93:28] Furthermore, the increase in agricultural
productivity has allowed us to increase
[93:32] the quantity of animals we eat, since
we need more -- or more productive --
[93:37] surfaces to eat animals that will
themselves need to eat what grows.
[93:41] 80% of what grows in France is used to
feed animals.
[93:45] This is true for meadows, it is true
for all the corn except for the few
[93:49] corns of the brands I will not name.
And that's true for half of the wheat.
[93:53] This is true for almost all of the
soybeans grown in the world, which is
[93:57] one of the four major grains grown.
So, roughly 80% of the cultivated land
[94:01] in Western countries is used to feed
animals that you will eat afterwards.
[94:06] And, what you see here -- so there I
didn't put the energy, I put the
[94:09] greenhouse gases, it doesn't matter.
What you see is that in food-related
[94:15] greenhouse gas emissions, where there
is meat or fish, you have a higher
[94:21] hydrocarbon-related portion.
And what you see is that the way of
[94:26] History, because of the increasing
energy supply, is to go from left to
[94:30] right.
Historically, we ate cereals and
[94:32] onions, that's why the farmers before
had stinky breaths.
[94:36] Cereals and onions, and then we started
eating small animals.
[94:40] First the product of the small animals:
the eggs; then the small animal itself
[94:43] – remember Henry IV.
People need to be able to eat small
[94:45] animals: chicken in a pot for example.
But chicken in the pot was already
[94:49] garbage, because it has laid eggs all
its life.
[94:51] It's an end-of-life waste, chicken.
You eat the chicken.
[94:54] Then we started eating broilers, then
we started eating pigs, then we started
[94:57] eating cows.
Being able to raise cows just to eat
[95:01] them is something that is the hallmark
of a country under energy infusion.
[95:09] It doesn't work… And the archetype is
the United States.
[95:11] It doesn't work in a country with a low
energy supply.
[95:15] And, because of the productivity
brought by the machines, this
[95:20] increasingly meaty food costs us less
and less.
[95:24] Here you have the share of food in the
household budget in the United States.
[95:29] So it's a long series.
I took
[95:31] United States because it is easy to
find long series on American sites.
[95:34] Despite the genius of French engineers,
finding long series of this nature in
[95:37] three mouse clicks on a French site is
something very difficult.
[95:40] I don't know why.
But then, in any case, it works very
[95:43] well in the United States.
So in the United States, what you see
[95:46] is that a small century ago, the
household food budget is a quarter of
[95:51] what they earn and at the time it's
essentially home catering.
[95:55] So, Mrs. Michu (sorry for this sexist
comment, but that's reality) buys raw
[96:02] products from the local farmer or from
the local market and makes delicacies
[96:09] for herself and Mr. Michu from leeks,
potatoes, eggs and chickens.
[96:15] Today, when you go to buy food -- in
fact, most of what you buy (80% of the
[96:22] French purchase food through
supermarkets),
[96:26] most of what you buy is not food.
The receipt at the exit of a
[96:31] supermarket store is the salary of a
cashier, or the salary of engineers
[96:37] from the company that made the
automatic payment terminals (it doesn't
[96:43] matter), it's space rental, it's
warehouse salary, it's carrier salary,
[96:49] it's Volvo Trucks' revenues, it's
Publicis' revenues, etc.
[96:53] I mean, it's anything but food.
When you look at the raw product in
[96:58] what you buy,
in the good cases, it is one third of
[97:01] the invoice.
In the bad ones it's 3%.
[97:04] Let's take the example of an egg box.
How much does it cost to buy an egg box
[97:07] in supermarkets?
The bad ones, the non-organic ones.
[97:11] No, these are the organic eggs that
cost 3 euros.
[97:15] Yes, 1.5 euros,
basically.
[97:16] So, 1.5 euros for 6 eggs.
So, since you're stronger than me at
[97:22] mental arithmetic, it puts the egg at?
It's hard: 15 divided by 6.
[97:29] How many is that?
That puts the egg at 25 cents.
[97:34] We agree with that.
Do you know how much the same egg is
[97:40] bought off the farm?
6-7 cents.
[97:45] You can see that, just on an egg box -- zero processing,
zero processing -- you have a factor of
[97:51] 4 between leaving the farm and what you
pay at the cash register.
[97:56] So, I insist, the receipt today is
anything but food.
[97:59] This means that when you do a series
over a long period of time, you
[98:02] actually have a massive inhomogeneity
between what you watch at the beginning
[98:06] of the series and what you watch at the
end of the series.
[98:08] Because at the beginning of the series,
it is really the egg as it comes out of
[98:12] the farmer's house bought at the market
by Mrs Michu.
[98:15] Today it's not that at all.
And outside the home it's even worse.
[98:21] The omelette at the local café, that's
not a 1.5 euros you're going to pay for it.
[98:24] You're going to pay it 5 or 6 euros for
[98:28] 3 eggs, for 75 cents of egg.
So you add a factor of 10.
[98:32] So, in fact, the real price of food
today, it basically was divided by a
[98:39] factor of 20 on this time scale, the
rest is service.
[98:43] We encounter again the dividing factor
of a few tens.
[98:50] So it varies according to the products,
thanks to the energy abundance.
[98:54] This abundance of energy has also
brought us the means of transport.
[98:57] Remember (without going into detail)
that the more modern a means of
[99:01] transport is, the higher its
consumption per kilometer.
[99:05] So we had bicycles, we had walking, we
had buses, we had trains, etc.
[99:11] And then, today, we have the airplane,
the most energy-intensive mode of
[99:15] transportation per person of all those
imaginable.
[99:18] Once we had these extremely efficient
means of transportation, we also took
[99:26] the opportunity to do something else
with them.
[99:30] So, just a little parenthesis.
In inhomogeneities, in long series, you
[99:35] have another thing to see: it is that
over time some objects may no longer be
[99:40] assigned only to their original
function.
[99:44] Because a car today is not just a means
of transport.
[99:48] It's also a living room on wheels.
So it's your own space that you carry
[99:51] to the office door.
And that is also something that has
[99:55] value and it is also an object of
status.
[99:57] So I will also make a small aside on
the inhomogeneity of the series.
[100:02] A car, when you compare it to something
else, sometimes it's hard to know what
[100:06] it is compared with, and that's the
last avatar of the car.
[100:09] This is the autonomous car “by IKEA”.
Is that a car?
[100:14] Is this a living room on wheels?
Is it a computer on wheels that
[100:18] transports you incidentally?
What the hell is that thing?
[100:21] The connected autonomous car.
So from time to time, you also have
[100:27] inhomogeneities that you have to be
careful about.
[100:32] But to return to the primary purpose of
moving:
[100:36] the more modern are the means, the more
they consume per kilometer.
[100:47] What I am saying is that the car
consumes less fuel than the plane,
[100:51] which is a more modern way.
And, the car consumes more than the
[100:55] train which is an older thing.
And more than the bus which is also
[101:00] older, the bus itself more than the
bicycle which is older, etc.
[101:04] So, basically, the more modern a
vehicle is, the higher its consumption
[101:09] per kilometer is, and in fact that's
what I represent here.
[101:12] What you have here is a graph that
gives you the amount of energy used in
[101:19] grams of oil equivalent.
So, this, this or this is really oil per
[101:25] passenger-kilometer.
That's what you have here.
[101:29] And you can see that, with time, it
rises.
[101:32] That is to say, it is lower for the
train than for the bus, lower for the
[101:36] bus than for the car, lower for the car
than for the plane.
[101:39] And there you have the number of
traveler-kilometers traveled in the
[101:42] year.
So the surface gives you the amount of
[101:43] energy that is allocated to each mode
of transport.
[101:45] And so here you understand that it is
the road that today dominates the
[101:50] transport that is carried out.
And I repeat, therefore, the way of
[101:54] History is to move from economical to
less economical means, because there
[101:59] was more and more energy available per
person.
[102:03] Who in this room has never flown
before?
[102:06] Two, did I count it right or not?
I would have asked the same question in
[102:15] 1950, I would have had to ask it the
other way around,
[102:18] that is: “Who in this room has ever
flown?” And I probably would have had
[102:24] two hands up.
The plane is something that, today, in
[102:28] your socio-professional category and in
your country, it is something that you
[102:33] use as you breathe.
It's extremely recent and, by the way,
[102:37] when you will be about my age, it's not
entirely certain that it will always be
[102:41] the case.
It's extremely recent because it's
[102:43] something that requires very, very
large amounts of energy.
[102:46] Remember that a round trip from Paris
to New York is a very, very large oil
[102:49] bathtub.
It is 400 to 500 liters of oil per
[102:53] person for one trip, which is about the
same as the annual consumption of
[102:59] someone using their car.
For one trip.
[103:04] That's a lot.
So, the opening of MinesParisTech
[103:08] school to foreign countries (excuse me,
I have to live with my time) in 2060...
[103:15] It is not completely out of the
question that it looks more like night
[103:19] trains to go to Sweden than to
fly to Kuala Lumpur or China.
[103:23] Or you will come back to the
semi-sailing boat to go to China, it
[103:28] will take you a month, it will give you memories.
[103:31] And you see here the way people move,
over two centuries.
[103:37] And you have in logarithmic scale here
the number of kilometers driven per
[103:43] person per day and there you have the
different means of transport.
[103:49] So, you see, the horse was the one that
gave the most traveler-
[103:55] kilometers per day (after the walk,
that is there in white) two centuries
[104:01] ago.
So, roughly two centuries ago, the
[104:04] daily journey of a human being was 3 km
on foot.
[104:08] (It wears out, it wears out...)
Because two centuries ago, as you saw
[104:11] earlier, the ordinary human being was a
peasant and therefore he went back and
[104:15] forth between the farm and the various
places where he needed to walk to do
[104:20] his job.
So its fields, orchards, meadows, etc.
[104:23] That's what he was doing during the
day: 3 km.
[104:26] And then, moreover, he lived all his
life without going a few hundred
[104:30] kilometers away.
Then you see: the horse.
[104:36] Here you see the rise of the train and
then you see above all the rise of the
[104:42] car, which has become the
dominant mode of transport today.
[104:48] But the year when cars replaced walking
as the dominant mode of transport in
[104:53] terms of passenger-kilometers per day
was the 1950s.
[104:57] I was about to be born.
My parents were born and well born.
[105:02] So my parents, who were already born at
that time, were born in a world in
[105:07] which the dominant mode of
transportation for the population as a
[105:11] whole was walking.
Also be aware of what this means in
[105:15] relation to the world in which you
live.
[105:19] We have reduced the number of farmers
and, as I said earlier, we have put
[105:26] these farmers somewhere.
So where do we conveniently make
[105:31] industry and then tertiary jobs?
In the cities.
[105:34] Historically, what is a city?
It is a place of exchange.
[105:36] When you look at the cities that were
built a long time ago, they are all
[105:41] organized around places of exchange
that are: the market place (I exchange
[105:45] goods), the place of worship (I
exchange beliefs and moral rules) – so
[105:50] the Church (to speak of France) is
always at the center --
[105:54] the town hall or equivalent (I exchange
rules of living together), the school
[105:58] (I exchange knowledge), etc.
So, the places of exchange are at the
[106:02] center and geometrically, the most
effective thing is a disk with everyone
[106:06] around it, that's where it's most
compact.
[106:08] The disk is the most compact shape.
Around places of exchange which are all
[106:13] placed in the center.
Once you develop abundant means of
[106:18] production and transport, at that
moment two phenomena will occur: 1) you
[106:25] will empty the countryside.
2) you will put people where it is most
[106:30] efficient to produce and then exchange
production.
[106:32] Where is it most efficient to produce
and exchange production?
[106:36] In the cities.
It is in cities that it is more
[106:39] effective to do this.
So you're going to put people in cities
[106:43] and by increasing energy, so that's
what I'm getting at, you're increasing
[106:47] the proportion of the population that
lives in cities.
[106:50] So that's how it works for the world as
a whole.
[106:53] In 1960 you have a little more than 30%
of the population living in the city
[106:57] with three tons of CO2 per person,
which represents the fossil energy we
[107:01] use, i.e. energy itself in a first
approximation.
[107:03] And you see that today we are at 5
tons, so we have increased the energy.
[107:09] This has made it possible to place
almost two thirds of the population in
[107:12] cities.
So, you see this evolution at an
[107:16] accelerated speed in countries that
have had accelerated access to energy.
[107:23] There is causality because you distort
the structure of employment.
[107:28] And because a system in which you would
have left all the craftsmen, each in
[107:31] their own corner with intermediate
transport, is much less efficient than
[107:34] a system in which you put 100 craftsmen
together.
[107:37] They are called workers, in a single
place that you will specialize for a
[107:40] production and it will become very
efficient.
[107:43] I'll put it another way.
To make cars, if you have the 12-bolt
[107:48] that is made in Brive and then the door
that is made in Aurillac and then the
[107:54] door piece that is made in Bordeaux,
you can't get away with it.
[107:59] So it's much easier to put everything
together in the same place and have
[108:03] operations that are assembled in the
same place.
[108:06] Then, when transport becomes more and
more accessible, you can go even
[108:10] further in there and specialize even
more on certain operations, on certain
[108:14] sites, since transport costs you
nothing.
[108:16] And then you take them to other places
where, in mass, you hyperspecialize on
[108:20] something else.
That's why, for example, there is a
[108:22] manufacturer who assembles his truck
cabins in a place other than where he
[108:26] paints them.
And in between, you carry unpainted
[108:30] truck cabins.
You have exactly the same evolution as
[108:35] you can see in China.
The same for Brazil, the same for
[108:38] Thailand, the same for Indonesia, etc.
More energy, I repeat, distorts the
[108:43] structure of employment in the way I
mentioned earlier and the jobs that
[108:48] appear are most effective if you
increase the size of cities.
[108:52] So you can increase the size of cities
while spreading them out, and that's
[108:56] exactly what happens when you have
access to abundant energy.
[108:59] Because, at that moment, moving in
mechanized mode becomes easy and so you
[109:03] try to do the best of both worlds.
That is, a little space for everyone,
[109:07] while having extremely important
exchange flows.
[109:10] And that, you can only do that if you
have plenty of energy.
[109:13] So in the energy-efficient city, the
most compact thing is the Haussmannian.
[109:17] Paris is one of the densest cities in
the world despite the fact that there
[109:20] are no very high towers.
Because, when you have very high
[109:23] towers, you have to start leaving a
little space around the towers.
[109:25] It is complicated to tighten the very
high towers as you tighten the
[109:28] Haussmann buildings that are stuck
together.
[109:31] You have no space between the
buildings, they all face the street and
[109:34] are all stuck together.
With 10-storey or 30-storey towers,
[109:36] it's more difficult to do that.
And, on the other hand, it is the most
[109:40] efficient mode when you don't have a
lot of energy to move around.
[109:45] Because you can do everything on foot
or by horse cart.
[109:48] When you give everyone a car, you go to
Los Angeles.
[109:51] That is to say, you keep the same urban
functions of exchange by being able to
[109:56] put the city in 100 or 150 km in
diameter with each having a car.
[109:59] You keep the same distances covered in
one hour in a considerably more spread
[110:06] out urban planning.
So that's why, when you look at
[110:10] Île-de-France for example: that's what
the distance between home and work
[110:17] looks like, which is representative of
the daily exchanges in 1975.
[110:24] So where it's white is that we don't
cover much distance.
[110:26] So, in 1975, there you have a dense
city.
[110:28] People walk to work.
There you are still in the countryside,
[110:31] people walk to go to their fields.
And then, that's how it evolves over
[110:36] time, and that's where we are in the
early 2000s.
[110:40] All these people have become urban,
peri-urban people whose profession has
[110:46] become an urban profession.
They are no longer farmers.
[110:49] They are employees of industry,
employees of services.
[110:51] So they have entered into this travel
system that is necessary for industry
[110:55] and services and they use their cars
because there is no public transit and
[111:00] there will never be one.
So you are starting to have extremely
[111:02] long distances between home and work.
By the way, where we're going to put
[111:05] the Grand-Paris metro is in there.
So, them, it will not solve their
[111:10] problem at all.
This abundant energy has also made it
[111:14] possible to increase the housing stock
and it has made it possible to increase
[111:19] it faster than the population.
In 1900, then, let's say at the time of
[111:24] the oil crises, the average housing in
France was 77 square meters and you had
[111:29] a little less than three people in it.
Today, you have a little more than two
[111:33] people per dwelling!
The housing itself having become
[111:37] larger.
So, obviously, it was energy that made
[111:40] it possible to do that, and therefore,
energy allowed divorces in particular.
[111:46] Because, to divorce, you have to have 2
dwellings where you only had one.
[111:50] Otherwise it's not called a divorce.
It's called domestic disputes, but it's
[111:55] not called a divorce.
Divorce is a physical separation.
[111:59] You have to have enough to house
people.
[112:01] And by the way, today, one of the
factors putting upward pressure on
[112:04] housing needs in France is divorce.
This is probably the first upward
[112:10] pressure factor.
You will find what I have just told you
[112:14] in this little graph, which this time
gives you, for a given year, the CO2
[112:20] emissions per person according to the
share of employment in services.
[112:26] And, you can see that this graph says
everything except that when you
[112:29] increase jobs in services, emissions
decrease proportionally.
[112:33] It tells you everything but that.
This is the only thing that cannot be
[112:37] seen in this graph.
So this is another way, this time in a
[112:41] dynamic way, for the world as a whole.
Again, you have the share of jobs in
[112:46] services in 1991 and 2014 with CO2
emissions per person.
[112:50] And you see that the two work together.
And it works together again when you
[112:54] look at countries taken one by one.
It works very well.
[113:00] Another evolution that abundant energy
has allowed is the increase in the flow
[113:04] of goods since transport has also
applied to trucks.
[113:07] There is also something we have to get
out of our brains, which is that we can
[113:10] dematerialize transport by replacing it
with information flows.
[113:13] Obviously, this is not true.
When you look at the concomitant
[113:16] evolution of information flows and
transport flows, whether it is goods or
[113:20] people, you get exactly the same
result.
[113:23] The two evolve together.
So, today, on a macroscopic scale,
[113:27] to say that to circulate more information would
allow us to circulate fewer people or
[113:32] fewer goods, that is not true.
That's not how it works.
[113:36] Then, we can ask ourselves why it
doesn't work like that, but the gross
[113:41] result is that it's not enough to
increase the amount of information that
[113:46] circulates to say : “Well, the result
I'm going to get is that there are
[113:52] fewer people moving or fewer goods
moving.”
[113:55] Energy has therefore restructured the
country.
[113:58] What I am presenting to you for France
has been applied in all the countries
[114:03] that have had access to energy, all of
them.
[114:06] You had populated countryside and not
too big cities.
[114:09] You have moved to much larger cities
and empty countryside. And the cities
[114:15] have spread out.
And all countries have followed the
[114:19] same trend.
The only countries that have not
[114:22] followed it are those that have had
geographical obstacles that have
[114:26] opposed this development.
So I'll give you an example.
[114:30] Switzerland has indeed expanded its
cities.
[114:33] It didn't spread them out much.
Why?
[114:34] Because when you have a city that is at
the bottom of a valley, spreading the
[114:37] city out means climbing up the
hillsides, and it's complicated.
[114:39] So they did it a little bit by putting
cottages everywhere, but they didn't do
[114:44] it in a massive way.
In particular, they did not make
[114:46] hypermarkets on the outskirts of the
city because putting the hypermarket on
[114:49] terraces at the top of the city is
more complicated than putting it on the
[114:52] outskirts of the cities.
So, the countries, once again, that
[114:55] have not followed this evolution, it is
because they have had a physical
[114:59] barrier that prevented them from
following it.
[115:02] This abundant energy has also been
applied to leisure activities.
[115:07] So leisure time has increased because,
like machines produce for us, it frees
[115:12] us up time.
So it frees up time for study.
[115:16] At a time when there were no machines,
there were no long studies.
[115:19] It frees up time for retirement.
At a time when there was no abundant
[115:23] energy, there was no pension.
It frees us up time for the holidays.
[115:27] It frees up time for us to do nothing
on weekends and it frees up time for us
[115:32] to work only 35 hours a week.
All the free time we have gained is due
[115:37] to the abundant energy.
So, here too, remember something that
[115:40] will apply not only to you but to the
people you will work with and live with
[115:44] for the rest of your life.
In a world with limited energy, it is
[115:49] not the increase in well-managed free
time that will apply.
[115:56] What you see here is one of the
occupations of free time, called
[116:01] tourism.
And so, a few years ago, I did a little
[116:03] calculation. I didn't do the
calculation again, but the order of
[116:07] magnitude is still the same.
It gives you the greenhouse gas
[116:10] emissions, so again the consumption of
fossil fuels, linked to the way you
[116:15] spend your holidays.
So, in there I put in the initial
[116:19] displacement.
Going to the holiday destination by
[116:22] train, car, plane.
I have included the possible
[116:25] manufacture of the object in which you
live during your holidays: the tent,
[116:29] the caravan.
The holiday home, I considered that if
[116:33] we built it, I counted something, if it
was the old mother-in-law we had to
[116:37] deal with, I didn't count anything
because she already had her house built
[116:42] a long time ago.
And then I also took into account local
[116:45] travel if there are any, etc.
If it is a skiing holiday, I have taken
[116:49] into account the heating of the
apartment, since skiing is generally
[116:52] complicated when it is very hot.
It is rather cold and therefore the
[116:56] apartments are heated, preferably with
fuel oil.
[116:59] So I took all these things into
account.
[117:02] And what you see is that the most
modern form of tourism (i.e. I'm going
[117:07] to walk around the hotel for three days
by plane), is also the one that
[117:12] involves the greatest amount of energy
consumed to afford a week's vacation.
[117:17] Conversely, the first one, which are
the forms of leisure that appeared when
[117:23] paid holidays appeared; that is, people
took their bicycles to go camping.
[117:28] Or they would take the train to go
camping, that's what they did at first.
[117:31] Here are the forms that are the most
economical in terms of fossil energy
[117:36] -- and therefore in terms of energy alone --
to be used.
[117:39] So, once again, energy abundance has
distorted our lifestyles.
[117:47] And we owe the fact that we can benefit
from this leisure offer to the fact
[117:53] that we are on an energy infusion, each
and everyone of us.
[117:58] That's why Sweden has been developing,
for example, in recent years (it's been
[118:03] in the media for a few weeks but in
fact when you look at the statistics,
[118:08] it's a few years ago) a beginning of a
decrease in the number of planes taken
[118:13] by Swedes that is now described by the
media as “Flygskam”.
[118:18] So, it is because Scandinavians have a
rather more developed environmental
[118:22] sensitivity than the rest of Europeans,
which can be explained by historical
[118:26] and geographical reasons.
We will find this again on the economic
[118:31] level with what it costs in terms of
working hours to fly.
[118:38] I'm telling you again, the real price
of things is the hours of working time.
[118:41] And what you see, is that the price
expressed in hours of working time to
[118:48] fly has been divided by an extremely
important factor in the space of a few
[118:55] decades.
This is another way of saying that
[118:58] energy has become more abundant.
That is to say, it is easier to pay for
[119:02] a full amount of it with one hour of
working time.
[119:04] It's the same way of saying it.
Energy also drives industrial machines
[119:09] and industrial machines will be used to
make all the objects that surround you
[119:14] today.
So, the tables on which you are leaning
[119:17] for some, the chairs on which you are
all sitting, the clothes you are
[119:22] wearing, the glasses for some, the
shoes, etc.
[119:25] All this was made by industrial
machines.
[119:29] So, the energy drives the industrial
machines.
[119:31] So, it is the exoskeleton that makes it
possible to do everything, including
[119:38] scissors, cosmetics and Netflix films.
But it is also used as a raw material.
[119:44] So you have a component in energy that
is sometimes called non-energy.
[119:48] So you'll tell me: “The «non-energy»
in energy is still a little
[119:50] complicated.”
In fact, when you see non-energy uses
[119:52] of energy, particularly oil and gas, it
is because it is used as a raw material
[119:57] for organic chemistry.
All organic chemistry is based on gas
[120:01] and oil derivatives.
So, there are Americans who have done a
[120:04] funny little test.
They have taken out of a house all the
[120:08] products that contain petroleum
products.
[120:11] Well, there's nothing left.
In fact they also had to tear off the
[120:14] floors because there is varnish on the
floors.
[120:17] They should have ripped the curtains
off.
[120:19] They should have ripped off the curtain
rod.
[120:20] They should have removed the paint.
I mean, they should have taken
[120:22] everything off.
So, oil today is not only something
[120:26] that drives a machine, it is also the
basis of organic chemistry to produce
[120:32] all the products that surround us.
Because you don't have (more or less) a
[120:38] single product that surrounds you in
which you don't have oil derivatives.
[120:44] These objects that surround us, we have
to make them.
[120:50] After, some of them will also use
energy.
[120:53] Here, for example, you have the
evolution of the rate of household
[120:56] appliances.
So, I didn't find a more recent series,
[120:59] the equipment rates have increased
considerably everywhere.
[121:04] But you don't have a single household
today in which you don't have a fridge,
[121:08] washing machine, etc.
You have a whole bunch of things that
[121:11] use energy.
So industry makes things and it
[121:15] requires energy.
And after, these objects (some of
[121:18] them), we will use them (up to the
lawnmower, etc.).
[121:20] And it's also going to use energy.
And you see that equipment rates are
[121:23] increasing roughly everywhere and all
the time.
[121:26] I already told you, I'm telling you
again: divorce is energy-consuming.
[121:31] Because when you divorce, you have to
double the housing, so you double the
[121:35] energy consumption of the housing.
More precisely, you increase it in
[121:40] proportion to the new area occupied.
You need to build more homes, which
[121:46] uses energy.
You need to furnish twice as many
[121:51] homes.
So there are things you don't really
[121:53] double, but there are things you
double.
[121:55] For example, you have twice as many
beds.
[121:56] Everyone sleeps in a bed.
You have twice as many sinks, twice as
[122:00] many hobs, twice as many etc.
And all that, you have to make it.
[122:04] When there are children (this is not
always the case)
[122:07] when there are children, they must then
be brought from one home to another.
[122:10] This requires additional travel,
sometimes quite long.
[122:12] As I told you earlier, a number of
things that are considered normal
[122:16] today, so I'm repeating once again
retirement, studies, etc.,
[122:20] it's energy.
When Mitterrand, in 1981, said:
[122:22] “Everyone must go to university” --
which was the implicit promise that
[122:26] afterwards everyone would have an
office job
[122:28] it was another way of saying: “I
promise you the society of infinite
[122:33] abundant energy”, since I showed you
earlier that everyone in an office is
[122:37] an extremely energy-intensive society.
So at the time, when Mitterrand said
[122:42] “Everyone must go to university”, in
fact he made the implicit promise that
[122:47] we would be able to live in a world of
machines for eternity.
[122:51] That is the implicit promise he made.
So you see that energy is not at all
[122:57] detachable from a whole bunch of things
even and including, the way we consider
[123:04] access to competence.
The hospital is also very energy
[123:09] consuming.
In France, hospitals account for about
[123:12] 5% of the country's carbon footprint.
So as a famous comedian put it: if it
[123:16] is the elderly that use the most health
services, all you have to do is remove
[123:22] the last year of life.
In the meantime, it still raises the
[123:26] question of how long in a world of
constrained energy we can continue to
[123:30] arbitrate in favor of people who ask
for very heavy equipment when they are
[123:35] already very old, and therefore at the
detriment of all others, including the
[123:40] young.
That's it, so energy is everywhere.
[123:43] So, once I told you that, we're going
to do a tiny little bit of economics.
[123:47] This is the planet Earth.
So, the planet Earth, as Coluche used
[123:50] to say, is square with its eyes in the
corners.
[123:52] No.
The planet Earth is made up of
[123:53] resources in an anthropocentric vision.
So I'm going to put it from the point
[123:57] of view of Men.
And, from a human perspective, planet
[123:59] Earth is a resource.
All right?
[124:00] This is where we live, this is our
home, this is where we live, so these
[124:02] are resources to which we have access.
These resources, I will classify them
[124:06] into two categories, which are on the
one hand resources that are renewed on
[124:09] short time scales.
I call them renewable.
[124:12] And, on the other hand, resources that
do not renew themselves on short time
[124:16] scales, that I call non-renewable.
Copper ore is definitely non-renewable.
[124:20] There is no large-scale transmutation
on Earth that replenishes the copper
[124:24] ore stock.
Fossil fuels are renewable if you wait
[124:26] a few tens of millions of years.
It's not a short time scale, so I put
[124:30] them in non-renewable.
On the other hand, grass or solar
[124:34] radiation is reasonably renewable on
short time scales.
[124:38] These resources are all free and they
are the result of everything that has
[124:43] happened since the Big Bang, all free
of charge.
[124:47] So, since the Big Bang, proton soup and
everything else, a whole bunch of
[124:51] processes have taken place.
And today, we have Mendeleev's table
[124:54] and all the combinations that it offers
to us on the surface of the planet.
[124:58] For free.
All this was done for free.
[125:02] We get there, and we decide to have a
productive activity.
[125:04] So, what is productive activity for
Men?
[125:07] It is using this great horn of
abundance of resources and transforming
[125:11] resources into something else that is
more interesting than the original
[125:14] resource.
For example, I have coarse flints: it
[125:17] is more interesting to have carved
flints to chase after my prey.
[125:21] For example, I have deers: it's more
interesting to have carved deer antlers
[125:25] to make a number of things out of them,
etc.
[125:27] So, the productive activity of Men is
just that: I use existing resources, I
[125:32] transform them, transformation =>
energy: I use energy.
[125:35] At the time, obviously just the one of
my arms, my legs and fire.
[125:38] And I do something else with it.
And then, over time, we will increase
[125:42] the energy we will seek to have at our
disposal.
[125:46] So I repeat: 500,000 years of energy
transition, which will make it possible
[125:50] to increase everyone's production
capacity.
[125:52] So we extract resources faster and
process them faster.
[125:57] As soon as non-renewable resources are
extracted from the environment and
[126:00] transformed into something else, the
stock of non-renewable resources
[126:02] declines.
So at first, it does not decline
[126:04] quickly, although it would seem, for
example, that on flints there may have
[126:08] been local shortages in the Paleolithic
period.
[126:10] So we have been able to have, from time
to time, local resource shortages.
[126:14] So, don't laugh because at the time
they were dying.
[126:17] And then, over time, we also understood
that there was a part of what we were
[126:22] transforming that we could keep to
accelerate future transformation.
[126:28] It's called capital.
So, capital is the part of production
[126:31] that is not consumed immediately and is
reusable to increase future production.
[126:38] So, this is all really good.
We grow and multiply.
[126:42] We are producing more and more, so we
are emptying non-renewable stocks more
[126:45] and more quickly.
And then, at some point, you become so
[126:48] productive and so numerous that you
also start emptying renewable stocks.
[126:53] Today, we have begun to empty stocks of
species that were renewable, for
[126:57] example.
We have started to empty the stocks of
[126:59] forests that were renewable.
We started to empty fish stocks that
[127:02] were renewable, and so on.
We are even beginning to empty the
[127:06] stocks of slowly renewing soils.
So we started to empty a number of
[127:11] stocks that were renewable.
And then I said transformation, so I
[127:15] said energy.
But I said transformation, so I also
[127:18] said undesirable by-products of
transformation.
[127:21] When you transform, there is always a
time when you have an unwanted
[127:25] by-product of the transformation.
These undesirable by-products of
[127:28] processing have been given a name in
French, it is called pollution.
[127:32] So pollution is all the undesirable
by-products of processing, i.e. those
[127:36] that will have an effect that we are
not looking for.
[127:39] And, not only are we not looking for,
but they’re bothering us instead.
[127:41] So, basically, pollution is all about
trouble.
[127:44] So, in more orthodox terms, it is all
the products that will be introduced
[127:48] into the environment and will have the
effect of degrading the quality of the
[127:52] remaining assets.
That's what pollution is.
[127:55] In there, with this definition, you can
bring in climate change, biodiversity
[128:01] erosion, overfishing, and so on.
And so, in this case, the economy that
[128:05] we have set up, which I will detail in
a little while, consists in counting
[128:10] that annual flow and considering that
that is all that matters.
[128:13] I will explain why.
So, basically, we count the moment when
[128:17] we transform, since transformation is
Man's action and money only pays men.
[128:22] So, in that case, we decided that the
only marker of this physical flow, of
[128:27] the system I am presenting to you here,
is the monetary counterpart of the
[128:32] annual transformation flow.
And this annual transformation flow, in
[128:36] the jargon of economists, is called
GDP, it is the monetary counterpart.
[128:40] We might as well have had an accounting
that would say: “I count «plus» what I
[128:44] do, «minus» what I destroy.
And then, on the day the marginal value
[128:49] of the last car I built is less than
the marginal value of the last bits of
[128:54] iron ore, copper ore, lithium ore,
vanadium, chromium and fossil fuels I
[128:59] used to make this car, I stop making
cars and live “happily ever after”
[129:04] with existing cars. ”
You can see that's not what we're
[129:07] doing.
In fact, the economic system is a
[129:09] system without absolute limits.
Nothing in the economic system tells
[129:12] you: “When GDP reaches 80 trillion
dollars on Earth, it stops.
[129:16] We made a system that is potentially
infinite, which is why it is so
[129:20] attractive.
Then why did we do it?
[129:22] Because, two centuries ago, when we
start theorizing about economics, you
[129:25] have a number of people who make the
following observation, they say:
[129:28] “Economics is the management of what is rare.”
[129:30] What is rare two centuries ago?
It is the human factor.
[129:34] You have lots of species, lots of space,
lots of World.
[129:37] The United States are just at the
beginning of their colonization, Russia
[129:40] is huge, and so on.
We don't know how far the ocean goes.
[129:43] No resource issues.
What is rare two centuries ago is the
[129:48] human factor.
And so, two centuries ago, economists
[129:51] like Mr Say, who wrote exactly what is
written here, said to themselves: “At
[129:56] first order, I will just look at the
limitation coming from Men, the rest I
[130:01] do not care, I do not count.”
And if I consider that the resources
[130:05] are infinite, you agree with me that
any variation in stock is zero.
[130:09] Delta-stock on infinity, it's always
zero.
[130:12] So I'm going to count for zero the
factors that don't come from Men.
[130:17] Approximation to the first order which
is still the one of the economy today.
[130:20] So I'm going to say something that will
hurt your Director of Studies who just
[130:25] came in.
The whole economy you are taught at
[130:27] school is wrong when it comes to
approaching the human system as a
[130:31] whole.
When it comes to approaching trade-offs
[130:33] within the human system, it works.
When it comes to approaching the whole
[130:38] of Men in their environment, it only
says nonsense.
[130:42] That's not what it's for.
So, in other words, the economics that
[130:46] I learned in school and that we are
still learning today is that the
[130:51] productive system is fuelled by two
factors of production, human capital
[130:55] and human labor, and that is enough to
fill the supermarket.
[130:59] It doesn't take into account machines,
it doesn't take into account resources.
[131:03] So it turns out that at the time, we
could have won the battle in another
[131:05] way.
It so happens that two centuries ago,
[131:08] Mr Charles Dupin, a polytechnician,
therefore someone very decent, baron
[131:12] of his state, made a first conversion
calculation in “slave-equivalents”.
[131:16] So, at the time, he didn't call them
“slave-equivalents”, he called them
[131:19] “worker-equivalents”.
And, Mr Dupin say: “I will look in
[131:22] France and Great Britain at the
productive resources available to us in
[131:27] addition to Men [so he had understood
everything about physics] and I will
[131:31] convert them in the equivalent of
human workers.
[131:35] So I take the population, I make them
human workers […]” and by the way, he
[131:38] counted children for a quarter and
women for half – and we wonder if
[131:41] that's not where “my half ” comes
from when one talks about one’s
[131:44] partner.
No, no, I assure you.
[131:46] Where else would it come from “my half”?
[131:48] So it could be half a couple, that's
another explanation.
[131:52] But we wonder if that's not where it's
coming from.
[131:55] So he is taking the population and he
is also taking the auxiliaries that
[132:03] are, at the time, boats, mills, etc.
And then, Mr Dupin, he says: “If I
[132:09] take the population AND the
auxiliaries, then it becomes normal
[132:13] that Great Britain, which has a
population about the same size as
[132:17] France, already has three times more
industrial production.
[132:21] This is normal because it is not only
Men who work.
[132:24] There are also mills, draught animals
and boats.
[132:30] If, at the time, we had listened to Mr
Dupin and not Mr Say, it is not
[132:35] completely certain that we would have
built the economy in the same way.
[132:40] It's not completely certain.
And what the physicist says is: “What
[132:44] I have on the right is my 92 elements
of Mendeleev's table arranged in a
[132:49] different way than what I had in the
original resources.
[132:53] It's just that.”
Do you agree with me?
[132:57] There is nothing but the 92 elements of
Mendeleev's table in all objects of
[133:00] everyday life.
Nothing else.
[133:02] Do we agree?
Except we didn't find them in this form
[133:04] in the environment.
So I found them in a form, and I
[133:07] transformed them.
So, for that I have to find my 92
[133:11] elements of Mendeleev's table, it's
called resources and transform them.
[133:18] My transformation capacity (it is the
order of magnitude calculations I
[133:24] showed you earlier) comes for 1 from the
muscles of Men and for 200 from Ironman.
[133:30] That is to say, from the park of
machines we have built.
[133:34] This is my ratio of 1 to 200 that I
developed for you earlier.
[133:37] The capital in this story is made like
everything else.
[133:41] That is to say, this building, which is
a capital element, was made like the
[133:43] rest by transforming natural resources.
So, this building is, like the rest,
[133:47] made by transforming iron ore, i.e.
iron and oxygen arranged in a certain
[133:53] way, i.e. stones (so natural
resources), i.e. paint (transformed
[133:57] natural resources), etc.
So it's done exactly the same way, just
[134:01] it doesn't get destroyed when you use
it.
[134:03] That is to say, while we are in this
room, for your greatest pleasure and
[134:06] for mine, it does not collapse.
And there you understand that it is not
[134:10] only Men who are a limiting factor of
the system.
[134:12] In the modern world, energy is a
limiting factor of the system.
[134:15] In other words, if I deprive my fleet of machines of energy, I will
[134:20] deprive my productive system of its
production capacity even if the bankers
[134:25] are very friendly and even if the
unemployed are ready to go to work.
[134:30] That is not enough in the world we live
in.
[134:32] And if I deprive the system of
resources, for example I have no fish
[134:35] to catch, the GDP of fishing is zero.
The GDP of Léon de Bruxelles is zero.
[134:40] Well they have to switch from mussels and
chips to steak and chips, but otherwise
[134:43] it is zero, and so on.
So if you don't have the resources and
[134:46] energy, you won't have the production
even if you have highly motivated
[134:51] workers and even if you have very
friendly bankers.
[134:54] So historically, until now, all this
has not been a limiting factor.
[134:58] The limiting factor is indeed Men.
You have here the reconstruction of GDP
[135:02] since the year zero.
That is, since the birth of Mr Jesus
[135:05] Christ.
So you see that, as long as there are
[135:07] no significant quantities of mechanical
auxiliaries, there is no growth.
[135:11] The population is reasonably stable at
that time as well.
[135:13] At that time too, as a man is
productive as his muscular system and
[135:16] no more, the most populated country in
the world has the first GDP on the
[135:20] planet. Which is?
[135:24] China.
Absolutely.
[135:27] So, China, today, is saying one thing in
the concert of nations: “Listen, don't
[135:31] make us laugh.
For two millennia, we have been the
[135:33] dominant economic power on the planet.
So just because a century of oil has
[135:36] put the United States in our place does
not mean that it will change our view
[135:39] of the world.
So first we'll find our place and then
[135:41] we'll talk.
That's about the way things are.
[135:50] Very few mechanical auxiliaries, very
little growth.
[135:52] With the mass arrival of mechanical
auxiliaries and fossil fuels, and bang,
[135:55] economic models say that we will have
three percent growth for all eternity.
[135:59] Then don't laugh.
I happen to be part of an organism
[136:02] called the High Council for Climate.
Three weeks ago, we were presented with
[136:06] the National Low Carbon Strategy drawn
up by some of your predecessors, whom
[136:12] were obliged to say that a sharp
reduction, a 6 to 7-fold reduction in
[136:17] the amount of fossil energy we would
bring in France, would increase the
[136:22] French GDP.
It's in there, it's in there.
[136:25] Because business models tell you that.
Because economic models can tell you
[136:30] that we increase GDP by dividing energy
by 10 since energy is not an input.
[136:35] There is no problem, no problem.
So in the meantime, that's not what's
[136:41] happening.
I present to you the best macroeconomic
[136:44] model in the world, called a straight
line.
[136:46] Here you have in abscissa the quantity
of energy used by Men, i.e. I repeat,
[136:50] the number of machines in service.
And so, in ordinates, the economic
[136:55] value of the production. Which follows in
a more or less linear fashion.
[137:00] Very simple.
Really very simple.
[137:03] This is valid in absolute value, it is
also valid in variation.
[137:06] Here you have in green the annual
variation in the amount of energy used
[137:10] on Earth, i.e. the annual variation in
the number of machines in service, and
[137:14] in blue, the annual variation in human
economic production.
[137:17] You see that: give me one, I give you
the other; and give me the other, I
[137:20] give you the one.
All right, I'll tell you again in a
[137:22] different way.
Euros only measure a flow in monetary
[137:27] terms, which kilowatt-hours physically
measure.
[137:32] So, it's two units of account that look
at the same thing, that is, a
[137:36] transformation flow.
I come back to my curve that I showed
[137:39] you earlier about energy supply per
person and I will make another comment
[137:43] this time.
You can see that over the period up to
[137:46] the oil crisis, the energy supply
increases by 2.5% per year per person.
[137:50] This means that the number of machines
per person is increasing by at least
[137:57] 2.5% per year.
You have a little bit of energy
[138:00] efficiency added.
This means that as long as you do not
[138:03] have limiting factors on the resources
to be processed, the physical
[138:06] production per person increases by at
least 2.5% per year.
[138:08] And so, the monetary counterpart of
this production increases by at least
[138:14] 2.5% per year.
Actually, you'll see, it's a little
[138:18] more.
After the oil shocks, you can see that
[138:21] the pace is slowing down.
So in fact, it is totally slowing down
[138:24] for the OECD countries, which are
called the rich countries, the western
[138:27] countries; and the surplus you have
there is the rise of China, and then
[138:30] later of the other emerging countries.
And that translates into a rise in the
[138:33] quantity of coal per person, which is
an average effect.
[138:36] In fact, in Western countries, the
amount of coal used is not increasing,
[138:39] even decreasing slightly.
However, it is exploding in China.
[138:42] And today, China uses half of the coal
consumed in the world.
[138:46] At this point, the system starts to
slow down a little.
[138:50] That is, we continue to have an
increase in physical production
[138:56] per person, but much lower, and much lower than
the rate of redistribution to which we had
[139:02] become accustomed during that period.
That is to say, in all the Western
[139:07] countries of the world, a welfare state
has been organized, more or less.
[139:13] More or less.
Less welfare in the United States, more
[139:16] welfare among the Scandinavians.
But in all countries of the world, a
[139:21] welfare state is organized that
redistributes part of what is produced
[139:25] and the growth rate of redistribution
is in line with the growth rate of
[139:30] production, i.e. a few percent per
year.
[139:33] And we do not put in the system the
capacity to correct it quickly if
[139:37] growth slows down.
In other words, we don't tell public
[139:40] agents: “Well, we warn you, if growth
runs out of steam, increased wages with
[139:44] seniority, it stops.”
We don't tell retirees: “We warn you,
[139:47] if the rate of growth slows down, you
will automatically retire later and be
[139:52] paid less.” Etc.
We're not saying that whole thing.
[139:55] We say: “No, no, if growth slows down, we
continue to pay you the same and we
[139:58] increase your wages with seniority in
the same way.”
[140:00] At that moment, you have to find the
money somewhere and you get into debt.
[140:02] In all Western countries, public debt
was non-existent before the oil shocks.
[140:07] It appears and develops… well very weak
before the oil shocks.
[140:11] It appears and develops everywhere.
So, it is not only the French
[140:14] politicians which are incompetent.
It appears and develops everywhere in
[140:17] all Western countries after the oil
shocks precisely for this reason.
[140:21] Because the rate of increase in
production per person is no longer
[140:25] sufficient to ensure the rate of
increase in redistribution per person.
[140:30] And starting from 2005 -- and I will tell you why in
the next few months -- the per capita
[140:35] energy supply is beginning to become
more or less constant again in the
[140:39] world.
In fact, it is declining in the OECD
[140:41] area, I will show you right after.
And then the system goes to hell:
[140:44] massive financial crisis of Lehman
Brothers which is a consequence of what
[140:48] I'm telling you (I'll show you in a
little while chronologically) and not a
[140:53] cause.
Debt begins to explode.
[140:56] We come to something that has been
unknown for a very long time called
[141:00] negative interest rates, etc.
And that is the system's response to
[141:04] the fact that we built something that
depended on energy abundance, and that
[141:10] this energy abundance is slowly
starting -- slowly starting -- to fray.
[141:14] And by the time you're my age, we're
going to accelerate in that direction.
[141:21] So that's why your future won't be a
continuation of the past.
[141:27] So, a few curves to finish.
You have here the variation in GDP per
[141:32] person in the world, and therefore the variation
of economic output per person in the world
[141:36] since 1960.
You see it here in terms of annual
[141:39] variation.
And then I put in orange the averages
[141:43] over three periods: until the oil
crisis, between the oil crisis 79 and
[141:49] the oil crisis of 2007-2008, and since
the shock of 2007-2008.
[141:54] There is a small artifact that I'm not
going to talk about today because it's
[141:57] too long, but debt is something that
makes it possible to make GDP without
[142:01] production.
It's a little complicated, but here
[142:04] you're starting to have a side effect.
What you see is that: in the era of the
[142:09] Glorious Thirty, energy grew strongly
per person, and production per person
[142:13] grew even more strongly, because there
was a gain in energy efficiency in
[142:18] between.
Engineers know how to make a more
[142:21] efficient car, which advances with less
oil if it is the same car, or a larger
[142:26] car sold more expensive with the same
amount of oil.
[142:30] After that, you see that the energy per
person is increasing less quickly
[142:35] (it is actually 1% rather than 0.5%) and
you see that the GDP per person is
[142:40] starting to grow less quickly.
And since the episode... Well it's very
[142:44] contrasted there, you also see that
there's a big episode of volatility.
[142:48] You can see it's dropping.
In fact, you have two regions in the
[142:51] world that are evolving in a very
discriminated way from that moment on:
[142:53] the OECD and the rest; and I will show to you
where we live, that is, the OECD.
[142:56] So the OECD: this is how a first piece
of the OECD evolves, i.e. the European
[143:04] Union in which we live.
Until the oil shocks, the energy supply
[143:08] per person increases sharply. Between
the oil shocks and 2006 -- and you see that
[143:12] the maximum is in 2006, two years before
Lehman Brothers.
[143:15] So it was not Lehman Brothers that
caused the economic crisis that caused
[143:19] a fall of the amount of energy used.
It was the contraction of the
[143:24] energy supply that slowed GDP and made
it impossible for borrowers to repay
[143:30] the debt they had started to incur when
the economy first slowed down here.
[143:36] It's a two-triggers-gun.
There, we start to get into debt to
[143:40] compensate for the fact that the energy
stops increasing, and there, at the
[143:44] moment when the energy starts to
decrease, we no longer even have the
[143:48] capacity to get back into debt at the
right speed to repay the Ponzi scheme
[143:52] we had started creating.
There you see an effect of the thing I
[143:56] will tell you about next time, which is
the replenishment of the world energy
[144:00] market with source rock oil and gas in
the United States, and oil in
[144:04] particular.
What you see in Europe at that time is:
[144:07] the GDP per person is rising sharply at
the time of the Glorious Thirty; energy
[144:12] per person is stopping growing but GDP
per person is still rising; and you see
[144:17] that ever since 2006, the increase has been
almost zero.
[144:20] And, by the way, Europe's industrial
production today is still lower than it
[144:25] was in 2007.
Ton-kilometers by truck today in Europe
[144:28] are lower than they were in 2007.
The construction index today in Europe
[144:32] is lower than it was in 2007.
So part of the increase in GDP that we
[144:36] have had since 2007 is false GDP.
It is an accounting artifact that is
[144:40] basically a bad correction of
inflation, if I say it differently.
[144:45] So, at that moment you ask British
people: “Are you happy?”
[144:49] British say “No”.
I would remind you that a referendum,
[144:53] in general, you answer the person who
asks the question, you do not answer
[144:56] the question.
De Gaulle learned it at his own
[144:59] expense and besides, you remember the
result of the first referendum in
[145:04] France on the European Union...
So, of course, we rephrased the question in a
[145:09] different way.
But so, historically, a referendum is
[145:12] still a very good way to answer to the
person who asks the question and not
[145:16] the question itself.
So the English say to the person asking
[145:18] the question: “We are not happy with
the way things are going.”
[145:21] By the way, as soon as the GDP per
person no longer increases and you
[145:26] create a space of free movement in an
area where you have a difference of 1
[145:32] to 5 between what people in the East
earn and what people in the West earn,
[145:38] what do you think is happening?
It balances out.
[145:41] So when you're in an expanding universe,
it doesn't matter. Because you can
[145:45] increase people's incomes on one side
while you continue to increase or at
[145:49] least you don't decrease people's
incomes on the other side.
[145:52] So, when Spain and Portugal join the
European Union at a time of strong
[145:55] growth, the purchasing power of the
French can continue to increase at the
[145:59] same time as the purchasing power of
the Spanish increases significantly.
[146:02] But when you bring in 2005 (that is to
say two years or a year before the
[146:06] maximum European energy level) the
Eastern European countries by telling
[146:11] them: “Come and dance, your GDP will
increase at the same time as ours will
[146:15] continue to increase.”
And then, crack, the energy per person
[146:18] starts to drop.
At that moment the GDP of the area no
[146:21] longer increases, your effect of
connected vessels applies, and all that
[146:25] the Eastern countries will take, it is
the Western countries that will lose it.
[146:28] It's mechanical.
[146:30] Then, there are two ways to lose it.
The Polish plumber comes to London and
[146:34] it gives you that result.
And the second way to lose it is
[146:37] Renault investing in Romania, and at
that moment, you have the French
[146:40] workers yelling.
And these are the two ways in which the
[146:43] rebalancing process applies.
This is just the beginning.
[146:47] As long as we stay, I'm not playing
politics with two pennies in my hand,
[146:51] but I'm just saying that as long
as we stay in a space where everyone
[146:55] moves and pays as they please, when you
have differences in initial potential
[146:59] that you can't homogenize from the top,
you're going to have rebalances with
[147:03] loss for a number of people.
So the temptation for Frexit, Italexit,
[147:09] Espaxit and Swedexit will increase.
All these pressures will increase
[147:16] because of this.
And, originally, you find energy.
[147:22] When you do a trend analysis, you note,
by the way, that this variation in
[147:27] energy supply per person is in fact
the result of a very strong trend (and
[147:32] I will come back to it in the next
course) that has been expressing itself
[147:38] for decades.
Here you have a curve that gives you
[147:41] the variation of the European Union's
energy supply.
[147:44] So it's not its supply, it's its
variation over the past 50 years.
[147:47] What you see is that the variation with
large gaps follows a trend where it is
[147:50] strong, a little less strong, a little
less strong, a little less strong, and
[147:55] at some point, we enter into negative
territory and, by the way, at that
[147:58] moment, we start to have something that
is reasonably volatile.
[148:01] If we say that this second derivative
has good reasons to be representative
[148:05] of the internal dynamics of the
process, then you tell yourself:
[148:09] “Well, the rest of the story is that
energy supply will continue to decline
[148:13] and therefore the GDP growth rate,
which was increasingly low over the
[148:17] same period, will continue to decline
and move into permanently negative
[148:21] territory.”
So the life that awaits you and me for
[148:25] the next few decades, if everything
goes well, is likely to be nothing like
[148:32] what I have known since I was born.
That is to say, it will not be a world
[148:38] of expansion, it will be a world of
contraction.
[148:40] So we're going to need your creative
genius because I assure you that
[148:45] managing a shrinking world is much more
challenging as a constrained
[148:49] optimization exercise than managing an
expanding world.
[148:52] So, we're really going to need you.
We also need me, but we're really going
[148:56] to need you... In the sense that we're
really going to need the best selected
[149:01] brains in the country to tackle one of
the toughest problems we will
[149:05] have to solve, which is to keep the
system more or less stable in a context
[149:10] of shrinking available resources.
I can assure you that what you saw in
[149:14] the written and oral part of the
contest was an easy part compared to
[149:18] that.
I take the OECD area as a whole and I'm
[149:21] going to end up with that.
Same motive, same punishment.
[149:24] The supply per person increases until
79, peaks in 2006 -- and this is also
[149:30] true in the United States.
In the United States, the energy supply
[149:35] per person went through a maximum two
years before Lehman Brothers, I insist.
[149:39] And, you also have this evolution that
actually reflects a trend evolution
[149:44] that has taken place for a very long
time, and therefore it will probably
[149:49] happen about the same thing in that
area and then in the world as a whole.
[149:54] There you go.
So, what I told you during this first
[149:56] module is that the world in which we
live has been enabled notably by -- not only by --
[150:00] but notably by the fact that we
have found free “pockets of sunlight”
[150:05] under our feet, as Yann Arthus Bertrand
puts it very nicely, that is to say fossil
[150:10] energy. Free, with a very high
calorific value -- so a very high
[150:13] exothermic capacity -- that allowed us to
transform at an accelerated rate all
[150:18] the other resources (also free) that we found
on Earth, and it has enabled us to
[150:23] build the socio-economic system in
which you grew up,
[150:27] that is, most of the people in the city,
most of the people in service activities,
[150:32] everyone eating steak at every meal,
people with a lot of free time and the
[150:36] demands of the MEDEF and the CGT that can be met without any problem.
[150:39] That's the world we grew up in.
[150:43] And, by the way, MinesParisTech's
international exchange program since
[150:47] you need planes for that.
And, the way I count the transformation
[150:52] flow is a way that is unlimited by
construction, since the only thing that
[150:57] was really annoying in the deal, that
is the fact that the Earth is 13,000
[151:03] kilometers in diameter and not 14,000
and not 1,5000, I ignored it, I put it
[151:08] under the rug.
And, on the basis of this axiom, which
[151:11] is only an approximation to the first
order, I have refined my visions for
[151:15] two centuries but without questioning a
fundamental axiom which is: Nature is
[151:18] free.
So, obviously, I don't see that limit
[151:21] because it's not in the system.
In the next course, we will not look at
[151:26] that, which is one of the first limiting
factors of the system, i.e. pollution,
[151:31] and we will focus on a very specific
pollution called climate change.
[151:35] So climate change is only the
downstream consequence of this
[151:40] transformation flow.
At the next course, what we will really
[151:43] look at, is the bottleneck that can
eventually apply upstream of the
[151:47] system, and which is called the supply
of fossil fuels.
[151:51] Obviously, if we had the time, we could look at
the supply of metals, this is another
[151:54] possible limiting factor for the
system.
[151:56] Species supply is another possible
limiting factor of the system, etc.
[152:00] But then, we will look at and discuss
the upstream supply of fossil fuels,
[152:06] i.e. of transformation capacity.
So that's the picture we're going to be
[152:12] in for the next course I'm going to
give you.
[152:16] Have a good evening.
![1 - L'énergie - Cours des Mines 2019 - Jancovici - [EN subtitles available] — Jean-Marc Jancovici](https://reducer.xgoose.org/media/thumbnail/13160.jpg)