Source: The Conversation – UK – By Peter Howson, Assistant Professor in International Development, Northumbria University, Newcastle
QQMinh88 / shutterstock
Bitcoin has long been promised to function as money. In practice, it rarely does.
While 99% of transactions are still speculative trading, for as long as bitcoin has been a thing it has been used to skirt governments’ economic controls. Cryptocurrencies are particularly attractive for countries facing sanctions.
The Iranian government is considering charging oil tankers for safe passage through the Strait of Hormuz in cryptocurrency. The reports have excited the bitcoin community with crypto markets jumping slightly in response. “Once the email arrives and Iran completes its assessment, vessels are given a few seconds to pay in bitcoin, ensuring they can’t be traced or confiscated due to sanctions”, an Iranian government spokesperson told the Financial Times.
$2 million per ship – in crypto
According to blockchain intelligence firm TRM Labs, Iran’s armed forces, the Islamic Revolutionary Guard Corps (IRGC), has accepted payments from ship operators since March, charging up to US$2 million per vessel to transit the strait. Payment can be made not only in bitcoin but also in Chinese yuan or the dollar-pegged “stablecoin” tether.
For shipping companies, the details remain unclear. But many ships are unlikely to set sail without assurances of safe passage from the IRGC.
The US has taken a hard line. President Donald Trump has accused Iran of extortion and stated that the US would hunt down and intercept any ships in international waters that paid the Iranian tolls.
The stalemate is likely to tighten an already narrow choke point. The war has reduced the passage of tankers to a trickle.
Practical problems
Our research has examined how individuals and governments facing sanctions use cryptocurrencies as a way to buy and sell oil, raise hard currency and sidestep economic embargoes. Iran is no stranger to crypto shenanigans. Around 4.5% of all bitcoin mining takes place there, allowing the country to purchase imports and bypass US sanctions.
Yet implementing a bitcoin-based toll system without US approval is not straightforward. Shipping companies will struggle to buy enough cryptocurrency from exchanges without alerting US regulators.
As the US has defined the IRGC a terrorist organisation, any exchanges doing business with Iran risk being added to sanctions lists. Two UK-registered crypto exchanges have found themselves in such a predicament this year.
Even if shipping companies had ready access to millions of dollars-worth of crypto, bitcoin is not truly anonymous. All transactions are logged in a transparent ledger, known as a blockchain, and can be traced with ease in real time.
The transit fee has been reported as the equivalent of US$1 per barrel of oil. US enforcement agencies need only check how much oil a ship is carrying and the time the vessel sailed the strait to guess whether or not a toll was paid.
Who wins from crypto crises
Iran’s plan is seemingly a challenge to the dominance of the US dollar in global oil markets. Accepting payment in yuan, in particular, could subvert the so-called “petrodollar” system. One strategist at Deutsche Bank says the conflict could see “the beginnings of the ‘petroyuan’”.
But China and Iran aren’t the only potential beneficiaries. Some of the biggest commercial proponents of bitcoin are US oil firms, like Exxon and ConocoPhillips. Both have been recognised by the World Bank for their “innovations”: using residual gas from oil wells to power their bitcoin mining machines. Both benefit enormously from a high global oil price and spiking crypto markets. By spurring demand for bitcoin, the crypto industry – centred in the US – will also win big.
In times of war, stocks in weapons companies have always been a safe investment. It looks like cryptocurrencies could be joining them. In a forthcoming book I have written with colleagues, Crypto Crises: how digital currencies accelerate global instability, we explain how cryptocurrencies are reproducing and intensifying geopolitical crises, transforming them into new opportunities for states and corporations to extract profits.
Trump himself initially suggested that the US and Iran might levy the Hormuz toll fees as a “joint venture”, declaring that US involvement would be “a beautiful thing”.
Together, these moves point to a broader shift. Bitcoin remains difficult to use on the high street, while its transparent ledger makes it a terrible choice for criminals. Instead, its real use lies elsewhere.
Crypto use is often a symptom of desperation, not innovation. It is being touted during economic blockades or other moments of geopolitical tension, when conventional financial systems are restricted or have broken down. In these circumstances, it can become a makeshift opportunity for survival, or a tool for making quick profits from instability.
Peter Howson has received funding from the British Academy.
The illustration published along with the story in the Illustrated Police News on May 2 1885.Royal Historic Society
The media exposes a scandal – a network of rich, powerful men are abusing teenage girls. Outrage spreads fast and the public demands that authorities reveal the evidence and bring the perpetrators to justice. Yet the system shields many of those involved, and few face serious consequences. This isn’t about Jeffrey Epstein – it’s a scandal that unfolded in Victorian London.
Our research focuses on the women and girls at the centre of those events. In July 1885, a series of newspaper articles ran in the Pall Mall Gazette with the headline The Maiden Tribute of Modern Babylon. They exposed systematic abuse and trafficking of young girls. From the day the articles were published, there was uproar. Parliament was inundated with petitions and there was a huge demonstration in Hyde Park.
MPs were forced to respond, passing legislation which raised the age at which girls could consent to sexual intercourse from 13 to 16. Records of those events are held in the Women’s Library at London School of Economics, and some are displayed in its current exhibition, The Women’s Library at 100.
The Maiden Tribute was the final step in years of campaigning for a higher age of consent. Before then, legislation which aimed to raise it had languished in parliament. According to rumours among campaigners and politicians, this was because some MPs were guilty themselves of abusing young girls. Indeed, opponents openly argued that such legislation would expose their own sons to the risk of prosecution.
Frustrated activists had turned to W.T. Stead, the editor of the Pall Mall Gazette. Feminist campaigner Josephine Butler, leading Salvation Army members and Stead undertook an investigation of child sexual exploitation, visiting everywhere from brothels to rescue homes. Stead even “purchased” a 13-year-old girl named Eliza Armstrong and sent her to France (in the Salvation Army’s care) to prove that such procuring and trafficking was possible.
Butler noted in a letter to a friend: “O! What horrors we have seen!”
The London scandal
The resulting articles took the reader through the process of recruiting and abusing young women. They portrayed a whole industry devoted to the exploitation of the girls: procurers and brothel-keepers, doctors who “certified” virginity and midwives who ministered to their wounds afterwards.
The series was swiftly syndicated around the world as “the London scandal” and people speculated on the identities of the men described. In New York, it was rumoured that many prominent American men visited the notorious brothel madam Mrs Jeffries’ houses. Some of her clients were named in the campaigning newspaper The Sentinel as MPs, Lords and Dukes, the Prince of Wales and King Leopold II of Belgium.
Popular outrage forced MPs to pass the Criminal Law Amendment Act by August. As well as raising the age of consent for girls, the legislation rushed to introduce new offences of procurement and brothel keeping.
Some of these offences further criminalised women rather than those exploiting them. For example, if two or more sex workers operated in shared premises for safety, they could become liable for brothel-keeping – that is still the law today. A late amendment introduced by Henry Labouchere MP also outlawed all consensual sexual activity between men; the new offence was used to convict the writer Oscar Wilde a decade later.
Ironically, only Stead and several of his colleagues were convicted as a result of these events. They were imprisoned for the kidnapping of Eliza Armstrong. Meanwhile, the men accused by campaigners of exploiting underage girls were unprosecuted and unpunished.
There is much to be learned from this history. First, some very influential people do not want child sexual exploitation eradicated, making effective reform difficult to achieve. It was only through public pressure that new laws were finally passed in 1885. However, a combination of haste, conservatism and deference to elite male interests meant that the law was deeply flawed and moralistic.
Second, the victims and survivors of abuse are too easily blamed, ignored or politically exploited. Reporting of the Maiden Tribute scandal furthered specific ends. In France and America, it was used as proof of aristocratic degeneracy. Meanwhile, the exploited girls were dismissed by respectable society as “fallen”. As the MP Charles Hopwood said in the House of Commons, working-class “girls who went upon the streets … had a familiarity with these things from an early age and were quite able to take care of themselves”.
The MP Charles Hopwood said that working-class ‘girls who went upon the streets … had a familiarity with these things from an early age and were quite able to take care of themselves’. WikiCommons
Victim-blaming drew attention away from procurers, such as Mrs Jeffries, who offered girls a route out of extreme poverty or lured them with false promises of legitimate jobs. The trafficking described in the 1880s used similar recruitment techniques and enforcement methods to today. Even those girls who benefited financially from their exploitation suffered greatly in their mental and physical health.
Third, the establishment tries very hard to cover up such abuse. In Victorian London, policemen were paid off and one who refused to be bought was constructively dismissed. Earlier in 1885, campaigners had brought a private prosecution against Mrs Jeffries because the police refused to take the case any further; the judge frequently reminded witnesses not to name clients; and Mrs Jeffries pleaded guilty mid-trial, before her VIP clientele was exposed. She escaped with a fine rather than imprisonment. In 1887, Mrs Jeffries would be prosecuted again under the new Act; her clients were not.
It is not easy to make the powerful face consequences. Of the leading figures exposed in the Maiden Tribute, the only person who ended up in jail was a woman: Mary Jeffries. The men faced no reckoning, except for gossip about their involvement.
The history, then, offers useful guidance for the present: put pressure on those in power to take effective and swift action, do not trust politicians exploiting abuse to gain power, rigorously uncover institutional corruption and ensure that money and influence do not protect abusers from rightful consequences. Most importantly, believe and centre the voices of victims and survivors.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
Awkwardness and acne are the first things that spring to mind when thinking of adolescence, but they’re not always the full picture. We asked eight of our experts to tell us which book they feel best represents the experience of being a teenager.
1. Natives by Akala
In this biographical polemic, Natives, Akala captures the experience of being a teenager as a time when young people begin to recognise the social injustices shaping the worlds they inhabit.
Akala reflects on his teenage years as a period of awakening. Experiences at school, encounters with authority, and immersion in music and culture all contributed to the formation of his own identity. For many teenagers, it is during these formative years that individual experiences become connected to wider social structures and for all too many teenagers, the limits placed upon them.
Akala conveys the confusion and anger that can arise when adolescents realise that society is not fair, particularly for those from minority backgrounds. His honest discussion of education, policing, and representation highlights how adolescence can be both challenging and simply unfair. At the same time, the book shows teenage years as a period of growth and empowerment. It demonstrates how young people develop their voice, values and sense of purpose as they wake up to living in 21st-century Britain.
Michael Amess is an assistant professor of secondary teacher education
2. The Catcher in the Rye by J.D. Salinger
The Catcher in the Rye remains one of the most enduringly accurate portrayals of teenage experience. It captures adolescence as a period of emotional turbulence, identity confusion and profound vulnerability.
This book exposes the internal contradictions many teenagers live with, including wanting independence yet fearing loneliness and craving authenticity while feeling alienated from the adult world. The book’s cynicism, intensity and sensitivity reflect the psychological push and pull that characterises adolescent development, especially as young people grapple with grief about the potential loss of childhood and its perceived safety or simplicity, transition and the pressure to be an adult before they feel ready.
What makes the novel resonate is how familiar the book’s internal perspectives still feel through the hyper-awareness, sense of injustice and longing for connection which mirrors what many teenagers struggle to articulate. The book captures not just the behaviours of adolescence, but the interior world behind them. This makes the novel a timeless exploration of what it feels like to stand in the liminal space between childhood and adulthood.
Sophie King-Hill is an associate professor specialising in sexual behaviours and assessment in children and young people
Frederica Potter has no friends. She is arrogant, academically competitive, dismissive of teenage preoccupations as beneath contempt, and generally spiky. She’s unable to resist an argument, even when it goes against her own interests. She is often irrationally angry. Unashamedly cerebral, she is physically awkward and socially inept, picking up social cues late, if at all.
She repeatedly gets into sexual entanglements with older men, mainly because she has no idea how to avoid these, submitting to their fumblings out of both curiosity and embarrassment – though she does, eventually, lose her burdensome virginity to someone sympathetic.
By the end, Frederica herself may not have learned much, but readers have been given a dispassionate portrait of a complex adolescent.
Carrie Paechter is a professor emerita of childhood, youth and family life
4. Radio Silence by Alice Oseman
Alice Oseman’s Radio Silence is a searing critique of the UK’s academic pressure cooker. While the creator of Netflix’s Heartstopper is famed for romance, this novel explores the hollow reality of being a study machine. For current further and higher education students, the protagonist Frances’ experiences reflect their real exhaustion within a system prioritising metrics over personhood.
Frances and her friend Aled find refuge from the mundane by collaborating on a viral, anonymous podcast, Universe City, featuring Frances’s digital art. This perfectly captures the modern teenage duality: performing academic compliance while seeking authentic identity in digital subcultures.
Frances and Aled’s fear that attending university is the only valid future mirrors the prescribed routes many students navigate. Radio Silence serves as a blueprint for reclaiming agency, valuing the essential, durable skills like critical literacy and voice that define the teenage experience today.
Joanne Bowser-Angermann specialises in post-16 English and resits
5. The Bell Jar by Sylvia Plath
Sylvia Plath’s 1963 account of a straight-A student’s descent into mental illness has been subject to an autobiographical critical lens that has often overlooked the more universal aspects of this coming-of-age narrative.
While most teenagers do not experience the extreme distress or invasive psychological therapies that heroine Esther Greenwood is subject to, her profound sense of alienation and detachment from conventional social goals is familiar teen territory. Like many young women today, Esther suffers from impostor syndrome. Coupling this is the dawning realisation that her intellectual and career success may be less valued than conforming to social beauty standards and “achieving” marriage and motherhood.
Esther is not a likeable character. She displays a lack of empathy and a tendency to judge others harshly. Yet, her psychological disintegration and rehabilitation arc marks her pathway to maturation through the rejection of prescribed values and the development of a more socially-aware and independently-minded adult character.
Roberta Garrett is a senior lecturer in creative writing
6. Needle by Patrice Lawrence
Patrice Lawrence’s Needle highlights a largely neglected group of teenagers in literature: teenage girls in care. The protagonist Charlene is multifaceted and complex, and Lawrence achieves the difficult task of making a frequently unlikable character sympathetic.
Charlene experiences being separated from her younger sister, having her creative work deliberately destroyed by her older foster brother, and the day-to-day microaggressions and racism that many Black people (especially teenagers) have to bear.
From a lesser author, Charlene would learn to deal with these acts of violence with grace. However, Lawrence understands that a day-by-day, drip-by-drip destruction of what matters to a teenager is much more likely to lead to rage. Charlene never conforms to what systems (such as the care system, prison system and educational system) expect from her. She often does exactly the opposite of what they require. But she keeps her sense of self, and this makes Needle’s Charlene a hero worth reading about.
Karen Sands-O’Connor is an expert on Black British children’s literature
7. Frankenstein by Mary Shelley
Famously, Mary Shelley started writing the novel Frankenstein when she herself was still a teenager.
She demonstrates a sense of adolescent ambivalence by dedicating the novel to her father on one page, but then using Adam’s complaint to God in Milton’s Paradise Lost as an epigraph. “Did I request thee, Maker, from my clay / To mould me man? Did I solicit thee / From darkness to promote me?”
Shelley tells the story of Victor Frankenstein, not the mad doctor of later adaptations, but a cocky undergraduate – a teenager – mansplaining science to his tutors.
Driven by grief and ambition to create new life, Victor makes a monster: a baby in adult form; in other words, a teenager. Some readers, both then and now, might identify with Frankenstein’s monster; angry, articulate, capable of gentleness and cruelty. Readers tend to find Victor whiny and unsympathetic, perhaps because his combination of vulnerability and monstrosity reminds us of our own teenage years.
Andrew McInnes is a reader in romanticisms
8. Carrie by Stephen King
Stephen King’s first novel, Carrie, is a horror tale that explores the teenage experience in an unconventional way.
In the school locker room, Carrie’s first period arrives publicly and unexpectedly, causing the other girls to shout in disgust and throw sanitary products at her. Carrie’s body violates social convention by making public a process that, at the time, was considered shameful. As a result, her relationships with her peers are adversely affected because she is labelled “other”. The main character is bullied because she has body odour and acne, menstruates publicly, and has a complicated relationship with her mother.
By attending the school prom, Carrie thinks she will finally be accepted, but that is not the case. She exercises her telekinetic ability in an act of revenge against her mother, her peers and her hometown. King uses this novel to explore the unpleasant and awkward experience of female adolescence.
Ailish Brassil is a PhD candidate in English literature researching girlhood fictions and domestic horror
Which book do you think best portrays the experience of being a teenager? Let us know in the comments below.
This article features references to books that have been included for editorial reasons, and may contain links to bookshop.org. If you click on one of the links and go on to buy something from bookshop.org The Conversation UK may earn a commission.
Andrew McInnes received funding from AHRC for his ECR Leadership Fellow project, ‘The Romantic Ridiculously’, 2020-2022, which looked at the funny side of Romantic Studies.
Ailish Kate Brassil, Carrie Paechter, Joanne Bowser-Angermann, Karen Sands-OConnor, Michael Amess, Roberta Garrett, and Sophie King-Hill do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
Glaciers in the Swiss alps are experiencing rapid melt due to climate change.Manuel Wild/Shutterstock
There is often a perception that geographical distance reduces vulnerability – an idea that can be particularly appealing in neutral countries with long-standing stable and strong economies.
Switzerland is a clear example: its long-standing neutrality, formally recognised at the Congress of Vienna in 1815 and still recognised as a central part of its foreign policy, combined with its economic strength, has helped keep it outside major conflicts historically and reinforced the perception that distance, stability and wealth provide protection.
But in a world where energy, food, finance and even the atmosphere are tightly interconnected, distance (and neutrality) doesn’t shield Switzerland, or any other nation.
Take the Strait of Hormuz. Roughly a fifth of the world’s oil and liquified natural gas passes through it. When it’s disrupted, the effects don’t stay local; they ripple outward through longer shipping routes, strained supply chains and shifting economic decisions in ways that reach far beyond the countries directly involved and could cause long-term environmental damage.
More often than not, this appears as subtle environmental and economic changes rather than sudden shocks.
Switzerland offers a particularly instructive example. It is neither an energy exporter nor a strategic actor in the conflict. Yet it sits at the intersection of multiple global systems: shipping and transport routes, European agriculture, high-value manufacturing and international finance.
Shipping routes and ice melt
When maritime routes are disrupted, as is currently happening, shipping does not stop. It adapts. Tankers take longer routes and fuel efficiency declines. The result is an increase in particulate emissions, including black carbon. These particles can travel vast distances. In high-altitude environments, their impact is amplified. When deposited on snow and ice, black carbon reduces reflectivity, increasing heat absorption and accelerating melt. In the Swiss Alps, where glaciers are already under pressure, even small increases can have measurable effects. Therefore, what begins as a logistical adjustment in global shipping can end up altering the physical state of distant mountain systems.
Switzerland’s industrial base offers another useful illustration. When firms face restricted or more expensive products, they often shift to alternative production methods. For instance, in the pharmaceutical industry, disruptions to chemical supply chains can force firms to switch suppliers or change elements used in production. While this may make economic sense, such changes are often not environmentally neutral. Different processes generate different byproducts, introducing new compounds into waste streams. The result may not be an immediate environmental crisis, but could create a gradual shift in the composition of pollutants.
Another example is the global fertiliser trade. In 2024, Iran, Qatar, Saudi Arabia, the UAE and Bahrain together accounted for 23% of global ammonia trade, 34% of global urea trade, and 18% of global ammoniated phosphate trade, key inputs for fertiliser production. Disruptions do not simply raise prices; they constrain availability, forcing adjustments across farming systems worldwide.
In parts of Europe, including Switzerland, there could be some positive and negative affects on the environment. Reduced fertiliser use may lower nutrient runoff into waterways, easing pressure on rivers such as the Rhine River and improving conditions in some lakes. Ecosystems long stressed by excess nitrogen may experience a degree of relief. Yet this comes with trade-offs. Swiss agriculture depends on high levels of this type of fertiliser and so may see declining yields and shifts in crops if this is reduced. Alpine pastures, in particular, depend on carefully managed nutrient balances influenced by nitrogen availability. Change can disrupt that equilibrium, exposing how deeply even local ecosystems depend on global supply chains.
Shipping routes are getting longer because of constraints on travelling through the Strait of Hormuz.
Environmental change can also be shaped by investment decisions. In periods of geopolitical tension, capital tends to become more cautious. Liquidity, resilience and short-term risk management take priority over long-term projects.
Finance and migration
For financial centres such as Switzerland – home to huge reinsurance firms such as Swiss Re – this shift matters. Roughly 25% of total global cross-border assets (financial investments outside your home country) are managed in Switzerland. When uncertainty rises, risk models are recalibrated and capital is redirected.
The unintended consequence is that long-term environmental investments – such as ecosystem restoration – can be delayed or scaled back. Environmental resilience depends on steady, long-term commitment; interruptions, even temporary ones, could be detrimental.
Large-scale conflicts also tend to reshape migration patterns, sometimes indirectly. Even countries that are not primary destinations can experience increased migration or adjust policies in response to broader European dynamics. In small countries such as Switzerland, even modest population increases translate into land-use pressures.
Housing demand pushes outward, infrastructure expands, and previously marginal areas come into use. Reports suggest that agricultural land in Switzerland is reducing. Approximately one square metre is lost every second, with about 80% converted into settlement areas and the remaining 20% transitioning into forests. The environmental impact is gradual: increased resource consumption, greater strain on water and waste systems. None of these changes is dramatic on its own, but together they form a pattern of slow encroachment.
The effects of distant conflicts on neutral or far away countries are rarely direct. They are mediated through systems that operate quietly, often below the threshold of public attention.
Switzerland is not unique in this respect. It is simply a clear example: a country where environmental conditions are closely tracked, where economic systems are deeply integrated, and where small shifts can be observed with unusual precision. Neutrality may shape foreign policy, but it does not deliver environmental or economic immunity. In an interconnected world, exposure is universal.
Nima Shokri is affiliated with Hamburg University of Technology.
Salome M. S. Shokri-Kuehni does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
La multiplication des bornes de recharge joue un rôle crucial dans la bascule en train de s’opérer.Michael Marais/Unsplash, CC BY
La voiture électrique n’a plus besoin du prix du pétrole pour s’imposer : la baisse des coûts et les effets de réseau suffisent désormais à enclencher la transition. Mais en changeant de dépendance, elle redessine aussi les risques.
Lorsque le détroit d’Ormuz s’est retrouvé fermé pour la première fois en mars et que le baril de pétrole a atteint 120 dollars (101 euros), une très vieille question a refait surface : est-ce enfin le moment où les véhicules électriques vont réellement décoller — ou simplement un nouveau faux départ ?
Le secteur des véhicules électriques a déjà connu ce scénario. Il a émergé après l’embargo pétrolier de 1973, avant de s’effondrer avec la baisse des prix du pétrole, puis de repartir à la hausse. Chaque vague s’est éteinte lorsque la pression extérieure s’est relâchée.
Cette fois, selon nous, la situation est différente. Dans un récent document de travail, nous soutenons que le modèle économique des véhicules électriques s’améliore désormais pour des raisons qui lui sont propres. Cela tient à l’évolution des batteries, et non au prix du pétrole. Les mêmes éléments montrent toutefois que cette transition fait émerger de nouveaux problèmes, aussi sérieux que ceux qu’elle prétend résoudre.
Des travaux sur l’industrie mondiale des batteries montrent qu’à chaque doublement de la production cumulée, les coûts baissent d’environ 9 %. Davantage d’acheteurs, davantage de production, des coûts plus faibles, donc encore plus d’acheteurs.
Une plateforme économique, pas seulement un moteur plus performant
La raison plus profonde pour laquelle cette vague ne s’essoufflera pas n’est pas technique — elle est économique. Un véhicule électrique est une plateforme. Sa valeur augmente à mesure que l’écosystème qui l’entoure se développe, de la même manière que les smartphones sont devenus indispensables non pas tant pour leur matériel que pour tout ce qui s’y connecte.
Chaque borne de recharge installée rend le véhicule électrique suivant plus attractif. Chaque mise à jour logicielle augmente la valeur de toutes les voitures déjà en circulation. Chaque batterie recyclée alimente la chaîne d’approvisionnement qui rend la suivante moins coûteuse. C’est aussi l’une des raisons pour lesquelles d’autres technologies, comme les véhicules à hydrogène à pile à combustible, peinent à se déployer à grande échelle : la technologie existe, mais l’ensemble des conditions nécessaires n’est pas encore réuni.
Une étude menée auprès de 8 000 conducteurs à Shanghai montre que l’angoisse de l’autonomie — la peur de tomber en panne de batterie — a un coût économique réel, en raison de trajets évités inutilement. Mais ce coût diminue rapidement, non pas parce que les batteries se sont améliorées, mais parce que les réseaux de recharge se sont étendus.
Rendre visible en temps réel la disponibilité des bornes pourrait ajouter entre 6 et 8 points de part de marché d’ici à 2030. Et comme la recharge des véhicules électriques est bien plus flexible que la plupart des autres usages domestiques de l’électricité, les conducteurs peuvent se détourner des heures de pointe avec une grande facilité lorsque le prix les y incite — transformant la voiture en un véritable atout pour le réseau, capable de stocker et de restituer de l’électricité selon les besoins. Il s’agit là d’effets de réseau économiques, et non de simples caractéristiques techniques.
Remplacer une dépendance par une autre
Mettre fin à la dépendance au pétrole ne supprime pas l’exposition géopolitique. Elle la déplace.
Fin 2025, la Chine a introduit des règles imposant une autorisation gouvernementale pour les exportations contenant plus de 0,1 % de terres rares. Le levier qui provenait autrefois du contrôle des flux pétroliers repose désormais sur la maîtrise des capacités de transformation et des chaînes d’approvisionnement en composants.
Les minerais en jeu — lithium, cobalt, nickel, graphite, néodyme, pour n’en citer que quelques-uns — comportent leurs propres risques géopolitiques et, comme nous l’avons montré ailleurs, des coûts humains importants pour les communautés qui les extraient. Cela alimente un cycle prévisible de contestation sociale qui menace de freiner la transition si l’industrie ne s’engage pas en faveur d’une innovation responsable et durable.
Le cobalt a longtemps permis aux véhicules électriques de parcourir de plus longues distances avec une même charge. Et lorsque les prix ont grimpé, la recherche s’est accélérée permettant de concevoir des batteries contenant moins de cobalt, voire pas du tout. Aujourd’hui, plus de la moitié des batteries de véhicules électriques vendues dans le monde n’en contiennent pas.
Des données sur quatre décennies de brevets montrent le même mécanisme : la hausse des prix des minerais réoriente systématiquement la recherche et développement vers des technologies plus économes en ressources.
La crise d’Ormuz rappelle le coût d’une dépendance énergétique concentrée. La transition vers les véhicules électriques n’en a pas besoin. La courbe d’apprentissage continue de baisser, la plateforme produit des effets cumulatifs, l’économie du modèle ne cesse de s’améliorer. C’est ce qui rend cette vague différente.
Ce qu’elle ne fait pas, en revanche, c’est éliminer les risques géopolitiques. Contrairement au pétrole, où le pouvoir repose sur les flux d’énergie, les chaînes d’approvisionnement des véhicules électriques concentrent le pouvoir autour des matériaux, des capacités de transformation et des goulets d’étranglement technologiques — des chaînes d’approvisionnement fortement concentrées et porteuses de risques sérieux. La dépendance au carburant devient une dépendance aux minerais. Et cette dépendance est, elle aussi, fortement concentrée.
Les régions automobiles traditionnelles absorbent déjà des pertes d’emplois concentrées, et l’histoire montre que ces bouleversements laissent des cicatrices durables, même lorsque les effets globaux à long terme sont positifs. Pourtant, l’assemblage des véhicules électriques se révèle plus intensif en main-d’œuvre dans les pays occidentaux que prévu — nécessitant davantage de travailleurs sur les chaînes de production, et non moins, du moins dans la phase de montée en puissance. À l’inverse, en Chine, l’automatisation massive a conduit à l’émergence d’« usines sombres » où la présence humaine est si réduite que l’éclairage n’est même plus nécessaire.
Les mêmes régions aujourd’hui confrontées aux pertes pourraient en tirer des bénéfices. Mais les gains et les pertes ne concernent pas les mêmes personnes. C’est là que réside encore l’essentiel du travail à accomplir.
Viet Nguyen-Tien reçoit des financements de l’ESRC via le Centre for Economic Performance (ES/T014431/1) et le Programme on Innovation and Diffusion (ES/V009478/1), et a précédemment été financé par la Faraday Institution dans le cadre du projet ReLiB (numéros de subvention FIRG005 et FIRG006).
Gavin D. J. Harper reçoit des financements de la Faraday Institution (numéros de subvention FIRG027, FIRG057 et FIRG085). Site du projet ReLiB : https://relib.org.uk/
Robert Elliott ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune autre affiliation que son organisme de recherche.
Wolfgang Amadeus Mozart is arguably the most celebrated child prodigy in history, composing his first pieces of music aged five, his first symphony at eight and his first opera at 11. After a study in 1993 found that listening to Mozart could improve spatial IQ – prompting headlines such as “Mozart makes your brain hum” – he became a symbol for intelligence and brain training.
The study was no doubt interesting. The scientists found that performance on spatial ability tests was improved when their study participants had listened to a Mozart sonata, compared with a relaxation tape or silence. The increase in performance translated to an astounding difference of up to nine spatial IQ points.
Although the effects were temporary, lasting less than 15 minutes, the idea exploded in popular culture. The “Mozart Effect” ignited a lucrative empire of parenting books, self-help manuals and CDs promising to harness the power of Mozart’s music to foster children’s cognitive development. That was despite the fact that the study had been carried out in adults and the evidence for the effect was later overtuned.
The hard fall for the Mozart Effect ultimately highlights the value that society places on intelligence as measured by cognitive tests (like the IQ test). The global market for cognitive assessment and training was valued at about $6.87 billion in 2024 (£5.18bn) but is projected to rise to $35.30 billion by 2032.
Mozart went on to compose over 600 outstanding works in his brief lifetime. But can we reliably predict future success from a child’s performance? Today, IQ tests are often used to spot early academic talent. But are they a good measure? A growing number of scientific studies suggest that IQ measured in childhood might tell us less than we think. Scientists are discovering that children’s IQ scores aren’t as stable as adults’ – they fluctuate substantially.
So why are schools using cognitive assessments? And what other factors can help predict children’s future success?
The rise of cognitive tests to identify potential
Fostering talent is central to human progress. Exceptionally talented individuals drive scientific and cultural innovation and push the boundaries of human knowledge. For over a century, scientists have therefore sought to understand and measure intelligence. This has been partly driven by countries gradually shifting away from mass production and towards becoming knowledge economies.
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One of the largest and longest running studies of giftedness, the Study of Mathematically Precocious Youth, has followed the lives of intellectually gifted people for over half a century. Over 1,600 talented 13-year-olds were invited to take part in the study if they had scored in the top 1% of ability on a standardised test, the SAT, widely used for US college admission. And indeed, four decades later, many of these young talents had achieved outstanding accomplishments. Some 4.1% had achieved tenure at a major university and 2.3% were top executives at Fortune 500 companies. They had published 85 books and secured 681 patents.
However, it is worth noting that these children were fairly old, already teenagers – and at the absolute top end of achievement. Cognitive tests, however, are taken by a much wider range of children today. Since the 1980s, cognitive ability tests have gradually replaced traditional academic subject exams as school entrance screeners. This was motivated by the idea that a cognitive test could be a more objective assessment of aptitude and potential than a child’s knowledge of the curriculum. Performance on cognitive tests is viewed by many as independent of external influences, such as a more resourceful school or a nurturing home environment.
Schools worldwide, from the US and the UK to Singapore and Vietnam now use standardised tests of cognitive abilities to select students at intake. Admission to many prestigious independent and selective high schools in the UK is often at least partly based on a cognitive ability test, such as the infamous CAT4, that hopeful ten-year-olds sit in the autumn term of their last year of primary school. The CAT4 test is also used in many state secondary schools to help determine sets, predict grades and allocate support and provisions.
One kind of IQ test item, modelled after items in the Raven’s Progressive Matrices test. wikipedia, CC BY-SA
The CAT4 takes around 2.5 hours to complete and is divided into four sections. There is verbal reasoning (thinking with words), non-verbal reasoning (thinking with shapes), quantitative reasoning (thinking with numbers) and spatial ability (thinking with shapes and space). Children who score exactly as expected for their age group would be given a score of 100. Scoring between 89 and 111 is considered to reflect “average” performance, while scores of 112 and above or 88 and below indicate above and below average performance, respectively.
Child IQ fluctuates
We know that the human brain is plastic, or changeable, particularly in childhood. It is the only organ in our body that isn’t fully developed when we are born. A newborn’s brain is about a quarter of the size of an adult brain, doubling in the first year of life. By age seven, it reaches 90% of its adult size. Beyond physical growth, our brains refine and consolidate the network of connections between neurons during this time.
Refining and whittling these connections is key to supporting cognitive and behavioural developmental milestones. Recent research shows that it’s possible to identify key “eras” of brain structural change over the life course. The first milestone – the transition from childhood to adolescence – happens at around age nine. From a brain perspective, adolescence lasts for a little over two decades and is defined by greater efficiency of connections across regions. This coincides with a steady increase in cognitive functions, including vocabulary, complex reasoning and learning.
We’ve known for some time that there is a link between intelligence, as measured by cognitive tests, and school achievement. Research from 2015 that combined data from over 100,000 students across 240 different studies did find a substantial association between intelligence and school grades. However, the magnitude of the link differed depending on children’s age. Intelligence was a much better predictor of school performance in secondary school than it was in primary school. This suggests that cognitive abilities might not be stable during the first decades of life, but vary significantly.
A 2024 analysis that combined data from 205 different studies including over 85,000 participants across 29 countries supports this view. The researchers set out to investigate how stable cognitive abilities are (whether they fluctuate) across the human lifespan and whether stability changes with age.
They discovered that the stability of cognitive abilities increased exponentially with age – and was low in the first decade of life. This means that each child’s positioning compared to their peers changes significantly in childhood. So a child’s IQ score might indeed change substantially during this time. The stability, however, increased throughout childhood and adolescence, plateauing around age 20 and remaining high throughout adulthood and old age.
But even when IQ starts stabilising, in adolescence, it can still fluctuate by up to 20 points. Somebody increasing their IQ score from 100 to 120 would move from the 50th percentile to about the 91st percentile – a 41% improvement. Indeed, one study, albeit with a small sample of students, could link such fluctuations to physical changes in the brain over time.
This means that it can be tricky to infer long-term consequences, such as later grades, from cognitive tests. Basing school intake, or more broadly selection into educational programmes on a single, unstable metric is likely to lead to systematic errors and unreliable decisions.
Worryingly, it may also result in attempts to manipulate the metric, potentially perpetuating systemic inequalities. This may be true of other tests too, but IQ tests are often seen as an exception. But research shows that you can actually train yourself to boost your IQ test score by roughly eight IQ points, for example by retaking the test. Parents with a lot of resources might be better placed to help prepare their children.
The myth of the child prodigy
Recent research has backed all this up by questioning the widely accepted myth of the child prodigy as someone destined for greatness, like Mozart. One 2025 study, which combined data from over 34,000 elite performers, from Nobel laureates and chess players to music composers and athletes, found that exceptional performance in childhood was a limited predictor of elite performance in adulthood.
In fact, about 90% of those who achieved elite performance in youth did not achieve equivalent adult status. Similarly, 90% of top performing secondary school students were no longer top performers at university. And even more strikingly, several Nobel laureates and elite athletes actually had lower childhood performance than their peers.
Mozart might have gone from strength to strength, but research shows that is unusual. neurobit/Shutterstock
The routes leading children and adults, respectively, to world-class performance also differed. Exceptional talent early in development was associated with intensive, discipline-specific progress at a young age. But adult world-class performance was more often achieved through extensive multi-faceted practice and gradual advancements.
This means that educational and talent programmes that prioritise early identification of intelligence may overlook a large proportion of future world-class innovators.
Environmental exposure
The idea behind identifying talent as early as possible so that it can be nurtured is founded on the belief that exposure to an enriched environment can impact ability and vice versa. Half a century of scientific discovery supports this proposition. Perhaps the most famous example is a study published in 1979 by paediatrician Herbert Needleman and his colleagues. This study provided the first robust evidence that exposure to the metal lead, even at levels previously considered negligible, could significantly impair a child’s cognitive performance.
By comparing children with high and low lead levels in baby teeth, while controlling for potentially confounding factors – such as the mother’s IQ and socio-economic status – the study showed that children with higher lead levels scored roughly four points lower on IQ tests. The evidence presented influenced major public health policies, including the removal of lead from gasoline and interior paint in the US.
A large number of other environmental exposures have been positively linked with cognitive development, from walking in nature to exercise and nutrition, albeit with mixed results. However, arguably the most successful environmental intervention to improve cognitive ability is administered every year to more than 85% of children worldwide: education.
By combining data collected across multiple studies from over 600,000 individuals, researchers found that education has a direct effect on the development of cognitive abilities. The study found that each year of education results in a gain of about one to five IQ points. These effects were remarkably robust, appearing across different cognitive domains and persisting throughout the lifespan. In fact, significant benefits were still measurable into people’s 80s and 90s. While a few IQ points per year may seem small, their cumulative impact at a societal level has been shown to be of great consequence.
Environmental factors that shift population IQ even modestly — like lead exposure, nutrition or education — carry enormous economic consequences. Economists have calculated that each gained IQ point is associated with roughly a 2% increase in lifetime earnings.
In the year 2000, a single IQ point gained or lost across the US population translated to between $110 and $319 billion in aggregate economic output. More recent analysis of the global economic impact of lead exposure on childhood IQ estimated the total cost of IQ loss at US$1.4 trillion globally in 2019, mainly affecting low and middle-income countries.
The role of parents
From the moment a child is born, parents invest vast amounts of energy, time and resources to promote their children’s physical and cognitive development. Not all parenting practices are supported by scientific evidence, nor is the Mozart Effect the sole parenting myth that has been busted. However, research has shown that parenting can nevertheless have profound effects on children’s early cognitive development.
Studies have found that the environment that parents provide for their children by reading to them, engaging them in stimulating activities and conversation, and maintaining a warm and organised household, has a significant positive effect on early cognitive development. This is particularly the case for the first five years of life. What makes early investment especially powerful seems to be that the benefits compound. Fostering a child’s early cognitive competence makes it easier for children to acquire new skills down the line.
However, the pathways to parental investment are complex. Reflecting on my own childhood illustrates this point. I was born in the mid-80s to parents in their early twenties. At the time, my mother was in medical school and my father designed and produced bespoke furniture. As a child, I had several ear infections which meant that I had to have regular checks with a specialist. One warm, sunny morning in early April, my mum and I set off for my otolaryngologist appointment, just the two of us. As the eldest of four children, this was a rare and special occasion.
After my check-up, we took a tram to Milan’s State University, where we attended a conference on HIV infections in vulnerable populations – the topic of my mother’s thesis. I remember sitting in the beautiful auditorium, admiring the frescos on the ceiling, and slowly adjusting a pair of disposable headphones to listen to the real-time translation of the talks. The panel of female scientists discussed the topic so eloquently and clearly that even a ten-year-old girl could grasp their main message.
I was hooked. It must be the best job in the world, I thought. It was only a quiet thought then, one that I never had the courage to privately contemplate or publicly share. That came much later, when I found the confidence to admit that a career in scientific research was for me. But this specific episode in my childhood was not an isolated peak. It was the pinnacle of many simpler, everyday moments when my parents invested time and effort to provide us with a nurturing and stimulating environment.
However, seeing these as merely environmental exposures would only provide part of the picture. Perhaps, the science-enriched environment that my mother created for us depended, at least in part, on her own, partly genetically driven, scientific aptitude.
The nature of nurture
Scientists have named this amalgamation of nature and nurture gene-environment correlation, or more intuitively, the nature of nurture. Parents who provide their children with intellectually stimulating environments may also pass on a greater disposition to doing well in school or performing well in cognitive tasks. Research has shown that accounting for genetic effects shared between mothers and children resulted in a reduction in the effect of parenting on educational attainment.
However, cognitively stimulating parenting remained a significant predictor of children’s educational outcomes beyond direct genetic inheritance and socio-economic status. It ultimately contributes to channelling children’s dispositions and translating them into academic outcomes.
Randomised control trials have demonstrated that early interventions are likely to lead to the greatest returns. Investing in children early — through parenting, stimulating environments and good nutrition — pays back far more than trying to catch up later. Every year of delay makes it harder to close the gap.
Interventions created to bridge this gap in groups of disadvantaged children through high-quality preschool education, such as the Perry Preschool Project, can lead to meaningful gains in cognitive performance. Interestingly, while the benefits on children’s cognitive performance faded over time, their long-term educational, economic and social benefits were remarkably far-reaching. So a high quality school education could indeed lead to better job prospects and higher salaries, regardless of IQ.
It follows that boosting cognitive ability may not be the only way to lasting educational, economic and health benefits. Non-cognitive skills — such as motivation, curiosity, self-regulation and social skills — are equally important.
What IQ tests fail to capture
Cognitive tests have never been viewed as instruments to capture the entire set of skills necessary for succeeding in school and life. In 1916, Alfred Binet and Theodore Simon, the inventors of the first IQ test, wrote that things other than intelligence also mattered to academic success, arguing “one must have qualities which depend especially on attention, will and character”.
Decades of research have shown that children who are emotionally stable, motivated and capable of regulating their attention and impulses do better at school, regardless of their level of cognitive ability. These important characteristics have been broadly described as “non-cognitive skills”.
Recent research by my own team shows that the importance of non-cognitive skills for learning also changes over the school years. We analysed data collected from over 10,000 children born in England and Wales who were followed throughout compulsory education, from age seven to 16. Non-cognitive skills not only predicted academic achievement at every developmental stage, but their role increased as the children got older. Still, at all ages, skills such as curiosity, creativity, motivation and self-efficacy predicted success in school in addition to what was predicted by cognitive abilities.
Similar to cognitive ability and learning, differences in non-cognitive skills are a complex product of nature and nurture. Partly based on their genetic dispositions, children encounter and select environmental experiences that contribute to the development of their motivation and curiosity. This in turn leads to differences in school achievement.
Ultimately, cognitive tests are thought to offer an objective measure of a child’s natural ability, one that is largely unaffected by upbringing or circumstances. But research shows that a range of factors, from environmental exposures to toxic agents, nutrition, differences in parenting and educational interventions, can change cognitive performance, particularly as the brain develops.
During childhood, when the brain is rapidly growing, cognitive test scores can fluctuate considerably from one year to the next. This means that a single test taken on a single day in primary school is not a reliable enough indicator for decisions as consequential as which school a child attends or which academic track they are placed on. These are decisions that can shape the entire course of their education.
Even later on, cognitive tests only capture part of what it takes to do well in school and in life. Curiosity, motivation and the belief that you can improve with effort are crucial to educational success, yet most education systems pay them little attention. Rather than treating a test score as a fixed marker of a child’s future, mounting evidence invites us to treat it as one factor among many. The best approach would be to invest in all children’s cognitive and non-cognitive development alike.
So don’t read too much into Mozart’s journey. He may have been a child prodigy destined for greatness, but chances are he was an exception rather than the rule.
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Margherita Malanchini’s research is currently funded by the UKRI Medical Research Council and by a Jacobs Foundation CIFAR Research Fellowship.
Running a marathon asks a great deal of the body. You need sustained energy, careful pacing, plenty of muscle endurance and smart hydration.
Marathons also ask a great deal of the mind. At some point, almost every runner has to deal with nerves, discomfort, self-doubt or the creeping sense that the finish line is still very far away.
That is why successful marathon running is not just about fitness. It’s about fuelling well, thinking clearly and responding effectively when the race starts to bite.
Here are some of the most useful nutritional and psychological strategies to get you through marathon day.
Fuel properly
For runners, carbohydrates are not the enemy. They are the body’s main fuel source at marathon pace. On race day, how and when you take them in matters enormously.
Once the race begins, your glycogen levels (a rapid-release form of energy stored in the body), steadily deplete. For many runners, these reserves begin to run low after roughly two hours of continuous effort, which is one reason people “hit the wall”.
Proper race-day fuelling helps delay that point. Runners should aim to consume around 60 grams of carbohydrate per hour during the race. Gels, chews or sports drinks – often available at aid stations – are great ways of topping up carbohydrate stores. Race day isn’t the moment to gamble, so whatever you plan to use should already be familiar with its effects from training.
Hydration is equally important and just as personal. Some runners lose fluid quickly, while others cannot comfortably drink large amounts while running.
A useful benchmark is try to limit fluid losses to around 2–3% of your body weight during the race. The aim is to replace some of what you’re losing during the race without overdoing it.
One practical approach is to drink to thirst – taking small, regular sips rather than large volumes. This helps avoid both dehydration and the opposite risk, drinking far too much, which can lead to discomfort – or, in rare cases, hyponatraemia (low blood sodium levels).
Finally, remember that fuelling is part of race management. Taking a gel just before a challenging section or grabbing a drink during a quieter stretch can help you manage the miles more effectively.
Enjoy the atmosphere
Marathons offer a one-in-a-lifetime experience for many of us.
The crowds, noise, music, volunteers and sheer occasion can all work in the runner’s favour. Psychologically, this can help shift attention away from the discomfort you may experience during the race.
So do not be afraid to take the day in. Smile at spectators. Acknowledge the cheers. Let yourself be lifted by the event.
That said, excitement can also be costly. A marathon punishes early over-confidence. The occasion may tempt you to run faster than planned, especially in the opening miles when adrenaline is high and the legs still feel fresh.
The best marathoners are not those who ignore the noise. They are often the ones who use it well while still listening to their bodies.
Remember your motivation
For many runners, the marathon is about much more than a finishing time.
Some are running for a cause close to their heart, as way of connecting with someone or proving something to themselves.
That deeper reason matters, especially when the race becomes difficult. Be clear about why you are doing it. If nerves surface at the start line or the pain surfaces at the harder miles late on, reconnecting with that reason can help steady the mind and restore perspective.
At those moments, one of the most powerful thoughts can be a very simple one: it’s a big race but the race is not bigger than me.
Be kind to yourself
Most runners will have a difficult patch at some point in the race. That does not mean the marathon is going badly. This is just the reality of running a marathon.
This is where your internal dialogue matters.
Before race day, decide what you want to say to yourself when things get hard. The most effective phrases are usually not dramatic. They are believable, calming and constructive, such as: I’ve trained for this. Keep moving. This is tough, but so am I.
Write the phrase down, maybe keep it with you on race day. Use it when the doubts arrive. Positive affirmations are deemed to be helpful in tough and pressurised sporting situations.
One of the most valuable psychological skills in endurance sport is not pretending the challenge does not exist. It’s responding well when it does.
Because in the end, marathon running is not just about getting to the finish. It is about how you fuel, think and cope along the way.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
Reconstitution artistique d’un embryon de LystrosaurusArtiste: Sophie Vrard, CC BY
Il y a entre 280 et 200 millions d’années vivait un groupe d’animaux à l’origine des mammifères, humains inclus : les thérapsides. Ils ont été décrits pour la première fois il y a plus de 150 ans à partir de fossiles découverts en Afrique du Sud, et de nombreux autres spécimens ont été mis au jour depuis lors.
James Kitching, l’un des chasseurs de fossiles sud-africains les plus talentueux du XXe siècle, a mis au jour plusieurs milliers de crânes et squelettes de thérapsides dans les roches du Karoo (une région semi-aride de l’intérieur du pays), ainsi que des œufs de dinosaures fossilisés. Néanmoins, ni lui ni aucun paléontologue après lui n’ont jamais trouvé d’œufs de thérapsides.
Ils devaient pourtant exister, car certains mammifères (l’ornithorynque et les échidnés) pondent bien des œufs. Mais Kitching a commencé à douter que les thérapsides en aient jamais pondu : peut-être, supposait-il, étaient-ils déjà vivipares (donnant naissance à des petits vivants), comme la plupart de leurs descendants mammifères.
Mes collègues et moi même, qui étudions les animaux disparus et les environnements dans lesquels ils vivaient il y a des millions d’années, venons de publier un nouvel article dans lequel nous décrivons, pour la première fois, l’œuf fossile contenant un embryon d’un ancêtre des mammifères vieux de 250 millions d’années. Il prouve enfin que les thérapsides étaient bel et bien ovipares. Cette découverte apporte un éclairage nouveau sur les stratégies de reproduction et de survie des thérapsides.
L’œuf sur le point d’être scanné au synchrotron de Grenoble. Fourni par l’auteur, CC BY
Un mystère vieux de 20 ans
L’œuf fossile et l’embryon que nous avons décrits ont été découverts près d’Oviston, dans la province du Cap-Oriental, en Afrique du Sud, par John Nyaphuli, un paléontologue de Bloemfontein, en 2008. Il est conservé dans les collections du Musée national de Bloemfontein. Nous savions qu’il appartenait à une espèce qui a vécu il y a entre 252 et 250 millions d’années, appelée Lystrosaurus, dont les adultes étaient de la taille d’un cochon, avaient la peau nue, un bec semblable à celui d’une tortue et deux défenses saillantes pointant vers le bas. Mais à sa decouverte, personne ne savait si il s’agissait réellement d’un œuf.
La raison pour laquelle il a fallu 20 ans pour prouver qu’il en était bien un est que la coquille n’est pas préservée. Seul un embryon recroquevillé est visible. S’il y avait une coquille, elle devait probablement être molle (faite de protéines) car seuls les dinosaures les plus évolués et les oiseaux pondent des œufs à coquille dure. De plus, les squelettes complets recroquevillé ne sont pas rares dans le Karoo, y compris chez des specimens adultes. Alors, comment prouver que ce jeune spécimen a été fossilisé à l’intérieur d’un œuf ?
La réponse à cette question est venue d’une étude basée sur la technologie de pointe de l’Installation européenne de rayonnement synchrotron à Grenoble, en France. Là-bas, nous avons utilisé une puissante source de rayons X pour obtenir des images de l’intérieur des os de l’embryon. Grâce à ce traitement, le fossile a révélé tous ses secrets, notamment son stade de développement embryonnaire.
Reconstitution 3D de l’embryon basée sur le scan synchrotron réalisé à l’ESRF. Fourni par l’auteur, CC BY
Nous avons découvert que les mâchoires inférieures de son bec n’étaient pas complètement soudées. Cette caractéristique développementale n’est observée que chez les embryons de tortues et d’oiseaux modernes, longtemps avant l’éclosion (leur permettant, à la naissance, d’avoir un bec soit suffisamment robuste pour se nourrir). Cela signifie que notre embryon de Lystrosaurus recroquevillé était mort in ovo (dans l’œuf), blotti dans sa coquille molle et aujourd’hui disparue. C’était la preuve que les paléontologues attendaient !
Grâce à l’examen synchrotron de sa mâchoire inférieure, nous avons enfin pu démontrer que cet embryon était bien celui d’un bébé Lystrosaurus dans son œuf non éclos.
Un célèbre survivant
Le Lystrosaurus est un thérapside herbivore (mangeur de plantes) célèbre pour avoir survécu à la « crise Permien-Trias», une crise biologique survenue il y a 252 millions d’années durant laquelle 90 % de tous les êtres vivants sur Terre ont péri. La vie a failli disparaître, ce qui en fait le deuxième événement le plus important de l’histoire de la vie sur Terre après l’origine de la vie elle-même.
La manière dont le Lystrosaurus a survécu à cet événement reste un mystère intrigant, mais l’œuf fournit quelques indices. Il montre d’abord que l’animal pondait des œufs relativement volumineux. Les œufs de grande taille sont produits par des espèces dont l’embryon se nourrit de vitellus (le jaune) à l’intérieur de l’œuf, alors que celles pondant de petits œufs, comme les monotrèmes (l’ornithorynque et l’échidné), nourrissent leurs petits après la naissance avec du lait. La grande taille de son œuf implique que le Lystrosaurus n’allaitait donc pas ses petits.
En ce qui concerne sa stratégie de survie, cela indique deux choses supplémentaires. Premièrement, cela signifie que l’œuf était moins sujet à la dessiccation (assèchement). Plus l’œuf est gros, plus sa surface est petite (toutes proportions gardées), de sorte que les œufs de Lystrosaurus perdaient moins d’eau à travers leur coquille molle que ceux d’autres espèces de la même époque. Compte tenu de l’environnement sec qui régnait pendant et immédiatement après l’extinction, cela constituait un avantage majeur, d’autant plus que les œufs à coquille dure n’évolueront pas avant au moins 50 millions d’années.
Deuxièmement, un gros œuf implique que le Lystrosaurus était probablement précoce, ce qui signifie que les bébés naissaient à un stade avancé de leur développement. Les nouveau-nés de Lystrosaurus étaient assez grands pour se nourrir seuls, fuir les prédateurs et atteignaient la maturité plus rapidement, ce qui leur permettait de se reproduire tôt.
Une croissance rapide, une reproduction précoce et une grande prolifération étaient les secrets de la survie du Lystrosaurus.
L’identification de cet œuf fossile nous aide ainsi à mieux comprendre l’origine de la biologie reproductive et de la lactation chez les mammifères, ainsi que la stratégie de survie du Lystrosaurus face à la crise biologique la plus dévastatrice que notre planète ait connue. Elle nous aide aussi à mieux saisir comment les espèces modernes pourraient faire face à la sixième extinction de masse des espèces qui se déroule actuellement.
Julien Benoit bénéficie d’un financement de la plateforme « African Origins » du DSTI-NRF et du Centre d’excellence GENUS en paléosciences.
Jennifer Botha ne travaille pas pour, ne conseille pas, ne détient pas d’actions et ne reçoit pas de financement de la part d’une entreprise ou d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune affiliation pertinente en dehors de son poste universitaire.
Vincent Fernandez travaille pour le synchrotron de l’ESRF et s’est vu attribuer du temps de faisceau à l’ESRF pour cette expérience.
Source: The Conversation – UK – By Jonathan Este, Senior International Affairs Editor, Associate Editor, The Conversation
This is the text from The Conversation UK’s World Affairs Briefing email. Sign up here to receive weekly analysis of the latest developments in international relations, direct to your inbox.
The US is reported to be greatly expanding the scope of its naval blockade of Iran, asserting the right to board and seize any ships it believes to be carrying “contraband” or “conditional contraband” bound for Iran from anywhere on the open seas. Respected maritime news and intelligence agency, Lloyd’s List, says this means that “almost any industrial cargo bound for Iran could plausibly be intercepted”. This will considerably raise the stakes in an already fraught situation.
Opinions are already divided as to how effective this “blockade of a blockade” is likely to be. The US president made the decision on April 12 to “seek and interdict every vessel in International Waters that has paid a toll to Iran. No one who pays an illegal toll will have safe passage on the high seas.” The intention was to make clear to Tehran that they were ultimately not in control of the strait and certainly wouldn’t be allowed to profit by imposing a charge on ships it allowed to pass through.
The problem for the US is that traffic through the strait remains largely at a standstill. Reuters’ live tracker of traffic in the strait suggests a considerable gathering of vessels on either side of the waterway, with very little evidence of ships actually transiting the strait.
It is, writes maritime strategy expert Basil Germond, of Lancaster University, a question of who can withstand more pain from the economic fallout. So the US plan to seek and seize ships wherever they are on suspicion of carrying almost any sort of industrial cargo is clearly aimed at increasing that pain for Iran.
But one of the dangers is how far and how fast the situation might escalate. There was a fraught moment on April 14 when it appeared as if a Chinese-linked tanker had transited the strait. The Rich Starry, registered in landlocked Malawi, is Chinese owned and crewed. Would the US try to board the boat? How would China react if it did?
China buys about 90% of Iranian oil and is one of the few countries whose tankers were getting in and out of Iranian ports unchallenged, writes Tom Harper, an expert in Xino-US relations at the University of East London. US seizure of any Chinese tankers would be bound to considerably ratchet up tensions between the two superpowers.
As it turned out, the Rich Starry turned back in the Gulf of Oman and re-entered the strait without being stopped or challenged by the US. But the new US operating instructions could well make a confrontation more likely. Harper explores the implications of the US-Iran conflict for relations between Washington and Beijing in the run-up to Donald Trump’s planned state visit to the Chinese capital next month.
Meanwhile the conflict between Israel and Hezbollah in Lebanon continues unabated. Ambassadors from the two countries met in Washington this week, where they resolved to hold direct, high-level talks. The US president has said that the leadership of the two countries would also speak, “for the first time in 34 years”, but the office of Lebanon’s president Joseph Aoun denied any knowledge of the arrangement, saying that a ceasefire would need to be in place before any talks could take place.
Whether the US president has the leverage over Israeli prime minister, Benjamin Netanyahu, to make that happen is another matter. The US and Israel certainly have one of the strongest partnerships of any two countries, write Bamo Nouri and Inderjeet Parmar of City St George’s, University of London. The US was the first country to formally recognise the state of Israel in 1948 and Washington has since provided the Jewish state with more than US$300 billion (£220 billion).
Wars against Soviet-aligned Arab states in the 1970s showed how Israel could be an important cold war bulwark against the spread of communism in the Middle East.
Israel’s influence in the US is often put down to the strength of the Jewish lobby there. But it is the perceived strategic value of the relationship, Nouri and Parmar believe, that is the key factor: “When core US strategic interests have been at stake, US policy has overridden lobbying pressure”.
To Hungary, where the 16-year prime ministership of Viktor Orbán came to a close in a landslide election on April 12. The two-thirds majority won by Orbán’s opponent, Péter Magyar, gives the incoming PM the power – if he so chooses – to reverse some of the more illiberal measures implemented by the authoritarian Orbán.
It was a resounding victory: 138 seats to Magyar’s Tisza party to just 55 for Orbán’s Fidesz. All the more remarkable when you consider how the comprehensive state capture of Hungary’s media over Orbán’s tenure and the ferocious propaganda campaign the outgoing prime minister waged, using every organ of state to boost his chances.
Alexander Bor, an expert in propaganda and election manipulation at Central European University, explains that Orbán’s campaign hit two snags: the people’s disillusionment at Hungary’s parlous economy and a well-run campaign by a credible challenger in Magyar.
Magyar’s victory went down well in Brussels, writes Michael Toomey, an expert in EU democracy at the University of Glasgow. Orbán’s warm relationship with Russian president, Vladimir Putin, was no secret. He did all he could to block EU aid packages for the defence of Ukraine and at one point was even revealed to be passing on information from closed EU ministerial meetings with his Russian friends.
“Had Orbán managed to prevail in the recent elections, the relationship between the EU and Hungary is likely to have reached a breaking point”, Toomey concludes.
One relationship which appears to be under a degree of strain is that between the US president and Pope Leo XIV. Leo, the first pope born in the US, has been a highly visible and vehement opponent of the US war with Iran, calling for peace and condemning “those who wage war”, whose hands he said, quoting scripture, “are full of blood”.
Trump replied, not quoting scripture, that the pope was “weak on crime” and “terrible for Foreign Policy,” adding that he was only elected to the papacy because he is American and the Catholic church “thought that would be the best way to deal with President Donald J. Trump.”
Massimo D’Angelo, an expert in the Catholic church’s diplomacy, explains why the US president is likely to come off worse in this particular contretemps.
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Source: The Conversation – in French – By Sabrina Rondeau, Postdoctoral Researcher in Pollinator Ecology, L’Université d’Ottawa/University of Ottawa
Une reine bourdon accumule des réserves nutritives en prévision de l’hivernage. Lucas Borg-Darveau
Les colonies de bourdons dépendent entièrement de la survie des reines pendant l’hiver. Une découverte surprenante montre qu’elles peuvent respirer sous l’eau et survivre à une immersion prolongée.
Chez la plupart des espèces de bourdons, les reines passent l’hiver enfouies sous terre dans une petite cavité de la taille d’un raisin. Pendant six à neuf mois, elles attendent le retour du printemps dans un état proche du sommeil profond appelé diapause. Mais avec le changement climatique, les pluies deviennent plus intenses dans de nombreuses régions et les reines qui hivernent sous terre sont de plus en plus exposées aux risques d’inondation.
Heureusement, ces insectes peuvent survivre plusieurs jours sous l’eau sans se noyer. De façon inattendue, nos nouvelles recherches montrent qu’elles y parviennent grâce à un processus qui leur permet de passer jusqu’à huit jours immergées tout en continant à respirer.
Tout a commencé par un accident de laboratoire
Nous avons d’abord découvert que les reines bourdons en hivernage pouvaient survivre à une immersion grâce à un accident.
Lors d’une expérience menée à l’Université de Guelph (Ontario, Canada), certains des tubes dans lesquels les reines passaient l’hiver dans un réfrigérateur de laboratoire se sont accidentellement remplis d’eau. Au départ, nous avons pensé que les reines étaient mortes. Mais après avoir vidé l’eau, elles ont commencé à bouger et se sont rapidement rétablies, suggérant que les reines bourdons étaient en mesure de survivre à une immersion.
Une reine bourdon respirant sous l’eau. (Charles-Antoine Darveau)
Nous avons alors conçu une expérience de suivi impliquant 143 reines du bourdon commun de l’Est (Bombus impatiens). Nos résultats ont confirmé qu’il ne s’agissait pas d’un simple hasard : les reines ont bel et bien résisté à une immersion complète pendant près d’une semaine.
Restait une question intrigante : comment cet insecte pollinisateur terrestre peut-il survivre sous l’eau ? Pour y répondre, il nous fallait adopter une nouvelle approche et étudier leur physiologie.
Au cœur de la colonie
La reine est le cœur d’une colonie de bourdons : elle est la seule capable d’assurer la génération suivante. Si l’on entend souvent le bourdonnement des ouvrières qui visitent les fleurs en été, les reines, elles, sont rarement visibles. Elles passent en effet une grande partie de la saison à l’intérieur du nid, où elles pondent des œufs qui donneront naissance aux ouvrières puis, plus tard dans l’été, aux mâles et aux nouvelles reines.
Lorsque l’hiver arrive, la plupart des membres de la colonie meurent et seules les reines nouvellement produites survivent. Après l’accouplement, elles se dispersent et s’enfouissent dans le sol, chacune s’installant dans une petite cavité où elle entre en diapause. Quand le printemps revient enfin, les reines qui ont survécu à ce long sommeil souterrain sortent de leur abri et entreprennent la tâche cruciale de fonder une nouvelle colonie.
Respirer sous l’eau
Pour comprendre comment ces reines peuvent survivre à une immersion, nous avons étudié leur respiration et leur métabolisme lors d’une expérience subséquente menée à l’Université d’Ottawa (Ontario, Canada). Pendant la diapause, les reines sont déjà dans un mode d’économie d’énergie extrême. L’énergie nécessaire à leur survie — leur taux métabolique — chute de plus de 99 %. Lorsqu’elles sont immergées, leurs besoins énergétiques diminuent encore davantage. Avec des besoins en oxygène aussi faibles, respirer sous l’eau devient possible.
Mais comment avons-nous pu déterminer que les reines respirent réellement sous l’eau ? Une méthode consiste à mesurer les échanges de gaz avec l’eau environnante. C’est ce que nous avons fait, et les résultats sont frappants : pendant huit jours d’immersion, les reines ont continué à consommer de l’oxygène et à libérer du dioxyde de carbone sous l’eau.
Une reine de bourdon dans son hibernaculum (terrier souterrain). (Sabrina Rondeau)
De nombreux insectes aquatiques utilisent une astuce simple pour respirer sous l’eau. Une fine couche d’air adhère à leur corps, ce qui leur permet d’utiliser leur système respiratoire habituel — le système trachéen. L’oxygène présent dans l’eau environnante se diffuse progressivement dans cette couche d’air. Les reines bourdons s’appuient probablement sur un mécanisme similaire.
Toutefois, la respiration sous l’eau ne suffit pas à couvrir entièrement leurs besoins énergétiques. Pour combler ce manque, les reines produisent aussi une partie de leur énergie grâce au métabolisme anaérobie — un processus qui ne nécessite pas d’oxygène. Cette voie produit de l’acide lactique, que nous avons effectivement détecté chez les reines pendant l’immersion.
Ces adaptations physiologiques leur permettent de survivre sous l’eau, mais elles ont un coût. Après être remontées à la surface, les reines doivent passer plusieurs jours à récupérer, en dépensant bien plus d’énergie que si elles n’avaient jamais été immergées.
Une résilience inattendue
Les reines bourdons passent l’hiver seules, enfouies sous terre et dépendantes des réserves d’énergie accumulées pour survivre jusqu’au printemps. Leur capacité à tolérer plusieurs jours d’immersion — et même à respirer sous l’eau — révèle une résilience inattendue face à l’un des dangers de cette vie souterraine.
C’est un point crucial, car les colonies de bourdons dépendent entièrement de la survie des reines qui hivernent. Si une reine meurt pendant l’hiver, la colonie qu’elle aurait fondée au printemps suivant ne verra jamais le jour.
Cette capacité à survivre à une immersion pourrait jouer un rôle important — et jusqu’ici largement sous-estimé — dans la résilience des populations de bourdons menacées. Même pour des insectes aussi familiers et relativement bien étudiés, il reste donc encore beaucoup à découvrir sur les façons parfois surprenantes dont ils parviennent à faire face aux défis environnementaux.
Sabrina Rondeau a reçu des financements du Conseil de recherches en sciences naturelles et en génie du Canada, du Fonds de recherche du Québec — Nature et technologies, ainsi que de la Fondation de la famille Weston.
Charles-Antoine Darveau reçoit des financements du programme de subventions à la découverte du Conseil de recherches en sciences naturelles et en génie du Canada.
Nigel Raine reçoit des financements du Conseil de recherches en sciences naturelles et en génie du Canada, du projet Horizon Europe ProPollSoil, du Fonds d’innovation de la Fondation canadienne pour l’innovation, du ministère de l’Agriculture, de l’Alimentation et de l’Agroentreprise de l’Ontario, de la Fédération canadienne de la faune et de la Fondation de la famille Weston.
