Teen drivers face unique challenges during ‘100 deadliest days’ of summer, but safety measures can make a difference

Source: The Conversation – USA (2) – By Shannon Roberts, Associate Professor of Industrial Engineering, UMass Amherst

Summer is the riskiest time of year for teenage drivers. Martin Novak/Moment via Getty Images

The last few weeks of summer, heading into Labor Day weekend, can sometimes mean vacations and driving more miles on the road for all people, including teens.

Traffic crashes are the No. 1 cause of death for teens, and the crash rate for teen drivers is disproportionately higher than the share of licensed teen drivers.

In addition to this grim statistic, summer is the riskiest time for teen drivers. The 100 deadliest days represent the period from Memorial Day to Labor Day when the number of fatal crashes involving teen drivers dramatically increases. A third of each year’s teen driver crashes occur during the summer.

We are scholars who research transportation safety and teen driver behavior. Our expertise helps us understand that these 100 days are not just a statistical fluke – they reflect a dangerous intersection of factors such as inexperience and a propensity to take risks.

A young woman turns to face a young man while sitting in a convertible car
More time on the road means more risk for inexperienced drivers.
Klaus Vedfelt/Digital Vision via Getty Images

What makes summer different?

Regardless of the season, some teen drivers engage in risky behaviors that increase their likelihood of a fatal crash, such as getting distracted, driving with friends in the vehicle, driving under the influence, not wearing seat belts and a lack of hazard awareness.

Teens also have more free time in the summer, since most aren’t in school. Combined with the longer days and better weather, teens drive more over the summer. More time on the road means more risk, especially for inexperienced drivers.

Teens may also be more likely to drive after dark during the summer, in comparison to more experienced drivers. But nighttime driving is also when visibility is reduced and crash risks are higher, particularly for teens who haven’t fully developed the skills necessary for night driving. This increased exposure, in addition to teens’ general risky driving tendencies, contributes to the 100 deadliest days for teen drivers.

The increased crash risk for teens over the summer isn’t equally distributed either. Crashes with teen drivers that lead to serious injuries are more likely to occur with male drivers, in rural areas, for those of lower socioeconomic status and for those with disorders, such as attention deficit and hyperactivity disorder.

A rear view of an instructor holding a clipboard and guiding a student during a driving lesson.
Driver’s education programs can be effective, but not all teenagers have access to them.
Antonio Diaz/iStock via Getty Images

Teaching young drivers

Driver’s education programs are the formal method to teach teen drivers the rules of the road.

In driver’s education programs, teens receive information about driver and road safety though classroom and behind-the-wheel instruction in preparation for the licensing exam. Some states require teens to complete a driver’s education course if they want to receive a license under the age of 18. Of teens who have a license, nearly 80% of them have gone through some form of driver’s education.

Though driver’s education programs can be helpful, their effects are not equally felt. In some states, teens and their guardians must pay out of pocket for driver’s education courses to obtain a license. This makes driver’s education and, as a consequence, obtaining a driver’s license inequitable.

There are also driving school deserts – areas where the poverty rate is 20% or above and there are no behind-the-wheel driver education courses within a 10- to 15-minute drive. This makes driver education courses inaccessible. Many of these driving school deserts happen to be in areas with high populations of minorities.

Over 20 years ago, graduated driver licensing was introduced to reduce teen crash rates. This is a phased licensing system wherein teen drivers are restricted in terms of when, where and with whom they can drive until they turn 18. Such a system allows teens to gradually learn and gain experience with driving over time.

Graduated driver licensing has been implemented in all 50 states, and it has been shown to reduce teen driver crash rates. However, its effectiveness is limited to those who participate in the system. A large number of teens are unlicensed and are of low socioeconomic status. Many of these unlicensed teens forgo the entire process and remain unlicensed but still drive, well into their 20s when the graduated driver licensing restrictions are lifted.

A father shows his teenage son the functions that buttons in a car performs.
Adults can serve as good role models for teenagers who are learning to drive.
fotostorm/E+ via Getty Images

Making summer safer

There are two things people can do to turn the 100 deadliest days into the 100 safest days.

First, it is important that communities offer free supplementary training programs for teen drivers, because becoming a safe and responsible teen driver shouldn’t be limited to those with resources. As one example, in collaboration with industry partners, we have developed a program called Risk-ATTEND. It is a free, online, evidence-based program that teaches teen drivers how to anticipate risks while driving. Our research has shown that programs such as these can improve teen driving skills and may be especially effective for teen drivers in high-poverty areas.

Second, our research has shown that parents and guardians still play an important role in influencing teen driver behavior. Studies show that teens mirror the behaviors they observe: If they see adults text and drive, they’re more likely to do the same.

Once teenagers become old enough to drive, it is also important to establish rules and guidelines about expectations to establish clarity and accountability. Written agreements or checklists can address high-risk conditions such as nighttime driving, driving with other young passengers, phone use and adherence to speed limits.

Systems to help monitor and enforce rules have been shown to be effective in improving teen driver behavior. One such program is Checkpoints, which is a Connecticut-based program in which families agree to limit teen driving during high-risk conditions. Teens face consequences for violating these limits, such as a temporary loss of driving privileges. However, the limits are gradually lifted as they gain driving experience.

A young woman with curly smiles as she drives a car.
Programs that monitor teen driver behavior have shown promising results.
Fotografía de eLuVe/Moment via Getty Images

More than rules matter

Ultimately, preventing crashes in the summer and beyond extends beyond mere adherence to regulations. Avoiding them fundamentally hinges on cultivating a robust safety culture that emphasizes a collective commitment to risk reduction and continuous improvement in driving practices.

For teens, the summer months present unique challenges and opportunities.

Drawing on best practices, such as training programs, teens can build essential skills in varied conditions before gaining full, unsupervised privileges.

The Conversation

Shannon Roberts receives funding from the Massachusetts Department of Transportation, National Science Foundation, Sloan Foundation, and US Department of Transportation. She has received funding from GM and Toyota Collaborative Safety Research Center in past years.

Anuj Kumar Pradhan receives funding from the Massachusetts Department of Transportation, National Institutes of Health, and the US Department of Transportation. He has received funding from Toyota Collaborative Safety Research Center and State Farm in past years.

ref. Teen drivers face unique challenges during ‘100 deadliest days’ of summer, but safety measures can make a difference – https://theconversation.com/teen-drivers-face-unique-challenges-during-100-deadliest-days-of-summer-but-safety-measures-can-make-a-difference-260899

‘KPop Demon Hunters’ is attracting huge audiences worldwide – young Philadelphians told us K-pop culture inspires innocence, joy and belonging

Source: The Conversation – USA (2) – By A. Stefanie Ruiz, Assistant Professor in Nonprofit Leadership, College of Behavioral, Social and Health Sciences, Clemson University

‘KPop Demon Hunters,’ released June 20, 2025, is Netflix’s most-watched original animated film ever.
Netflix

“Born with voices that could drive back the darkness,” the character Celine, a former K-pop idol, narrates at the start of Netflix’s new release “KPop Demon Hunters.” “Our music ignites the soul and brings people together.”

The breakout success of “KPop Demon Hunters,” Netflix’s most-watched original animated film, highlights how “hallyu,” or the Korean Wave, keeps expanding its pop cultural reach. The movie, which follows a fictional K-pop girl group whose members moonlight as demon slayers, amassed over 26 million views globally in a single week and topped streaming charts in at least 33 countries.

From K-pop and K-dramas to beauty products and e-sports, hallyu – which refers to the global popularity of South Korean culture – has drawn in millions of fans worldwide. But beyond entertainment, many young people describe how their engagement with Korean culture supports their mental health and sense of belonging.

We conducted interviews with 30 non-Korean hallyu fans aged 18-30 in Philadelphia in 2019 to understand how they experience Korean cultural content. Our findings were recently published in the peer-reviewed World Leisure Journal.

The core themes, such as the emotional support, community building and cultural exploration offered by hallyu, remain relevant today, especially as Korean media continues to expand their global influence and resonate with new generations of fans.

A light space in a heavy world

Participants described hallyu, especially K-pop and K-dramas, as a refuge from the stress and negativity they associate with mainstream Western media.

“I think Western music is a lot … more mellow,” a 24-year-old social worker explained. “It’s like a blunt kind of depression … it doesn’t make you go out in the world and smile at everything.”

In contrast, K-pop was often described as uplifting, playful and emotionally resonant. This contrast was especially important for individuals who felt overwhelmed by the hypersexualized or violent content common in Western pop culture.

“I feel like the stories in [Korean dramas] make more of an effort to connect with people,” said a 22-year-old communications associate. “They’re not as explicit. [For instance, simply] holding hands is a huge deal.”

Another participant, a 19-year-old college student and part-time barista who identified as asexual, shared: “I really like seeing content where they portray a hug or simple kisses as extremely intimate. … [I]t just makes me more comfortable.”

Music as emotional medicine

For many interviewees, hallyu had become a form of emotional self-care.

“It supplements my happiness,” a 25-year-old researcher said. “I’m a pretty optimistic person; it just kind of supplements that baseline optimism.”

Others described how specific songs helped them through difficult times. The college student and barista recalled listening to the boy band BTS’ “Magic Shop” during a spell of depression. “I would just wrap a blanket around myself, sip tea … and it made me feel immensely better,” she said.

‘Magic Shop’ by BTS.

This therapeutic effect is not accidental. BTS, one of the most globally recognized K-pop groups, has built its brand around messages of self-love and mental health awareness.

“They try to spread a message of loving yourself,” a 24-year-old medical assistant explained. “Like no one can love you unless you love yourself first.”

Building community online and offline

Another key benefit of hallyu culture is the sense of community it fosters. Individuals from all backgrounds and ages connect through social media, fan clubs and local events.

“I’ve met a lot of people through [the K-pop club] on Temple’s campus,” one participant said. “We’d watch K-pop and K-dramas together. … [T]hat is still one of our major connections.”

Online platforms also play a crucial role. Individuals share translations, create fan art and organize charity projects in honor of their favorite idols.

“We do projects for BTS’ birthdays,” a 28-year-old government appraiser said. She also donated blood on the birthday of Mingyu, a member of the K-pop group Seventeen.

Exploring identity and culture

For many Asian American fans, hallyu has also become a way to explore and affirm their cultural identity.

“I think the Asian cultural dynamic … is familiar to me,” a Chinese American participant said. “It encouraged me to be more proud of my own culture.”

Another Chinese American participant, a third-year college student, reflected on how Korean dramas helped her appreciate traditional values: “They made me more aware … of how you should talk or act around people. It’s constantly reminding me of ways I can self-improve.”

Even non-Asian fans connected with the values portrayed in Korean media. One Jewish participant, a 26-year-old Ph.D. candidate, noted the similarities between Korean and Jewish family structures: “Our morals, our values … just fit very well together.”

A meaningful investment of time

While some fans acknowledged that their engagement with hallyu could be time-consuming, many saw it as a worthwhile investment.

“It’s probably an embarrassing amount of time,” one participant admitted. “But pretty much anytime I’m bored, I turn to K-pop.”

Another compared their hallyu consumption to “therapy sessions.”

Others described how, over time, they became more involved in fan communities or online content, and this deeper level of engagement often led to skill-building and personal growth as they learned video editing, translation, event planning and even fundraising. Participants who raised money for animal shelters or dance studios, for example, said they were inspired by the values promoted in hallyu culture. These efforts helped them feel more connected to both their idols and one another.

“I created a huge analysis on costuming in a certain music video for Seventeen,” a 26-year-old restaurant manager said. “I just couldn’t help myself.”

In a media landscape often dominated by cynicism and spectacle, the Korean Wave offers an alternative: a space where joy, vulnerability and connection are not only possible, but celebrated.

‘Don’t Wanna Cry’ by Seventeen.

Read more of our stories about Philadelphia.

The Conversation

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

ref. ‘KPop Demon Hunters’ is attracting huge audiences worldwide – young Philadelphians told us K-pop culture inspires innocence, joy and belonging – https://theconversation.com/kpop-demon-hunters-is-attracting-huge-audiences-worldwide-young-philadelphians-told-us-k-pop-culture-inspires-innocence-joy-and-belonging-262179

A toxicologist’s guide to poison ivy’s itch and bee stings’ burning pain – 2 examples of nature’s chemical warfare

Source: The Conversation – USA (3) – By Christopher P. Holstege, Professor of Emergency Medicine and Pediatrics, University of Virginia

There’s a lot to explore out there. aldomurillo/E+ via Getty Images

Enjoying the outdoors carries the danger of running into nature’s less-friendly side: toxic plants and animals.

As toxicologists at the University of Virginia’s Blue Ridge Poison Center, we see many patients each year suffering from itchy rashes from poison ivy and stings from wasps or bees.

Plants and animals deploy toxins most often in order to defend themselves. Learning how they do that and what happens when the human body is exposed to these substances can offer insights on how to prevent or manage these encounters with nature.

The goal is not to scare people away from the outdoors, but to equip them with the knowledge to appreciate these organisms’ intricate self-preservation strategies and to protect themselves in return.

Poison ivy, a ubiquitous source of itch

Whether in a remote state park or on a city playground, most people have encountered poison ivy. This plant is recognizable by its characteristic arrangement of leaves growing in groups of three with edges that vary from smooth to jagged. It can take many forms: a single small plant, a mass of ground cover, a small bush, or a climbing vine reaching many feet up a tree or building.

Poison ivy with big leaves growing on a tree
Poison ivy contains an oily chemical called urushiol that most people are allergic to.
Chris Light via Wikimedia Commons, CC BY

Poison ivy – its scientific name is Toxicodendron radicans – and its close relatives poison oak and poison sumac contain an oily substance called urushiol. This chemical is found in every part of the plant: the leaves, roots, stems and even the small white berries it produces in late summer.

About 75% of people will develop an allergic reaction on contact with urushiol. Urushiol has antimicrobial properties, and scientists think its job in the poison ivy plant is to protect it from diseases.

Because it is so oily, urushiol spreads easily. It can transfer from the plant to your skin, clothes, garden tools or even your pets. Direct plant contact isn’t the only risk: If urushiol is on your clothing or a pet’s fur and your skin later brushes against it, you can develop the same rash as you’d get from directly touching the plant.

A white goat munches plants including poison ivy.
Goats happily munch poison ivy as part of their expansive vegetarian diet. Only people and perhaps some other primates are allergic to poison ivy.
Terry Donovan via flickr, CC BY

From plant to skin

Urushiol triggers a delayed allergic reaction. When the oil touches your skin, it binds to skin cells, changing their shape. A molecule called CD1a then clocks urushiol as a foreign substance, prompting the immune system to mount an attack on the cells – hence the rash.

The symptoms do not appear instantly; the rash usually appears 12 to 48 hours after exposure. It often starts as redness and itching, then develops into small bumps or fluid-filled blisters. The reaction can be mild or severe, depending on how sensitive you are and how much urushiol got on your skin.

The rash itself isn’t contagious. Fluid from the blisters doesn’t spread it. What spreads the rash to other areas of your body or to others is the urushiol lingering on your skin, clothing, tools or pets. Once the oil is adequately washed away, the rash can’t spread to other people or to other areas of your body.

If you have touched poison ivy, wash the area as soon as you can with soap and water and change your clothes if possible. After that, the rash will eventually resolve on its own. You can help alleviate symptoms by using a topical steroid or anti-itch cream on the rash. In severe cases, or if the face is affected, patients may require oral steroids to treat the symptoms.

Bees and wasps: Home defenders

Bees and wasps are most active in the late summer. Because of this, we receive more frequent poison center calls about them during this season.

A bee sitting on a red and yellow flower
Stinging is how bees protect themselves and their hives from predators and attackers.
Ionenlaser via Wikimedia Commons, CC BY

Bees and wasps generally sting to defend their hives or nests or to protect themselves from perceived threats. They store venom in their abdominal sacs. When they sting, the venom flows through their stinger and is injected into their target’s skin.

This venom is a clear, slightly acidic liquid loaded with various active ingredients. For example, it contains enzymes such as phospholipase A2 that break down cell membranes, and peptides such as melittin that cause pain. The venom also contains natural chemicals such as histamine and epinephrine that affect blood vessels and the immune system.

Sting mechanics

Unlike with poison ivy, where the immune system’s reaction to the substance causes irritation, with bee and wasp stings it’s primarily the substance itself that causes pain – although immune response can still play a role. As soon as the venom enters a person’s skin, their body reacts.

A sharp, burning pain comes first as the components of the venom begin to inflict damage, followed by redness and then swelling of the area. Symptoms commonly peak within a few hours and fade within a day. However, some people have stronger reactions with larger areas of swelling that can last for several days. This is because everyone’s immune system is slightly different, and some people tend to have stronger reactions than others to foreign substances.

A closeup of a bee's stinger
A bee’s stinger is sharp and barbed, and it can continue to deliver venom for up to a minute if it remains stuck in your skin.
US Geological Survey via Wikimedia Commons

In rare cases, the immune system overreacts, releasing large amounts of histamine and other chemicals all at once. Histamine is most often released in response to a foreign substance, causing symptoms of an allergic reaction. This can lead to anaphylaxis, a severe allergic reaction that can make breathing difficult, lower blood pressure and cause airway swelling, and which can quickly become life-threatening.

Getting stung multiple times at once can also be life-threatening due to the sheer amount of venom injected, even in people without a bee venom allergy.

If you’re stung and the stinger is stuck in the skin, it should be removed immediately by the quickest means available. Bee stingers are barbed and can continue to deliver venom for up to a minute. Most bee or wasp stings require only symptomatic treatment, such as an over-the-counter steroid cream or oral antihistamine to reduce itching and swelling.

However, people who begin to develop more severe symptoms such as full body hives, vomiting or difficulty breathing should immediately seek emergency care. Anaphylactic reactions require rapid treatment with a medication called epinephrine and close monitoring in the hospital.

The Conversation

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

ref. A toxicologist’s guide to poison ivy’s itch and bee stings’ burning pain – 2 examples of nature’s chemical warfare – https://theconversation.com/a-toxicologists-guide-to-poison-ivys-itch-and-bee-stings-burning-pain-2-examples-of-natures-chemical-warfare-261156

Vaccines hold tantalizing promise in the fight against dementia

Source: The Conversation – USA (3) – By Anand Kumar, Professor and Department Head of Psychiatry, University of Illinois Chicago

Researchers are in the earliest phase of piecing together how the shingles vaccine could play a role in lowering the risk of dementia. PM Images/DigitalVision via Getty Images

Over the past two centuries, vaccines have been critical for preventing infectious diseases. The World Health Organization estimates that vaccination prevents between 3 million and 5 million deaths annually from diseases like diphtheria, tetanus, influenza, measles and, more recently, COVID-19.

While there has long been broad scientific consensus that vaccines prevent or mitigate the spread of infections, there is new research suggesting that the therapeutic impact might go beyond the benefit of preventing infectious diseases.

An April 2025 study published in the prominent journal Nature found tantalizing evidence that the herpes zoster – or shingles – vaccine could lower the risk of dementia in the general population by as much as 20%.

We are a team of physician scientists with expertise in the clinical and basic science of neurodegenerative disorders and dementia.

We believe that this study potentially opens the door to other breakthroughs in understanding and treating dementia and other degenerative disorders of the brain.

A role for vaccines in reducing dementia risk?

One of the major challenges researchers face when trying to study the effects of vaccines is finding an unvaccinated “control group” for comparison – a group that is similar to the vaccine group in all respects, save for the fact that they haven’t received the active vaccine. That’s because it’s unethical to assign some patients to the control group and deprive them of vaccine protection against a disease such as shingles.

The Nature study took advantage of a policy change in Wales that went into effect in 2013, stating that people born on or after September 2, 1933, were eligible for the herpes zoster vaccination for at least a year, while those born before that cutoff date were not. The vaccine was administered to prevent shingles, a painful condition caused by the same virus that causes chickenpox, which can lie dormant in the body and be reactivated later in life.

The researchers used the policy change as a natural laboratory of sorts to study the effect of shingles vaccination on long-term health outcomes. In a statistically sophisticated analysis of health records, the team found that the vaccine reduced the probability of getting dementia by one-fifth over a seven-year period. This means that people who received the shingles vaccine were less likely to develop clinical dementia over the seven-year follow-up period, and women benefited more than men.

The study design allowed researchers to compare two groups without actively depriving any one group of access to vaccination. The two groups were also of comparable age and had similar medical comorbidities – meaning similar rates of other medical conditions such as diabetes or high blood pressure.

Results from this and other related studies raise the possibility that vaccines may have a broader role in experimental therapeutics outside the realm of infectious diseases.

These studies also raise provocative questions about how vaccines work and how our immune system can potentially prevent dementia.

How vaccines might be protective

One scientific explanation for the reduction of dementia by the herpes zoster vaccine could be the direct protection against the shingles virus, which may play a role in exacerbating dementia.

However, there is also the possibility that the vaccine may have conferred protection by activating the immune system and providing “trained immunity,” in which the immune system is strengthened by repeated exposure to vaccines or viruses.

The study did not differentiate between different types of dementia, such as dementia due to Alzheimer’s disease or dementia due to stroke. Additionally, researchers cannot draw any definitive conclusions about possible mechanisms for how the vaccines could be protective from an analysis of health records alone.

The next step would be a prospective, randomized, double-blind, placebo-controlled study – the “gold standard” for clinical trials in medicine – to directly examine how the herpes zoster vaccine compares with a placebo in their ability to reduce the risk of dementia over time. Such studies are necessary before any vaccines, as well as other potential therapies, can be recommended for routine clinical use in the prevention of dementia.

Brain image of early Alzheimer's disease
Randomized, placebo-controlled trials are needed in order to determine how the shingles vaccine compares with a placebo over time in protecting against dementia.
Peter Dazeley/Getty Images News

The challenges of untangling dementia

Dementia is a major noncommunicable disease that is a leading cause of death around the world.

A January 2025 study provided updated figures on lifetime dementia risk across different subsets of the U.S. population. The researchers estimate that the lifetime risk of dementia after age 55 is 42% – more than double earlier estimates. The dementia risk was 4% by age 75, and 20% by age 85, with the majority of risk occurring after 85. The researchers projected that the number of new cases of dementia in the U.S. would double over the next four decades from approximately 514,000 cases in 2020 to 1 million in 2060.

Once considered a disease largely confined to the developed world, the deleterious effects of dementia are now apparent throughout the globe, as life expectancy increases in many formerly developing countries. While there are different forms of dementia with varying clinical manifestations and underlying neurobiology, Alzheimer’s disease is the most common.

Prospective studies that specifically test how giving a vaccine changes the risk for future dementia may benefit from studying patient populations with specific types of dementia because each version of dementia might require distinct treatments.

Unfortunately, for the past two to three decades, the amyloid hypothesis of Alzheimer’s disease – which posits that accumulation of a protein called amyloid in the brain contributes to the disorder – dominated the scientific conversation. As a result, most of the efforts in the experimental therapeutics of Alzheimer’s disease have focused on drugs that lower the levels of amyloid in the brain.

However, results to date have been modest and disappointing. The two recently approved amyloid-lowering therapies have only a minimal impact on slowing the decline, are expensive and have potentially serious side effects. And no drug currently approved by the Food and Drug Administration for clinical use reverses the cognitive decline.

Studies based on health records suggest that past exposure to viruses increase the risk of dementia, while routine vaccines, including those against tetanus, diphtheria, pertussis, pneumonia, shingles and others, reduce the risk.

Innovation and an open mind

There is sometimes a tendency among scientists to cling to older, familiar models of disease and a reluctance to move in more unconventional directions.

Yet the process of doing science has a way of teaching researchers like us humility, opening our minds to new information, learning from our mistakes and going where that data takes us in our quest for effective, lifesaving therapies.

Vaccines may be one of those paths less traveled. It is an exciting possibility that may open the door to other breakthroughs in understanding and treating degenerative disorders of the brain.

The Conversation

Jalees Rehman receives funding from NIH.

Anand Kumar does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. Vaccines hold tantalizing promise in the fight against dementia – https://theconversation.com/vaccines-hold-tantalizing-promise-in-the-fight-against-dementia-257807

Suplemento cultural: este nuestro verano

Source: The Conversation – (in Spanish) – By Claudia Lorenzo Rubiera, Editora de Cultura, The Conversation

bepsy/Shutterstock

Este texto se publicó por primera vez en nuestro boletín Suplemento cultural, un resumen quincenal de la actualidad cultural y una selección de los mejores artículos de historia, literatura, cine, arte o música. Si quiere recibirlo, puede suscribirse aquí.


Hoy empieza agosto y aprovechamos este comienzo para hacer una pausa en el Suplemento hasta septiembre.

Esperamos que en nuestra ausencia disfruten del descanso (quien lo tenga). Y les dejamos con un boletín algo más extenso de lo normal, buscando que los artículos, en muchos casos, sirvan para abrir boca y sean puertas a otros mundos literarios, cinematográficos o musicales.

Como habrán visto, las redes sociales bullen con actualizaciones en época estival. Muchos retratan sus vacaciones, sus actividades y sus compañías con honestidad. Otros aprovechan el marco virtual para elaborar narraciones algo más alejadas de la realidad.

Si quitamos las redes de la ecuación, nos quedamos con la esencia del ser humano, esa parte que nos impulsa a presumir hasta, en ocasiones, vernos inmersos en una maraña de inexactitudes y mentiras. Es decir, que a veces por aparentar decimos que hicimos mucho más de lo que realmente conseguimos.

Pero esto no es exclusivo de nuestro tiempo. Ya en el Medievo algunos peregrinos, como cuentan Déborah González y Raquel Jabares, escribían sobre los grandes logros de un Camino de Santiago que, en realidad, no habían hecho.

Tiempo para leer

Una buena candidata a convertirse en lectura de verano es la epopeya fantástica Olvidado rey Gudú, de Ana María Matute (cuyo centenario celebramos este 2025).

Según Sergio Ferrer, editor de Ciencia en The Conversation y devoto de la novela, es una narración exigente que, sin embargo, da mucho a cambio, nunca frustra: “Lo facilón sería decir una verdad: si este libro se hubiera escrito en inglés habría varias películas y series sobre él y estaría a la altura de las grandes obras del género. Son casi 1 000 páginas y el estilo puede ser denso, pero si te dejas caer en él y te dejas atrapar te sabe a poco. Y no es fácil que un libro tan largo sepa a poco”. ¿Es un libro adecuado para el verano?, le pregunté. Pues depende del verano, añade. El reto puede ser grande, pero dicen que la recompensa también lo es.

Si de efemérides hablamos, el mundo anglosajón (y todos los demás, porque su arte es universal) está tirando la casa por la ventana con los fastos por el 250 aniversario del nacimiento de Jane Austen: exposiciones, bailes, adaptaciones, miniseries, reescrituras… Rosa García-Periago resume todo un año dedicado a la autora, para que sepamos por dónde empezar a hincarle el diente. Aunque una cosa queda clara: lo mejor que se puede hacer para celebrarla es leerla.

Y para cerrar el capítulo de los aniversarios, aprovechamos un mismo evento para recordar a Carmen Martín Gaite (que haría cien años este otoño) y a Mario Vargas Llosa, que falleció hace unos meses: el Premio Biblioteca Breve de 1962, que ganó este último con La ciudad y los perros y en el que la autora quedó finalista con otra apuesta arriesgada: Ritmo lento.

Aya de Yopougon es un cómic que cuenta las aventuras de la mencionada Aya, una chica de Costa de Marfil, narrando sus sueños, sus ilusiones y su día a día en el barrio. Con esta obra Marguerite Abouet ha arrasado internacionalmente y ha demostrado que no sólo hay una vida en África que merece ser contada más allá de la tragedia que siempre se intenta buscar en los relatos de ese continente, sino que el mundo está muy interesado en conocer esa realidad alejada de los estereotipos.

Acabamos la parte literaria con ese salseo de las últimas semanas que ha involucrado a Coldplay, una cámara pública en un concierto y el descubrimiento de una infidelidad. Este relato, magnificado por las redes sociales, terminó con los participantes abandonando sus puestos de trabajo, una consecuencia que parece exagerada para un asunto que, en el fondo, no dejaba de ser privado. Pero ya en los grandes dramas decimonónicos (y en los contemporáneos) queda claro que todo lo que ocurre en casa tiene reverberaciones en el mundo exterior.

De pantalla en pantalla

Viajemos momentáneamente a Lothlórien, el reino élfico de la Tierra Media. Al imaginarlo probablemente muchos piensen en los paisajes que Peter Jackson recreó en su trilogía de El señor de los anillos. Lara López Millán cuenta cómo la estética del ‘medievalismo suave’, nacida en Londres a mitad del siglo XIX, impregna actualmente muchas de las películas y series fantásticas que vemos, con su delicadeza, la vivacidad del color y su atención a la flora.

¿Alguna vez han dicho, ante una comedia, eso de “no es buena pero te ríes”? Esa coletilla, que todos añadimos, indica muchas veces que la película tiene una calidad superior a la que le atribuimos. Después de todo, hacer reír no es tan fácil como parece. De provocar carcajadas sabían mucho los ZAZ, David Zucker, Jim Abrahams y Jerry Zucker, artífices de algunas de las películas paródicas más desternillantes de la historia. Este agosto se estrena el remake de The Naked Gun (Agárralo como puedas en España, ¿Y dónde está el policía? en Hispanoamérica) y eso sirve de excusa para analizar qué hizo que los ZAZ fuesen unos maestros de la risa.

Hace unos días se subastó el Birkin original (por una cantidad de dinero estratosférica), un bolso que la marca Hermès creó para la actriz y cantante inglesa Jane Birkin y que después se convirtió en uno de los diseños más famosos del mundo. Aprovechando el ruido, Ana María Iglesias Botrán repasa la carrera artística de una mujer que, en muchos casos, fue recordada por ser compañera personal y profesional de Serge Gainsbourg pero que se labró un nombre propio y que triunfó en la gran pantalla y en los escenarios.

Y aprovechamos para felicitar a Gonzalo Suárez, al que ya recordamos el verano pasado en su 90 cumpleaños, por el Goya de Honor 2026 que se le entregará el año que viene. Las obras de autores libres, inclasificables y creativos siempre merecen ser premiadas.

Los días lentos

“Agora que por fin entama’l branu

y l’azul blanco del cielu inunda

la tierra entera y tamién el ríu,

yá ye tiempu, yá tengo tiempo

pa esperar imperceptibles cambios

nes nubes que pasen pa contra allá,

pa contra otru país de ceniza”.

Con estos versos, con ese “ahora que al fin comienza el verano”, quería cerrar el Suplemento cultural de esta semana, recordando a Xuan Bello, el escritor que contó desde Asturias el mundo entero. El autor de Historia universal de Paniceiros falleció recientemente, dejando un poquito más huérfana a la literatura española.

Las palabras de Bello nos remiten a una estación en la que los días se dilatan, se expanden, son infinitos y lentos. Tal vez en el fondo todos queramos, cuando llegan las vacaciones, regresar a aquellas eternas jornadas de los veranos de nuestra infancia.

Con ese espíritu recordamos dos artículos de hace algún tiempo. En el primero, Txetxu Ausín hace una defensa, a propósito del exitazo de Luis Fonsi y Daddy Yankee, del vivir “des-pa-ci-to”.

En el segundo vemos cómo Julio Cortázar y Carol Dunlop, sin saberlo, siguieron esta máxima al pie de la letra y atravesaron Francia con calma, tardando 33 días en recorrer 800 kilómetros en coche.

Esperamos que disfruten de un muy feliz agosto. Nos vemos en septiembre,

The Conversation

ref. Suplemento cultural: este nuestro verano – https://theconversation.com/suplemento-cultural-este-nuestro-verano-262538

Lors des canicules, notre cerveau ne s’aligne pas toujours avec le thermomètre et peut nous mettre en danger

Source: The Conversation – in French – By Elisabeth Bourgeois, Économiste, centrée sur les enjeux de climat, d’énergie et de vulnérabilités sociales, Université Savoie Mont Blanc

Pourquoi avons-nous tant de mal à nous adapter au changement climatique ? Quand l’asphalte chauffe, le thermomètre ne suffit pas à guider notre action : c’est notre manière de lire ses chiffres qui va décider de nos gestes. Perceptions, émotions et normes sociales forment un récit qui guide nos comportements – et qui façonne nos vulnérabilités face aux chaleurs extrêmes.


Il est 13 heures pile à l’école Joliot‑Curie dans une ville du Val‑de‑Marne. Un élève braque un thermomètre infrarouge sur la dalle : 52 °C. Trois pas plus loin, sous le paillis d’un jeune tilleul planté dans le cadre du programme européen OASIS – présenté comme étude de cas sur le portail Climate‑ADAPT de l’Agence européenne de l’environnement – le thermomètre tombe à 38 °C. Les enfants, médusés, rebaptisent la zone « four » et déplacent leur ballon vers l’ombre : en quelques secondes, la température devient un récit collectif qui reprogramme des gestes.

Pour réussir l’adaptation au changement climatique, à l’image de ces écoliers, nous devons voir les vagues de chaleur comme un récit partagé, avec des actions modulables. À cet égard, on dispose déjà d’une décennie de recherche internationale – et de l’expérience de quelques villes qui ont déjà mis ces travaux au service de la fraîcheur.

Les personnes en bonne santé plus susceptibles d’ignorer les risques de la chaleur

Au printemps 2025, nous avons publié une enquête, avec deux collègues économistes de l’énergie, dans la revue scientifique Climate Policy. Trois cents Français de plus de 55 ans, issus de 13 régions, étaient appelés à réagir à deux scénarios : l’un de cinq jours annoncés à 33 °C et, le deuxième, de cinq jours à 36 °C.

Ils devaient cocher, parmi une liste de cinq gestes protecteurs (boire plus d’eau, adapter sa tenue vestimentaire, prendre des mesures pour réguler au mieux la température de son logement, solliciter une aide extérieure et chercher un lieu frais), ceux qu’ils prévoyaient de réaliser.

Leurs réponses nous ont permis d’évaluer leurs croyances dans la probabilité d’une canicule et sa gravité pour leur santé, ainsi que la nature de leurs émotions face à ces scénarios.

De fait, les participants se disant « en pleine forme » passaient en moyenne de 3,6 gestes envisagés à 33 °C à 1,8 geste à 36 °C : près de deux fois moins. Ceux qui se déclaraient « un peu inquiets » suivaient le mouvement inverse : de 2,9 gestes à 4,4 (+ 52 %).

Certes, l’exercice reste déclaratif : il mesure l’intention et pas l’action. Mais des synthèses de psychologie sociale montrent qu’environ 40 % des comportements observés s’éclairent par les intentions déclarées. Dit autrement : quand l’intention augmente, le comportement suit souvent – pas toujours, mais suffisamment pour orienter à bon escient l’action publique.

Il suffit de trois degrés de plus pour que la vigilance change de camp et que la lecture de la situation change du tout au tout. Ces résultats prolongent ceux d’une méta‑analyse publiée dans Nature Climate Change. Notre perception du risque, notre sentiment d’efficacité et nos émotions expliquent près d’un tiers des conduites d’adaptation individuelles, davantage encore que l’âge ou la prise de médicaments comme des bêta-bloquants !

Le cerveau, pour le dire vite, règle le thermostat du corps. C’est notre « état intérieur » qui dicte pour beaucoup notre aptitude à nous adapter – et donc, notre vulnérabilité face aux chaleurs extrêmes.

Environnement, individu et comportement : un triptyque indissociable

Comme cela a été mis en évidence par une vaste revue de littérature publiée en 2019, les comportements face à la chaleur résultent toujours de la conjonction de trois types de facteur :

  • un facteur environnemental (géométrie urbaine, albédo – la capacité d’une surface à réfléchir la lumière –, circulation d’air…),

  • un facteur personnel (âge, santé, attentes, croyances…),

  • et, enfin, un facteur comportemental (type d’activité, normes sociales…).

Ces trois piliers sont indispensables pour prendre en compte la diversité des situations individuelles.

Les indicateurs utilisés pour évaluer le confort thermiques ne sont pertinents qu’en intérieur, et ne s’appliquent donc pas aux personnes actives en extérieur.
CC BY-NC-SA

Des indicateurs couramment utilisés pour évaluer le confort thermique, le Predicted Mean Vote (PMV) et le Physiologically Equivalent Temperature (PET) l’illustrent bien : le premier estime le « vote thermique moyen » d’un groupe assis dans un bureau climatisé et le second traduit l’état thermique équivalent pour un individu immobile.

Parfaits en intérieur, ces outils montrent leurs limites lorsqu’on les applique à un joggeur, à un ouvrier ou à des enfants dans une cour d’école. Autant dire que prédire la sensation d’un joggeur marseillais avec un modèle mis au point dans une chambre climatique danoise équivaudrait à calibrer un sous‑marin avec un altimètre.




À lire aussi :
Végétaliser les cours de récréation pour encourager la curiosité des enfants


Pourquoi et comment s’adapter au changement climatique

Les chiffres sont têtus et l’impact des vagues de chaleur difficile à ignorer. Par exemple :

L’adaptation n’a donc de sens que si l’on agit, en même temps, sur la façon dont les habitants lisent, ressentent et anticipent les degrés supplémentaires. Un espace vert ou un refuge climatisé ne suffisent pas : encore faut‑il que chacun sache où ils sont, quand ils ouvrent, ce qu’on y trouve et qu’on s’y sente légitime. C’est le rôle des récits collectifs.

Le retour d’expérience des villes pionnières montre que c’est possible :

Le parc de la citadelle, à Barcelone (Espagne), est un exemple de refuge climatique.
Barcelona for Climate

Mais les infrastructures ne suffisent pas. Elles rendent possible le geste (se déplacer, s’abriter, ralentir…), mais c’est d’abord le message ciblé qui fournira la clé cognitive pour le faire (« Je suis concerné », « Je sais quoi faire », « Je peux effectivement le faire »).

Adaptation et action publique : comment débusquer le biais d’invulnérabilité

Il est donc essentiel de tenir compte des éléments de psychologie et des biais de perception, mentionnés plus haut, pour améliorer l’adaptation climatique, et, en particulier, l’action publique dans ce domaine.

Réécrire les alertes est la première évidence. Ainsi, des messages d’ordre général comme « Buvez de l’eau » glisseront sur les profils les plus optimistes. Au contraire, un SMS nominatif rappelant, par exemple, qu’un traitement diurétique triple le risque de déshydratation va augmenter significativement l’adoption de gestes de protection et réduire le risque de stress thermique chez les personnes âgées.

En Finlande, par exemple, le service météorologique publie des avertissements relatifs aux températures et l’institut finnois pour la santé et le bien-être (THL) publie des guides spécifiques pour les crèches et écoles. La Ville d’Helsinki a d’ailleurs évalué l’adaptation au climat de ses écoles et de ses garderies.

Reste le cas des « invincibles volontaires » – ceux qui ont décidé qu’ils supporteront la chaleur. Là, l’outil le plus efficace n’est pas le gobelet d’eau mais l’autodiagnostic.

Un quiz de deux minutes, intégré à une appli de running par exemple, pourrait faire virer l’écran au rouge dès que l’humidex – indice combinant température et humidité – tutoie le seuil de danger. La liberté d’aller courir demeure, mais le sportif ne peut plus ignorer les risques.

Planter des arbres, enfin, est utile en ville pour limiter l’effet îlot de chaleur urbain (ICU), mais doit être fait avec discernement. Selon la Commission européenne, couvrir 30 % de la surface urbaine par le feuillage des arbres (canopée) permettrait d’éviter plus de 2 500 décès prématurés en Europe chaque été. Mais si un tilleul avenue Montaigne (Paris) va simplement flatter Instagram, le même tilleul à Clichy‑sous‑Bois (Seine-Saint-Denis) devient un acte de santé publique.

Ces enseignements ne suffiront probablement pas à dompter l’été 2050. Ils rappellent cependant que la chaleur meurtrière n’est pas qu’une donnée météorologique, mais avant tout un récit à réécrire sans cesse – avec des SMS, des cours, des QR codes sur les abribus et des arbres là où ils comptent.

Retour à Joliot‑Curie. Les élèves ont rangé le thermomètre et filent sous l’ombre maigre mais tangible du jeune tilleul. Le thermomètre ment rarement, mais nos certitudes, elles, peuvent tuer. Les tempérer – par un message bien tourné, un tilleul bien placé, un voisin bien informé – est tout aussi important que de faire tomber la température.

The Conversation

Elisabeth Bourgeois a reçu des financements de l’ANR (ANR‑18‑EURE‑0016 – Solar Academy) et de la Public Trust in Health Chair (Grenoble École de Management). Aucun autre intérêt déclaré.

ref. Lors des canicules, notre cerveau ne s’aligne pas toujours avec le thermomètre et peut nous mettre en danger – https://theconversation.com/lors-des-canicules-notre-cerveau-ne-saligne-pas-toujours-avec-le-thermometre-et-peut-nous-mettre-en-danger-261012

Canicule : soulignons, sans état d’âme, nos progrès d’adaptation depuis 2003

Source: The Conversation – in French – By François Lévêque, Professeur d’économie, Mines Paris – PSL

Depuis 2003, l’Europe a réalisé des progrès conséquents dans l’adaptation aux vagues de chaleur : en proportion, on meurt moins, même si les températures sont plus élevées. Et demain ?


La chaleur tue : on a recensé plusieurs centaines de décès à Paris ainsi que dans d’autres grandes capitales européennes lors de la canicule de mi-juin à début juillet 2025. Le nombre de morts aurait triplé par rapport à la normale du fait du changement climatique, selon une estimation réalisée par des chercheurs britanniques.

Ces chiffres font peur. Ils masquent cependant les grands progrès réalisés pour limiter notre vulnérabilité face à la multiplication des vagues de chaleur. La chaleur tue mais de moins en moins, grâce à nos actions individuelles et collectives d’adaptation. Il faut s’en féliciter, et non l’ignorer.

Les données d’observation de mortalité par les agences sanitaires n’étant pas encore disponibles, le calcul qui précède repose sur des modèles et des méthodes, connus des spécialistes. La plupart sont désormais suffisamment au point pour rendre compte en confiance de leurs résultats sur les progrès de l’adaptation.

La canicule de 2003, ou l’Année zéro

Commençons notre examen en prenant pour point de repère la canicule de 2003 en France. Cet été-là le pays a connu une véritable hécatombe : près de 15 000 décès en excès.

En contrecoup, les pouvoirs publics ont décidé toute une série d’actions préventives pour protéger la population des grandes chaleurs : mise en place d’un système d’alerte annonçant les canicules, campagnes d’information auprès du public sur les façons de se protéger, formation du personnel de santé, ouverture d’espaces climatisés dans les maisons de retraite et les services hospitaliers, etc.

Quelques années plus tard, une équipe regroupant des chercheurs de l’Inserm, de Météo France et de Santé publique France s’est demandé si ces mesures avaient bien été suivies d’effet. À partir d’un modèle reliant mortalité et températures observées en France sur vingt-cinq ans, ils ont estimé que la canicule de l’été 2006 s’était traduite par une baisse de plus de moitié du nombre de décès en excès.

Ce progrès ne peut pas, bien sûr, être imputé aux seules actions publiques. La canicule de 2003 a été à l’origine d’une prise de conscience généralisée des méfaits de la chaleur, de changement des comportements individuels et d’achat d’appareils de rafraîchissement, tels que ventilateurs et climatiseurs, mais aussi d’équipements plus innovants apparus plus tard sur le marché, comme les rafraîchisseurs d’air ou les pompes à chaleur réversibles.

Attention, le frigidaire distributeur de glaçons ne fait pas partie de cette panoplie ! En cas de fortes températures, il faut éviter de boire de l’eau glacée pour se rafraîchir. Elle ralentit la sudation, mécanisme fondamental de l’organisme pour lutter contre la chaleur.

Pourquoi il est délicat de comparer 2022 et 2003

L’été 2022 a constitué la seconde saison la plus chaude jamais enregistrée dans l’Hexagone. Le nombre de décès en excès a été toutefois cinq fois moindre que celui de 2003, mais on ne sait pas précisément quelle part de cette baisse est simplement due à des conditions caniculaires un peu moins défavorables.

La comparaison 2003/2022 est tout aussi délicate au niveau européen. On dispose bien, à cette échelle, de travaux d’estimation de la surmortalité en lien avec la chaleur aux deux dates, mais ils reposent sur des méthodes différentes qui rendent leurs résultats peu comparables : 74 483 décès pour la canicule de 2003 en Europe contre 61 672 morts lors de la canicule de 2022.

En effet, le premier chiffre mesure des décès en excès par rapport à une période de référence, tandis que le second découle de l’application d’une méthode épidémiologique. Celle-ci, plus sophistiquée, mais aussi plus rigoureuse, consiste à estimer pour une ville, une région ou un pays, le risque de mortalité relatif en fonction de la température, à tracer une « courbe exposition-réponse », selon le jargon des spécialistes.

Pour l’Europe entière, le risque est le plus faible autour de 17 °C à 19 °C, puis grimpe fortement au-delà. Connaissant les températures journalières atteintes les jours de canicule, on en déduit alors le nombre de décès associés à la chaleur.

Quelles canicules en Europe à l’horizon 2050 ?

Résumé ainsi, le travail paraît facile. Il exige cependant une myriade de données et repose sur de très nombreux calculs et hypothèses.

C’est cette méthode qui est employée pour estimer la surmortalité liée aux températures que l’on rencontrera d’ici le milieu ou la fin de ce siècle, en fonction, bien sûr, de différentes hypothèses de réchauffement de la planète. Elle devrait par exemple être décuplée en Europe à l’horizon 2100 dans le cas d’un réchauffement de 4 °C.

Ce chiffre est effrayant, mais il ne tient pas compte de l’adaptation à venir des hommes et des sociétés face au réchauffement. Une façon de la mesurer, pour ce qui est du passé, consiste à rechercher comment la courbe exposition-réponse à la température se déplace dans le temps. Si adaptation il y a, on doit observer une mortalité qui grimpe moins fortement avec la chaleur qu’auparavant.

C’est ce qui a été observé à Paris en comparant le risque relatif de mortalité à la chaleur entre la période 1996-2002 et la période 2004-2010. Aux températures les plus élevées, celles du quart supérieur de la distribution, le risque a diminué de 15 %.

Ce chiffre ne semble pas très impressionnant, mais il faut savoir qu’il tient uniquement compte de la mortalité le jour même où une température extrême est mesurée. Or, la mort associée à la chaleur peut survenir avec un effet de retard qui s’étend à plusieurs jours voire plusieurs semaines.

La prise en compte de cet effet diminue encore le risque entre les deux périodes : de 15 % à 50 %. Cette baisse de moitié est plus forte que celle observée dans d’autres capitales européennes comme Athènes et Rome. Autrement dit, Paris n’est pas à la traîne de l’adaptation aux canicules.

De façon générale et quelle que soit la méthode utilisée, la tendance à une diminution de la susceptibilité de la population à la chaleur se vérifie dans nombre d’autres villes et pays du monde développé. L’adaptation et la baisse de mortalité qu’elle permet y est la règle.

La baisse de la mortalité en Europe compensera-t-elle l’augmentation des températures ?

C’est une bonne nouvelle, mais cette baisse de la surmortalité reste relative. Si les progrès de l’adaptation sont moins rapides que le réchauffement, il reste possible que le nombre de morts en valeur absolue augmente. En d’autres termes, la mortalité baisse-t-elle plus vite ou moins vite que le réchauffement augmente ?

Plus vite, si l’on s’en tient à l’évolution observée dans dix pays européens entre 1985 et 2012. Comme ces auteurs l’écrivent :

« La réduction de la mortalité attribuable à la chaleur s’est produite malgré le décalage progressif des températures vers des plages de températures plus chaudes observées au cours des dernières décennies. »

En sera-t-il de même demain ? Nous avons mentionné plus haut un décuplement en Europe de la surmortalité de chaleur à l’horizon 2100. Il provient d’un article paru dans Nature Medicine qui estimait qu’elle passerait de 9 à 84 décès attribuables à la chaleur par tranche de 100 000 habitants.

Mais attention : ce nombre s’entend sans adaptation aucune. Pour en tenir compte dans leurs résultats, les auteurs de l’article postulent que son progrès, d’ici 2100, permettra un gain de mortalité de 50 % au maximum.

Au regard des progrès passés examinés dans ce qui précède, accomplis sur une période plus courte, une réduction plus forte ne semble pourtant pas hors de portée.

Surtout si la climatisation continue de se développer. Le taux d’équipement d’air conditionné en Europe s’élève aujourd’hui à seulement 19 %, alors qu’il dépasse 90 % aux États-Unis. Le déploiement qu’il a connu dans ce pays depuis un demi-siècle a conduit à une forte baisse de la mortalité liée à la chaleur.

Une moindre mortalité hivernale à prendre en compte

Derrière la question de savoir si les progrès futurs de l’adaptation permettront de réduire la mortalité liée à la chaleur de plus de 50 % en Europe, d’ici 2100, se joue en réalité une autre question : la surmortalité associée au réchauffement conduira-t-elle à un bilan global positif ou bien négatif ?

En effet, si le changement climatique conduit à des étés plus chauds, il conduit aussi à des hivers moins rudes – et donc, moins mortels. La mortalité associée au froid a été estimée en 2020 à 82 décès par 100 000 habitants. Avec une élévation de température de 4 °C, elle devrait, toujours selon les auteurs de l’article de Nature Medicine, s’établir à la fin du siècle à 39 décès par 100 000 personnes.

Si on rapporte ce chiffre aux 84 décès par tranche de 100 000 habitants liés à la chaleur, cités plus haut, on calcule aisément qu’un progrès de l’adaptation à la chaleur de 55 % suffirait pour que la mortalité liée au froid et à la chaleur s’égalisent. Le réchauffement deviendrait alors neutre pour l’Europe, si l’on examine la seule mortalité humaine liée aux températures extrêmes.

Mais chacun sait que le réchauffement est aussi à l’origine d’incendies, d’inondations et de tempêtes mortelles ainsi que de la destruction d’écosystèmes.

Sous cet angle très réducteur, le réchauffement serait même favorable, dès lors que le progrès de l’adaptation dépasserait ce seuil de 55 %. Si l’on ne considère que le cas de la France, ce seuil est à peine plus élevé : il s’établit à 56 %.

Des conclusions à nuancer

La moindre mortalité hivernale surprendra sans doute le lecteur, plus habitué à être informé et alarmé en période estivale des seuls effets sanitaires négatifs du réchauffement. L’idée déroutante que l’élévation des températures en Europe pourrait finalement être bénéfique est également dérangeante. Ne risque-t-elle pas de réduire les motivations et les incitations des Européens à diminuer leurs émissions de gaz à effet de serre ?

C’est peut-être cette crainte qui conduit d’ailleurs les auteurs de l’article de Nature Medicine à conclure que :

« La mortalité nette augmentera substantiellement si l’on considère les scénarios de réchauffement les plus extrêmes et cette tendance ne pourra être inversée qu’en considérant des niveaux non plausibles d’adaptation. »

Notons également que ces perspectives concernent ici l’Europe. Dans les pays situés à basse latitude, la surmortalité liée aux températures est effroyable. Leur population est beaucoup plus exposée que la nôtre au changement climatique ; elle est aussi plus vulnérable avec des capacités d’adaptation qui sont limitées par la pauvreté.

À l’horizon 2100, la mortalité nette liée aux températures est estimée à plus de 200 décès pour 100 000 habitants en Afrique sub-saharienne et à près de 600 décès pour 100 000 habitants au Pakistan.

Concluons qu’il ne faut pas relâcher nos efforts d’adaptation à la chaleur en Europe, quitte à ce qu’ils se soldent par un bénéfice net. Les actions individuelles et collectives d’adaptation à la chaleur sauvent des vies. Poursuivons-les. Et ne relâchons pas pour autant nos efforts de réduction des émissions, qui sauveront des vies ailleurs, en particulier dans les pays pauvres de basses latitudes.


François Lévêque a publié, avec Mathieu Glachant, Survivre à la chaleur. Adaptons-nous, Odile Jacob, 2025.

The Conversation

François Lévêque 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.

ref. Canicule : soulignons, sans état d’âme, nos progrès d’adaptation depuis 2003 – https://theconversation.com/canicule-soulignons-sans-etat-dame-nos-progres-dadaptation-depuis-2003-262091

This stone tool is over 1 million years old. How did its maker get to Sulawesi without a boat?

Source: The Conversation – Global Perspectives – By Adam Brumm, Professor of Archaeology, Griffith University

A stone tool from 1.04 million year ago. M.W. Moore/University of New England

Stone tools dating to at least 1.04 million years ago have been found on the Indonesian island of Sulawesi. This means early hominins made a major sea crossing from the Asian mainland much earlier than previously thought – and they likely didn’t have any boats.

This discovery, made by a team of Indonesian archaeologists working in collaboration with Australian researchers, is published today in Nature.

It adds to our understanding of how extinct humans once moved across the Wallace Line – an imaginary boundary that runs through the Lombok Strait in the Indonesian archipelago.

Beyond this line, unique and often peculiar animal species – including hominins – evolved in isolation.

Hominins in Wallacea

The oceanic island zone between the Asian and Australian landmasses is known as Wallacea.

Previously, archaeologists have found hominins lived here from at least 1.02 million years ago, thanks to discoveries of stone tools at Wolo Sege on the island of Flores. Meanwhile, tools dated to around 194,000 years ago have been found at Talepu on Sulawesi.

The human evolutionary story in the islands east of the Asian landmass is strange.

The ancient human species that used to live on the island of Flores were small in stature. We know this thanks to the fossils of Homo floresiensis (popularly known as “hobbits”), as well as the 700,000-year-old fossils of a similar small-bodied hominin.

These discoveries suggest it could have been the extinct Asian hominin Homo erectus that breached the formidable marine barrier between this small Wallacean island and mainland Southeast Asia. Over hundreds of thousands of years, their body size reduced in what’s known as island dwarfism.

To the north of Wallacea, the island of Luzon in the Philippines has also yielded evidence of hominins from around 700,000 years ago. Just recently, fossils of a previously unknown diminutive hominin species, Homo luzonensis, were found here.

So how and when did ancient human species cross the Wallace Line?

The Sulawesi stone tools

Our new study reveals the first evidence a sea crossing to Sulawesi may have happened at least 1 million years ago. That’s much earlier than previously known, and means humans reached here at about the same time as Flores, if not earlier.

A field team led by senior archaeologist Budianto Hakim from the National Research and Innovation Agency of Indonesia (BRIN), excavated a total of seven stone artefacts from the sedimentary layers of a sandstone outcrop in a modern corn field at Calio in southern Sulawesi.

In the Early Pleistocene, there was a river channel nearby. This would have been the site of hominin tool-making and other activities such as hunting.

The Calio artefacts consist of small, sharp-edged fragments of stones (flakes) that the early human tool-makers struck from larger pebbles they most likely found in nearby riverbeds.

To produce these flakes, the hominins hit the edge of one stone with another in a controlled manner. This would fracture the first stone in a predictable way.

This tool-making activity left telltale marks on the stones that can be clearly distinguished from naturally broken rocks. So we can say unequivocally that hominins were living in this landscape, making stone tools, at the time the ancient river sediments that comprise the sandstone rock were accumulating.

And that was a very long time ago. Indeed, the team confirmed an age of at least 1.04 million years for the stone artefacts based on paleomagnetic dating of the sandstone itself, along with direct dating of a pig fossil found alongside the artefacts.

A group of people on an archaeological dig under a blue shade cloth.
Excavations at the Early Pleistocene site of Calio in South Sulawesi, Indonesia.
BRIN

Who were these hominins and how did they get to Sulawesi?

As noted earlier, previous research has shown that archaic, stone tool-making hominins managed to get across from the Asian continental landmass to colonise at least some islands in Wallacea.

The discovery of the extremely old stone tools at Calio is another significant new piece of the puzzle. This site has yet to yield any hominin fossils, however. So while we now know there were tool-makers on Sulawesi 1 million years ago, their identity remains a mystery.

Indeed, there are many fascinating questions that remain unanswered, including how these hominins were able to cross the Wallace Line in the first place.

When sea levels were at their lowest, the shortest possible distance between Sulawesi and the nearest part of the adjacent Asian landmass would have been about 50 kilometres.

This is too far to swim, especially since the ocean currents are far too strong. It’s also unlikely these archaic hominins had the cognitive ability to develop watercraft capable of making sea voyages. Setting sail over the horizon to an unseen land would have required advanced planning to gather resources – something they probably weren’t capable of.

Most likely, then, they crossed to Sulawesi from the Asian mainland in the same way rodents and monkeys are suspected to have done – by accident. Perhaps they were castaways on natural “rafts” of floating vegetation.

Our discovery also leads us to wonder what might have happened to Homo erectus on the world’s 11th largest island. Sulawesi is more than 12 times the size of Flores, and much closer to the adjacent Asian mainland.

In fact, Sulawesi is a bit like a mini-continent in itself, which sets it apart from other Wallacean islands. If hominins were cut off in the ecologically rich habitats of this enormous island for a million years, would they have undergone the same evolutionary changes as the Flores hobbits? Or might something completely different have happened?

To unravel this fascinating story, we will continue to search the islands of Wallacea – especially those close to the Asian mainland – for ancient artefacts, fossils and other clues.

The Conversation

Adam Brumm receives funding from the Australian Research Council.

Basran Burhan is a researcher at Pusat Kolaborasi Riset Arkeologi Sulawesi (BRIN-Universitas Hasanuddin).

Gerrit (Gert) van den Bergh has received funding from the Australian Research Council.

Maxime Aubert receives funding from the Australian Research Council.

Renaud Joannes-Boyau receives funding from the Australian Research Council.

ref. This stone tool is over 1 million years old. How did its maker get to Sulawesi without a boat? – https://theconversation.com/this-stone-tool-is-over-1-million-years-old-how-did-its-maker-get-to-sulawesi-without-a-boat-262337

Is Israel committing genocide in Gaza? We asked 5 legal and genocide experts how to interpret the violence

Source: The Conversation – Global Perspectives – By Melanie O’Brien, Associate Professor in International Law, The University of Western Australia

In January 2024, the International Court of Justice (ICJ) issued a provisional ruling in a case brought by South Africa against Israel, alleging genocide in Gaza. The court found Palestinians have a “plausible” right to protection from genocide in Gaza and that Israel must take all measures to prevent a genocide from occurring.

Since then, United Nations experts and human rights groups have concluded that Israel is committing genocide in Gaza. In recent weeks, others have done the same, including leading genocide scholars and two Israeli human rights groups.

While the ICJ case may take years to play out, we asked five Australian experts in international law and genocide studies what constitutes a genocide, what the legal standard is, and whether the evidence, in their view, shows one is occurring.

The Conversation

Melanie O’Brien is the president of the International Association of Genocide Scholars (IAGS). This piece does not represent the view of IAGS.

Ben Saul is the United Nations special rapporteur on human rights and counter-terrorism, an independent expert appointed by consensus of the member states of the United Nations Human Rights Council.

Eyal Mayroz served as a counterterrorism specialist with the Israeli Defence Forces in the 1980s.

Paul James and Shannon Bosch 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.

ref. Is Israel committing genocide in Gaza? We asked 5 legal and genocide experts how to interpret the violence – https://theconversation.com/is-israel-committing-genocide-in-gaza-we-asked-5-legal-and-genocide-experts-how-to-interpret-the-violence-262688

Climate-fuelled El Niño events are devastating butterflies, beetles and other tropical insects

Source: The Conversation – Global Perspectives – By Nigel Stork, Emeritus Professor in the Centre for Planetary Health and Food Security, Griffith University

Insects are arguably the most important animals on the planet. Their variety is unparalleled in nature, and they carry out vital tasks such as pollinating plants and providing food for other animals.

But all is not well in the insect world. Research over the last few years has shown sustained declines in insect species and numbers. It appeared Earth was witnessing a global-scale crash in insects – and climate change was partly to blame.

The evidence was mostly confined to temperate regions in the Northern Hemisphere. But our new research – published today in Nature – shows it’s also happening in the tropics, where most of Earth’s species live.

We found significant biodiversity loss in spiders, as well as insects including butterflies and beetles. The likely culprit is long-term changes to the El Niño cycle, caused by climate change. It suggests the life-support system underpinning the tropics is at serious risk in a warmer world.

Uncovering the effects of El Niño

El Niños vary massively across tropical regions, but are often characterised by hot and dry conditions (as opposed to the cool and moist conditions of La Niña).

Alternating El Niño and La Niña events can naturally cause many insects to come and go. That’s due to changes in temperature and moisture levels which can affect insect breeding, life cycles and behaviour.

But as climate change worsens, strong El Niño events are becoming more frequent and intense. We wanted to know how this affected insects in tropical regions.

To find out, we examined 80 existing studies of insects in relatively pristine tropical forests – mostly from the tropical Americas. We linked that data to measures of strength in El Niño and La Niña through time.

We found cause for concern. El Niño events appear to cause a rapid decline in both insect biodiversity, and the ecological tasks they perform. These trends were persistent and highly unnatural.

Several types of insects have become more rare in the tropical Americas over recent decades. These included butterflies, beetles and “true bugs” – insects from the order Hemiptera distinguished by two sets of wings and piercing mouthparts used to feed on plants. Butterflies in tropical Asia were also declining.

The strongest declines were in rare insects that would naturally decrease during El Niño. These insect populations would usually bounce back in a La Niña. But climate-fuelled El Niños are causing many populations to fall so far, they cannot recover.

Drastic changes to forests

Our findings suggest the diversity of tropical insects could be chipped away with every El Niño event. This is not just a problem for the species themselves, but other parts of the ecosystem that depend on them.

Our research also involved modelling the decomposition and consumption of leaves by insects across the tropical Americas, Asia and Africa. Both processes are crucial to the health of tropical forests.

Decomposition fluctuated in line with the abundance of termites, which are probably the most important decomposers in the tropics. And worryingly, the amount of live leaves consumed by insects appears to have crashed in recent decades. This correlated strongly with the crash in butterflies and beetles.

These drastic changes may have implications for food webs and other organisms that rely on insects.

a black beetle
The diversity of tropical insects could be chipped away with every El Niño event.
Li Ajang/Shtterstock

A difficult future ahead

Our research could not take in the huge diversity of tropical insects – most of which have not yet been formally described by scientists. But it points to a difficult future for insects – and their habitats – as climate change worsens.

Little data exists on insect numbers in Australia’s Wet Tropics, in Queensland. However, monitoring work is underway at facilities such as the Daintree Rainforest Observatory. Such projects will help us better understand changes in insect biodiversity under climate change.

More research is also needed at other locations around the world. Given the fundamental role insects play in supporting life on Earth, the urgency of this work cannot be overstated.

The Conversation

Nigel Stork receives funding from Australian Research Council grant DP200103100

Adam Sharp receives funding from Hong Kong University Grants Committee Collaborative Research Fund (C7048-22GF).

ref. Climate-fuelled El Niño events are devastating butterflies, beetles and other tropical insects – https://theconversation.com/climate-fuelled-el-nino-events-are-devastating-butterflies-beetles-and-other-tropical-insects-262625